Electrode assembly for long stick out submerged arc welding.

Abstract

The disclosed technology relates generally to welding technology, and more particularly to electrode assemblies for arc welding, such as submerged arc welding. In one aspect, an electrode assembly for submerged arc welding (SAW) includes a head portion having a contact nozzle, and an extension portion removably and continuously mounted to the contact nozzle and disposed proximate to an arcing tip of a consumable electrode relative to the contact nozzle. The extension portion includes a ceramic sleeve configured to slidably feed the consumable electrode therethrough, and a pair of metallic sheaths covering opposite ends of the ceramic sleeve.

Description

[Technical field]

[0001] Incorporation by reference of any priority application Any and all applications in which foreign and domestic priority claims are identified in an Application Data Sheet filed with this application are hereby incorporated by reference under 37 CFR 1.57.

[0002] This application claims the benefit under 35 U.S.C. §119(e) to U.S. Provisional Patent Application No. 63 / 264,358, entitled “ELECTRODE ASSEMBLY FOR ARC WELDING,” filed November 19, 2021, and U.S. Provisional Patent Application No. 63 / 370,430, entitled “ELECTRODE ASSEMBLY FOR ARC WELDING,” filed August 4, 2022, each of which is hereby incorporated by reference in its entirety.

[0003] The disclosed technology relates generally to welding technology, and more particularly to electrode assemblies for arc welding, such as submerged arc welding. [Background technology]

[0004] Various welding techniques utilize a welding wire that acts as a source of metal. For example, in metal arc welding, an electric arc is created when a voltage is applied between a consumable welding electrode wire, which acts as one electrode, advanced toward the workpiece, and the workpiece, which acts as the other electrode. The arc melts the tip of the metal wire, thereby creating droplets of molten metal wire that are deposited on the workpiece to form a weldment or weld bead. Summary of the Invention [Problem to be solved by the invention]

[0005] Technical and economic demands on welding technologies continue to grow in complexity. For example, the need for relatively high bead quality in both appearance and mechanical properties, including high yield strength, ductility, and fracture toughness, continues to grow. At the same time, relatively high bead quality is often required while maintaining economic viability. Some welding technologies aim to address these competing demands by improving consumables, for example, by improving the physical design and / or composition of the electrode wire.

[0006] Submerged arc welding (SAW) can provide a very economical solution for some applications, with the large deposition rates achieved by the submerged arc being primarily responsible for the economies realized by the process. [Means for solving the problem]

[0007] In one aspect, an electrode assembly for submerged arc welding (SAW) includes a head portion having a contact nozzle, an extension portion removably and continuously mounted to the contact nozzle and disposed proximate to an arcing tip of a consumable electrode relative to the contact nozzle, the extension portion having a ceramic sleeve configured to slidably feed the consumable electrode therethrough, and a pair of metallic sheaths covering opposite ends of the ceramic sleeve.

[0008] In another aspect, an extension portion configured for a submerged arc welding electrode assembly includes a ceramic sleeve and a pair of metallic sheaths covering opposite ends of the ceramic sleeve, the ceramic sleeve configured to surround a consumable electrode, the extension portion configured to be disposed contiguously with a head portion of the submerged arc welding electrode assembly.

[0009] In another aspect, an electrode assembly for submerged arc welding (SAW) has a head portion and an extension portion arranged successively to feed a consumable electrode therethrough such that the head portion is disposed distal to the arcing tip of the consumable electrode and the extension portion is disposed proximal to the arcing tip of the consumable electrode during SAW. The head portion includes a contact tip configured to electrically contact the consumable electrode to supply power to the consumable electrode. The extension portion has a ceramic sleeve configured to slidably feed the consumable electrode therethrough after passing the contact tip, and a pair of metallic sheaths covering opposite ends of the ceramic sleeve. [Brief description of the drawings]

[0010] [Figure 1] 1 illustrates a schematic of a submerged arc welding (SAW) system in accordance with an embodiment of the present technique; [Diagram 2] 1 shows a conventional electrode assembly for a SAW system. [Figure 3A] 1 shows a conventional electrode assembly for a SAW system on a workpiece having a shallow groove. [Figure 3B] A long stick-out (LSO) electrode assembly for a SAW system on a workpiece having shallow grooves is shown. [Figure 4A] 1 shows a conventional electrode assembly for a SAW system on a workpiece having deep grooves. [Figure 4B] 1 shows an LSO electrode assembly for a SAW system on a workpiece having deep grooves. [Diagram 5] 1 is a graph showing an experimental comparison of deposition rate versus current in both a conventional SAW assembly and an LSO-SAW assembly. [Figure 6A] FIG. 1 is an isometric view of an LSO electrode assembly in accordance with an embodiment of the present technology. [Figure 6B] 6B depicts a perspective view of the LSO electrode assembly of FIG. 6A. [Figure 6C] FIG. 6B is an isometric view of the LSO electrode assembly of FIG. 6A in a groove in a workpiece. [Figure 7A] FIG. 1 is an exploded view of an LSO electrode assembly in accordance with an embodiment of the present technology. [Figure 7B] FIG. 7B is a cross-sectional view of the LSO electrode assembly depicted in FIG. 7A. [Figure 7C] FIG. 1 is a perspective view of a body portion for an LSO electrode assembly in accordance with an embodiment of the present technology. [Figure 7D] 7D is a cross-sectional view of the body portion depicted in FIG. 7C taken along line AA. [Figure 7E] FIG. 1 is a perspective view of a contact nozzle for an LSO electrode assembly in accordance with an embodiment of the present technique; [Figure 7F] FIG. 7F is a cross-sectional view of the contact nozzle depicted in FIG. 7E taken along line BB. [Figure 7G] FIG. 1 is a perspective view of an extension for an LSO electrode assembly in accordance with an embodiment of the present technology. [Figure 7H] 7B is a cross-sectional view of the extension depicted in FIG. 7G taken along line CC. [Figure 8A-8B] 1 illustrates a multi-arc LSO-SAW assembly in accordance with an embodiment of the present technique. [Figure 9A-9C] 1 shows a cross-sectional view of an extension for an LSO electrode assembly in accordance with an embodiment of the present technology. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] In processes that use consumable electrodes, the electrode or wire is melted to provide additive metal that fills the gap to form a weld joint that joins two metal workpieces. Welding processes that use consumable electrodes include, among others, shielded metal arc welding (SMAW), gas metal arc welding (GMAW) or metal inert gas (MIG) welding, flux cored arc welding (FCAW), metal cored arc welding (MCAW), and submerged arc welding (SAW).

[0012] Submerged Arc Welding FIG. 1 illustrates a schematic of a submerged arc welding (SAW) system 100 for depositing a filler or weld metal onto a workpiece 102. The system 100 includes a bare metal electrode wire 104 having a tip 106, a contact tip 110 coupled to the electrode 104, and a power source 108 electrically coupled to the contact tip 110 and the workpiece 102. The system 100 also includes a flux delivery system 112 configured to dispense a flux 114 onto the workpiece 102 in a SAW process. The electrode 104 generally comprises a metal or alloy, while the flux comprises a granular fusible material. In the SAW process, heat is derived from an arc 116 between the bare metal electrode 104 and the workpiece 102. The arc is shielded by a blanket of flux 114 disposed on the joining area in front of the arc 116. Filler metal is primarily obtained from the electrode wire 104, which is continuously fed through a blanket of flux 114 into the arc 116 and pool 122 of molten flux. Additional filler metal can be obtained by adding cold wire to the weld pool 122 or from metal powder contained within the flux 114. Thus, in SAW, unlike other flux-based processes, two consumables are used (electrode wire 104 and flux 114), and these two consumables can be fed separately.

[0013] A distinguishing feature of SAW is the flux 114, which covers the weld area and prevents arc radiation, sparks, scatter, and fumes from escaping. The flux 114 allows for high deposition rates and high quality weld deposit characteristics to be achieved. In addition to shielding the arc 116 from view, the flux 114 protects the weld metal 120 as it cools, deoxidizes and refines the weld metal 120, and provides slag 118 that insulates the weld to reduce the cooling rate and aid in shaping the weld profile.

[0014] In the SAW process, the heat of the arc 116 melts a portion of the flux 114 along with the tip 106 of the electrode 104 to form a weld pool 122, as shown in FIG. 1. The tip 106 of the electrode 104 and the weld zone are always surrounded and shielded by the molten flux 114, which is itself covered by a layer of unmolten flux 114. The electrode 104 is held a short distance above the workpiece 102 with an arc 116 formed between the electrode 104 and the workpiece 102. As the electrode 104 advances along the joint, the relatively light molten flux 114 floats as a slag above the molten metal in the weld pool 122. The weld metal, which has a relatively high melting point (freezing point), solidifies while the slag above it remains molten. The slag then solidifies on the newly solidified weld metal, thereby continuing to protect the metal from contamination as it becomes very hot, and will react with the atmospheric oxygen and nitrogen. After cooling and removing any unmelted flak for reuse, the solidified slag 118 can be easily removed from the weld.

[0015] A power supply 108 generates the voltage and current for the system 100, and the voltage and current are applied to the workpiece 102 and the electrode 104. The current is applied to the electrode through a contact tip 110. High currents can be used in submerged arc welding, and extremely high heat can be generated. Because the current is applied to the electrode 104 a short distance above its tip 106, relatively high amperage can be used on a small diameter electrode. This results in extremely high current densities on the relatively small cross section of the electrode. Currents as large as or exceeding 600 amps can be delivered on electrodes as small as 64'', giving densities on the order of 100,000 amps per square inch, which is 6 to 10 times that delivered on a stick electrode.

[0016] Due to the high current density, the melt-off rate is much greater for a given electrode diameter than that associated with stick electrode welding, and is affected by the electrode material, flux 114, current type, polarity, and the length of the wire beyond the point of electrical contact in the gun or head.

[0017] Submerged arc welding can be performed with DC or AC power. Direct current gives better control of bead shape, penetration, and welding speed, and is easier to initiate. Bead shape is usually best with DC electrode positive (DCEP or reverse polarity), which also provides maximum penetration. Maximum deposition rate and minimum penetration can be obtained with DC electrode negative (DCEN). Alternating current minimizes arc blow and provides penetration between that of DCEP and DCEN.

[0018] The insulating blanket of flux 114 above the arc 116 prevents the heat from escaping quickly and concentrates it in the weld zone. Not only is the base metal of the electrode 104 and workpiece 102 melted quickly, but the melt is deep into the base metal. The deep penetration allows for the use of a small weld groove, thereby minimizing the amount of filler / joint area, and allows for a fast welding speed. The high speed welding in turn minimizes the total heat input into the assembly, and thus minimizes thermal distortion problems. Even relatively thick joints can be welded in one pass with submerged arc welding.

[0019] Welds performed under a protective layer of flux 114 have good ductility and impact resistance, as well as uniformity in bead appearance. Mechanical properties at least equal to those of the base metal are obtained in a consistent manner. In single pass welds, the molten base material is large compared to the amount of filler metal used. Thus, in such welds, the base metal can have a significant effect on the chemical and mechanical properties of the weld. For this reason, it is often not necessary to use electrodes of the same composition as the base metal to weld many of the low alloy steels. However, the chemical composition and properties of multi-pass welds are relatively less affected by the base metal and depend to a relatively greater extent on the composition of the electrode, the activity of the flux, and the welding conditions.

[0020] Through adjustments of current, voltage, and travel speed, the operator can exercise tight control over penetration to provide any depth ranging from deep and narrow with high crown reinforcement to wide, nearly flat beads with shallow penetration. A bead with deep penetration may contain molten base metal at a level of 70%, while a shallow bead may contain as little as 10% base metal. In some instances, the deep penetration properties of submerged arc welding can be used to eliminate or reduce the expense of edge penetration.

[0021] Fluxes serve several functions in submerged arc welding. These include covering the molten weld metal to protect it from the atmosphere, and acting as a slag to refine the molten deposit by removing oxides and other non-metallic inclusions. Metal additions to the flux can increase the alloy content of the deposit and can deoxidize it.

[0022] There are four types of fluxes based on their method of manufacture: fused, cemented, agglomerated, and mechanically mixed.

[0023] Fluxes are also identified as alkaline, acidic, and neutral. Alkaline fluxes contain oxides of metals that dissociate easily, while acidic fluxes contain oxides that dissociate only to a small extent. Neutral fluxes do not increase or decrease the composition of the weld deposit. Fluxes with a ratio of CaO or MnO to SiO2 greater than 1 are considered alkaline, those near 1 are considered neutral, and those below 1 are acidic.

[0024] With the proper selection of equipment, submerged arc is widely applicable to industrial welding requirements. It can be used with all types of joints and allows welding of a full range of carbon and low alloy steels, from 16 gauge sheet to the thickest plate. It is also applicable to some high alloy steels, heat treated steels, and stainless steels, and is the preferred process for rebuilding and hardfacing. Any degree of mechanization can be used, from hand-held semi-automatic guns to boom or truck carried and fixture-held multiple weld heads.

[0025] The high quality, high deposition rate, deep penetration, suitability of the process for full mechanization, and pleasant characteristics (no glare, no sparks, no spatter, no smoke, or excessive heat radiation) of submerged arc welding make it the preferred process in steel manufacturing. It is used extensively in ship and barge construction, railroad car fabrication, pipe manufacturing, and the manufacture of structural beams, girders, and columns where long welds are required. Automated submerged arc equipment is also a major feature of the welding areas of plants that manufacture mass-produced assemblies joined by repetitive short welds.

