Welding repair of steel alloy components

Abstract

This invention provides an exemplary welding repair system and method for steel alloy articles. [Solution] A method for repairing a steel alloy article is provided. The method includes using a first welding process to deposit a first welded repair layer 106-1 over the surface of a steel alloy article 100 to be repaired. The first welded repair layer forms a heat-affected zone (HAZ) 110 in the steel alloy article beneath the surface. The method also includes using a second welding process to temper the heat-affected zone by depositing a second welded repair layer 106-2 over the first welded repair layer. The first welding technique differs from the second welding process in that it induces a lower heat input to the steel alloy article than the second welding process, and the thickness of the first welded repair layer is thinner than the thickness of the second welded repair layer.

Description

Technical Field

[0001] The field of the present disclosure generally relates to welding processes, and more particularly, to welding repair systems and methods for steel alloy components.

Background Art

[0002] Chromium-molybdenum (CrMo) and chromium molybdenum vanadium (CrMoV) steel alloys are commonly used in a variety of components within turbines, turbomachinery, and other industrial equipment. Components fabricated from CrMo and CrMoV steel alloys generally exhibit a long service life, but over time, wear, erosion, corrosion, impact, fatigue, and / or overstress can occur, and depending on the severity of the component damage, repair and / or replacement of the component may be required. The repair of such components typically involves at least some welding, where the damaged portion of the component is removed and a structural member is welded in place or a weld is built at the location of the damaged portion of the component.

[0003] Depending on the size of the repair area and / or the thickness of the material adjacent to the repair location, the heat input from the welding process can create a hardened heat affected zone (HAZ). The HAZ is the area adjacent to the repair area of the component that can undergo a change in its properties as a result of being exposed to relatively high temperatures during the welding process. Depending on the severity of the exposure to high temperatures, the quality and / or functionality of the repaired component can be impaired within the HAZ area.

[0004] To facilitate the reduction of HAZ effects, at least some known welding processes utilize post-repair tempering. For example, in some known welding processes, the entire article undergoes heat treatment after the completion of the weld repair. However, this tempering technique may be limited because furnaces may not be readily available on-site and / or the size of the furnace may not be suitable for accommodating the article. Thus, depending on the article being repaired, extensive disassembly of the article and / or the associated machinery in which the article is used may be required. Such disassembly is labor-intensive and costly and / or can extend the downtime of the article and / or the machinery. Furthermore, heat treatment may introduce distortion into the article, making reassembly of the article and / or rejoining the article with the machinery difficult.

[0005] Another known tempering method, torch tempering, involves performing localized heat treatment after welding without removing the workpiece from the machine for heat treatment. Torch tempering uses a torch to heat-treat the workpiece, which presents the risk of an open flame. Furthermore, the heat input in torch tempering is difficult to control, which can make it difficult to control the quality of tempering and / or repair. In addition, the workpiece may warp from the heat treatment during torch tempering, which may impair the functionality of the workpiece and the machine.

[0006] Another known tempering method uses temperbead tempering to temper the HAZ area. In typical temperbead tempering, a first layer of weld repair is applied, and a second layer with increased heat input is applied on top of the first layer to temper the HAZ in the substrate. However, the deposition of the second layer requires precise control to reduce the scattering band in temperbead tempering (see, for example, curve 202tb in Figure 2, described later). Furthermore, the relatively high heat input from the second layer for tempering can distort the material and impair the functionality of the material and machine. In addition, the process can be labor-intensive and / or costly because the height of the first layer of temperbead can often be manually ground before the second layer can be deposited.

[0007] Therefore, there is a need for improved welding processes that are cost-effective and reliable, and that facilitate reducing the risk of material damage in the HAZ area. [Overview of the project]

[0008] In one embodiment, a method for repairing a steel alloy article is provided. The method includes using a first welding process to deposit a first weld repair layer over the surface of the steel alloy article to be repaired. The first weld repair layer forms a heat-affected zone (HAZ) in the steel alloy article beneath the surface. The method also includes using a second welding process to temper the heat-affected zone by depositing a second weld repair layer over the first weld repair layer. The first welding technique differs from the second welding process in that it induces a lower heat input into the steel alloy article than the second welding process, and the thickness of the first weld repair layer is thinner than the thickness of the second weld repair layer.

