A welding method for nickel-based alloy composite plates

Abstract

This invention discloses a welding method for a nickel-based alloy composite plate, the nickel-based alloy composite plate comprising a substrate layer and a nickel-based alloy composite layer, wherein a transition layer is provided at the interface between the substrate layer and the nickel-based alloy composite layer; wherein: a trapezoidal bevel is machined on the welding cross-section of the nickel-based alloy composite plate corresponding to the position of the substrate layer; a U-shaped bevel is machined on the welding cross-section of the nickel-based alloy composite plate corresponding to the position of the transition layer; no bevel is machined on the welding cross-section of the nickel-based alloy composite plate corresponding to the position of the nickel-based alloy composite layer; a nickel-based alloy welding wire matching the nickel-based alloy composite layer is used to weld the nickel-based alloy composite layer using single tungsten inert gas welding to form a composite layer weld; a nickel-based alloy welding wire matching the nickel-based alloy composite layer is used to weld the transition layer using single tungsten inert gas welding to form a transition layer weld; the substrate layer is welded to form a substrate layer weld, wherein a double tungsten inert gas welding is used to weld the first weld pass of the substrate layer.

Description

Technical Field

[0001] This invention relates to a welding method, and more particularly to a welding method for composite plates. Background Technology

[0002] Nickel-based alloy composite plates contain two metals with drastically different compositions and properties, requiring multi-layer, multi-pass welding for connection. This involves dividing the weld into a cladding layer, transition layer, and base layer, each welded separately. In certain industrial applications, such as the final sealing welding of small pressure vessels and oil and gas pipelines, limited operating space necessitates single-sided welding starting from the cladding layer. Because nickel-based alloys have very high contents of alloying elements like Cr, Ni, and Mn, the carbon steel weld adjacent to the nickel-based alloy is highly susceptible to modification due to the incorporation of these elements, resulting in a significant deterioration in toughness. Therefore, controlling the weld toughness of nickel-based alloy composite plates under this welding sequence is challenging. The current main industrial solution is to use nickel-based alloy welding wire for the entire weld seam. However, this significantly increases the amount of nickel-based alloy welding wire used, raising welding costs and reducing the overall structural strength of the welded joint.

[0003] The paper "Additive manufacturing of functionally graded transition joints between ferritic and austenitic alloys" reported the deterioration of weld microstructure and properties when nickel-based alloys and carbon steel welding materials were mixed in a certain proportion. Due to the mutual dilution of the two welding materials, the mixed weld bead would harden significantly, thereby reducing the ductility and toughness of the joint.

[0004] Chinese patent document with publication number CN112122783A and publication date of December 25, 2020, entitled "A laser butt welding method for carbon steel-nickel alloy composite plates", discloses that: under the condition of limited construction space and the requirement to weld the cladding layer first, the connection of the cladding layer is achieved by using laser self-fusion or filler wire welding. However, it focuses on the problem that the composite plate cannot be welded on one side under this welding sequence, without paying attention to the performance changes of the mixed weld bead of nickel-based alloy and carbon steel.

[0005] Chinese patent document CN113042895A, published on June 29, 2021, entitled "A Welding Method for a Nickel-Steel Composite Structure," discloses that, in the case of welding the cladding layer first, laser self-fusion welding is used to complete the connection of the cladding layer, and then cold metal transfer welding is used to weld the adjacent weld beads, thereby completing the connection of the nickel-based alloy composite plate under this welding sequence. However, it mainly addresses the problem of reduced corrosion resistance of the cladding layer caused by element migration at the interface between the cladding layer and the base layer, and does not solve the problem of reduced toughness of the mixed weld beads of nickel-based alloy and carbon steel.

[0006] Furthermore, the aforementioned patents all employ laser autofusion or filler wire welding during composite plate welding. These welding methods require extremely high assembly precision for the components, and the equipment is expensive, cumbersome to operate, and difficult to maintain. Summary of the Invention

[0007] One objective of this invention is to provide a welding method for nickel-based alloy composite plates. This method, through the coordinated design of bevel design and welding techniques, effectively reduces the excessive melting of nickel-based alloy elements into the first weld bead of carbon steel, significantly improving weld toughness and achieving a reliable connection of the composite plates. Furthermore, because the optimized method of this invention uses mixed metal filler, it can significantly reduce welding costs while improving the structural strength of the weld.