[0026] Factors other than deposition rate participate in lowering welding costs. Continuous electrode feed from coils ranging in weight from 60 to 1000 pounds contributes to high utilization rates. Expenses are reduced where the deep penetration nature of the process allows for the elimination or reduction of joint preparation. Cleaning costs are minimized due to the removal of spatter by protective fluxes after the weld is performed.

[0027] When submerged arc equipment is used properly, the weld bead is smooth and uniform, so that grinding or machining is rarely required. The rapid heat input of the process minimizes distortion, reducing the cost of straightening the completed assembly, especially if a carefully planned welding sequence is performed. Submerged arc welding, in fact, often allows for pre-machining of the parts, further increasing manufacturing cost savings.

[0028] Due to these and other advantages provided by SAW, there is a desire and need to further improve various aspects of SAW, including even higher productivity and weld quality. For example, because one of the technical advantages of SAW is derived from pre-heating of the consumable electrode, there is a desire and need to further improve the pre-heating configuration through improved electrode assembly designs.

[0029] Long stick-out electrode assembly for submerged arc welding. FIG. 2 illustrates an electrode assembly 200 defining an electrical stick-out and positioned on a workpiece 202. The electrode assembly 200 includes a head portion 204 configured to receive a consumable electrode 206. The head portion 204 includes a contact tip 210, an electrode guide tube 212, and an insulated guide 214. The contact tip 210 is radially disposed around the electrode 206 and configured to transfer current from a power source (e.g., power source 108 shown in FIG. 1) to the electrode 206. The electrode 206 includes a tip portion 208 configured to extend beyond the head portion 204. The portion of the electrode 206 extending between the end portion 208 and the end of the head portion 204 is referred to as the visible stick-out 218, while the portion of the electrode 206 extending between the tip portion 208 and the contact tip 210 is referred to as the electrical stick-out or electrical electrode extension 216. Unless otherwise stated, stick-out length as used herein refers to the length of the electrical stick-out 216, which is the parameter that primarily affects the electrical response of the electrode assembly 200. During operation of the electrode assembly 200, the tip portion 208 is positioned adjacent to the workpiece 202, and the distance between the contact tip 210 and the workpiece 202 is referred to as the contact tip to workpiece distance (CTWD) 220.

[0030] The electric stick-out 216 of the electrode wire 206 is preheated by Joule heating. If the electric stick-out 216 is not long enough, the electrode wire 206 may not be preheated sufficiently. On the other hand, increasing the length of the electric stick-out 216 increases the electrical resistance of the circuit, which increases the heating and therefore the temperature of the tip 208 of the electrode 206, resulting in an increase in the melting and deposition rate. And the length of the electric stick-out 216 controls the size of the weld bead because the length of the filler wire extension affects the burn-off rate. Furthermore, the electric stick-out 216 affects the penetration through its effect on the welding current. As the length of the electric stick-out 216 increases, the preheating of the electrode wire 206 and the voltage drop across it increases. A relatively large voltage drop can result in a relatively convex bead shape, which can be overcome by increasing the voltage by 2 to 5 volts. The length of the electric stick out 216 distance can be approximately 3-10 times the diameter of the electrode 206 for conventional steel welding processes depending on the type of steel being welded.

[0031] FIG. 3A depicts an electrode assembly 300A positioned over a workpiece 302 having a groove 303. In the illustrated configuration, the stick-out portion 316A of the electrode 306A extends a conventional distance (e.g., 3-12 electrode diameters) beyond the contact tip 310A. The electrode assembly 300A is positioned such that the head portion 304A is positioned over the groove 303 and the tip 308A of the electrode 308A is within the groove 303. More specifically, the head portion 304A is positioned such that the tip 308A is adjacent the bottom of the groove 303 without the head portion 304A contacting the workpiece 302. In the illustrated embodiment, the tip 308A is positioned within the groove such that the CTWD 320A is approximately 25 mm. Positioning the tip 308A closely adjacent to the bottom of the groove 303 allows for better and more consistent arcing between the tip 308A and the workpiece 302, resulting in more consistent deposition of filler metal into the groove 303 and improved weld quality and efficiency.

[0032] To further improve the submerged arc welding (SAW) technology, the long stick-out (LSO) or extended stick-out technology developed by Lincoln Electric Company can be utilized. Long stick-out SAW refers to a SAW process in which the length of the wire protruding from the electrode contact tip ("stick-out length"), i.e., the contact tip to workpiece length (CTWD), is increased relative to conventional SAW processes, such as, for example, greater than about 25 mm. As used herein, LSO refers to an electrode configuration in which the electrical stick-out exceeds about 10 times the diameter of the electrode 306A. The relatively long stick-out length allows a relatively large length of the electrode to be preheated prior to melting at the electrode tip. The preheating allows the melt-off rate to be increased as a result, since it is easier to melt the preheated electrode wire at a given current density. The LSO-SAW process can provide significant improvements in productivity and can provide up to a 100% increase in deposition rate for submerged arc welding compared to conventional SAW processes. The LSO-SAW process can reduce or eliminate arc striking problems by allowing perfect matching of arc starting characteristics. LSO-SAW can also provide improved control over the energy input into the weld, less heat input (less distortion), and reduced flux / wire ratios.

[0033] FIG. 3B depicts an electrode assembly 300B positioned over a groove 303 in a workpiece 302. The electrode assembly 300B utilizes LSO techniques such that the electrode stick-out 316B extends beyond the contact tip 310B by a distance greater than the stick-out 316A, which extends beyond the contact tip 310A (FIG. 3A). For example, in some embodiments, the stick-out 316B can have a length between 10 and 40 times the diameter of the electrode 308B. In some embodiments, the stick-out 316B can have a length greater than 40 times the diameter of the electrode 308B. The increased length of the stick-out portion 316B allows a relatively large length of the electrode 306B to be preheated prior to melting of the electrode tip, thereby allowing for increased melt-off and deposition rates, as discussed above.

[0034] Also, the increased length of the stick-out portion in the LSO-SAW system allows the LSO system to be used to easily fill grooves that conventional SAW systems do not have the ability to fill or can only fill using very precise configuration and high operator skill. In particular, while conventional SAW systems can be used with wide and / or short grooves, conventional SAW systems usually cannot be easily used with relatively deep and / or relatively narrow grooves. Figures 4A and 4B depict electrode assemblies 400A, 400B positioned on a workpiece 402, where electrode assembly 400A is generally similar to assembly 300A shown above in connection with Figure 3A, and electrode assembly 400B is generally similar to assembly 300B shown above in connection with Figure 3B. Workpiece 402 has a groove 403 that is significantly deeper and narrower than groove 303 shown above in Figures 3A and 3B. Thus, when the assemblies 400A and 400B are positioned over the groove 403, the head portions 404A, 404B are positioned away from the bottom of the groove, resulting in a CTWD 420 that is much greater than 25 mm. For example, in some embodiments, the CTWD or electrical stick-out can be 125 mm or greater. When the electrode assembly 400A is positioned over the workpiece 402 such that the tip 408A is in the groove 403, the size and shape of the head portion 404A prevents the head portion 404A from being positioned away in the groove 403 without contacting and interacting with the workpiece 402. As a result, the tip 408A is spaced too far from the bottom of the groove 403, which results in poor arcing between the electrode 406A and the workpiece 402, which results in poor filler metal deposition rate and poor weld quality. Thus, the conventional stick-out length 416A of the electrode assembly 400A prevents the electrode assembly 400A from forming high quality welds with deep and / or narrow grooves.In contrast, when the electrode assembly 400B is positioned on the workpiece 402B such that the tip 408B is in the groove 403, the increased stick-out length of the assembly 400B allows the tip 408B to be adjacent to the bottom of the groove. The reduced distance between the tip 408B and the bottom of the groove 403 results in better arcing between the electrode 406B and the workpiece 402. Thus, in addition to improving weld quality and deposition rate by allowing more pre-heating of the electrode before arcing, the LSO-SAW technique also allows for the deposition of filler metal into deeper and narrower grooves than conventional SAW techniques.

[0035] According to various embodiments, the LSO-SAW electrode assembly has the ability to achieve a much higher relative deposition rate compared to a conventional SAW electrode assembly for the same current. In a welding process, current is transferred into the electrode by the contact tip at a certain amperage and voltage. As the current flows through the electrode toward the tip of the electrode, the voltage drops and the electrode heats up. At the tip of the electrode, the current arcs to the workpiece. In the case of the LSO-SAW assembly, the increased length of the electrode results in a relatively larger percentage of the total voltage drop occurring in the electrode than in a conventional SAW assembly. In some embodiments, the LSO-SAW assembly can be configured such that the voltage drop between the contact tip and the tip of the consumable electrode is at least 5%, at least 10%, at least 15%, or at least 20% (or a value within a range defined by any of these values) of the total voltage drop across the total CTWD. In other embodiments, the electrode assembly is configured such that the voltage drop between the contact tip and the tip of the consumable electrode represents at least 1 / 30 of the total voltage drop across the CTWD, 1 / 15 of the total voltage drop across the CTWD, 1 / 10 of the total voltage drop across the CTWD, 1 / 7 of the total voltage drop across the CTWD, 1 / 5 of the total voltage drop across the CTWD, or a value within a range defined by any of these values. For example, in a conventional SAW electrode assembly with a total voltage drop along the CTWD of 30V, only about 1V of the total voltage drop may occur in the consumable electrode, while the remaining portion (about 29V) may drop across the length of the arc. In contrast, in the case of an LSO-SAW system with the same total voltage drop of 30V, about 4V of the drop may occur across the CTWD, while the remaining portion (about 26V) may drop across the length of the arc. The increased voltage drop through the relatively long electrodes results in the electrodes being heated to a higher temperature than in conventional SAW configurations, and as a result, the deposition rate is increased.

[0036] Experiments have shown that the deposition rate / current for the LSO-SAW assembly can exceed 0.05 lb / hr / A, 0.06 lb / hr / A, 0.07 lb / hr / A, 0.08 lb / hr / A, or values ​​within the range defined by any of these values ​​during welding. FIG. 5 shows an experimental comparison of deposition rate vs. current for both conventional SAW assemblies and LSO-SAW assemblies, where the dashed line represents the deposition rate for the conventional SAW assembly and the solid line represents the deposition rate for the LSO-SAW assembly. In this experiment, the CTWD for the conventional SAW assembly was 1.25'', the CTWD for the LSO-SAW assembly was 5'', and the electrode diameter was 5 / 32''. Three different power supply methods were used: positive constant DC power, balanced square wave AC power, and 25% balanced square wave AC power. For LSO-SAW assemblies, deposition rates in excess of 35 lbs / hr can be achieved with currents of less than about 900 A, 850 A, 800 A, 750 A, 700 A, or within a range defined by any of these values, e.g., at about 700 A to 750 A. However, for conventional SAW electrode assemblies, similar deposition rates are only estimated to be achieved at currents greater than about 900 A. Advantageously, the improvement in deposition rate compared to conventional SAW electrodes is due to the reduced Joule heating (I 2 R) varies as the square of the current, increasing at relatively large currents, i.e., the relative improvement in deposition rate is presumed to increase with increasing current.

[0037] In an LSO-SAW system, the consumable electrode (e.g., electrode 306B, 406B) extends beyond the end of the head portion (e.g., head portion 304B, 404B) such that the arcing tip (e.g., tip 308B, 408B) is visible. As discussed above, the portion of the electrode that extends beyond the contact tip portion is referred to as the electrical stick-out. In some embodiments, the electrical stick-out is based on the diameter of the electrode. The length of the electrical stick-out in a SAW may depend on the type of steel being welded, such as whether the steel being welded is a low alloy steel containing less than about 8% by weight of non-ferrous elements or a high alloy steel containing more than about 8% by weight of non-ferrous elements. In a conventional SAW for welding low and medium alloy steels, the electrical stick-out length may be about 7-10 times the diameter of the electrode. In a conventional SAW for welding high alloy steels, the electrical stick-out length may be about 3-5 times the diameter of the electrode. For example, in an embodiment where the electrode has a diameter of 5 / 32'', the visible stick-out length may be about 1 to 1.5 inches. In contrast, in an LSO-SAW according to various embodiments, the stick-out to diameter ratio, or the ratio between the electrical stick-out distance measured between the contact tip portion disposed at the end of the head portion and the arcing tip of the consumable electrode and the diameter of the electrode, has a value that exceeds 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, or within a range defined by any of these values. For example, these ratios can be obtained with an electrical stick-out distance that exceeds 125 mm, 130 mm, 135 mm, 140 mm, 145 mm, 150 mm, 155 mm, 160 mm, 165 mm, or within a range defined by any of these values, and an electrode diameter that has a value of any of 2.5 mm to 5.0 mm. For example, with an electrical stick-out length of 155 mm and an electrode diameter of 3.2 mm, the stick-out to diameter ratio is approximately 48, while with an electrical stick-out length of 125 mm and an electrode diameter of 4.0 mm, the stick-out to diameter ratio is approximately 31.