[0009] In another embodiment, a method for repairing a steel alloy article is provided. The method comprises depositing a first weld repair layer over the surface of the steel alloy article using a gas tungsten arc welding (GTAW) technique. The first weld repair layer forms a heat-affected zone in the steel alloy article beneath the surface. The method also comprises tempering the heat-affected zone by depositing a second weld repair layer over the first weld repair layer using a gas metal arc welding (GMAW) technique. The GTAW technique has a lower heat input than the GMAW technique, and the thickness of the first weld repair layer is thinner than the thickness of the second weld repair layer.

[0010] These and other features, aspects, and advantages of this disclosure will be better understood by reading the following detailed description with reference to the accompanying drawings. In the accompanying drawings, similar reference numerals represent similar parts throughout the drawings. [Brief explanation of the drawing]

[0011] [Figure 1] This is a schematic partial cross-sectional view of an exemplary restored steel alloy article. [Figure 2] This is a graph showing the hardness of an exemplary restored steel alloy article. [Figure 3A] This is a flowchart illustrating an exemplary method for repairing steel alloy articles. [Figure 3B] This is a schematic diagram of an exemplary embodiment of the method shown in Figure 3A. [Figure 3C] This is a schematic diagram of an exemplary pattern that can be used for weave bead welding. [Modes for carrying out the invention]

[0012] This disclosure describes exemplary weld repair systems and methods for steel alloy articles. Steel alloy articles made from materials such as chromium-molybdenum (CrMo) and / or chromium-molybdenum vanadium (CrMoV) are commonly used, for example, in turbine components such as steam or gas turbines, turbomachinery, or other industrial equipment. By repairing damaged areas of such components using welding, a heat-affected zone (HAZ) may be created in the substrate of the steel alloy article. The welding processes described herein utilize tempering to facilitate the improvement of the physical properties in the HAZ area and to facilitate the reduction of the possibility that the material in the HAZ area may be damaged as a result of exposure to the heat used in the weld repair process.

[0013] Figure 1 is a schematic diagram of a partial cross-section of an exemplary steel alloy article 100 that has been repaired via a welding process. In one embodiment, article 100 is a component used in a turbine. Furthermore, in an exemplary embodiment, article 100 includes a base material 102 on which a weld 104 is fabricated, i.e., on which multiple material layers are deposited during the welding process as described herein. The weld 104 is fabricated to a size and thickness that facilitates the restoration of article 100 to its original dimensions after the damaged portion is removed from article 100 to be repaired. The weld 104 includes one or more weld repair layers 106 deposited on the surface 108 of the base material 102 such that at least a first weld repair layer 106-1 is deposited directly on the surface 108 of the base material 102, and at least a second weld repair layer 106-2 is deposited on at least a portion of the first weld repair layer 106-1. The deposition of the first weld repair layer 106-1 may generate a HAZ 110 in the substrate 102 in areas below the surface 108 and adjacent to the repair area.

[0014] Figure 2 is a graph showing exemplary hardness variation of HAZ110 (shown in Figure 1) under various conditions, where hardness is plotted as a function of distance from the fusion line 108. The fusion line refers to the interface formed between the weld repair area and the substrate of article 100 (shown in Figure 1). After welding is initiated and after its completion, the hardness of the substrate 102 increases in HAZ110 (see curve 202-w). This increase in hardness can adversely affect the physical properties of the substrate 102, including, but not limited to, increasing the brittleness of the substrate 102 and / or increasing the likelihood of future cracking of the substrate 102 within that area. Furthermore, the increase in hardness may reduce the overall effectiveness of the weld repair.

[0015] As mentioned above, post-repair tempering can facilitate the reduction of hardness within the HAZ110, and thus facilitate the relaxation of stress induced by the welding repair process. Furthermore, post-repair tempering can also promote a reduction in the overall dimensions of the HAZ (see curve 202-sr). However, as mentioned above, known tempering processes can be limited, labor-intensive, costly, and / or time-consuming.

[0016] The systems and methods described herein address problems in known weld repair methods. The inventions described herein offer the unexpected result of making it easier to improve both the overall weld repair speed and the overall quality of the repaired articles. Therefore, the systems and methods described herein are advantageous in providing a fast weld repair process because post-weld heat treatment is unnecessary, thereby saving time and cost from, for example, the disassembly and reassembly of machinery. Furthermore, it becomes easier to reduce and / or eliminate distortion from post-weld heat treatment, and as a result, it becomes easier to reduce the difficulty of reassembling and maintaining the functionality of articles and machinery. Further localized tempering, such as torch tempering, is not required as it also eliminates the risks associated with open flames and distortion in the article from the relatively high heat input in localized tempering.

