Method and apparatus for controlling the penetration profile by means of applying a shielding gas in the inner region of the workpiece

Abstract

A method for controlling a penetration profile on a workpiece (306) having an outer region and an inner region is described. The method includes the step of applying energy to the outer region of the workpiece by a welding machine (302) to create a weld pool (304). The method also includes the steps of penetrating the workpiece (306) such that the weld pool (304) spans between the outer region and the inner region, and also applying a shielding gas to the inner region at a pressure that provides a force that limits the penetration. A corresponding apparatus is also defined.

Description

[0001] This application is a divisional application of the invention patent application No. 201480081057.7, filed on February 7, 2017, entitled "Method and apparatus for controlling weld penetration profile by means of applying a protective gas in the internal region of a workpiece". Technical Field

[0002] The embodiments described below relate to the field of welding, and more specifically, to methods and related equipment for improving the internal weld profile. Background Technology

[0003] Welding is a manufacturing process well known in the art, in which metals are joined together by joining (usually by melting workpieces together, and sometimes by adding filler material to form a weld pool of molten metal). The molten weld pool eventually cools to form a continuous bond.

[0004] There are many different welding methods, such as Gas Metal Arc Welding (GMAW or MIG), Shielded Metal Arc Welding (SMAW), and Gas Tungsten Arc Welding (GTAW or TIG). Different energy sources (such as electric arcs, lasers, gas flames, etc.) are used to melt the workpiece and form a weld pool. In most welding methods, filler wire or electrode is fed into the weld pool. An inert or semi-inert shielding gas is typically released above the weld pool to protect it from oxidation.

[0005] GTAW welding, for example, involves a tungsten electrode protruding from the ceramic jacket of a handheld or machine-mounted welding torch. The electrode is positioned close to the desired weld zone in the base metal, while an orifice within the ceramic jacket emits a shielding gas, such as argon or helium, to create an inert protective atmosphere above the weld zone. An electric arc is generated between the electrode and the base metal to form a weld pool. The weld pool penetrates the base metal while filler wire is fed into the weld pool, although this is not strictly necessary. Both the base metal and the filler wire are melted by the arc and eventually cool to form a weld joint.

[0006] During the construction of a flow meter, several parts must be welded together. For flow meter applications, flanges, conduits, and flow tubes must be precisely welded, meaning full penetration is required, but excessive penetration is unacceptable. If a weld joint is deemed to have insufficient or excessive penetration, it must be ground down and re-welded. In some flow meter sections, it is impossible to access internal parts (such as the inner diameter of conduits) after the first weld pass. Therefore, full penetration is essential for all weld joints on the first weld pass. This raises a problem because up to 90% of the welds require at least some form of rework to meet the requirements.

[0007] Figure 1 Provided is an example of a flow meter in the prior art. Conduit sensors (such as Coriolis mass flow meters and vibrating hydrometers) typically operate by detecting the motion of a vibrating conduit containing flowing material. Properties associated with the material in the conduit (such as mass flow, density, etc.) can be determined by processing measurement signals received from a motion transducer associated with the conduit. The vibration modes of a system filled with vibrating material are typically influenced by the combined mass, stiffness, and damping characteristics of the conduit and the material contained within it.

[0008] It is well known that vibrating flow meters are used to measure the mass flow and other properties of materials flowing through pipes. For example, vibrating Coriolis flow meters are disclosed in U.S. Patent No. 4,491,025 to J.E. Smith et al. and Re. 31,450 to J.E. Smith. These flow meters have one or more fluid tubes (or “flow tubes”). Each flow tube in a Coriolis mass flow meter is configured with a set of natural vibration modes, which can be simple bending, torsional, radial, lateral, or coupled types. Each flow tube is driven to oscillate resonantly in one of these natural modes. The vibration modes are typically influenced by the combined mass, stiffness, and damping characteristics of the flow tube and the material contained therein; therefore, the mass, stiffness, and damping are typically determined using known techniques during the initial calibration of the flow meter.

[0009] Material flows into the flow meter from the connecting pipe on the inlet side. The material is then guided through one or more flow tubes and exits the flow meter into the pipe connected to the outlet side.

[0010] A driver, such as a voice coil actuator, applies a force to one or more flow tubes. This force causes the flow tubes to oscillate. When no material flows through the flow meter, all points along the flow tube oscillate with the same phase. When material begins to flow through the flow tube, Coriolis acceleration causes each point along the flow tube to have a different phase relative to the other points along the flow tube. The phase at the inlet side of the flow tube lags behind the driver, while the phase at the outlet side leads the driver. Sensors are typically placed at two different points on the flow tube to generate a sinusoidal signal representing the motion of the flow tube at the two points. The phase difference between the two signals received from the sensor is calculated in units of time.

[0011] The phase difference between two sensor signals is proportional to the mass flow rate of the material flowing through a flow tube or multiple flow tubes. The mass flow rate is determined by multiplying the phase difference by a flow calibration factor. The flow calibration factor depends on the material properties and cross-sectional properties of the flow tube. A key characteristic of the flow tube affecting the flow calibration factor is its stiffness. The flow calibration factor is determined through a calibration process before the flow meter is installed in the pipeline. During calibration, fluid is passed through the flow tube at a given flow rate, and the ratio between the phase difference and the flow rate is calculated. As is generally known in the art, the stiffness and damping characteristics of the flow tube are also determined during the calibration process.