[0038] Although an increased stick-out length may advantageously provide certain benefits, such as a relatively high deposition rate, various problems may arise when a conventional electrode assembly is used, for example, a stick-out length exceeding 25 mm. For example, the heated wire may move out of alignment and may displace within the weld groove as the stick-out distance increases. This may pose a problem when welding deep and narrow grooves, which may be used to minimize the time and cost of joining thick sections, since the LSO welding electrode assembly may be too bulky to reach the bottom of the groove. To address this and other challenges, some electrode assemblies include an extension that acts as an insulated guide for the electrode. The extension provides mechanical rigidity to the heated electrode, as well as electrical and thermal insulation, among other things. However, some extensions may not be suitable for some applications, such as for filling narrow and deep grooves, such as triangular or U-shaped grooves with a depth exceeding 4 inches and an apex angle that is 16 degrees or less. Some designs of electrode assemblies that include extensions may fall short in relation to one or more of optimized vertical and lateral dimensions, thermal and electrical insulation, instability of the arc generated by the magnetic material, and compact flux delivery. In contrast, various embodiments of electrode assemblies for submerged arc welding described herein address these and other needs.

[0039] Long stick-out electrode assembly with single-piece insulated extension Disclosed herein are various electrode assemblies for improved LSO-SAW and methods of making and using the same. In various embodiments, the insulating extension portion has a solid ceramic tip between the contact tip portion and the exposed portion of the wire. FIGS. 6A and 6B show an electrode assembly 600 configured for long stick-out submerged arc welding including an insulating tip according to various embodiments. The electrode assembly 600 according to various embodiments includes a head portion 602 and an extension portion 604. The head portion 602 and the extension portion 604 are arranged contiguously and are configured to feed a consumable electrode 606 therethrough. The extension portion is formed from a single piece of insulating article configured for the consumable electrode to eventually pass through before the arcing tip is exposed. The electrode assembly 600 is configured for SAW. Thus, according to embodiments, the electrode assembly 600 is configured for use in a SAW system without a shielding gas.

[0040] The head portion 602 has a body portion 608 and a contact nozzle 612. The extension portion 604 is removably, but rigidly, attached to the head portion 602 at the contact nozzle 612 such that the extension portion 604 remains in alignment with the head portion 602 during the welding process. As will be described in more detail below, the body portion 608 has a cylindrical shape, while the contact nozzle 612 and the extension portion 604 each have a generally cylindrical shape that tapers inwardly toward the end from which the consumable electrode 606 emerges. Thus, with this configuration, the electrode assembly 600 also has a generally cylindrical shape that tapers inwardly such that the width of the electrode assembly 600 at the body portion 608 is greater than the width of the electrode assembly 600 at the extension portion 604.

[0041] The electrode assembly 600 also includes an attachment nipple 614 that is rigidly coupled to the end of the contact nozzle 612. The attachment nipple 614 is configured to be rigidly mounted to a wire feed unit and has an opening formed therethrough. During welding, the wire feed unit is configured to provide the consumable electrode 606 to the electrode assembly 600 by passing the consumable electrode 606 through the opening in the attachment nipple 614.

[0042] The body portion 608 includes an electrical contact portion 610 configured to be electrically connected to a power source and configured to receive power from the power source during welding. At least an outer portion of the body portion 608 is formed from an insulating material, such as, for example, fiberglass, while the electrical contact portion 604 and the contact nozzle 612 are both formed from an electrically conductive material, such as a copper-based alloy, such that when the electrical contact portion 610 receives power from a power source, the contact nozzle 612 receives power through the electrical contact portion 610. As described in more detail below, the contact nozzle 612 includes a contact tip configured to be in electrical contact with the consumable electrode 606 and to provide this power to the consumable electrode 606 during the welding process.

[0043] The electrode assembly 600 receives a consumable electrode 606 through an attachment nipple 614, and the consumable electrode 606 passes through the head portion 602 and the extension portion 604. The consumable electrode 606 includes an arcing tip 622, and the consumable electrode extends through the extension portion 604 such that the arcing tip 624 extends beyond the extension portion 604. As a result, the head portion 602 is disposed distal to the arcing tip 624, and the extension portion 604 is disposed proximal to the arcing tip 624. During welding, the electrode assembly 600 is configured such that the arcing tip 624 is positioned adjacent to a workpiece.

[0044] The extension portion 604 is formed of a solid insulating material, such as, for example, a ceramic, configured to surround the consumable electrode 606 and thereby electrically insulate the consumable electrode 606 from the workpiece during welding. The solid insulating material may be a machinable material such that the extension portion 604 may be machined to have various physical attributes as described herein. In some implementations, the solid insulating material may be a composite or layered insulator, such as, for example, a composite or layered ceramic. During welding, the consumable welding electrode 618 is preheated within the insulated extension portion 604 by Joule heating before being melted at the arcing tip 624 of the consumable electrode 606. In some embodiments, the electrode assembly 600 is configured to heat the portion of the consumable electrode 608 within the extension portion 604 to a temperature of up to 600° C., up to 700° C., up to 800° C., up to 900° C., or within a range defined by any of these values, during welding. Solid insulating materials are suitable materials capable of withstanding such elevated temperatures.

[0045] 6C shows the electrode assembly 600 in a narrow groove 618 formed in a workpiece 616. An attachment device 620 mounted on the body portion 608 can be used to hold the electrode assembly firmly in place and in a desired orientation. In some embodiments, the attachment device 620 includes a clamping device configured to clamp onto the insulated outer layer of the body portion 608.

[0046] In various embodiments, the extension portion 604 has a shape, length, and width that is configured to electrically insulate the consumable electrode 606 from the workpiece 614 and that allows the extension portion 604 to be capable of being inserted into a narrow groove 618. The solid insulating material allows, among other things, the shape and width of the extension portion 604 to be optimized for insertion into a narrow groove as described herein. For example, in some embodiments, the extension portion 604 can have a width of about 18 mm. Additionally, as described in more detail below, in some embodiments, the extension portion 604 can have a tapered shape such that the end of the extension portion 604 near the contact nozzle 612 is wider than the end of the extension portion 604 near the arcing tip 622. Additionally, the extension portion 604 can be long enough and the consumable electrode 606 can project far enough away from the end of the extension portion 604 to ensure that the extension portion 604 and the consumable electrode are within the groove 618 while a portion of the head portion 602 can be disposed outside and above the groove 618 during welding. Additionally, the reduced width and tapered shape of the extension portion 604 allows the extension portion 604 to not contact the sidewalls of the narrow groove 616 during welding. For example, during welding, the extension portion 604 can be configured such that the tip 622 of the consumable electrode 606 contacts the apex while not contacting the sidewalls of a triangular trench having a depth exceeding a value within a range defined by 4 inches, 5 inches, 6 inches, 7 inches, or any of these values, and having an apex angle that is less than a value within a range defined by 16 degrees, 12 degrees, 10 degrees, 8 degrees, 6 degrees, or any of these values. It should be appreciated that the shallower the groove, the narrower the apex angle. For example, the relationships may follow example dependencies such as those shown, without limitation, in Table 1. It should be understood that the grooves or trenches need not have a triangular shape in cross section. Instead, some grooves may have, for example, a rectangular or tapered rectangular shape. In these shapes, the "apex" angle or acceptance angle may be defined by the arctan of the width over the depth of the trench.

[0047] [Table 1]

[0048] In various embodiments, the consumable electrode 606 is electrically insulated from at least a portion of the body portion, the electrical contact portion 610, and the contact nozzle by an electrically insulating tube disposed within the head portion and surrounding at least a portion of the consumable electrode 606. Figure 7A shows an exploded view of an electrode assembly 700, which may be generally similar to the electrode assembly 600 shown above in Figures 6A-6C, and Figure 7B shows a cross-sectional view of the electrode assembly 700. The electrode assembly 700 includes a head portion 702 and an extension portion 704, where the head portion 702 has a body portion 708, an electrical contact portion 710, and a contact nozzle 712. The contact nozzle 712 includes a contact tip 718 configured to be in contact with the consumable electrode and configured to provide power to the electrode during welding. It should be appreciated that in the illustrated embodiment, due to the contiguous arrangement of the head portion 702 and extension portion 704, the contact tip 718 and extension portion 704 are also contiguous such that no portion of the extension portion 704 formed from a single piece article overlaps with the contact tip 718. Furthermore, the outer surface of the extension portion 704 forms the outermost surface of the electrode assembly 700 adjacent the exposed arcing tip of the consumable electrode. The electrode assembly 700 includes opposed first and second ends 706A and 706B, where the extension portion 704 defines a first end 706A and an attachment nipple 714 connects to the body portion 708 at the second end 706B.

[0049] The electrode assembly 700 further includes an electrically insulating tube 716 disposed within the head portion 702. The electrically insulating tube 716 extends through openings in the attachment nipple 714, the body portion 708, the electrical contact portion 710, and a portion of the contact nozzle 712. Specifically, the electrically insulating tube 716 extends through a portion of the contact nozzle 712 between the contact tip 718 and the electrical contact portion 710, but does not extend through the contact tip 718. Thus, the electrically insulating tube 716 has a size and shape sufficient to allow the electrically insulating tube to extend from the second end 706B, through the body portion 708, and at least partially through the contact nozzle 712 while allowing the consumable electrode to be disposed within the electrically insulating tube 716. For example, in some embodiments, the electrically insulating tube 716 has a length of 385 mm and a width of 12 mm, although in other embodiments the insulating tube 716 has a different length and width. For example, in some embodiments, the insulating tube has a length of 300 mm, 325 mm, 350 mm, 375 mm, 400 mm, 425 mm, or a value within a range defined by any of these values, and a width of 20 mm, 15 mm, 10 mm, 5 mm, or a value within a range defined by any of these values. The electrically insulating tube 716 has a generally cylindrical shape and includes an opening 720 extending along the length of the tube 716 through which the consumable electrode passes. Thus, the opening 720 is wide enough for the consumable electrode to pass through. In some embodiments, the opening 720 has a width of 3.2 mm to 6 mm. In some embodiments, the width of the opening 720 depends on the size of the consumable electrode being used. For example, in some embodiments, the consumable electrode has a diameter of about 3.2 mm. In these embodiments, the opening 720 can have a width of 3.2 mm, 3.4 mm, 3.6 mm, 3.8 mm, 4 mm, or a value within a range defined by any of these values. In other embodiments, the consumable electrode has a diameter of about 4 mm.In these embodiments, the opening 720 may have a width of 4 mm, 4.2 mm, 4.4 mm, 4.6 mm, 4.8 mm, 5 mm, or a value within a range defined by any of these values.

[0050] The electrically insulating tube 716 may be formed from a suitable electrically insulating material. More specifically, the insulating tube is formed from a material having a high dielectric strength. For example, in some embodiments, the electrically insulating tube 716 is formed from polytetrafluoroethylene (PTFE) or Teflon®. However, in other embodiments, other electrically insulating materials may be used. For example, in some embodiments, the electrically insulating tube 716 may be formed from fluorinated ethylene propylene (FEP), Kapton®, polyurethane, or polyvinyl chloride. Advantageously, forming the electrically insulating tube 716 from a material having a high dielectric strength allows the electrically insulating tube 716 to act as an insulator such that it electrically insulates the consumable electrode from the head portion 702 before the consumable electrode passes through the contact tip 718. As described in more detail elsewhere in this application, the body portion 708, the electrical contact portion 710, and the contact nozzle 712 comprise metal and are configured to receive an electrical current received by the electrical contact portion 710 from a power source during welding. Thus, the electrically insulating tube 716 helps ensure insulation of the consumable electrode from the energized portion of the head portion 702 so that the consumable electrode does not inadvertently contact the head portion 702 and prematurely receive power which would result in inconsistent and unpredictable welding.

[0051] FIG. 7C is a perspective view of body portion 708, and FIG. 7D depicts a cross-sectional view of body portion 708 taken along line AA. Body portion 708 has opposed first and second ends 722A, 722B and includes an inner layer 726, an outer layer 728, and an electrical contact portion 710. Inner layer 726 defines a channel 724 extending between ends 722A, 722B. Channel 724 is configured to receive electrical insulation tube 716 such that electrical insulation tube 716 is disposed within channel 724 and extends from second end 722B through first end 722A. Second end 722B is configured to receive attachment nipple 714. In some embodiments, second end 722B includes threads configured to allow attachment nipple 714 to be screwed therein.

[0052] In some embodiments, the channel 724 has a length of about 200 mm, although in other embodiments, the channel 724 has a different length. For example, in some embodiments, the channel 724 has a length of 250 mm, 225 mm, 175 mm, 150 mm, 100 mm, less than 100 mm, or a value within a range defined by any of these values. In some embodiments, the channel 724 has a width such that the electrically insulating tube 716 is in direct contact with a surface of the inner layer 726 when the electrically insulating tube 716 is disposed within the channel 724. For example, in some embodiments, the channel 724 has a width of about 12 mm, although in other embodiments, the channel 724 has a different width. For example, in some embodiments, the channel 724 has a width of 20 mm, 15 mm, 10 mm, 5 mm, or a value within a range defined by any of these values. In some embodiments, the width of the channel 724 may be the same as the width of the electrically insulating tube 716 or may be only slightly greater than the width of the electrically insulating tube 716. For example, in an embodiment in which the electrically insulating tube 716 has a width of 12 mm, the channel 724 can have a width of 12 mm, 12.5 mm, 13 mm, 14 mm, 15 mm, or a value within a range defined by any of these values.