[0017] The systems and methods described herein may utilize different welding techniques when depositing the first and at least second layers of the weld repair. The first weld repair layer deposited via the first welding technique is formed to a relatively thin thickness and therefore involves a relatively low heat input. As a result, the first weld repair layer produces a HAZ110 with relatively small dimensions on the substrate compared to one produced using known welding processes. Thus, the amount of heat that needs to be transferred from the second layer to the substrate to temper the HAZ110 is easily reduced compared to known welding processes. In exemplary embodiments, the second layer and any subsequent layers are subjected to a second welding technique that generates a higher heat input and is more efficient than the first welding technique. Thus, the second layer and the second welding technique facilitate the tempering of the HAZ110 while increasing the overall repair rate.

[0018] The systems and methods described herein offer the advantage of a relatively thin first weld repair layer without requiring interpass machining, as is required in at least some known temper bead methods. This facilitates reductions in overall repair costs, labor costs, and repair duration. As a result, the scattering band 204 is reduced and easily positioned close to the fusion line (as shown, for example, in the curve 202-sr of the stress-relaxed article). Because the heat input from depositing the first layer of weld repair is relatively small, the strain from the heat input is also relatively small compared to known weld repair methods, thereby facilitating a reduction in the adverse effects of the weld repair process on the functionality of the associated article and / or machine. The systems and methods described herein are also advantageous for using commercially available filler materials for weld repair, thereby facilitating cost reductions by sourcing filler materials compared to the costs associated with known torch tempering methods.

[0019] Figures 3A and 3B illustrate exemplary methods 300 for repairing steel alloy articles. More specifically, Figure 3A is a flowchart of exemplary weld repair method 300. In exemplary embodiments, method 300 includes depositing a first weld repair over the surface of a steel alloy article using a first welding technique 302. Depositing the first weld repair creates a heat-affected zone (HAZ) in the steel alloy article beneath the surface. Method 300 also includes tempering the HAZ by depositing a second weld repair layer on top of the first weld deposit layer using a second welding technique 304. The first welding technique uses a lower heat input to induce heat in the article compared to the second welding technique. The thickness of the first weld repair layer is thinner than the thickness of the second weld repair layer.

[0020] Figure 3B shows an exemplary embodiment of Method 300. In the exemplary embodiment, Method 300 includes depositing a first weld repair layer 302. In some embodiments, the article 100 is prepared for welding before the first weld repair layer is deposited 302. For example, a surface 108 of the article 100 adjacent to the defect may be ground and / or drilled to form a drill 350, and the surface 108 in contact with the drill 350 is cleaned to prepare the surface 108 for depositing filler material. In depositing the first weld repair layer 302, a first welding technique is used. For example, in one embodiment, the first welding technique is a gas tungsten arc welding (GTAW) process. In other embodiments, other welding techniques, such as plasma arc welding (PAW) processes, may be used, but are not limited to, in order to enable the system and method to operate as described herein. In the GTAW technique, the heat input is relatively low, and the thickness 351-1 of the deposited first weld repair layer 106-1 is relatively thin.

[0021] Relatively low heat input is advantageous for reducing the overall size of the HAZ 110 due to the heat generated during the deposition of the first weld repair layer 106-1. The relatively thin first weld repair layer 106-1 is also advantageous for facilitating heat transfer to the HAZ 110 during the deposition of the second weld repair layer for tempering the HAZ 110. When depositing the first weld repair layer 106-1, the deposition can begin in the central region 354 of the drilling 350 and proceed toward the outer perimeter 356 of the drilling 350. Starting from the central region 354 allows the welding torch to access the relatively narrow drilling 350 relatively easily. In some embodiments, the deposition of the first weld repair layer begins from the outer perimeter 356 of the drilling 350 toward the central region 354 of the drilling 350. Deposition starting from the central region 354 and proceeding toward the outer perimeter 356, or starting from the outer perimeter 356 toward the central region 354, facilitates heat distribution while reducing hot spots. Welding toward the outer perimeter 356 may be performed alternately between different deposition passes. For example, if the welded repair is deposited from the central region 354, in the first pass the weld may proceed toward the first side 356-1, and in the second pass the weld may proceed toward the second side 356-2 from the central region 354, i.e., toward the side of the repair opposite to the first side 356-1 in the second pass. The process should be repeated alternately between both sides of the repair area to facilitate the substantially uniform induction of heat input into the drilling 350.