[0012] One advantage of Coriolis flow meters is that the accuracy of the measured mass flow rate is largely unaffected by wear on moving parts within the flow meter, as there are no moving parts in the vibrating flow tube. The flow rate is determined by multiplying the phase difference between two points on the flow tube by a flow calibration factor. The only input is a sinusoidal signal from the sensor indicating the oscillations at the two points on the flow tube. The phase difference is calculated from the sinusoidal signal. Because the flow calibration factor is proportional to the material and cross-sectional properties of the flow tube, the phase difference measurement and the flow calibration factor are unaffected by wear on moving parts within the flow meter.

[0013] A typical Coriolis mass flow meter includes one or more transducers (or pickoff sensors, or simply "sensitive elements"), which are typically used to measure the vibrational response of one or more flow ducts and are usually located upstream and downstream of the actuator. The sensitive elements are connected to electronic instruments. The instruments receive signals from both sensitive elements and process these signals to derive mass flow rate measurements, etc.

[0014] A typical Coriolis flow meter measures flow and / or density by using coils and magnets as sensing elements to measure the motion of (multiple) vibrating flow tubes within the meter. The mass flow rate through the meter is determined based on the phase difference between the signals from multiple sensing elements located near the inlet and outlet of the flow tubes within the meter. However, it is possible to measure flow using strain gauges instead of coil / magnet sensing elements. The fundamental difference between the two sensor types is that coil / magnet sensing elements measure the velocity of the flow tube, while strain gauges measure the strain of the flow tube, which is proportional to the tube's displacement. Therefore, the positioning of each type of sensor will not necessarily be in the same location.

[0015] The embodiments described below provide means for welding flanges, conduits, flow tubes, flow meters, and other non-flow meter-related workpieces. One object is to provide an embodiment for welding workpieces that present limited access to their internal regions. One object is to provide an embodiment for providing a protective gas to the internal regions of a workpiece. One object is to provide an embodiment for providing means for controlling the pressure of the protective gas within the internal regions of a workpiece. One object is to provide an embodiment that introduces a protective gas into the internal regions of a workpiece at a buffered weld pool pressure to control the internal weld profile. Summary of the Invention

[0016] According to an embodiment, a method is provided for controlling the weld penetration profile on a workpiece having an outer region and an inner region. According to the embodiment, the steps include: applying energy to the outer region of the workpiece using a welding machine to create a weld pool; welding through the workpiece such that the weld pool spans between the outer and inner regions; and applying a shielding gas to the inner region at a pressure that provides a force limiting weld penetration.

[0017] According to an embodiment, an apparatus is provided for controlling the weld penetration profile on a workpiece having an outer region and an inner region. According to the embodiment, a welding machine is configured to produce a weld joint from the outer region of the workpiece, wherein the weld joint penetrates from the outer region of the workpiece to the inner region of the workpiece; a gas supply in fluid communication with the inner region is configured to provide a shielding gas to the inner region of the workpiece, wherein the pressure of the shielding gas provides a force limiting weld penetration; and a pressure gauge is in communication with the inner region, wherein the pressure gauge is configured to measure the pressure of the shielding gas present in the inner region.

[0018] According to an embodiment, a method is provided for controlling the weld penetration profile on a portion of a flow meter having an outer region and an inner region. According to the embodiment, the steps include: applying energy to the outer region of the portion of the flow meter using a welding machine to create a weld pool; welding through the portion of the flow meter such that the weld pool spans between the outer and inner regions; applying a shielding gas to the inner region at a pressure providing a force limiting weld penetration; maintaining a substantially constant pressure of the shielding gas in the inner region, wherein the pressure of the shielding gas is between approximately 0.01 psi and 2.0 psi; measuring the pressure of the shielding gas in the inner region to generate the measured pressure; comparing the measured pressure to a predetermined range of acceptable pressures; and if the measured pressure is outside the acceptable pressure range, adjusting the pressure of the shielding gas in the inner region to be within the acceptable pressure range.

[0019] aspect According to one aspect, a method for controlling the weld penetration profile on a workpiece having an outer region and an inner region includes the steps of: applying energy to the outer region of the workpiece using a welding machine to create a weld pool; welding through the workpiece such that the weld pool spans between the outer region and the inner region; and applying a protective gas to the inner region at a pressure that provides a force limiting the weld penetration.

[0020] Preferably, the method includes the step of maintaining a substantially constant pressure of the protective gas within the internal region.

[0021] Preferably, the pressure of the protective gas is between approximately 0.01 psi and 1.0 psi.

[0022] Preferably, the pressure of the protective gas is between approximately 0.03 psi and 0.30 psi.

[0023] Preferably, the pressure of the protective gas is between approximately 0.04 psi and 0.245 psi.

[0024] Preferably, the method includes the steps of: measuring the pressure of a protective gas in an internal region; comparing the measured pressure with a predetermined range of acceptable pressures; and if the measured pressure falls outside the acceptable pressure range, adjusting the pressure of the protective gas in the internal region to the acceptable pressure range.

[0025] Preferably, the method includes the step of providing filler metal into a molten pool of metal.

[0026] Preferably, the welding is self-fusion.

[0027] Preferably, the surface is prevented from being welded through to a depth of approximately 0.0625 inches beyond the defined internal area.

[0028] Preferably, the weld is prevented from penetrating beyond approximately 10% of the surface workpiece thickness of the defined internal area.

[0029] According to one aspect, an apparatus for controlling the weld penetration profile on a workpiece having an outer region and an inner region includes: a welding machine configured to produce a weld joint from the outer region of the workpiece, wherein the weld joint penetrates from the outer region of the workpiece to the inner region of the workpiece; a gas supply in fluid communication with the inner region, configured to provide a shielding gas to the inner region of the workpiece, wherein the pressure of the shielding gas provides a force limiting the weld penetration; and a pressure gauge in communication with the inner region, wherein the pressure gauge is configured to measure the pressure of the shielding gas present in the inner region.