[0008] To achieve the above objectives, the present invention provides a welding method for a nickel-based alloy composite plate, wherein the nickel-based alloy composite plate comprises a substrate layer and a nickel-based alloy composite layer, and a transition layer is provided at the interface between the substrate layer and the nickel-based alloy composite layer; the welding method includes the following steps:

[0009] A trapezoidal bevel is machined on the welding section of the nickel-based alloy composite plate at the position corresponding to the base material layer; a U-shaped bevel is machined on the welding section of the nickel-based alloy at the position corresponding to the transition layer; no bevel is machined on the welding section of the nickel-based alloy composite plate at the position corresponding to the nickel-based alloy composite layer.

[0010] Using a nickel-based alloy welding wire that matches the nickel-based alloy composite layer, the nickel-based alloy composite layer is welded using single tungsten inert gas welding to form a composite layer weld.

[0011] Using nickel-based alloy welding wire that matches the nickel-based alloy composite layer, the transition layer is welded using single tungsten inert gas welding to form a transition layer weld.

[0012] The substrate layer is welded to form a substrate layer weld, wherein the first weld bead of the substrate layer is welded using double tungsten inert gas welding.

[0013] In this invention, the bevel of the corresponding substrate layer is designed as a trapezoid, which can ensure the operability of the substrate layer weld in the double tungsten inert gas welding.

[0014] Furthermore, in the welding method for nickel-based alloy composite plates described in this invention, the distance b4 between the bottom of the trapezoidal bevel and the interface between the substrate layer and the nickel-based alloy composite layer is 1-2 mm.

[0015] Furthermore, in the welding method for nickel-based alloy composite plates described in this invention, the angle α between the inclined portion of the trapezoidal bevel and the vertical direction is ≥ (1.5b1)°, where b1 represents the distance from the surface of the substrate layer to its interface with the nickel-based alloy composite layer, and its unit parameter is mm.

[0016] Furthermore, in the welding method for nickel-based alloy composite plates described in this invention, the bottom single-side width w2 of the trapezoidal bevel is ≥ (5 + 0.1b1), where b1 represents the distance from the surface of the substrate layer to its bonding interface with the nickel-based alloy composite layer, and its unit parameter is mm.

[0017] Furthermore, in the welding method for nickel-based alloy composite plates described in this invention, the single-side width w1 of the U-shaped groove is 0.5-1mm.

[0018] Furthermore, in the welding method for nickel-based alloy composite plates described in this invention, the radius r of the arc portion of the U-shaped bevel is ≥ 0.5w1, where w1 represents the width of one side of the U-shaped bevel, and its unit parameter is mm.

[0019] In this implementation, due to the poor fluidity of the nickel-based alloy molten pool, in order to ensure good weld formation of the base layer and avoid defects such as incomplete fusion at the bottom of the molten pool, the transition layer weld position should be machined into a U-shaped bevel, wherein the width w1 on the top single side is controlled within the range of 0.5 to 1 mm.

[0020] Furthermore, in the welding method for nickel-based alloy composite plates described in this invention, in the step of welding the nickel-based alloy composite layer using single tungsten inert gas welding: a single-sided welding double-sided forming process is adopted, and the welding voltage is controlled at 10-12V, the welding current at 80-110A, the welding speed at 90-110mm / min, and the wire feeding speed at 0.4-0.8m / min.

[0021] Furthermore, in the welding method for nickel-based alloy composite plates described in this invention, in the step of welding the nickel-based alloy composite layer using single tungsten inert gas welding: the assembly gap w3 = (3-2w1) mm is controlled, where w1 represents the width of one side of the U-shaped groove.

[0022] Furthermore, in the welding method for nickel-based alloy composite plates described in this invention, in the step of welding the transition layer using single tungsten inert gas welding: the welding voltage is controlled at 7-10V, the welding current at 50-80A, the welding speed at 50-70mm / min, and the wire feed speed at 0.2-0.6m / min.