[0022] In exemplary embodiments, the deposition of the first weld repair layer can be easily controlled by controlling the thickness of the first weld repair layer and the heat input from the weld. The heat input can be controlled by controlling the voltage and / or amperage of the current used for welding, and / or the speed of the welding head during welding. The exemplary thickness of the first weld repair layer 106 may be in the range of about 0.5 mm to about 1.5 mm.

[0023] In an exemplary embodiment, method 300 also includes depositing a second weld repair layer 358 using a second welding technique different from the first welding technique. An exemplary second welding technique is a gas metal arc welding (GMAW) process. Without departing from the systems and methods described herein, other welding techniques such as shielded metal arc welding (SMAW) or flux cored arc welding (FCAW) can be used. Other exemplary combinations of the first and second welding techniques may be laser welding as the first welding technique and SMAW as the second welding technique, or SMAW as the first welding technique and submerged arc welding (SAW) as the second welding technique. The first and second welding techniques are not limited to these examples. The first and second welding techniques are selected such that the heat input from the second welding technique is greater than the heat input from the first welding technique. The heat induced from the deposition of the second weld repair layer 106-2 penetrates the first weld repair layer 106-1 and facilitates the tempering of the HAZ in the base material 102. The thickness 351-2 of the second weld repair layer 106-2 is thicker than the first weld repair layer 106-1. The increase in the thickness of the second weld repair layer 106-2 is possible because the efficiency possible using the second welding technique is higher compared to the efficiency possible with the first welding technique with respect to the deposition rate of the weld repair. In depositing the second weld repair layer 358, the heat input and the thickness of the second weld repair layer are controlled. For example, in an exemplary embodiment, the heat input from depositing the second weld repair layer 358 is controlled by controlling the voltage and / or amperage of the current and / or the traverse speed of the welding head. An exemplary range of the thickness of the second weld repair layer is from about 1 mm to about 3.5 mm. The heat input in depositing the second weld repair layer 358 is controlled to facilitate the tempering of the HAZ 110 in the base material without creating an additional HAZ in the base material.

[0024] The fact that the thickness of the first welding repair layer is thinner than that of the second welding repair layer is advantageous for annealing the HAZ in the base material by the second welding repair layer. Without the initial deposition of the thinner first welding repair layer, the heat input from the third welding repair layer is insufficient to properly penetrate the relatively thick second welding repair layer to anneal the underlying HAZ. For example, if the thinner first welding repair layer is formed with a thickness of about 1 mm and the material within the HAZ has a thickness of about 3 mm, the heat input from the second welding repair layer is sufficient to penetrate the first welding repair layer and anneal the HAZ. However, if the thinner first welding repair layer is not deposited first, the second welding repair layer is formed with a thickness of 3 mm, and thus the thickness of the material within the HAZ increases to about 5 mm due to the increased heat input during the deposition of the second welding repair layer. Therefore, the heat input from the third welding repair layer, i.e., the subsequent welding repair layer, may be insufficient to penetrate a total thickness of about 8 mm to anneal the HAZ.

[0025] In an exemplary embodiment, in depositing the second welding repair portion 358, weave bead welding is used. In weave bead welding, weaving in welding, or welding in a weaving pattern, the welding head moves left and right during welding. FIG. 3C shows an exemplary weaving pattern 380. Alternatively, any other weaving pattern such as a triangular pattern or a curved pattern may be used for welding. During weaving, the welding head remains in a relative position for an increased period compared to other welding patterns, and as a result, the heat input by the weave bead welding is likely to increase. Therefore, annealing of the HAZ in the base material becomes easier with improved efficiency. As described above, the heat input from depositing the second welding repair layer 358 is controlled by controlling the voltage and / or amperage of the current, and / or the traverse speed of the welding head. For weaving, the traverse speed 382 (see FIG. 3C) of the welding head can be adjusted by adjusting the width 384 of the weaving pattern and / or by adjusting the moving speed of the welding head.