[0053] The inner layer 726 and the electrical contact portion 710 may each be formed from a metal and are electrically connected such that electrical current received by the electrical contact portion 710 during welding may flow into the inner layer 726. In some embodiments, the inner layer 726 and the electrical contact portion 710 are formed from a single piece of metal. During welding, the consumable electrode passes through an electrically insulating tube 716 disposed within the channel 724, and the electrically insulating tube 716 prevents the consumable electrode from contacting the inner layer 726. As a result, the electrically insulating tube 716 may electrically insulate the consumable electrode from electrical current received by the electrical contact portion 710 as the consumable electrode moves through the body portion 708.

[0054] The outer layer 728 completely surrounds the inner layer 726 and, in some embodiments, is formed from an electrically insulating material having high dielectric strength. For example, in some embodiments, the outer layer 728 is formed from a glass fiber based material or a polymer based material such as polytetrafluoroethylene (PTFE) or Teflon®. In some embodiments, an attachment device (e.g., the attachment device 620 shown in FIG. 6C) may be attached to the outer layer 728. Advantageously, forming the outer layer 728 from an electrically insulating material may prevent electrical current received at the electrical contact portion 710 from flowing through the inner layer 726 into the attachment device.

[0055] FIG. 7E is a perspective view of contact nozzle 712, and FIG. 7F is a cross-sectional view of contact nozzle 712 taken along line BB. Contact nozzle 712 has opposite first and second ends 730A, 730B and has a wall 732 defining a channel 734 and a cavity 738. Channel 734 extends from second end 730B to contact tip 718 and is configured to receive electrically insulating tube 716 (FIG. 7A) from body portion 708. Cavity 738 extends from first end 730A to contact tip 718 and is configured to receive an end of extension portion 704. Contact tip 718 is formed from a relatively thickened portion 740 of wall 732 that defines contact tip channel 736. Contact tip channel 736 extends between channel 734 and cavity 738 such that contact tip channel 736 connects channel 734 and cavity 738. Cavity 738 can be threaded to receive the threaded end of extension portion 704. Configured in this manner, the consumable electrode fed through insulating tube 716 remains electrically insulated from wall 732 until such time that the consumable electrode contacts the wall of contact tip channel 736.

[0056] The contact nozzle 712 has a generally cylindrical shape. In some embodiments, the contact nozzle 712 can have a length of 185 mm. In some embodiments, the walls 732 of the contact nozzle 712 taper inwardly toward the first end 730A such that the width of the contact nozzle 712 at the first end 730A is less than the width of the contact nozzle 712 at the first end 730B. For example, in some embodiments, the first end 730A of the contact nozzle 712 has a width of about 18 mm while the second end 730B of the contact nozzle 712 has a width of about 30 mm. In some embodiments, the width of the contact nozzle 712 can remain constant between the second end 730B and the midpoint of the contact nozzle, but can begin to taper inwardly from the midpoint to the first end 730A. Advantageously, the tapered first end 730A allows the contact nozzle 712 to be inserted into a narrow groove without contacting the sidewalls of the groove. Additionally, as described in further detail elsewhere in this application, the tapered first end 730A advantageously allows multiple electrode assemblies to be positioned in relatively close proximity to one another when used in a multi-arc configuration.

[0057] During the welding process, the electrically insulating tube 716 is disposed within the channel 734, and the consumable electrode passes through the electrically insulating tube 716 until it reaches the contact tip 718. At this point, the consumable electrode passes through the contact tip channel 736 and into the extension portion 706, which is disposed within the cavity 738. The contact tip channel is sized and shaped such that as the consumable electrode passes through the contact tip channel 736, the consumable electrode contacts the relatively thick portion 740 of the wall 732. The wall 732 of the contact nozzle 712 is formed from a metal, and the second end 730B is configured to be inserted directly into the first end 722A of the body portion 708 such that the wall 732 is in electrical contact with the metal inner layer 726 and the electrical contact portion 710. Thus, during the welding process, when power is provided to the body portion 708 via the electrical contact portion 710, electrical current flows within the wall 732 of the contact nozzle 712. When the consumable electrode contacts the thicker portion 740 of the wall 732, current flows through the consumable electrode.

[0058] The contact nozzle 712 is configured to allow the electrically insulating tube 716 to pass through the channel 734. Specifically, the channel 734 has a sufficient length and width such that the electrically insulating tube 716, when disposed within the channel 734, extends from the second end 730B to the contact tip 718 and is terminated by the relatively narrow contact tip channel 736. For example, in some embodiments, the channel 734 has a length of about 165 mm and a width of about 12 mm. However, in other embodiments, the channel 734 has a length of 140 mm, 150 mm, 160 mm, 170 mm, 180 mm, 190 mm, or a value within a range defined by any of these values, and a width of 6 mm, 8 mm, 10 mm, 12 mm, 14 mm, 16 mm, or a value within a range defined by any of these values. In some embodiments, the width of the channel 734 is the same as the width of the channel 724 within the body portion 708. In some embodiments, the width of channel 734 may be the same as or only slightly greater than the width of electrically insulating tube 716. For example, in embodiments in which electrically insulating tube 716 has a width of about 12 mm, channel 734 may have a width of 12 mm, 12.5 mm, 13 mm, 14 mm, 15 mm, or a value within a range defined by any of these values.

[0059] The channel 734 has a size and shape sufficient to allow the electrically insulating tube 716 to pass therethrough, while the contact tip 718 is configured such that the consumable electrode may pass through the contact tip channel 736, but the electrically insulating tube 716 may not pass into the contact tip channel 736. Thus, the contact tip 718 is configured such that the width of the contact tip channel 736 (i.e., the distance between the relatively thickened portions 740 of the walls 732) is less than the width of the electrically insulating tube 716, but greater than the diameter of the consumable electrode. In some embodiments, the width of the contact tip channel 736 is only slightly larger than the consumable electrode, such that as the consumable electrode passes through the contact tip channel 736 during welding, the consumable electrode contacts the relatively thickened portions 740 of the walls 732 of the contact nozzle 720, thereby allowing the contact tip 718 to apply a current into the consumable electrode. For example, in some embodiments, the contact tip channel 736 has a width of 4.2 mm. In some embodiments, the width of the contact tip channel 736 is dependent on the size of the consumable electrode. For example, in an embodiment in which the consumable electrode has a diameter of 3.2 mm, the contact tip channel 736 can have a width of 3.2 mm, 3.3 mm, 3.4 mm, 3.5 mm, 3.6 mm, or a value within a range defined by any of these values. In an embodiment in which the consumable electrode has a diameter of 4 mm, the contact tip channel 736 can have a width of 4 mm, 4.1 mm, 4.2 mm, 4.3 mm, 4.4 mm, or a value within a range defined by any of these values.

[0060] Configured in this manner, the contact tip channel 736 can define the point where the electrical stick-out begins. As described herein, the lower end of the contact tip channel 736 defines one end of the electrical stick-out, while the arcing tip defines the other end of the electrical stick-out.

[0061] FIG. 7G is a perspective view of the extension portion 704, and FIG. 7H is a cross-sectional view of the extension portion 704 taken along line CC. The extension portion 704 includes first and second ends 742A, 742B and a channel 750 extending between the first and second ends 742A, 742B and configured to receive a consumable electrode therein. The extension portion 704 further includes a threaded end portion 746 at the second end 742B. As described in more detail below, the threaded end portion 746 is configured to be releasably mounted within a cavity 738 at the first end 730A of the contact nozzle 712 (FIGS. 7E and 7F). In some embodiments, the threaded end portion 746 can have a width substantially the same as the width of the cavity 738. For example, in some embodiments, the cavity 738 and the threaded end portion 746 can each have a width of 12 mm. The threaded end portion 746 has threads configured to match threads in the cavity 738 such that the extension portion 704 can be threaded into the cavity 738 of the contact nozzle 712. As a result, the extension portion 704 can be easily replaced with an alternative extension portion if necessary.

[0062] During welding, the extension portion 704 is configured to be inserted into a narrow groove in a workpiece so that the electrode assembly can deposit metal into the groove. Thus, the extension portion 704 is sized and shaped so that it can be easily inserted into the narrow groove without substantially contacting the sidewalls of the groove. As described elsewhere in this application, in various embodiments, the extension portion 704 has a generally cylindrical shape with at least a portion tapered inwardly toward the first end 742 such that the width of the extension portion 704 near the first end 742A is less than the width of the extension portion 704 near the second end 742B. For example, in some embodiments, a portion of the extension portion 704 near the second end 742B (e.g., a portion of the extension portion 704 adjacent the threaded end portion 746) can have a width of about 18 mm, while a portion of the extension portion 704 near the first end 742A has a width of about 14 mm. However, in other embodiments, the extension portion 704 can have different widths. For example, in some embodiments, a portion of the extension 704 near the second end 742B can have a width of 24 mm, 22 mm, 20 mm, 18 mm, 16 mm, 14 mm, greater than 24 mm, less than 14 mm, or a value within a range defined by any of these values, and a portion of the extension 704 near the first end 742A can have a width of 20 mm, 18 mm, 16 mm, 14 mm, 12 mm, 10 mm, greater than 20 mm, less than 10 mm, or a value within a range defined by any of these values. In some embodiments, the width of the extension 704 can remain constant between the portion of the extension 704 adjacent the threaded end portion 746 and a midpoint of the extension 704, but can begin to taper inwardly from the midpoint to the first end 742A. For illustrative purposes only, approximately half of the length of the illustrated extension 704 is tapered. However, it should be understood that any suitable percentage of the length may be tapered, including substantially the entire length, such as, for example, more than 20%, 40%, 60%, or 80%, 100%, or a value within a range defined by any of these values.It should be further understood that the tapered sidewalls do not have to be straight and the degree of tapering can vary with length. For example, the degree of tapering can vary, for example, continuously or discontinuously throughout the tapered portion. So configured, the extension portion 704 can be configured not to contact the sidewalls of a narrow groove, such as a generally triangular trench, as described elsewhere in this application. Any portion of the tapered portion can be configured to form a triangle or cone with an apex angle where the tangent of the outer sidewall is less than 16 degrees, 12 degrees, 10 degrees, 8 degrees, 6 degrees, or a value within a range defined by any of these values. Advantageously, the tapered first end 742A allows the extension portion 704 to be inserted into a narrow groove without contacting the sidewalls of the groove. In addition, as described in further detail elsewhere in this application, the tapered first end 742A advantageously allows multiple electrode assemblies to be positioned relatively closely adjacent to one another when used in a multi-arc configuration.

[0063] In various embodiments, the extension portion 704 is configured to electrically and thermally insulate the consumable electrode from the workpiece and has a sufficient length such that the consumable electrode can be preheated by Joule heating to a higher temperature than in a conventional SAW system. For example, in some embodiments, the extension portion 704 has a length of 125 mm. In other embodiments, the extension portion 704 has a length of 90 mm. However, in still other embodiments, the extension portion 704 can have a different length. For example, in some embodiments, the extension portion 704 can have a length of 25 mm, 50 mm, 75 mm, 100 mm, 125 mm, 150 mm, 175 mm, less than 25 mm, greater than 175 mm, or a range of values ​​defined by any of these values. Additionally, the extension portion 704 can be long enough such that only the extension portion 704 is in the groove while the remainder of the electrode assembly 700 is at least partially outside the groove during welding.

[0064] This configuration also allows the length of the electrical stick-out to be substantially longer than in conventional SAW assemblies. As discussed above, the electrical stick-out is the distance between the contact tip (e.g., contact tip 718 shown in FIGS. 7B and 7F) and the arcing tip (e.g., arcing tip 622 of consumable electrode 606 shown in FIGS. 6A and 6C). Thus, the electrical stick-out of electrode assembly 700 is the sum of the length of extension portion 704 and the length of the visible stick-out. The visible stick-out of electrode assembly 700 is the portion of the consumable electrode that extends beyond first end 742A of extension portion 704 during welding and is therefore visible. In some embodiments, the visible stick-out length can be about 7 to 10 times the diameter of the consumable electrode. For example, in an embodiment in which the consumable electrode has a diameter of 3.2 mm, the visible stick-out can be about 22 mm to about 30 mm in length. Similarly, in an embodiment in which the consumable electrode has a diameter of 4 mm, the visible stick-out can be about 28 mm to about 40 mm in length. However, in other embodiments, the length of the visible stick-out may be based on many different factors, including electrode diameter, current, voltage, deposition rate, workpiece composition, and electrode composition. In addition, an operator of the electrode assembly 700 may dynamically adjust the visible stick-out length as needed during the welding process. This configuration therefore allows the electrical stick-out to be substantially longer than that of a conventional SAW system. For example, in an embodiment in which the extension portion 704 has a length of 125 mm, the electrical stick-out length may be 155 mm. However, in other embodiments, the electrical stick-out length may be different. For example, in some embodiments, the electrical stick-out length may exceed 125 mm, 130 mm, 140 mm, 150 mm, 160 mm, 170 mm, 180 mm, or may be within a range defined by any of these values. Similarly, in an embodiment in which the extension portion 704 has a length of about 90 mm, the electrical stick-out length may be about 120 mm.However, in other embodiments, the electrical stick-out length can be greater than 90 mm, 100 mm, 110 mm, 120 mm, 130 mm, 140 mm, or can be within a range defined by any of these values. Advantageously, the longer electrical stick-out substantially improves the deposition rate at a given current density due to the longer Joule heated area provided by the extension portion 704. In addition, the longer electrical stick-out also results in a lower flux-to-wire consumption ratio than conventional SAW assemblies because the electrode deposition rate increases while flux consumption remains constant.