[0030] Preferably, the valve, which is in fluid communication with the internal region, is configured to regulate the pressure of the protective gas within the internal region.

[0031] Preferably, the system electronics are connected to both the pressure gauge and the valve, wherein the system electronics are configured to receive a pressure signal from the pressure gauge and adjust the valve accordingly to maintain the pressure within the internal area within a predetermined pressure range.

[0032] Preferably, the predetermined pressure range is between approximately 0.01 psi and 1.0 psi.

[0033] Preferably, the predetermined pressure range is between approximately 0.03 psi and 0.30 psi.

[0034] Preferably, the predetermined pressure range is between approximately 0.04 psi and 0.245 psi.

[0035] Preferably, the welding machine includes tungsten inert gas welding (GTAW) equipment.

[0036] Preferably, the welding machine includes manual arc welding (SMAW) equipment.

[0037] Preferably, the welding machine includes a gas metal arc welding (GMAW) device.

[0038] Preferably, the welding machine includes at least one of a laser beam welder, an electroslag welder, a magnetic pulse welder, and a friction stir welder.

[0039] Preferably, the protective gas includes argon.

[0040] Preferably, the protective gas includes at least one of nitrogen, helium, carbon dioxide, oxygen, hydrogen, nitrogen oxides, sulfur hexafluoride, and dichlorodifluoromethane.

[0041] Preferably, the workpiece comprises alloy steel.

[0042] Preferably, the workpiece includes at least one of steel, stainless steel, aluminum, magnesium, copper, platinum, nickel, carbon, chromium, cobalt, niobium, tungsten, vanadium, zirconium, and molybdenum.

[0043] Preferably, the workpiece includes a conduit.

[0044] Preferably, the workpiece includes a flange.

[0045] Preferably, the workpiece includes at least a portion of the flow meter.

[0046] According to one aspect, a method for controlling the weld penetration profile on a portion of a flow meter having an outer region and an inner region includes the steps of: applying energy to the outer region of the portion of the flow meter using a welding machine to create a weld pool; welding through the portion of the flow meter such that the weld pool spans between the outer region and the inner region; applying a shielding gas to the inner region at a pressure that provides a force limiting the weld penetration; maintaining a substantially constant pressure of the shielding gas in the inner region, wherein the pressure of the shielding gas is between approximately 0.01 psi and 2.0 psi; measuring the pressure of the shielding gas in the inner region to generate the measured pressure; comparing the measured pressure with a predetermined range of acceptable pressures; and if the measured pressure is outside the range of acceptable pressures, adjusting the pressure of the shielding gas in the inner region to the range of acceptable pressures.

[0047] Preferably, the pressure of the protective gas is between approximately 0.03 psi and 0.30 psi.

[0048] Preferably, the surface is prevented from being welded through to a depth of approximately 0.0625 inches beyond the defined internal area.

[0049] Preferably, the weld is prevented from penetrating beyond approximately 10% of the surface workpiece thickness of the defined internal area. Attached Figure Description

[0050] In all the accompanying drawings, the same reference numerals denote the same elements. The drawings are not necessarily to scale.

[0051] Figure 1 The diagram illustrates a conventional flow meter. Figure 2 Other prior art embodiments of sensor assemblies with external housings are illustrated; Figure 3 Without an adapter or flange, Figure 2 A view of a prior art embodiment of a sensor component; Figure 4 The diagram illustrates the flange and adapter used for the flow meter, indicating the weld location; Figure 5The diagram illustrates the flange, extension tube, and adapter used for the flow meter, indicating the weld location; Figure 6 The illustration shows a device according to an embodiment; Figure 7 The diagram shows... Figure 6 A cross-sectional view of the equipment; Figure 8 Another device according to an embodiment is illustrated; Figure 9 The diagram illustrates a flowchart describing the method of an embodiment; and Figure 10 A flowchart illustrating another method of an embodiment is shown. Detailed Implementation

[0052] Figures 1-10 The following description depicts specific examples to teach those skilled in the art how to create and use embodiments of methods and related equipment for weld profile control. For the purpose of teaching the principles of the invention, some conventional aspects have been simplified or omitted. Those skilled in the art will understand that variations derived from these examples fall within the scope of the invention. Those skilled in the art will understand that the features described below can be combined in various ways to form multiple variations of the invention. Therefore, the invention is not limited to the specific examples described below, but only to the claims and their equivalents.

[0053] Figure 1 The illustration shows a prior art flow meter 5, which can be any vibrating meter, such as a Coriolis flow meter. The flow meter 5 includes a sensor assembly 10 and metering electronics 20. The sensor assembly 10 is responsive to the mass flow rate and density of the process material. The metering electronics 20 is connected to the sensor assembly 10 via leads 100 to provide density, mass flow rate, and temperature information along path 26, as well as other information. The sensor assembly 10 includes flanges 101 and 101', a pair of manifolds 102 and 102', a pair of parallel flow tubes 103 (first flow tube) and 103' (second flow tube), an actuator 104, a temperature sensor 106 (such as a resistance temperature detector (RTD)), and a pair of sensing elements 105 and 105' (such as a magnet / coil sensing element, strain gauge, optical sensor, or any other sensing element known in the art). Flow tubes 103 and 103' have inlet branches 107 and 107' and outlet branches 108 and 108', respectively. The flow tubes 103 and 103' are bent at at least symmetrical locations along their length and are substantially parallel throughout their length. Each flow tube 103, 103' oscillates about axes W and W', respectively.