[0026] In exemplary embodiments, in depositing the second weld repair layer 358, the deposit may begin in the central region 354 of the excavation 350 and proceed toward the outer perimeter 356 of the excavation 350. In some embodiments, the deposit of the second weld repair layer begins from the outer perimeter 356 of the excavation 350 to the central region 354 of the excavation 350. Deposits that begin from the central region 354 toward the outer perimeter 356, or from the outer perimeter 356 toward the central region 354, facilitate substantially uniform heat distribution. As described above, welding of the outer perimeter 356 may be performed alternately between different deposit passes.

[0027] In exemplary embodiments, method 300 further includes depositing at least a third weld repair layer over a second weld repair layer 360. The same welding process used to deposit the second weld repair layer can be used to deposit the third weld repair layer 106-3. In some embodiments, a different welding technique can be used than the one used to deposit the second weld repair layer. Using the same welding technique for depositing the second weld repair layer and subsequent weld repair layers saves the effort and cost associated with switching between different welding techniques and equipment. When depositing the third weld repair layer, the heat input from depositing the third weld repair layer is controlled by controlling the voltage and / or amperage of the current, and / or the traverse speed of the welding head. The heat input from depositing the third layer is controlled to a level such that the depositing of the third layer does not introduce an additional HAZ into the substrate.

[0028] In exemplary embodiments, when depositing the third weld repair layer, the deposit may begin in the central region 354 of the excavation 350 and proceed toward the outer perimeter 356 of the excavation 350. In some embodiments, the deposit of the third weld repair layer begins from the outer perimeter 356 of the excavation toward the central region 354 of the excavation. Deposits that begin from the central region 354 toward the outer perimeter 356, or vice versa, facilitate substantially uniform heat distribution. As described above, welding of the outer perimeter 356 may be performed alternately between different deposit passes.

[0029] In exemplary embodiments, method 300 further includes depositing a subsequent weld repair layer 370 on top of a previous weld repair layer. For example, a fourth layer may be deposited on top of a third layer, a fifth layer on top of a fourth layer, and so on. The weld repair layers are deposited in the drilling 350 until the defect is repaired, filling, for example, the cavity or drilling 350 created from the removal of the defect. The deposit of the fourth layer and subsequent layers can be the same welding technique as the second welding technique, such as GMAW. In some embodiments, a different welding technique can be used when depositing the fourth layer and subsequent layers than the second welding technique. The welding technique may be different from or the same as the one previously used when depositing one of the fourth layer and subsequent layers from another layer.

[0030] In exemplary embodiments, when depositing the fourth weld repair layer and subsequent weld repair layers, the deposit may begin in the central region 354 of the drilling 350 and proceed toward the outer perimeter 356 of the drilling 350. In some embodiments, the deposit of the subsequent weld repair layer begins from the outer perimeter 356 of the drilling toward the central region 354 of the drilling. Deposits that begin from the central region 354 toward the outer perimeter 356, or vice versa, facilitate substantially uniform heat distribution. As described above, welding of the outer perimeter 356 may be performed alternately between different deposit passes.

[0031] To limit the introduction of HAZ from subsequent weld repair layers, subsequent weld repair layers are deposited only on top of the immediately preceding weld repair layer. For example, the second weld repair layer 106-2 is deposited only on top of the first weld repair layer 106-1, the third weld repair layer 106-3 is deposited only on top of the second weld repair layer 106-2, and so on.

[0032] The third weld repair layer and subsequent weld repair layers facilitate filling of the excavation 350. Therefore, depositing the third weld repair layer and subsequent weld repair layers can be done using stringer bead welding or welding in a stringer pattern, where the welding head moves forward without moving from side to side, thereby increasing the deposition rate. In some embodiments, weave bead welding can be used when depositing the third layer and subsequent layers. In other embodiments, the pattern used in the welding process may differ from layer to layer.

[0033] In exemplary embodiments, the filler material for weld repairs has a relatively low carbon content, thereby reducing the likelihood of hardening due to heat input from subsequently deposited layers and providing relatively good ductility when applied in the as-welded state. As a result, the likelihood of the previous layer hardening due to the deposition of the second and subsequent layers is reduced, and tempering of the weld repair is not required. The relatively low carbon filler also provides a balance between strength and room temperature ductility. Exemplary fillers are 80S-B3L [low carbon 2.25Cr 1.0Mo] containing about 2.25% Cr and about 1.0% Mo by weight, or 70S-B2L [low carbon 1.25Cr 0.5Mo] containing about 1.25% Cr and about 0.5% Mo by weight. 80S-B3L may be used at higher operating temperatures than 70S-B2L.