[0023] In this implementation, since the nickel-based alloy has a high content of alloying elements, in order to reduce the amount of alloying elements melted into the base layer weld, especially the carbon steel weld that is in direct contact with the transition layer weld, the above-mentioned welding specifications should be adopted to reduce the top width of the transition layer weld.

[0024] Furthermore, in the welding method for nickel-based alloy composite plates described in this invention, in the step of welding the first weld pass of the substrate layer using double tungsten inert gas welding: the tungsten electrode arrangement direction is parallel to the welding direction, the tungsten electrode spacing is controlled at 1-1.5 mm, the welding voltage is 13.0-15.0 V, the welding current is 260-300 A, the welding speed is 270-300 mm / min, the wire feed speed is 6.0-7.0 m / min, and the welding torch is tilted 15-20° against the welding direction.

[0025] In this implementation, due to the high alloying element content of the nickel-based alloy, the dilution rate control requirement for the first weld pass of the base layer is very high. Therefore, double tungsten inert gas (TIG) welding is used to minimize the weld penetration. To ensure operability, the centerline of this weld pass is set at the exact center of the trapezoidal groove. Through a specially designed process, the transition layer weld ensures that the dilution level of the carbon steel weld pass relative to the cladding weld is less than 2.0%, thus preventing the weld pass from transforming entirely into martensite and maintaining good ductility and toughness.

[0026] Furthermore, in the welding method for nickel-based alloy composite plates described in this invention, in the step of welding the substrate layer, single tungsten inert gas welding is used to weld all weld passes except the first weld pass. The welding voltage of the single tungsten inert gas welding is controlled to be 13-16V, the welding current is 180-240A, the welding speed is 120-180mm / min, and the wire feed speed is 1.8-3.0m / min.

[0027] The welding method for nickel-based alloy composite plates described in this invention has the following advantages and beneficial effects compared to the prior art:

[0028] The welding method described in this invention can achieve reliable connection of nickel-based alloy composite plate components with a cascade welding sequence, significantly reduce the dilution rate of the substrate layer-nickel-based alloy mixed weld bead, and effectively improve the impact toughness of the joint weld.

[0029] The welding method described in this invention uses mixed welding materials to fill the gaps during the welding process, which significantly reduces welding costs while ensuring the structural strength of the joint. At the same time, the welding of each layer of weld seam adopts the arc welding method, which is simple to operate, has low equipment requirements, and has good scalability.

[0030] This invention can be applied to the multi-layer, multi-pass welding connection process of single-sided nickel-based alloy medium-thick composite plates with a thickness of 1 mm or more, used in fields such as petroleum, chemical, light industry, marine engineering, and nuclear industry. Attached Figure Description

[0031] Figure 1 The diagram schematically illustrates the bevel used in the beveling method for the nickel-based alloy composite plate described in this invention.

[0032] Figure 2 The cross-sectional morphology of the optimized joint of the nickel-based alloy composite plate in an embodiment employing the method of the present invention is shown. Detailed Implementation

[0033] The welding method for nickel-based alloy composite plates described in this invention will be further explained and described below with reference to specific embodiments and accompanying drawings. However, this explanation and description do not constitute an undue limitation on the technical solution of this invention.

[0034] The purpose of this invention is to provide a welding method for nickel-based alloy composite plates. Figure 1 The image shows two spliced ​​nickel-based alloy composite plates, A and B. Figure 1 The dashed line O in the figure represents the splicing seam. The nickel-based alloy composite plate includes a carbon steel substrate layer 1 and a nickel-based alloy composite layer 2, with a transition layer at the interface between the carbon steel substrate layer and the nickel-based alloy composite layer. Figure 1 The label “b1” indicates the distance between the surface of the carbon steel substrate layer and the interface between it and the nickel-based alloy composite layer, and the label “b2” indicates the distance between the surface of the nickel-based alloy composite layer and the interface between it and the carbon steel substrate layer.

[0035] In one specific embodiment, a nickel-based alloy composite plate with the grade Incoloy 825 / X52 can be used, i.e., the substrate layer material is X52 and the nickel-based alloy composite layer material is Incoloy 825. The thickness of the nickel-based alloy composite plate is 13mm, wherein b2 of the nickel-based alloy composite plate is 3mm and b1 is 10mm.