[0065] In an exemplary embodiment, the extension portion 704 comprises a single piece insulating article formed from a suitable insulating material that thermally and electrically insulates the electrode as it passes through the extension portion 704. Advantageously, forming the extension portion 704 from an insulating material allows for increased pre-heating of the consumable electrode in the welding process because the insulating material prevents the heat imparted by the pre-heated electrode from being transferred to the surrounding air. Instead, the extension portion 704 ensures that heat is efficiently retained within the extension portion 704, thereby increasing the pre-heating of the electrode, which results in greater deposition and melt-off rates and higher productivity.

[0066] In some embodiments, the insulating material allows the extension portion 704 to contact the groove sidewall of the workpiece during welding without risk of electrical shorting. The insulating material may lose a portion of its resistivity when the electrode is heated to the temperatures described above during welding. To prevent electrical shorting between the workpiece sidewall and the consumable electrode when the extension portion 704 contacts the sidewall, the solid insulating material is configured to withstand a voltage difference of at least 5V, 10V, 15V, 20V, 25V, or a value within a range defined by any of these values, without substantial conduction or breakdown when the outer surface of the extension portion 704 contacts the workpiece.

[0067] In some embodiments, the extension portion 704 is formed as a single piece article from an insulating ceramic material. For example, in some embodiments, the extension portion 704 is formed from alumina (Al2O3) or silicon carbide (SiC). However, in other embodiments, other insulating materials can be used. In some embodiments, the extension portion 704 comprises silicon nitride, magnesia stabilized zirconia, yttria stabilized zirconia, magnesium oxide, or zirconia reinforced alumina. The ceramic extension portion 704 can be manufactured using a variety of methods, such as powder pressing, cold isostatic pressing, hot pressing, injection molding, and slip casting. Additionally, in some embodiments, the extension portion 704 is machined, while in other embodiments, the extension portion 704 is not machined.

[0068] The extension portion 704 is configured to pass from the contact nozzle 712 into the channel 744 after the consumable electrode contacts the contact tip 718. Thus, the channel 744 can be sized to allow the consumable electrode to pass through it. As shown in the illustrated embodiment, the single piece insulating article is configured to directly surround the consumable electrode without any intervening features or structures other than air. The channel 744 has first and second portions 748A, 748B, where the first portion 748A is located at the first end 742A of the extension portion 704 and the second portion 748B is located at the second portion 742B of the extension portion 704. In some embodiments, the first portion 748A is narrower than the second portion 748B. For example, in some embodiments, the first portion 748A has a width of about 5 mm, while the second portion 748B has a width of about 6.5 mm. In some embodiments, the first portion 748A has a width that is approximately 1 mm wider than the electrode diameter, while the second portion 748B has a width that is approximately 1.5 mm wider than the electrode diameter. These widths allow relatively free movement of the electrode while preventing excessive excursion of the electrode. Advantageously, the relatively narrow end portion 748A allows relatively little movement of the electrode's arcing tip while allowing the consumable electrode to be positioned relatively precisely within the groove.

[0069] One additional advantage of utilizing a relatively narrow extension as described herein is that it facilitates the use of multiple electrode assemblies in a multi-arc setup. When welding together large pieces of metal, it is often desirable to use multiple electrode assemblies simultaneously to further increase the deposition rate of filler metal. During multi-arc welding, the tips of the electrodes must be positioned closely adjacent to each other so that each of the electrode tips is disposed in the same weld pool. However, using conventional SAW electrode assemblies in a multi-arc setup is often difficult because the large diameter of the head portion of the conventional electrode assembly (e.g., head portion 204 (FIG. 2), 304A (FIG. 3A), 304B (FIG. 3B)) makes it difficult for multiple electrode assemblies to be positioned close enough to each other to facilitate multi-arc welding. In addition, the short length of the electrode stick-out portions (e.g., stick-out portions 316A, 416A) used in conventional SAW assemblies may require the welding torches to be positioned at a large angle relative to one another to allow the arcing tips of the individual electrodes to be close enough to one another to be positioned in the same weld pool. Thus, it is difficult to use conventional SAW electrode assemblies in a multi-arc setup because the large size of the head portion and the short stick-out length limit the number of electrode assemblies that can be used in a multi-arc setup while also making it difficult to position the torch when attempting to weld in a groove. These and other problems can be alleviated by the extensions according to the embodiments having relatively narrow extensions as described herein.

[0070] 8A illustrates a multi-arc SAW system 800A having first, second, and third electrode assemblies 802A, 802B, 802C. The first electrode assembly 802A includes a consumable electrode 810A having a head portion 804A, an extension portion 806A, and a tip 812A. Similarly, the electrode assembly 802B includes a consumable electrode 810B having a head portion 804B, an extension portion 806B, and a tip 812B, and the electrode assembly 802C includes a consumable electrode 810C having a head portion 804C, an extension portion 806C, and a tip 812C. The electrode assemblies 802A, 802B, 802C are generally similar to the electrode assembly 600 described above in connection with FIGS. 6A-6C and 7A-7H. System 800A also includes attachment devices 808A, 808B, 808C and a flux supply system 814A. Attachment devices 808A, 808B, 808C are generally similar to attachment device 620 shown in FIG. 6C and may be configured to securely hold its corresponding electrode assembly 802A, 802B, 802C, respectively, in a fixed position and in a desired orientation. The flux supply system is configured to dispense flux onto the workpiece in a SAW process and may be configured so as not to limit the size of a groove in the workpiece into which extensions 806A, 806B, 806C may be inserted.

[0071] As described above, the electrode assemblies 802A, 802B, 802C have a generally cylindrical shape that tapers inwardly such that the width of the electrode assemblies 802A, 802B, 802C near the extensions 806A, 806B, 806C is less than the width of the electrode assemblies 802A, 802B, 802C away from the extensions 806A, 806B, 806C. For example, the extensions 806A, 806B, 806C may have a width of about 14 to about 18 mm, while the body portion may have a width of up to 30 mm. In addition, the electrode assemblies may be configured such that the visible stick-out length of the consumable electrode is about 40 mm. With this configuration, the first, second, and third electrode assemblies 802A, 802B, 802C can be positioned such that the distance between adjacent tips 812A, 812B, 812C of the electrodes 810A, 810B, 810C is small enough to allow efficient multi-arc welding. Specifically, the shape, length, and width of the electrode assemblies 802A, 802B, 802C described herein allow the extensions 806A, 806B, 806C to be simultaneously positioned in narrow and deep grooves such that the tips 812A, 812B, 812C are disposed in the same weld pool in a SAW process without the extensions contacting the sidewalls of the groove. For example, in some embodiments, the electrode assemblies 802A, 802B, 802C can be positioned such that during welding, the distance between adjacent tips 812A, 812B, 812C is about 15 mm, while the angle between adjacent electrode assemblies 802A, 802B, 802C is about 20 degrees or less, although in other embodiments, the distance between adjacent tips and the angle between adjacent electrode assemblies 802A, 802B, 802C can vary. For example, the distance between adjacent tips 812A, 812B, 812C is 30 mm, 25 mm, 20 mm, 15 mm, 10 mm, 5 mm, or a value within a range defined by any of these values, and the electrode assemblies 802A, 802B, 802C are oriented such that the angle between adjacent electrode assemblies 802A, 802B, 802C is 40 degrees, 35 degrees, 30 degrees, 25 degrees, 20 degrees, 15 degrees, 10 degrees, 5 degrees, or a value within a range defined by any of these values.One of the electrode assemblies 802A, 802B, 802C can extend in a substantially vertical direction.

[0072] In the embodiment shown in FIG. 8A, the system 800A included three electrode assemblies 802A, 802B, 802C. However, this is by way of example only. In other embodiments, the multi-arc welding system can include a different number of electrode assemblies. Specifically, in various embodiments, the multi-arc SAW system can include two, three, four, five, or six electrode assemblies. For example, FIG. 8B depicts another multi-arc SAW system 900B having four electrode assemblies 802A, 802B, 803C, and 802D, where each of the electrode assemblies 802A, 802B, 802C, 802D is configured as described above in connection with FIG. 8A. The size, shape, and width of the electrode assemblies 802A, 802B, 802C, 802D herein allow the extensions 806A, 806B, 806C, 806D to be positioned simultaneously in narrow and deep grooves such that the electrode tips 812A, 812B, 812C, 812D are all disposed in the same weld pool in a SAW process without the extensions contacting the sidewalls of the groove. Specifically, the electrode assemblies 802A, 802B, 802C, 802D can be configured such that the distance between adjacent tips 812A, 812B, 812C, 812D is 30 mm, 25 mm, 20 mm, 15 mm, 10 mm, less than 10 mm, or a value within a range defined by any of these values, and the angle between adjacent electrode assemblies 802A, 802B, 802C, 802D is 40 degrees, 35 degrees, 30 degrees, 25 degrees, 20 degrees, 15 degrees, 10 degrees, 5 degrees, or a value within a range defined by any of these values.

[0073] System 800B also includes attachment devices 808A, 808B, 808C, 808D, and also includes an alignment device 816. Attachment devices 808A, 808B, 808C, 808D are generally similar to attachment device 620 shown in FIG. 6C, and can be configured to securely hold its corresponding electrode assembly 802A, 802B, 802C, 802D in a fixed position and in a desired orientation. Alignment device 816 can be used in conjunction with attachment devices 808A, 808B, 808C, 808D, and can be used to ensure that electrode assemblies 802A, 802B, 802C, 802D are aligned in an optimal orientation. In particular, the alignment device 816 can be used to ensure that the electrode assemblies 802A, 802B, 802C, 802D are positioned in a desired location and orientation relative to the workpiece and to each other, while the attachment devices 808A, 808B, 808C, 809D can be used to maintain the electrode assemblies 802A, 802B, 802C, 802D in a desired location and orientation during welding. Additionally, the flux delivery system 814B can be attached to the alignment device 816 to ensure that the flux delivery system 814 remains in proper alignment with the electrode assemblies 802A, 802B, 802C, 802D during welding.

[0074] 8A and 8B, according to an embodiment, each of the first, second, third (and fourth) electrode assemblies 802A, 802B, 802C (and 802D) is configured such that each of the multiple electrodes independently receives power from a dedicated power source (e.g., power source 108 shown in FIG. 1). With this configuration, each of the electrode assemblies can independently receive a controlled power, which allows for relatively consistent and efficient deposition of the filler material. In addition, the current provided to each electrode assembly can be varied for each electrode assembly such that each electrode assembly can receive a different current. However, in other embodiments, each of the electrode assemblies used in a multi-arc setup can be coupled together in parallel such that each of the electrode assemblies shares the same current.

[0075] Extension for long stick-out electrode assembly with partially covered ceramic sleeve As discussed above, various design considerations of a submerged arc welding (SAW) electrode assembly configured for long stick out (LSO), such as, for example, the design of the extension portion, can be important to provide the ability to weld narrow grooves with high deposition rates. Of the various design considerations discussed above, maintaining the alignment of the heated electrode between an insulated guide tip, such as, for example, a ceramic sleeve, can be particularly beneficial to stably guide the electrode during welding. It should be understood that while ceramic materials may be suitable to provide the requisite electrical and thermal insulation, they may be brittle and prone to breakage. In addition, machining of ceramic materials may be costly. To address these and other needs, disclosed herein is a cost-effective design for an electrode assembly configured for LSO with a mechanically stable extension portion that is relatively inexpensive to manufacture.

[0076] 9A-9C show extensions 900A-900C configured for use with long stick-out electrode assemblies (e.g., electrode assemblies 600, 700, and 800) having partially covered ceramic sleeves according to embodiments. Extensions 900A-900C share various advantageous features with the extensions shown and described above (e.g., extensions 604, 704, 804), such as physical dimensions and insulating capabilities adapted for welding narrow grooves. However, unlike the extensions described above, extensions 900A-900C each include a ceramic sleeve and a pair of metallic sheaths that cover the opposing ends of the ceramic sleeve.

[0077] 9A illustrates an extension portion 900A according to some embodiments. The extension portion 900A includes a ceramic sleeve 902A, a lower metallic sheath 904A or end cap, and an upper metallic sheath 906A or end cap. The ceramic sleeve 902A has opposing upper and lower ends 908A, 910A, where the lower metallic sheath 906A covers the lower end 910A and the upper metallic sheath 904A covers the upper end 908A. The ceramic sleeve 902A has a generally cylindrical shape, and the upper and lower metallic sheaths 904A, 906A are configured to extend around the circumference of the ceramic sleeve 902A. The relatively simple shape of the ceramic sleeve 902A allows it to be manufactured without machining, thereby reducing manufacturing costs. The extension portion 900A is configured to be removably attached to a contact tip portion (e.g., contact tip 718, FIG. 7F) of a head portion (e.g., head portion 602, FIG. 6A-6C, 702, FIG. 7A) and is disposed proximal to the arcing tip of the consumable electrode relative to the contact tip portion. The ceramic sleeve 902A further includes a channel 912A extending between the upper end 908A and the lower end 910A and configured to slidably feed the consumable electrode therethrough. The channel 912A may be configured similarly to the channel 744, or a portion thereof, described above in connection with FIG. 7H.