[0034] Any of the welding techniques described herein can be applied manually by a welding machine or automatically by a robot. In some embodiments, some processes of the methods described herein are performed manually, while other processes are performed by a robot.

[0035] At least one technical effect of the systems and methods described herein is to (a) deposit a first weld repair layer on the surface of an article using a first welding technique and deposit a second weld repair layer on the first weld repair layer using a second welding technique, wherein the first welding technique induces a lower heat input to the article being repaired than the second welding technique induces, and the thickness of the first weld repair layer is thinner than that of the second weld repair layer; (b) use GTAW when depositing the first weld repair layer and GMAW when depositing the second weld repair layer; and (c) use weave bead welding when depositing the second weld repair layer.

[0036] The systems and methods described herein are advantageous in providing weld repairs that are performed with improved speed and quality while facilitating a reduction in the overall cost of repairs. Because post-weld heat treatment is unnecessary, the reduction and / or elimination of distortion caused by post-weld heat treatment is facilitated. Furthermore, localized tempering, such as torch tempering, is unnecessary, thus eliminating the risks associated with open flames and distortion from relatively high heat input. Additionally, the need for inter-pass machining, common in at least some known temper bead methods, is eliminated, thereby reducing the cost and time of repairs. The systems and methods described herein utilize commercially available filler materials, thereby facilitating cost reductions by eliminating the need to procure filler materials.

[0037] Further aspects of the present invention are provided by the subject matter of the following clauses.

[0038] A method for repairing a steel alloy article, comprising: using a first welding process to deposit a first weld repair layer over the surface of the steel alloy article to be repaired, wherein the first weld repair layer forms a heat-affected zone (HAZ) in the steel alloy article beneath the surface; and using a second welding process to temper the heat-affected zone by depositing a second weld repair layer over the first weld repair layer, wherein the first welding technique induces a lower heat input to the steel alloy article than the second welding process, and the thickness of the first weld repair layer is thinner than the thickness of the second weld repair layer.

[0039] The method according to the preceding clause, further comprising depositing the first weld repair layer using a gas tungsten arc welding (GTAW) process.

[0040] The method according to any one of the preceding clauses, further comprising depositing the second weld repair layer using a gas metal arc welding (GMAW) process.

[0041] The method according to any one of the preceding clauses, further comprising depositing the second weld repair layer while using a weaving pattern.

[0042] The method according to any one of the preceding clauses, further comprising controlling the deposition of the second weld repair layer by controlling the thickness of the second weld repair layer and the heat input induced through the second welding process.

[0043] The method according to any one of the preceding clauses, further comprising controlling the deposition of the first weld repair layer by controlling the thickness of the first weld repair layer and the amount of heat input induced through the first welding process.

[0044] The first weld repair layer and the second weld repair layer each include 80S-B3L, as described in any one of the preceding clauses.

[0045] The first weld repair layer and the second weld repair layer each include 70S-B2L, as described in any one of the preceding clauses.

[0046] The method according to any one of the preceding clauses, further comprising depositing the second weld repair layer by starting from the central region of the drilling in the steel alloy article and welding toward the outer periphery of the drilling, and / or depositing the second weld repair layer by starting from the outer periphery of the drilling and extending toward the central region of the drilling.

[0047] The method according to any one of the preceding clauses, further comprising depositing the second weld repair layer alternately between the first side and the second side of the outer perimeter of the excavation, wherein the first side is on the opposite side of the second side of the outer perimeter.

[0048] The method according to any one of the preceding clauses, further comprising depositing the first weld repair layer starting from the central region of the drilling in the steel alloy article and welding toward the outer periphery of the drilling, and / or depositing the first weld repair layer starting from the outer periphery of the drilling and toward the central region of the drilling.

[0049] The method according to any one of the preceding clauses, further comprising depositing the first weld repair layer alternately between a first side and a second side of the outer periphery of the excavation, wherein the first side is on the opposite side of the second side of the outer periphery.

[0050] The method according to any one of the preceding clauses, further comprising depositing a third weld repair layer over the second weld repair layer using the second welding process.

[0051] The method according to any one of the preceding clauses, further comprising depositing the third weld repair layer in a stringer pattern.