[0054] Branch pipes 107, 107', 108, and 108' of flow pipes 103 and 103' are fixedly attached to flow pipe mounting blocks 109 and 109', and these blocks are in turn fixedly attached to manifolds 102 and 102'. This provides a continuous closed material path through sensor assembly 10.

[0055] When flanges 101 and 101' are connected to a process line (not shown) carrying the measured process material, the material passes through a first orifice in flange 101 (in... Figure 1 (Not visible in the view) The material enters the first end 110 of the flow meter 5 and is guided through the manifold 102 to the flow tube mounting block 109. Within the manifold 102, the material is separated and conveyed through flow tubes 103 and 103'. After exiting the flow tubes 103 and 103', the process material is recombined into a single flow within the manifold 102' and is subsequently conveyed out of the second end 112, which is connected to the process line (not shown) via a flange 101'.

[0056] Flow tubes 103 and 103' are selected and suitably mounted to flow tube mounting blocks 109 and 109' so that they have approximately the same mass distribution, moment of inertia, and Young's modulus about the bending axes W--W and W'--W', respectively. Since the Young's modulus of flow tubes 103 and 103' changes with temperature, and this change affects the calculation of flow and density, a temperature sensor 106 is mounted to flow tubes 103 and 103' to continuously measure the temperature of the flow tubes. The temperature of the flow tubes, and therefore the voltage appearing across temperature sensor 106 for a given current transmitted through temperature sensor 106, is primarily governed by the temperature of the material transmitted through the flow tubes. The temperature-dependent voltage appearing across temperature sensor 106 is used by metering electronics 20 in a known manner to compensate for changes in the elastic modulus of flow tubes 103 and 103' due to any changes in the flow tube temperature. The temperature sensor is connected to metering electronics 20.

[0057] Both flow tubes 103 and 103' are driven by actuator 104 in opposite directions about their respective bending axes W and W' in what is known as the flow meter's first out-of-phase bending mode. Actuator 104 may include any of a number of known arrangements, such as a magnet mounted to flow tube 103' and opposing coils mounted to flow tube 103, through which alternating current is transmitted to vibrate both flow tubes. A suitable drive signal is applied to actuator 104 by metering electronics 20 via lead 113.

[0058] Metering electronics 20 receives a temperature signal on lead 114 and left and right velocity signals appearing on leads 115 and 115', respectively. Metering electronics 20 generates a drive signal appearing on lead 113 leading to driver 104 and causes flow tubes 103, 103' to vibrate. Metering electronics 20 processes the left and right velocity signals and temperature signals to calculate the mass flow rate and density of the material passing through sensor assembly 10. This information, along with other information, is applied by metering electronics 20 to path 26 leading to the utility device.

[0059] A Coriolis flowmeter structure has been described, but it will be apparent to those skilled in the art that the invention can be practiced on vibrating tube hydrometers without the additional measurement capabilities provided by a Coriolis mass flowmeter. In fact, the invention can be used in pipes, conduits, and flanges of all sizes, with or without means for measuring mass flow, density, etc. The invention can also be practiced in the absence of any flowmeter 5.

[0060] Figure 2 Another embodiment of a prior art sensor assembly 10 enclosed by a housing 200 is illustrated. Many parts of the sensor assembly 10 are concealed from view by means of the housing 200, but the manifolds 102, 102' and flanges 101, 101' are visible. In this embodiment, adapters 202, 202' are soldered to connect the flanges 101, 101' to their respective manifolds 102, 102'. Figure 3 The diagram shows... Figure 2 The prior art sensor assembly 10 is an embodiment, but for clarity, adapters 202, 202' and flanges 101, 101' are missing.

[0061] Figure 4 and Figure 5 An example of a portion of a sensor assembly 10 requiring welding is illustrated, wherein access to the internal surface is restricted. Figure 4 The illustration shows that it is also present. Figure 2 The adapter 202 and flange 101 are shown in the diagram. Figure 5 The illustration shows an adapter 202, a flange 101, and an extension conduit 204 disposed between the adapter 202 and the flange 101. The extension conduit 204 provides additional clearance between the flange 101 and the sensor assembly 10. Figure 4 and Figure 5The diagram illustrates locations A, B, C, and D. These are the points where flange 101 is welded to adapter 202 (location A), adapter 202 is welded to manifold 102 (location B), extension conduit 204 is welded to flange 101 (location C), and extension conduit 204 is welded to adapter 202 (location D). These locations are merely examples of weldable portions of sensor assembly 10 and are not intended to limit the scope of the claims or specification.

[0062] First refer to Figure 6 According to an embodiment, an apparatus 300 for controlling weld penetration is provided. A welding apparatus (welding machine) 302 is provided as a means for providing the necessary energy to form a molten pool (weld pool) 304 of metal on a workpiece 306.

[0063] The welding machine 302 can be any type of welding machine known in the art capable of performing full penetration welding. For example (but not limited to), the welding machine 302 may include an electric welding power source configured to generate an arc between the electrode 308 and the base material to melt the workpiece 306, thereby creating a weld pool 304 at the weld point. The electric welding power source will utilize direct current (DC) or alternating current (AC). In other embodiments, the power source may utilize gases, lasers, electron beams, ultrasonic energy, resistance, magnetism, friction, and any other means known in the art for welding. Figure 6 In this process, electrode 308 receives power from welding machine 302 via connection 324. Electrode 308 is held by electrode holder 309.