[0078] The ceramic sleeve 912A may be formed from materials similar to those described above in connection with the insulating material of the extension portion 704 (FIGS. 7G and 7H). The insulating material may be selected from the group consisting of silicon nitride, magnesia stabilized zirconia, yttria stabilized zirconia, silicon carbide, magnesium oxide, alumina, or zirconia reinforced alumina. The ceramic sleeve 912A may be manufactured using a variety of methods, such as powder pressing, cold isostatic pressing, hot pressing, injection molding, and slip casting. Advantageously, the ceramic sleeve 912A does not have to be machined due to its relatively simple shape.

[0079] The upper and lower sheaths 904A and 906A are formed from metal. Advantageously, metal is much easier to machine than ceramic, thereby allowing the upper and lower sheaths 904A, 906A to be machined with substantially greater flexibility and less expense. In addition, metal is substantially tougher than ceramic and has a smaller tendency to brittle fracture. Thus, attaching the metallic sheaths 904A, 906A to the ceramic sleeve 902 can increase the toughness and durability of the extension portion 902A because the ceramic sleeve 902 is less likely to crack or break when the extension portion 900A contacts or hits a workpiece during a welding process.

[0080] The extension portion 900A is configured to be mechanically coupled to a contact nozzle (e.g., contact nozzle 612 shown in FIGS. 6A-6C, 712 shown in FIGS. 7A and 7B) through an upper metallic sheath 906A. In the illustrated embodiment, the upper metallic sheath 904A includes a threaded nipple 914A configured to mate with threads on a contact nozzle (e.g., threads in cavity 738 shown in FIG. 7F) to allow the upper metallic sheath 904A to be releasably coupled to the contact nozzle. In addition, because the upper metallic sheath 904A (as well as the lower metallic sheath 904A) are formed from metal, the threads on the threaded nipple 914A can be substantially more durable and less likely to break, which can increase the useful life of the extension portion 900A and thereby reduce costs.

[0081] In various embodiments, the metallic sheaths 904A, 906A can be suitably fixed onto the ceramic sleeve 902A. For example, in some embodiments, the metallic sheaths 904A, 906A can be glued, soldered, or brazed onto the ceramic sleeve 902A. Advantageously, the metallic sheaths 904A, 906A are rigidly attached to the ceramic sleeve 902A using a suitable sealant that fills any gaps that may exist between the inner surface of the metallic sheaths 904A, 906A (e.g., the surface of the sheaths 904A, 906A that is configured to face and directly adjacent to the ceramic sleeve 902A) and the outer surface of the ceramic sleeve, such that the ceramic sleeve 902A and the metallic sheaths 904A, 906A are immobilized relative to one another. A suitable sealant may be a relatively soft material and may act as a shock absorbing layer between the ceramic sleeve 902A and the metallic sheaths 904A, 906A such that cracking of the ceramic sleeve 902A under mechanical or thermal stress is inhibited or prevented. Furthermore, even if the ceramic sleeve 902A breaks, the sealant may effectively prevent loose pieces from detaching and falling onto the workpiece. In some implementations, the ceramic sleeve 902A is brazed onto the metallic sheaths 904A, 906A using a suitable brazing metal having a melting temperature significantly lower than the melting temperature of the metallic sheaths 904A, 906A. Without limitation, suitable brazing metals include, for example, copper-based alloys such as Cu / Sn alloys. In some other implementations, the ceramic sleeve 902A and the metallic sheaths 904A, 906A are immobilized relative to one another using a suitable glass sealant having a glass transition temperature significantly lower than the melting temperature of the metallic sheaths. Without limitation, suitable glass sealants include doped silica, such as, for example, doped aluminosilicate glass or highly doped sodium silicate glass. Other sealants may be possible, such as, for example, high temperature epoxies that can withstand the outside temperature of the ceramic sleeve.

[0082] The metallic sheaths 904A, 906A are disposed at opposite ends 908A, 910A of the ceramic sleeve 902A and are separated from one another by a gap 916A therebetween that exposes an outer surface of the ceramic sleeve. In some embodiments, the size of the gap 916A (e.g., the distance between the metallic sheaths 904A, 906A) is large enough to prevent electrical shorting therebetween (e.g., at an electrical bias therebetween of greater than 30V) during welding.

[0083] The channel 912A has a suitable diameter slightly larger than the diameter of the electrode for sliding the electrode therethrough. While most of the middle portion of the channel 912A has a relatively constant diameter, one or both end portions of the channel 912A may, in some embodiments, have a larger diameter than that of the middle portion of the channel 912A, thereby flaring out to improve wire transfer therethrough.

[0084] The ceramic sleeve 902A has a straight cylindrical shape along substantially its entire length. In this configuration, each of the metallic sheaths 904A, 906A has a straight cylindrical inner wall portion in a corresponding manner so that the cylindrical end of the ceramic sleeve 902A can be fitted therein. The resulting metallic sheaths 904A, 906A surround the straight cylindrical portion of the ceramic sleeve. However, in other embodiments, the ceramic sleeve can have a tapered end and the metallic sheath is shaped to conform to the tapered end. For example, Figures 9B and 9C show alternative extensions 900B, 900C. The extensions 900B and 900C can be generally similar to the extension 900A. For example, extension portion 900B has a ceramic sleeve 902B, upper and lower ends 908B of ceramic sleeve 902B, upper and lower sheaths 904B, 906B attached to 910B, and a channel 912B extending along the length of ceramic sleeve 902B. Similarly, extension portion 900C has a ceramic sleeve 902C, upper and lower ends 908C of ceramic sleeve 902C, upper and lower sheaths 904C, 906C attached to 910C, and a channel 912C extending along the length of ceramic sleeve 902C. However, while ceramic sleeve 902 of extension portion 902A has a straight cylindrical shape, ceramic sleeves 902B, 902C are cylindrical and have tapered or chamfered outer surface portions extending from one or both ends thereof. For example, the ceramic sleeve 902B is tapered inwardly at both ends 908B, 908B such that the width of the ceramic sleeve 902B at the ends 908B, 910B is less than the width of the ceramic sleeve 902B at the midpoint of the ceramic sleeve 902B. The tapering of the ceramic sleeve 902B can be in accordance with the tapering of the extensions without the upper and lower sheaths 904B, 906B described elsewhere in this application, which can be advantageously inserted into a narrow groove.Each of the metallic sheaths 904B, 906B has a cylindrical inner wall portion tapered in a corresponding manner that surrounds the tapered portion of the ceramic sleeve, so configured that the ceramic sleeve can be slid into the metallic sheath with relative ease.

[0085] Also shown in Figure 9C is a ceramic sleeve 902C having tapered ends. In addition, the ceramic sleeve 902C is formed with rounded ends 908C, 910C or both. The rounded ends can further improve resistance to chipping or cracking. Additionally, the lower metallic sheath 906C also has rounded outer edges.

[0086] Further examples 1. An electrode assembly for submerged arc welding, comprising: a head portion and an extension portion arranged contiguously therewith and configured to feed a consumable electrode therethrough, wherein during welding, the head portion is disposed distal to an arcing tip of the consumable electrode and the extension portion is disposed proximal to the arcing tip of the consumable electrode; In this case, the extension portion is configured to electrically insulate the consumable electrode from the workpiece when the solid insulating material surrounds the consumable electrode during welding.

[0087] 2. An electrode assembly for submerged arc welding, comprising: a head portion and an extension portion arranged contiguously therewith and configured to feed a consumable electrode therethrough, wherein during welding, the head portion is disposed distal to an arcing tip of the consumable electrode and the extension portion is disposed proximal to the arcing tip of the consumable electrode; In this case, the extension portion has a shape, length, and lateral dimensions configured to electrically insulate the consumable electrode from the workpiece and configured to have the ability to not contact the sidewalls of a triangular trench having a depth greater than 4 inches and an apex angle that is less than 16 degrees while the tip of the consumable electrode contacts the apex.

[0088] 3. An electrode assembly for submerged arc welding, comprising: a head portion and an extension portion arranged contiguously therewith and configured to feed a consumable electrode therethrough, wherein during welding, the head portion is disposed distal to an arcing tip of the consumable electrode and the extension portion is disposed proximal to the arcing tip of the consumable electrode; In this case, the extension portion is configured to electrically insulate the consumable electrode from the workpiece during welding, with the extension portion having an outer surface formed from a substantially non-magnetic material surrounding the consumable electrode.

[0089] 4. An electrode assembly for submerged arc welding, comprising: a head portion and an extension portion arranged contiguously therewith and configured to feed a consumable electrode therethrough, wherein during welding, the head portion is disposed distal to an arcing tip of the consumable electrode and the extension portion is disposed proximal to the arcing tip of the consumable electrode; The extension portion is configured to electrically insulate the consumable electrode from the workpiece and has a shape, length, and lateral dimensions such that the contact tip-to-workpiece distance (CTWD) between the head portion and the tip of the consumable electrode during welding exceeds 125 mm.

[0090] 5. An electrode assembly for submerged arc welding, comprising: a head portion and an extension portion arranged contiguously therewith and configured to feed a consumable electrode therethrough, wherein during welding, the head portion is disposed distal to an arcing tip of the consumable electrode and the extension portion is disposed proximal to the arcing tip of the consumable electrode; a head portion and an extension portion, the extension portion being configured to electrically insulate the consumable electrode from the workpiece during welding; a flux supply system fixedly attached to the extension portion and configured such that the flux supply system does not limit the size of a groove in a workpiece into which the extension portion is capable of being inserted; has.

[0091] 6. An electrode assembly for submerged arc welding, comprising: a head portion and an extension portion arranged contiguously therewith and configured to feed a consumable electrode therethrough, wherein during welding, the head portion is disposed distal to an arcing tip of the consumable electrode and the extension portion is disposed proximal to the arcing tip of the consumable electrode; In this case, the extension portion is configured to electrically insulate the consumable electrode from the workpiece and the electrode assembly is configured to achieve a deposition rate / current in excess of 0.05 lbs / hr / A during welding.

[0092] 7. An electrode assembly for submerged arc welding, comprising: a head portion and an extension portion arranged contiguously therewith and configured to feed a consumable electrode therethrough, wherein during welding, the head portion is disposed distal to an arcing tip of the consumable electrode and the extension portion is disposed proximal to the arcing tip of the consumable electrode; In this case, the extension portion has a shape, length, and lateral dimensions configured to electrically insulate the consumable electrode from the workpiece and to cause the electrode assembly to achieve a deposition rate in excess of 35 lbs / hour at currents less than 900 A during welding.

[0093] 8. An electrode assembly for submerged arc welding, comprising: a head portion and an extension portion arranged contiguously therewith and configured to feed a consumable electrode therethrough, wherein during welding, the head portion is disposed distal to an arcing tip of the consumable electrode and the extension portion is disposed proximal to the arcing tip of the consumable electrode; In this case, the extension portion is configured to electrically insulate the consumable electrode from the workpiece and has a shape, length, and lateral dimensions such that the electrode assembly is configured to drop at least 5% of the total voltage drop across the contact tip-to-workpiece distance (CTWD) between the head portion and the tip of the consumable electrode.

[0094] 9. An electrode assembly for submerged arc welding, comprising: a head portion and an extension portion arranged contiguously therewith and configured to feed a consumable electrode therethrough, wherein during welding, the head portion is disposed distal to an arcing tip of the consumable electrode and the extension portion is disposed proximal to the arcing tip of the consumable electrode; In this case, the extension portion is configured to electrically insulate the consumable electrode from the workpiece and has a shape, length, and lateral dimensions such that the electrode assembly is configured to drop a percentage of the total voltage across the contact tip-to-workpiece distance (CTWD) between the head portion and the tip of the consumable electrode that exceeds 2 V.

[0095] 10. An electrode assembly for submerged arc welding, comprising: a head portion and an extension portion arranged contiguously therewith and configured to feed a consumable electrode therethrough, wherein during welding, the head portion is disposed distal to an arcing tip of the consumable electrode and the extension portion is disposed proximal to the arcing tip of the consumable electrode; In this case, the extension portion has a shape, length, and lateral dimensions configured to electrically insulate the consumable electrode from the workpiece and such that the electrode assembly is configured to heat the consumable electrode by Joule heating within the extension portion to a temperature of up to 800°C.

[0096] 11. An electrode assembly for submerged arc welding, comprising: a head portion and an extension portion arranged contiguously therewith and configured to feed a consumable electrode therethrough, wherein during welding, the head portion is disposed distal to an arcing tip of the consumable electrode and the extension portion is disposed proximal to the arcing tip of the consumable electrode; In this case, the extension portion is configured to electrically insulate the consumable electrode from the workpiece by a solid insulating material during welding, and in this case the solid insulating material has sufficient resistance such that it is configured to withstand a voltage difference of at least 5 V without substantially conducting when an outer surface of the extension portion contacts the workpiece.