[0052] The method according to any one of the preceding clauses, further comprising depositing the third weld repair layer starting from the central region of the drilling in the steel alloy article and welding toward the outer periphery of the drilling, and / or depositing the third weld repair layer starting from the outer periphery of the drilling and toward the central region of the drilling.

[0053] The method according to any one of the preceding clauses, further comprising depositing a subsequent weld repair layer over a previous weld repair layer using the second welding process described above.

[0054] The method according to any one of the preceding clauses, further comprising depositing the subsequent weld repair layer over the preceding weld repair layer in a stringer pattern using the second welding process.

[0055] The method according to any one of the preceding clauses, further comprising depositing the subsequent weld repair layer only on top of the immediately preceding weld repair layer.

[0056] A method for repairing a steel alloy article, comprising: depositing a first weld repair layer over the surface of the steel alloy article using a gas tungsten arc welding (GTAW) technique, wherein the first weld repair layer forms a heat-affected zone in the steel alloy article beneath the surface; and tempering the heat-affected zone by depositing a second weld repair layer over the first weld repair layer using a gas metal arc welding (GMAW) technique, wherein the GTAW technique has a lower heat input than the GMAW technique, and the thickness of the first weld repair layer is thinner than the thickness of the second weld repair layer.

[0057] Exemplary embodiments of systems and methods for weld repair are described in detail above. The systems and methods are not limited to the specific embodiments described herein; rather, the components of the systems and / or the operations of the methods may be used separately and independently of other components and / or operations described herein. Furthermore, the components and / or operations described may also be defined or used in combination with other systems, methods, and / or devices, and are not limited to the systems described herein.

[0058] Throughout this specification and the claims, the approximation language can be applied to modify any quantitative expression that can vary to a reasonable extent without altering the fundamental function of the expression. Thus, values ​​modified by one or more terms such as “about,” “approximately,” and “substantially” are not limited to the exact value stated. In at least some examples, the approximation language may correspond to the precision of the instrument used to measure the value. Herein, and throughout this specification and the claims, limitations on ranges are interchangeable and / or substitutable, and unless the context or wording specifically indicates otherwise, such ranges are identified and include all subranges encompassed therein. “Approximately” and / or “substantially,” applied to specific values ​​within a range, may indicate + / - 10% of the stated value, unless applied to the values ​​at both ends and particularly dependent on the precision of the instrument used to measure the value.

[0059] Where used herein, elements or steps listed in the singular and following the word “a” or “an” should be understood not to exclude multiple elements or steps unless such exclusions are explicitly listed. Furthermore, references to “examples” or “an example” in this disclosure are not intended to be construed as excluding the existence of additional examples that also incorporate the listed features. Moreover, wherever the terms “includes,” “including,” “has,” “contains,” and their variations are used herein, such terms are intended to be as inclusive as the term “comprises” as open transitional terms, without excluding additions or other elements.

[0060] Certain features of various embodiments of the present invention may be shown in some drawings and not in others, but this is merely for convenience. According to the principles of the present invention, any feature in the drawings may be referenced and / or claimed in combination with any feature in any other drawing.

[0061] This specification discloses the invention in best mode and uses examples to enable those skilled in the art to practice the invention, including the fabrication and use of any device or system, and the implementation of any incorporated method. The patentable scope of the invention is defined by the claims and may include other examples that will be conceived by those skilled in the art. Such other examples are intended to be within the claims if they have structural elements that are not different from the language of the claims, or if they include equivalent structural elements that are substantially different from the language of the claims. [Explanation of Symbols]

[0062] 100 Steel alloy articles 102 Base material 104 Welded section 106-1 First weld repair layer 106-2 Second weld repair layer 106-3 Third Weld Repair Layer 108 Surface / fusion line 110 Heat-Affected Zone (HAZ) 202-tb curve 202-w curve 202-sr curve 204 Scattering Band 300 ways 350 drilling 351-1 Thickness 351-2 Thickness 354 Central area 356 Outer perimeter 380 Weaving Patterns 382 Traverse Speed 384 width

Claims

1. A method (300) for repairing a steel alloy article (100), A first welding process is used to deposit a first weld repair layer (106-1) over the surface of the steel alloy article (100) to be repaired (302), wherein the first weld repair layer (106-1) forms a heat-affected zone (HAZ) (110) in the steel alloy article (100) below the surface. Tempering the heat-affected zone (110) (304) by depositing a second weld repair layer (106-2) over the first weld repair layer (106-1) (358), wherein the first welding technique, unlike the second welding process, induces a lower heat input to the steel alloy article (100), and the thickness (351-1) of the first weld repair layer (106-1) is thinner than the thickness (351-2) of the second weld repair layer (106-2). Method (300), including the method (300).