[0064] In the Figure 6 In the illustrated example, electrode 308 is non-consumable, but consumable electrodes are also considered. Due to tungsten's relatively high melting point (3,422°C), non-consumable electrodes used in GTAW welding typically consist mostly of tungsten. Electrodes that have been cleaned or polished are also considered. The diameter of the electrodes considered for GTAW embodiments of the invention can vary between approximately 0.5 and 7.0 mm. In the embodiment, the diameter is approximately 3.1 mm. In addition to pure tungsten, tungsten alloys comprising cerium oxide, lanthanum oxide, thorium oxide, and / or zirconium oxide are also considered.

[0065] Metal filler 310 can be introduced into the solder pool 304, but this is not strictly necessary in all cases. Metal filler 310 can be added manually to the solder pool 304, or alternatively, it can be automatically fed from a filler spool 312 or a similar automated device configured to supply a stable feed of metal filler 310. Figure 6 In the process, the welding machine 302 is connected to the filler spool 312 and controls the rate of filler deposition via the connection 322.

[0066] It is also considered to introduce shielding gas into the area surrounding the weld pool 304. Shielding gas protects the welding zone from, for example, atmospheric oxygen, an oxidizing agent that promotes weld defects, porosity, and weld brittleness. Shielding gas also facilitates heat transfer from the electrode to the base metal and, in the case of an electric welding machine, promotes a more stable arc. Figure 6 In this process, gas supply 314 supplies protective gas via a first gas line 318 through a sleeve 316 surrounding electrode 308. Welding machine 302 meteres the gas supply and controls the release of the protective gas via connection 320. In a preferred embodiment, the protective gas comprises argon. In another embodiment, the protective gas comprises a mixture of argon and carbon dioxide (e.g., C-50, C-25, C-15, etc.). In another embodiment, the protective gas comprises a mixture of argon and oxygen (e.g., O-5, O-2, O-1, etc.). In another embodiment, the protective gas comprises a mixture of argon and helium (e.g., A-75, A-50, A-25, etc.). In another embodiment, the protective gas comprises a mixture of argon and hydrogen (e.g., H-35, H-10, H-2, etc.). In another embodiment, the protective gas includes argon, carbon dioxide, and helium; or argon, carbon dioxide, and hydrogen; or argon, carbon dioxide, and nitrogen; or argon, carbon dioxide, and oxygen; or argon, helium, and hydrogen; or argon, helium, carbon dioxide, and hydrogen. In another embodiment, the protective gas includes at least one of nitrogen oxides, sulfur hexafluoride, and dichlorodifluoromethane.

[0067] In an embodiment, gas supply 314 supplies gas to the internal region 338 of workpiece 306 via a second gas line 326 in any manner that can maintain the internal pressure of the internal region (see [link]). Figure 7 A protective gas is provided. It should be noted that the protective gas supplied to the weld pool 304 via the first gas line 318 and the protective gas supplied to the internal region 338 of the workpiece 306 via the second gas line 326 may be the same or different protective gases. A valve 328 provides a means of opening or closing the supply of protective gas to the internal region 338 of the workpiece 306. In the case of an open conduit workpiece 306, a seal may be oriented near the conduit end to form a significantly sealed internal region that prevents the protective gas from escaping through the conduit end (although gas may escape through the pre-welded interface of the workpiece). The seal 330 may have the capacity to receive, for example, the second gas line 326. In an embodiment (not shown), the seal may have a pressure gauge 332 attached thereto. Figure 6 In the embodiment illustrated, pressure gauge 332 is directly attached to workpiece 306. Pressure gauge 332 is configured to measure the pressure of the protective gas introduced into the internal region 338 of workpiece 306.

[0068] During welding, the weld pool 304 can partially or completely penetrate the weld joint 334. If only partial penetration occurs, for a butt joint, this means that the weld pool 304 does not reach the side of the workpiece 306 opposite to the electrode 308. This is generally unacceptable, and it will be necessary to grind down the weld joint 334 and re-weld at least a portion of it. However, if the penetration is too great, the material will "sag" beyond the butt joint to a degree considered unacceptable, which varies depending on the welding standards followed. In conduits, excessive penetration will result in large molten beads on the inner diameter of the weld joint 334, which can cause turbulence, weak points, or otherwise affect the integrity of the system utilizing such a conduit.

[0069] Turn Figure 7 The diagram illustrates a cross-section of the weld joint 334. According to an embodiment, the apparatus 300 controls the weld penetration profile on the workpiece 306, which has an outer region 336 and an inner region 338, to prevent excessive penetration beyond the inner surface 340. In this embodiment, the workpiece 306 is mounted in a lathe that rotates the workpiece so that circumferential welding can be performed using a fixed electrode 308. In this case, as in... Figure 7 As illustrated, the workpiece 306 is rotated while the electrode 308 holds the weld pool 304. This causes a weld joint 334 to deposit circumferentially on the workpiece 306, thereby sealing any gaps with the help of molten metal. The weld joint 334 completely penetrates the workpiece 306, and thus extends from the outer region 336 to the inner surface 340. The fully penetrated weld extends to the inner surface 340 of the inner region 338, and may slightly exceed the inner surface 340 of the inner region 338. The molten metal flows relatively and may drip or sag, thus causing the penetration to be greater than what is considered acceptable. In some cases, the degree of penetration beyond the inner surface is limited to 10% of the workpiece thickness. Therefore, if the workpiece thickness is 3.0 mm, the acceptable depth of penetration beyond the inner surface cannot be greater than, for example, but not limited to, 0.3 mm. In other cases, the acceptable depth of penetration can be a predetermined distance, which is not necessarily limited to a percentage of the workpiece thickness. Therefore, for example, but not limited to, the penetration limit can be 1 / 16 inch or 1 / 8 inch, regardless of the workpiece thickness.