[0097] 12. An electrode assembly for submerged arc welding, comprising: a head portion and an extension portion arranged contiguously therewith and configured to feed a consumable electrode therethrough, wherein during welding, the head portion is disposed distal to an arcing tip of the consumable electrode and the extension portion is disposed proximal to the arcing tip of the consumable electrode; In this case, the extension portion has an insulated tip portion formed from a solid insulating material configured to surround the consumable electrode and thereby electrically insulate the consumable electrode from the workpiece during welding.

[0098] 13. An electrode assembly according to any one of the preceding claims, wherein the solid insulating material comprises a ceramic material.

[0099] 14. An electrode assembly as claimed in any one of the preceding claims, wherein the solid insulating material has an insulating sleeve configured to pass the consumable electrode therethrough.

[0100] 1. An electrode assembly for submerged arc welding configured for a long electrode stick-out length of greater than 15.25 mm, comprising: A contact tip portion; an extension portion removably attached to the contact tip portion and disposed relative to the contact tip portion so as to be proximal to the arcing tip of the consumable electrode; having The extension part is a ceramic sleeve configured to slidably receive a consumable electrode therethrough; a pair of metallic sheaths covering opposite ends of the ceramic sleeve; has.

[0101] 16. The electrode assembly of Example 15, wherein the gap between each of the ceramic sleeve and metallic sheath is filled with a sealant such that the ceramic sleeve and metallic sheath are immobilized relative to one another.

[0102] 17. The electrode assembly of Example 16, wherein the sealant has a melting temperature or glass fiber temperature substantially lower than the melting temperature of the metallic sheath.

[0103] 18. The electrode assembly of Example 16, where the ceramic sleeve is brazed onto the metallic sheath such that the sealant comprises the brazing material.

[0104] 19. The electrode assembly of Example 16, wherein the sealant comprises a glass sealant.

[0105] 20. The electrode assembly of any one of Examples 15 to 19, wherein the metallic sheaths at opposite ends are separated in the length direction of the ceramic sleeve by a separation distance, thereby exposing the ceramic sleeve such that electrical shorts are substantially prevented between the metallic sheaths at electrical biases in excess of 30 V.

[0106] 21. The electrode assembly of any one of Examples 15 to 20, wherein the extension portion is mechanically coupled to the contact tip portion through one of the metallic sheaths that is distal to the arcing tip relative to the contact tip portion.

[0107] 22. The electrode assembly of Example 21, wherein one of the metal sheaths that mechanically couples the extension portion to the contact tip portion has a threaded nipple.

[0108] 23. The electrode assembly of any one of Examples 15 to 22, wherein the ceramic sleeve has a straight cylindrical portion, and wherein each of the metallic sheaths has a straight cylindrical inner wall portion in a corresponding manner surrounding the straight cylindrical portion of the ceramic sleeve.

[0109] 24. The electrode assembly of any one of Examples 15 to 23, wherein the ceramic sleeve has a tapered portion formed at one or both ends thereof, and wherein each of the metallic sheaths has a cylindrical inner wall portion tapered in a corresponding manner surrounding the tapered portion of the ceramic sleeve.

[0110] 25. The electrode assembly of any one of Examples 15 to 24, wherein the inner cavity of the ceramic sleeve has one or both end portions flared to have a diameter greater than that of the intermediate portion of the inner cavity.

[0111] 26. The electrode assembly of any one of Examples 15-25, wherein one or both outer edges of the ceramic sleeve are rounded.

[0112] 27. The electrode assembly of any one of Examples 15-26, wherein the metallic sheath formed at the end relatively close to the stick-out portion of the electrode has a rounded outer edge.

[0113] 28. The electrode assembly of any one of Examples 15-27, wherein the metallic sleeve is formed from steel.

[0114] 29. The electrode assembly of any one of Examples 15 to 28, wherein the ceramic sleeve is formed from a material selected from the group consisting of silicon nitride, magnesia-stabilized zirconia, yttria-stabilized zirconia, silicon carbide, magnesium oxide, alumina, or zirconia-toughened alumina.

[0115] 30. The electrode assembly of any one of Examples 15-29, wherein the extension portion has a shape, length, and lateral dimensions configured to electrically insulate the consumable electrode from the workpiece and configured to have the ability to not contact the sidewalls of a triangular trench having a depth greater than 4 inches and an apex angle less than 16 degrees when the tip of the consumable electrode is in contact with the apex.

[0116] 31. The electrode assembly of any one of Examples 15 to 30, wherein the extension portion is configured to electrically insulate the consumable electrode from the workpiece during welding, with the extension portion having an outer surface formed of a substantially non-magnetic material surrounding the consumable electrode.

[0117] 32. The electrode assembly of any one of Examples 15-31, wherein the extension portion is configured to electrically insulate the consumable electrode from the workpiece and has a shape, length, and lateral dimensions such that a contact tip-to-workpiece distance (CTWD) between the contact tip portion and the tip of the consumable electrode during welding exceeds 125 mm.

[0118] 33. The electrode assembly of any one of Examples 15 to 32, further comprising a flux supply system fixedly attached to the extension portion and configured such that the flux supply system does not limit the dimensions of a groove in the workpiece into which the extension portion is capable of being inserted.

[0119] 34. The electrode assembly of any one of Examples 15-33, wherein the extension portion is configured to electrically insulate the consumable electrode from the workpiece and has a shape, length, and lateral dimensions such that the electrode assembly is configured to achieve a deposition rate / current in excess of 0.05 lbs / hr / A during welding.

[0120] 35. The electrode assembly of any one of Examples 15-34, wherein the extension portion is configured to electrically insulate the consumable electrode from the workpiece and has a shape, length, and lateral dimensions such that the electrode assembly is configured to achieve a deposition rate in excess of 35 pounds per hour at a current of less than 900 A during welding.

[0121] 36. The electrode assembly of any one of Examples 15-35, wherein the extension portion is configured to electrically insulate the consumable electrode from the workpiece and has a shape, length, and lateral distance such that the consumable electrode drops at least 5% of the total voltage drop across a contact tip-to-workpiece distance (CTWD) between the contact tip portion and the tip of the consumable electrode.

[0122] 37. The electrode assembly of any one of Examples 15-36, wherein the extension portion is configured to electrically insulate the consumable electrode from the workpiece and wherein the stick-out portion of the consumable electrode has a shape, length, and lateral dimensions to provide a total voltage drop of at least 2 V across a contact tip-to-workpiece distance (CTWD) between the contact tip portion and the tip of the consumable electrode.

[0123] 38. The electrode assembly of any one of Examples 15-37, wherein the extension portion is configured to electrically insulate the consumable electrode from the workpiece and has a shape, length, and lateral dimensions such that the electrode assembly is configured to heat the consumable electrode by Joule heating within the extension portion to a temperature of up to 800°C.

[0124] 39. The electrode assembly of any one of Examples 15-38, wherein the extension portion is configured to electrically insulate the consumable electrode from the workpiece during welding by a solid insulating sleeve, wherein the solid insulating sleeve has sufficient resistance such that it is configured to withstand a voltage difference of at least 5 V without substantially conducting when an outer surface of the extension portion contacts the workpiece.

[0125] 40. An electrode assembly for submerged arc welding (SAW), comprising: a head portion and an extension portion arranged continuously to feed the consumable electrode therethrough such that during SAW the head portion is disposed distal to the arcing tip of the consumable electrode and the extension portion is disposed proximal to the arcing tip of the consumable electrode; In this case, the head portion includes a contact tip configured to electrically contact the consumable electrode to supply power to the consumable electrode; and In this case, the extension portion is comprised of a single piece of insulating article configured for the consumable electrode to eventually pass through after passing the contact tip and before the arcing tip is exposed.

[0126] 41. The electrode assembly of Example 40, configured such that during a SAW having a consumable electrode inserted therethrough, the ratio between the electrical stick-out distance measured between a contact tip disposed at one end of the head portion and the arcing tip of the consumable electrode and the diameter of the consumable electrode exceeds 30.

[0127] 42. The electrode assembly of Example 41, wherein the extension portion has a length of 80 mm or more for a consumable electrode having a diameter of 3 mm or more.

[0128] 43. The electrode assembly of example 40, wherein the head portion is A main body part, a contact nozzle disposed between the body portion and the extension portion and having a contact tip configured to electrically contact the consumable electrode for supplying power to the consumable electrode; has.

[0129] 44. The electrode assembly of Example 43, further comprising an electrical contact portion disposed between the body portion and the contact nozzle, wherein the electrical contact portion is electrically connected to the contact nozzle and configured to receive power from the power source and to supply power to the contact tip.

[0130] 45. The electrode assembly of Example 44, further comprising an electrically insulating tube inserted through the head portion and configured to guide the consumable electrode.

[0131] 46. ​​The electrode assembly of example 45, wherein: the contact tip is configured to apply power to the consumable electrode; and The electrically insulating tube is configured to electrically insulate the consumable electrode from the body portion, the electrical contact portion, and at least a portion of the contact nozzle.

[0132] 47. The electrode assembly of Example 43, wherein the contact nozzle has a length of greater than 140 mm.

[0133] 48. The electrode assembly of example 43, wherein the contact nozzle having opposed first and second ends; a first end of the contact nozzle coupled to an electrical contact; The contact tip is located at the second end, and An electrically insulating tube extends through the first end to the second end.

[0134] 49. The electrode assembly of Example 48, wherein the consumable electrode passes through an electrically insulating tube such that the electrically insulating tube is positioned between the consumable electrode and the body portion, the electrical contact portion, and a portion of the contact nozzle.

[0135] 50. The electrode assembly of example 49, wherein: The contact nozzle includes a sidewall extending between the first end and the contact tip; The portion of the contact nozzle tip includes a sidewall and a first end; and The contact tip is in direct contact with the consumable electrode.

[0136] 51. The electrode assembly of Example 43, wherein the head portion and the contact nozzle have metal.

[0137] 52. The electrode assembly of Example 45, wherein the electrically insulating tube comprises polytetrafluoroethylene.

[0138] 53. An electrode assembly for submerged arc welding (SAW), comprising: a head portion having a contact tip configured to electrically contact the consumable electrode for supplying power to the consumable electrode; an extension portion arranged contiguous with the head portion in a wire feed direction, wherein the head portion and the extension portion are configured to feed the consumable electrode therethrough; In this case, the extension portion is configured to be disposed proximate to the arcing tip of the consumable electrode relative to the head portion; and The extension portion is formed from a single piece of insulating article disposed contiguous with the contact tip.

[0139] 54. The electrode assembly of Example 53, wherein the extension portion has a single piece of insulating material.

[0140] 55. The electrode assembly of Example 54, wherein the single piece of insulating material comprises a ceramic.

[0141] 56. The electrode assembly of Example 53, wherein the extension portion has a length of greater than 80 mm.

[0142] 57. The electrode assembly of Example 56, wherein the extension portion has a length of greater than 120 mm.

[0143] 58. The electrode assembly of Example 53, wherein the extension portion has a shape, length, and width configured such that, with the tip of the consumable electrode contacting the apex, the extension portion is configured not to contact the sidewalls of a triangular groove having a depth greater than 4 inches and having an apex angle that is less than 16 degrees.

[0144] 59. An extension configured for a submerged arc welding electrode assembly, comprising: a single piece insulating article formed from a ceramic material having a length of greater than 80 mm and configured to surround a consumable electrode; In this case, the extension portion is configured to be disposed contiguous with the contact tip of the head portion of the submerged arc welding electrode assembly.

[0145] 60. The extension of Example 59, wherein the extension has a length of greater than 120 mm.

[0146] 61. An extension of Example 59, the extension portion having opposite first and second end portions; the first end portion is configured to be positioned proximally relative to the head portion and has a first width; The second end portion is configured to be positioned distally relative to the head portion and has a second width; and The second width is less than the first width.

[0147] 62. The extension of example 61, wherein the first width is 18 mm and the second width is 14 mm.

[0148] 63. The extension of Example 61, wherein the extension has a tapered portion whose width decreases toward the arcing tip, wherein the tapered portion is configured such that a tangent to an exterior surface of the extension forms a triangle or cone having an apex angle that is less than 16 degrees.

[0149] 64. The extension of Example 63, wherein the extension has a shape, length, and lateral dimensions such that, with the tip of the consumable electrode contacting the apex, the extension is configured not to contact a sidewall of a triangular groove having a depth greater than 4 inches and having an apex angle that is less than 16 degrees.

[0150] 65. The extension of Example 61, wherein the first end portion has threads configured to releasably engage with the threads on the head portion.

[0151] 66. An electrode assembly for submerged arc welding (SAW), comprising: a head portion having a contact nozzle; an extension portion removably and continuously attached to the contact nozzle and disposed relative to the contact nozzle so as to be proximate to the arcing tip of the consumable electrode; and the extension portion is a ceramic sleeve configured to slidably receive a consumable electrode therethrough; a pair of metallic sheaths covering opposite ends of the ceramic sleeve; has.

[0152] 67. The electrode assembly of Example 1, configured such that during a SAW having a consumable electrode inserted therethrough, the ratio between the electrical stick-out distance measured between a contact tip disposed at one end of the head portion and an arcing tip of the consumable electrode and the diameter of the consumable electrode exceeds 30.