2. Depositing the first weld repair layer (106-1) (302) is, Depositing the first weld repair layer (106-1) using a gas tungsten arc welding (GTAW) process. The method according to claim 1, further comprising (300).

3. Depositing the second weld repair layer (106-2) (358) Depositing the second weld repair layer (106-2) using a gas metal arc welding (GMAW) process. The method according to claim 1, further comprising (300).

4. The method according to claim 1 (300), wherein depositing the second weld repair layer (106-2) (358) further comprises using a weaving pattern while depositing the second weld repair layer (106-2).

5. The method according to claim 1 (300), wherein the deposition of the second weld repair layer (106-2) (358) further comprises controlling the deposition of the second weld repair layer (106-2) by controlling the thickness (351-2) of the second weld repair layer (106-2) and the heat input induced through the second welding process.

6. The method according to claim 1 (300), wherein the deposition of the first weld repair layer (106-1) (302) further comprises controlling the deposition of the first weld repair layer (106-1) by controlling the thickness (351-1) of the first weld repair layer (106-1) and the amount of heat input induced through the first welding process.

7. The method according to claim 1 (300), wherein the first weld repair layer (106-1) and the second weld repair layer (106-2) each contain 80S-B3L.

8. The method according to claim 1 (300), wherein the first weld repair layer (106-1) and the second weld repair layer (106-2) each contain 70S-B2L.

9. Depositing the second weld repair layer (106-2) (358) Depositing the second weld repair layer (106-2) starting from the central region (354) of the excavation (350) in the steel alloy article (100) and welding toward the outer periphery (356) of the excavation (350), and / or Starting from the outer periphery (356) of the excavation (350), the second weld repair layer (106-2) is deposited up to the central region (354) of the excavation (350). The method according to claim 1, further comprising (300).

10. Depositing the second weld repair layer (106-2) (358) The excavation (350) is arranged alternately between the first side (356-1) and the second side (356-2) of the outer circumference (356), wherein the first side (356-1) is on the opposite side of the second side (356-2) of the outer circumference (356). The method according to claim 9 (300), further comprising:

11. Depositing the first weld repair layer (106-1) (302) is, Depositing the first weld repair layer (106-1) starting from the central region (354) of the excavation (350) in the steel alloy article (100) and welding toward the outer periphery (356) of the excavation (350), and / or Starting from the outer periphery (356) of the excavation (350), deposit the first weld repair layer (106-1) up to the central region (354) of the excavation (350), and optionally, The excavation (350) is arranged alternately between the first side (356-1) and the second side (356-2) of the outer circumference (356), wherein the first side (356-1) is on the opposite side of the second side (356-2) of the outer circumference (356). The method according to claim 1, further comprising (300).

12. The method according to claim 1 (300), further comprising depositing a third weld repair layer (106-3) over the second weld repair layer (106-2) using the second welding process (360).

13. Depositing the third weld repair layer (106-3) (360) is, Deposit the third weld repair layer (106-3) using a stringer pattern. The method according to claim 1, further comprising (300).

14. Depositing the third weld repair layer (106-3) (360) is, Depositing the third weld repair layer (106-3) starting from the central region (354) of the drilling (350) in the steel alloy article (100) and welding toward the outer periphery (356) of the defect, and / or Starting from the outer periphery (356) of the excavation (350), deposit the third weld repair layer (106-3) up to the central region (354) of the excavation (350), and optionally, The excavation (350) is arranged alternately between the first side (356-1) and the second side (356-2) of the outer circumference (356), wherein the first side (356-1) is on the opposite side of the second side (356-2) of the outer circumference (356). The method according to claim 1, further comprising (300).

15. Using the second welding process described above, a subsequent weld repair layer is deposited over the previous weld repair layer (370), and optionally, Using the second welding process described above, the subsequent weld repair layer is deposited over the previous weld repair layer in a stringer pattern, and / or The subsequent weld repair layer is deposited only on top of the immediately preceding weld repair layer. The method according to any one of claims 1 to 14, further comprising (300).

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