[0070] Continue to refer to Figure 6 and Figure 7In this embodiment, a protective gas from gas supply 314 is introduced into the internal region 338 of workpiece 306. A pressure gauge 332 measures the pressure in the internal region 338. Since it is desired to maintain a predetermined pressure of the protective gas in the internal region 338, an adjustable valve 328 is used during the welding process. As an example, workpiece 306 may have a relatively large seam requiring welding, so the internal region 338 is filled with protective gas to achieve the predetermined pressure. Since the protective gas can escape from the seam, the gas flow introduced into the internal region 338 is adjusted to maintain the pressure, regardless of the escaping gas. However, as workpiece 306 is welded and the weld joint 334 is formed, the area where the protective gas can escape from the internal region 338 is reduced, and therefore the gas pressure tends to increase. Therefore, as the weld joint develops, the adjustable valve 328 is used to reduce the flow of protective gas into the internal region 338 in order to maintain the desired internal gas pressure. This can be done manually or automatically. By carefully adjusting the shielding gas pressure in the inner region 338, the weld profile maintains the desired penetration and prevents protrusion beyond any predetermined penetration limit, as the shielding gas pressure effectively acts as a buffer, thereby applying force to the molten weld pool 304 and reducing sagging.

[0071] Workpiece 306 may be constructed of any weldable metal. For example, but not limited to, workpieces may include: steel, alloy steel, stainless steel, aluminum, magnesium, copper, platinum, nickel, carbon, chromium, cobalt, niobium, tungsten, vanadium, zirconium, molybdenum, or any combination thereof. In one embodiment, workpiece 306 is made of stainless steel. In another embodiment, the workpiece is made of Hastelloy®. In yet another embodiment, the workpiece is made of bimetal.

[0072] The pressure of the shielding gas in the internal region 338 varies primarily depending on the welding process, workpiece material, and workpiece thickness. For example, the pressure of the shielding gas in the internal region 338 may be maintained between approximately 0.05 psi and 2 psi. In another non-limiting example, a stainless steel workpiece 306 undergoing a GTAW welding process may have an internal shielding gas pressure maintained between approximately 0.1 psi and 0.3 psi in the internal region 338. In yet another non-limiting example, a Hastelloy® workpiece 306 undergoing a GTAW welding process may have an internal shielding gas pressure maintained between approximately 0.03 psi and 0.1 psi in the internal region 338. It should be noted that these values ​​assume a flat welding position, meaning that the electrode 308 is positioned above the workpiece 306. This disclosure considers other welding positions, and the pressure of the shielding gas may be varied to accommodate different welding positions.

[0073] exist Figure 8In the embodiment illustrated, system electronics 400 are in communication with pressure gauge 332 and also with valve 328. In this embodiment, valve 328 is automatic, such as a pneumatic valve, hydraulic valve, electric valve, or optical valve. Valve 328 is in fluid communication with gas supply 314 and also with internal region 338 of workpiece 306. Valve 328 controls the volume of protective gas introduced into internal region 338.

[0074] System electronics 400 may include a general-purpose computer, a microprocessor system, logic circuits, or some other general-purpose or custom processing device. System electronics 400 can be distributed across multiple processing devices. System electronics 400 can include any type of integrated or separate electronic storage medium, such as a computer-readable storage system. In one embodiment, system electronics 400 includes a digitizer, wherein the pressure gauge signal includes an analog sensor signal. The digitizer samples and digitizes the analog sensor signal and generates a digital sensor signal. The interface / digitizer can also perform any desired decimation, wherein the digital sensor signal is decimated to reduce the amount of signal processing required and reduce processing time. System electronics 400 can perform any necessary or desired signal conditioning, such as any type of formatting, amplification, buffering, etc.

[0075] System electronics 400 receives sensor signals from a pressure gauge or other pressure sensor on line 401. System electronics 400 processes the sensor signals to obtain the pressure value of the protective gas within internal region 338. System electronics 400 can send a signal on line 403 to actuate valve 328. The signal can be electronic, optical, hydraulic, and / or pneumatic. In one embodiment, valve 328 includes a solenoid valve capable of metering gas flow. In another embodiment, valve 328 includes a needle valve capable of metering gas flow. In yet another embodiment, valve 328 includes a spool valve capable of metering gas flow. System electronics 400 can read a pressure signal from pressure gauge 332 and compare this pressure within workpiece 306 with a predetermined pressure range. If the pressure within workpiece 306 falls outside the predetermined pressure range, system electronics 400 sends a signal on line 403 to valve 328, which increases or decreases the gas pressure within the workpiece so that the pressure changes to the predetermined pressure or falls within the predetermined pressure range.

[0076] The system electronics 400 may include a communication path 404. The communication path 404 enables communication between the system electronics 400, the welding machine 302, and external devices. The communication path can enable any form of electronic, optical, or wireless communication.

[0077] Turn now Figure 9The embodiment includes a method for controlling the weld penetration profile on a workpiece 306 having an outer region 336 and an inner region 338, wherein the workpiece 306 is made of a base metal. In step 500, energy is provided to the outer region 336 of the workpiece 306 by means of a welding machine 302 to create a molten pool (weld pool) 304 of metal by melting at least the base metal. The energy is electrical, laser, ultrasonic, from a gas flame, friction, or any other welding energy source known in the art. In one embodiment, the welding machine 302 includes a tungsten inert gas welding (GTAW) apparatus. In another embodiment, the welding machine 302 includes a manual arc welding (SMAW) apparatus. In yet another embodiment, the welding machine 302 includes a gas metal arc welding (GMAW) apparatus. As will be readily apparent to those skilled in the art, any other type of welding machine 302 known in the art is also contemplated. In step 502, the workpiece 306 is fully penetrated such that the weld pool 304 spans between the outer region 336 and the inner region 338. This is considered a full penetration weld. In step 504, a protective gas is supplied to the inner region 338 at a pressure that provides a buffering force to limit weld penetration.