[0153] 68. The electrode assembly of Example 1, where the electrical stick-out distance exceeds 125 mm.

[0154] 69. The electrode assembly of Example 1, wherein the gap between each of the ceramic sleeve and metallic sheath is filled with a sealant such that the ceramic sleeve and metallic sheath are immobilized relative to one another.

[0155] 70. The electrode assembly of Example 69, wherein the sealant has a melting temperature or glass fiber temperature substantially lower than the melting temperature of the metallic sheath.

[0156] 71. The electrode assembly of Example 69, wherein the ceramic sleeve is brazed onto the metallic sheath such that the sealant comprises the brazing metal.

[0157] 72. The electrode assembly of Example 69, wherein the sealant comprises a glass sealant.

[0158] 73. The electrode assembly of Example 1, wherein the metallic sheaths at opposite ends are separated in the length direction of the ceramic sleeve by a separation distance, thereby exposing the ceramic sleeve such that electrical shorting is substantially prevented between the metallic sheaths at electrical biases in excess of 30V.

[0159] 74. The electrode assembly of Example 1, wherein the extension portion is mechanically coupled to the contact nozzle through one of the metallic sheaths that is distal to the arcing tip relative to the contact nozzle.

[0160] 75. The electrode assembly of Example 9, wherein one of the metal sheaths that mechanically couples the extension to the contact nozzle has a threaded nipple.

[0161] 76. An extension configured for a submerged arc welding electrode assembly, comprising: a ceramic sleeve configured to surround the consumable electrode; a pair of metallic sheaths covering opposite ends of the ceramic sleeve; having In this case, the extension portion is configured to be disposed contiguous with the head portion of the submerged arc welding electrode assembly.

[0162] 77. The extension of Example 11, wherein the extension is configured such that during welding with a consumable electrode inserted therethrough, the ratio between the electrical stick-out distance measured between a contact tip portion disposed at one end of the head portion and the arcing tip of the consumable electrode and the diameter of the electrode exceeds 30.

[0163] 78. The extension of Example 11, wherein the gap between each of the ceramic sleeve and metallic sheath is filled with a sealant such that the ceramic sleeve and metallic sheath are immobilized relative to one another.

[0164] 79. The extension of Example 11, wherein the ceramic sleeve has a straight cylindrical portion, and wherein each of the metallic sheaths has a straight cylindrical inner wall portion in a corresponding manner surrounding the straight cylindrical portion of the ceramic sleeve.

[0165] 80. The extension of Example 11, wherein the ceramic sleeve has a tapered portion formed at one or both ends thereof, and wherein each of the metallic sheaths has a cylindrical inner wall portion tapered in a corresponding manner surrounding the tapered portion of the ceramic sleeve.

[0166] 81. The extension of Example 80, wherein the extension has a tapered portion at an end relatively close to the arcing tip, wherein the width decreases toward the arcing tip, and wherein the tapered portion is configured such that a tangent to the outer surface of the extension forms a triangle or cone having an apex angle that is less than 16 degrees.

[0167] 82. The extension of Example 81, wherein the extension has a shape, length, and lateral dimensions such that, with the tip of the consumable electrode contacting the apex, the extension is configured not to contact a sidewall of a triangular groove having a depth greater than 4 inches and an apex angle less than 16 degrees.

[0168] 83. The extension of Example 11, wherein the inner cavity of the ceramic sleeve has one or both end portions flared to have a larger diameter than that of the middle portion of the inner cavity.

[0169] 84. The extension of Example 11, wherein the outer edge of one or both ends of the ceramic sleeve is rounded.

[0170] 85. An extension of Example 11 in which the metallic sheath formed at the end relatively close to the stick-out portion of the consumable electrode has rounded outer edges.

[0171] 86. The extension of Example 11, wherein the metallic sleeve is formed from steel.

[0172] 87. The extension of example 11, wherein the ceramic sleeve is formed from a material selected from the group consisting of silicon nitride, magnesia stabilized zirconia, yttria stabilized zirconia, silicon carbide, magnesium oxide, alumina, or zirconia toughened alumina.

[0173] 88. An electrode assembly for submerged arc welding (SAW), comprising: a head portion and an extension portion arranged continuously therethrough to feed the consumable electrode such that during SAW the head portion is disposed distal to the arcing tip of the consumable electrode and the extension portion is disposed proximal to the arcing tip of the consumable electrode; In this case, the head portion includes a contact tip configured to electrically contact the consumable electrode to supply power to the consumable electrode; and In this case, the extension part is a ceramic sleeve configured to slidably feed a consumable electrode therethrough after it has passed the contact tip; a pair of metallic sheaths covering opposite ends of the ceramic sleeve; has.

[0174] 89. The electrode assembly of Example 23, wherein the gaps between each of the ceramic sleeve and metallic sheath are filled with a sealant such that the ceramic sleeve and metallic sheath are immobilized relative to one another.

[0175] 90. The electrode assembly of Example 23, wherein the extension portion is mechanically coupled to the contact tip through one of the metallic sheaths that is distal to the arcing tip relative to the contact tip.

[0176] 91. The electrode assembly of Example 23, wherein the ceramic sleeve comprises a single piece of ceramic material selected from the group consisting of silicon nitride, magnesia stabilized zirconia, yttria stabilized zirconia, silicon carbide, magnesium oxide, alumina, or zirconia reinforced alumina.

[0177] Unless the context clearly requires otherwise, throughout the description and claims, the terms "comprise," "comprising," "include," "including," and the like, are to be construed in an inclusive or exhaustive sense, i.e., "including without limitation," rather than an exclusive sense. The term "coupled," as generally used herein, means two or more elements that may be directly connected or connected through one or more intermediate elements. Similarly, the term "connected," as generally used herein, means two or more elements that may be directly connected or connected through one or more intermediate elements. In addition, the terms "herein," "above," "below," and similar incorporation terms, when used in this application, shall refer to this application as a whole and not to any particular portion of this application. Also, where the context permits, terms in the above "Detailed Description" using the singular or plural may include the plural or singular, respectively. The term "or" referring to a list of two or more items covers all interpretations of the term: any of the items in the list, all of the items in the list, and any combination of the items in the list.

[0178] Furthermore, conditional language used herein, such as, among others, "can," "could," "might," "may," "eg," "for example," "such as," and the like, is generally intended to convey that a particular embodiment includes certain features, elements, and / or conditions where other embodiments do not, unless specifically claimed otherwise or understood otherwise within the context in which it is used. Thus, such conditional language is generally not intended to imply that features, elements, and / or conditions are required in any manner for one or more embodiments or whether those features, elements, and / or conditions are required to be included or performed in any particular embodiment.

[0179] Although specific embodiments have been described, these embodiments are presented for illustrative purposes only and are not intended to limit the scope of the disclosure. Indeed, the novel apparatus, methods, and systems described herein may be embodied in a variety of other forms, and various omissions, substitutions, and changes in the forms of the methods and systems described herein may be made without departing from the spirit of the disclosure. For example, while blocks are presented in a given configuration, alternative embodiments may perform similar functions with different components and / or circuit topologies, and may perform deletions, movements, additions, subdivisions, combinations, and / or modifications of some of the blocks. Each of these blocks may be implemented in a variety of different ways. Any suitable combination of elements and acts of the various embodiments described above may be combined to provide further embodiments. The various features and processes described above may be implemented independently of each other or may be combined in various ways. All possible combinations and subcombinations of features of the present disclosure are intended to be within the scope of the present disclosure.

Claims

1. 1. An electrode assembly for submerged arc welding (SAW), comprising: a head portion having a contact nozzle; an extension portion detachably and continuously attached to the contact nozzle and disposed proximal to the arcing tip of the consumable electrode relative to the contact nozzle; and The extension portion is a ceramic sleeve configured to slidably feed the consumable electrode therethrough; a pair of metallic sheaths covering opposite ends of the ceramic sleeve; An electrode assembly comprising:

2. 2. The electrode assembly of claim 1, wherein a SAW having the consumable electrode inserted therethrough is configured such that a ratio between an electrical stick-out distance measured between a contact tip disposed at one end of the head portion and the arcing tip of the consumable electrode and a diameter of the consumable electrode exceeds 30.

3. 3. The electrode assembly of claim 2, wherein the electrical stick-out distance exceeds 125 mm.

4. 2. The electrode assembly of claim 1, wherein a gap between each of the ceramic sleeves and the metallic sheaths is filled with a sealant such that the ceramic sleeves and the metallic sheaths are immobilized relative to one another.

5. 5. The electrode assembly of claim 4, wherein the sealant has a melting or glass fiber temperature substantially lower than the melting temperature of the metallic sheath.

6. 5. The electrode assembly of claim 4, wherein the ceramic sleeve is brazed onto the metallic sheath such that the sealant comprises a brazing metal.

7. The electrode assembly of claim 4 , wherein the sealant comprises a glass sealant.

8. 2. The electrode assembly of claim 1, wherein the metallic sheaths at the opposite ends are separated in the lengthwise direction of the ceramic sleeve by a separation distance, thereby exposing the ceramic sleeve such that electrical shorting is substantially prevented between the metallic sheaths at an electrical bias in excess of 30 V.

9. 2. The electrode assembly of claim 1, wherein the extension portion is mechanically coupled to the contact nozzle through one of the metallic sheaths that is distal to the arcing tip relative to the contact nozzle.

10. 10. The electrode assembly of claim 9, wherein said one of said metallic sheaths mechanically coupling said extension portion to said contact nozzle has a threaded nipple.

11. 1. An extension configured for a submerged arc welding electrode assembly, comprising: a ceramic sleeve configured to surround the consumable electrode; a pair of metallic sheaths covering opposite ends of the ceramic sleeve; and The extension portion is configured to be disposed contiguously with a head portion of the submerged arc welding electrode assembly.

12. 12. The extension portion of claim 11, wherein the extension portion is configured such that during welding with the consumable electrode inserted therethrough, a ratio between an electrical stick-out distance measured between a contact tip portion disposed at one end of the head portion and an arcing tip of the consumable electrode and a diameter of the consumable electrode exceeds 30.

13. 12. The extension of claim 11, wherein a gap between each of the ceramic sleeves and the metallic sheaths is filled with a sealant such that the ceramic sleeves and the metallic sheaths are immobilized relative to one another.

14. 12. The extension portion of claim 11, wherein the ceramic sleeve has a straight cylindrical portion, and each of the metallic sheaths has a corresponding straight cylindrical inner wall portion surrounding the straight cylindrical portion of the ceramic sleeve.

15. 13. The extension portion of claim 12, wherein the ceramic sleeve has a tapered portion formed at one or both ends thereof, and each of the metallic sheaths has a correspondingly tapered cylindrical inner wall portion surrounding the tapered portion of the ceramic sleeve.

16. 16. The extension portion of claim 15, wherein the extension portion has a tapered portion at the end relatively proximate to the arcing tip, wherein the width decreases toward the arcing tip, and the tapered portion is configured such that a tangent to an outer surface of the extension portion forms a triangle or cone having an apex angle that is less than 16 degrees.

17. 17. The extension of claim 16, wherein the extension has a shape, length, and lateral dimensions configured such that, with the arcing tip of the consumable electrode in contact with the apex, the extension does not contact sidewalls of a triangular groove having a depth greater than 4 inches and an apex angle less than 16 degrees.

18. 12. The extension of claim 11, wherein the inner cavity of the ceramic sleeve has one or both end portions flared to have a larger diameter than a middle portion of the inner cavity.

19. 12. The extension of claim 11, wherein the outer edges of one or both ends of the ceramic sleeve are rounded.

20. 12. The extension of claim 11, wherein the metallic sheath formed at an end relatively proximate the stick-out portion of the consumable electrode has rounded outer edges.

21. The extension of claim 11 , wherein the metallic sheath is formed from steel.

22. 12. The extension of claim 11, wherein the ceramic sleeve is formed from a material selected from the group consisting of silicon nitride, magnesia-stabilized zirconia, yttria-stabilized zirconia, silicon carbide, magnesium oxide, alumina, or zirconia-toughened alumina.

23. 1. An electrode assembly for submerged arc welding (SAW), comprising: a head portion and an extension portion arranged continuously to feed the consumable electrode therethrough such that the head portion is disposed distal to the arcing tip of the consumable electrode and the extension portion is disposed proximal to the arcing tip of the consumable electrode during SAW; the head portion includes a contact tip configured to electrically contact the consumable electrode to supply power to the consumable electrode; and The extension portion is a ceramic sleeve configured to slidably feed the consumable electrode therethrough after passing the contact tip; a pair of metallic sheaths covering opposite ends of the ceramic sleeve; An electrode assembly comprising:

24. 24. The electrode assembly of claim 23, wherein a gap between each of the ceramic sleeves and the metallic sheaths is filled with a sealant such that the ceramic sleeves and the metallic sheaths are immobilized relative to one another.

25. 24. The electrode assembly of claim 23, wherein the extension portion is mechanically coupled to the contact tip through one of the metallic sheaths that is distal to the arcing tip relative to the contact tip.

26. 24. The electrode assembly of claim 23, wherein the ceramic sleeve comprises a single piece of ceramic material selected from the group consisting of silicon nitride, magnesia stabilized zirconia, yttria stabilized zirconia, silicon carbide, magnesium oxide, alumina, or zirconia toughened alumina.

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