[0078] exist Figure 10The illustration shows a related embodiment comprising a method for controlling the weld penetration profile on a workpiece having an outer region and an inner region, wherein the workpiece is made of a base metal. In step 600, energy is supplied to the outer region 336 of the workpiece 306 by means of a welding machine 302 to create a molten pool (weld pool) 304 of metal by melting at least the base metal. In step 602, the workpiece 306 is fully welded through such that the weld pool 304 spans between the outer region 336 and the inner region 338. In step 604, a shielding gas is supplied to the inner region 338 at a pressure that provides a force limiting weld penetration. Once the desired pressure is reached in step 604, a substantially constant pressure of the shielding gas is maintained in the inner region as shown in step 606. In one embodiment, the shielding gas pressure is between approximately 0.01 psi and 1.0 psi. In another embodiment, the shielding gas pressure is between approximately 0.03 psi and 0.30 psi. In yet another embodiment, the shielding gas pressure is between approximately 0.04 psi and 0.245 psi. In step 608, the pressure of the protective gas within the inner region is measured. In step 610, this measured pressure value is then compared to a predetermined range of acceptable pressures. This helps confirm that the gas pressure is within the acceptable range. In step 612, if the measured pressure is outside the acceptable pressure range, the pressure of the protective gas within the inner region is adjusted to within the acceptable pressure range. By providing appropriate pressure for a specific metal type, welding machine type, and base metal size, penetration beyond approximately 0.0625 inches of the defined inner region is prevented. In another embodiment, penetration beyond approximately 10% of the workpiece thickness of the defined inner region is prevented.

[0079] Methods for controlling weld penetration profiles may include providing filler metal to a molten pool of metal. However, the weld may alternatively be self-fluxing. In embodiments, multiple weld passes are formed on a single joint, and each weld pass may be self-fluxing or use filler metal.

[0080] The detailed description of the above embodiments is not an exhaustive description of all embodiments considered by the inventors to be within the scope of the invention. In fact, those skilled in the art will recognize that specific elements of the above embodiments can be combined or eliminated differently to produce more embodiments, and these more embodiments fall within the scope and teachings of the invention. It will also be apparent to those skilled in the art that the above embodiments can be combined in whole or in part to produce additional embodiments within the scope and teachings of the invention.

[0081] Therefore, although specific embodiments of the invention and examples of its application have been described herein for illustrative purposes, various equivalent modifications are possible within the scope of the invention, as will be recognized by those skilled in the art. The teachings provided herein can be applied to other apparatuses and methods, and not only to the embodiments described above and shown in the accompanying drawings. Accordingly, the scope of the invention should be determined according to the appended claims.

Claims

1. A method for controlling the weld penetration profile on a workpiece having an outer region, an inner region, and one or two open conduit ends, wherein the inner region is sealable, the method comprising the steps of: Energy is applied to the outer region of the workpiece using a welding machine to create a weld pool; The workpiece is welded through, such that the weld pool spans between the outer region and the inner region; Keep the welding machine in a stationary position; The workpiece is rotated relative to the welding machine using a lathe. A seal is placed at the end of the conduit, oriented close to the opening, to form a significantly sealed internal area that prevents protective gas from escaping through the conduit end. A protective gas is applied to the internal region at a pressure that provides limiting weld penetration, wherein the protective gas will escape only through the pre-welded interface of the workpiece, wherein the workpiece includes at least a portion of a flow meter; and Measure the pressure of the protective gas within the internal region; Compare the measured pressure with the predetermined pressure range; If the measured pressure falls outside the predetermined pressure range, the pressure of the protective gas in the internal region is electronically adjusted to the predetermined pressure range solely because gas escapes at a variable rate through the pre-welded boundary as welding progresses, thereby maintaining a constant pressure of the protective gas in the internal region; and Wherein, the force provided by the pressure of the protective gas prevents the weld penetration from exceeding 10% of the workpiece thickness on the surface defining the internal region, wherein the predetermined pressure range is selected based on at least one of the following: conduit thickness, welding position, welding machine type, and selected conduit material; The pressure of the protective gas is between 0.04 psi and 0.245 psi; and Specifically, the solder penetration is prevented from exceeding 0.0625 inches beyond the surface defining the internal region.

2. The method for controlling the weld penetration profile on a workpiece according to claim 1, characterized in that, Includes the following steps: Maintain a constant pressure of the protective gas within the internal region.

3. The method for controlling the weld penetration profile on a workpiece according to claim 1, characterized in that, Includes the following steps: Provides a molten pool for filling metal into metal.

4. The method for controlling the weld penetration profile on a workpiece according to claim 1, characterized in that, The welding is self-fusing.

5. An apparatus (300) for controlling the weld penetration profile on a rotatable workpiece (306), the workpiece having an outer region (336), an inner region (338), and one or two open conduit ends, wherein the inner region is sealable, the apparatus comprising: A welding machine (302) is held in a stationary position and configured to produce a weld joint (334) from the outer region (336) of the workpiece (306), wherein the weld joint (334) penetrates from the outer region (336) of the workpiece (306) into the inner region (338) of the workpiece (306). A seal is positioned close to the end of the conduit opening to form a significantly sealed internal area that prevents the protective gas from escaping through the conduit end. A gas supply (314) in fluid communication with the internal region (338) is configured to provide a protective gas to the internal region (338) of the workpiece (306), wherein the workpiece includes at least a portion of a flow meter, and wherein the pressure of the protective gas provides a force limiting weld penetration; and A pressure gauge (332) communicating with the internal region (338), wherein the pressure gauge (332) is configured to measure the pressure of the protective gas present in the internal region (338); A lathe in which the workpiece (306) is mounted, wherein the lathe is configured to rotate the workpiece (306); The seal (330) is engaged to fluid seal the inner region (338), wherein, when the seal (330) is engaged, if the protective gas supplied by the gas supply (314) is supplied to the inner region (338) at a pressure greater than that of the inner region (338), the protective gas will escape only through the pre-welded joint of the workpiece (306); A valve (328) in fluid communication with the internal region (338) is configured to regulate the pressure of the protective gas within the internal region (338); and A system electronics (400) connected to both the pressure gauge (332) and the valve (328), wherein the system electronics (400) is configured to receive a pressure signal from the pressure gauge (332) and accordingly adjust the valve (328) so as to maintain a constant pressure within the internal region (338) within a predetermined pressure range only due to the gas escaping at a variable rate through the pre-welded interface as welding progresses; and The predetermined pressure range is selected based on at least one of the following: the force provided by the pressure of the protective gas prevents the weld penetration from exceeding 10% of the workpiece thickness on the surface defining the internal region; the force is provided by the pressure of the protective gas. The predetermined pressure range is between 0.04 psi and 0.245 psi; and Specifically, the solder penetration is prevented from exceeding 0.0625 inches beyond the surface defining the internal region.

6. The apparatus (300) for controlling the weld penetration profile on a rotatable workpiece (306) according to claim 5, characterized in that, The welding machine (302) includes a tungsten inert gas welding (GTAW) device.

7. The apparatus (300) for controlling the weld penetration profile on a rotatable workpiece (306) according to claim 5, characterized in that, The welding machine (302) includes a manual arc welding (SMAW) device.

8. The apparatus (300) for controlling the weld penetration profile on a rotatable workpiece (306) according to claim 5, characterized in that, The welding machine (302) includes a gas metal arc welding (GMAW) device.

9. The apparatus (300) for controlling the weld penetration profile on a rotatable workpiece (306) according to claim 5, characterized in that, The welding machine (302) includes at least one of a laser beam welding machine, an electroslag welding machine, a magnetic pulse welding machine, and a friction stir welding machine.

10. The apparatus (300) for controlling the weld penetration profile on a rotatable workpiece (306) according to claim 5, characterized in that, The protective gas includes argon.

11. The apparatus (300) for controlling the weld penetration profile on a rotatable workpiece (306) according to claim 5, characterized in that, The protective gas includes at least one of nitrogen, helium, carbon dioxide, oxygen, hydrogen, nitrogen oxides, sulfur hexafluoride, and dichlorodifluoromethane.

12. The apparatus (300) for controlling the weld penetration profile on a rotatable workpiece (306) according to claim 5, characterized in that, The workpiece (306) comprises alloy steel.

13. The apparatus (300) for controlling the weld penetration profile on a rotatable workpiece (306) according to claim 5, characterized in that, The workpiece (306) includes at least one of steel, stainless steel, aluminum, magnesium, copper, platinum, nickel, carbon, chromium, cobalt, niobium, tungsten, vanadium, zirconium, and molybdenum.

14. The apparatus (300) for controlling the weld penetration profile on a rotatable workpiece (306) according to claim 5, characterized in that, The workpiece (306) includes a conduit.

15. The apparatus (300) for controlling the weld penetration profile on a rotatable workpiece (306) according to claim 5, characterized in that, The workpiece (306) includes a flange.

16. The apparatus (300) for controlling the weld penetration profile on a rotatable workpiece (306) according to claim 5, characterized in that, The workpiece (306) includes at least a portion of the flow meter (5).

17. A method for controlling the weld penetration profile on a portion of an outer region and an inner region of a flow meter, wherein the inner region is sealable, characterized in that, The method includes the following steps: Energy is applied to the outer region of the portion of the flow meter using a welding machine to create a weld pool; The portion of the flow meter is welded through, such that the weld pool spans between the outer region and the inner region; Keep the welding machine in a stationary position; The flow meter portion is rotated relative to the welding machine using a lathe; A protective gas is applied to the internal region at a pressure that provides a limiting force for weld penetration, wherein the protective gas will escape only through the pre-welded junction of the portion of the flow meter; Maintain a constant pressure of the protective gas within the internal region, wherein the pressure of the protective gas is between 0.04 psi and 0.245 psi; The pressure of the protective gas within the internal region is measured to generate the measured pressure; The measured pressure is compared with a predetermined pressure range; If the measured pressure falls outside the predetermined pressure range, the pressure of the protective gas in the inner region will be adjusted to the predetermined pressure range only because the gas escapes at a variable rate through the pre-welded boundary as welding progresses. The force provided by the pressure of the protective gas prevents the weld from penetrating beyond 10% of the thickness of the portion of the flow meter defining the internal region. Specifically, the solder penetration is prevented from exceeding 0.0625 inches beyond the surface defining the internal region; A second protective gas is supplied to the weld pool through a gas pipeline connected to the welding machine. The second protective gas and the protective gas have different compositions.

Images