[0036] In some embodiments, the welding method for nickel-based alloy composite plates includes the steps of:

[0037] 100: Processing at the welding position of the two spliced ​​nickel-based alloy composite plates A and B as follows Figure 1The bevel pattern is shown. Specifically, a trapezoidal bevel is machined on the welding section of the nickel-based alloy composite plate corresponding to the base material layer. This trapezoidal bevel includes a vertically inclined portion 7 and a horizontally inclined portion 8 arranged sequentially. A U-shaped bevel is machined on the welding section of the nickel-based alloy corresponding to the transition layer. This U-shaped bevel includes a vertical portion 9 and a transition arc 10 arranged sequentially. No bevel is machined on the welding section of the nickel-based alloy composite plate corresponding to the nickel-based alloy composite layer, retaining a blunt edge; that is, the welding surface of the nickel-based alloy composite layer is a vertical plane 11. Figure 1 The label “b3” indicates the thickness of the blunt edge; in a specific example, b3 can be 2 mm.

[0038] 200: The nickel-based alloy composite layer is welded using single tungsten inert gas welding, and a nickel-based alloy welding wire that matches the nickel-based alloy composite layer is used to form the composite layer weld 3.

[0039] 300: The transition layer is welded using single tungsten inert gas welding, using nickel-based alloy welding wire that matches the nickel-based alloy composite layer to form the transition layer weld 4.

[0040] 400: The first weld bead of the substrate layer is welded using double tungsten inert gas welding to form the first weld bead 5 of the substrate layer.

[0041] 500: Use single tungsten inert gas welding to fill other welds in the base layer. The welding wire used is a carbon steel welding wire that matches the carbon steel base layer, forming other welds 6 in the base layer.

[0042] Preferably, in some embodiments, the distance b4 between the bottom of the trapezoidal bevel and the interface between the substrate layer and the nickel-based alloy composite layer is 1-2 mm.

[0043] Preferably, in some embodiments, the angle α between the inclined portion of the trapezoidal bevel and the vertical direction is ≥ (1.5b1)°, where b1 represents the distance from the surface of the substrate layer to the interface between it and the nickel-based alloy composite layer, and its unit parameter is mm.

[0044] Preferably, in some embodiments, the bottom single-side width w2 of the trapezoidal bevel is ≥ (5 + 0.1b1), where b1 represents the distance from the surface of the substrate layer to the interface between it and the nickel-based alloy composite layer, and its unit parameter is mm.

[0045] Preferably, in some embodiments, in order to balance welding formation and dilution rate control, the position between the inner and outer sides of the transition layer weld is machined into a U-shape, and the width w1 of one side of the U-shaped groove is 0.5-1mm.

[0046] Preferably, in some embodiments, the radius r of the arc portion of the U-shaped bevel is ≥ 0.5w1, where w1 represents the width of one side of the U-shaped bevel, and its unit parameter is mm.

[0047] Preferably, in some embodiments, in step 200, the welding wire is a nickel-based alloy welding wire ERNiCrMo-3 that matches the cladding layer. The welding method is to use single tungsten inert gas welding to weld the nickel-based alloy cladding layer weld 3. A single-sided welding double-sided forming process is used. The welding voltage is controlled at 10-12V, the welding current at 80-110A, the welding speed at 90-110mm / min, the wire feed speed at 0.4-0.8m / min, and the assembly gap w3 = (3-2w1)mm is controlled, where w1 represents the width of one side of the U-shaped bevel.

[0048] In step 300, welding is performed using ERNiCrMo-3 nickel-based alloy welding wire with performance not lower than that of the cladding layer. The welding method is single tungsten inert gas welding to form the cladding layer weld 4. The welding voltage is controlled at 7-10V, the welding current at 50-80A, the welding speed at 50-70mm / min, and the wire feed speed at 0.2-0.6m / min.

[0049] In step 400, carbon steel welding wire ER50-6, which is matched with the base material, is used for welding. The welding method is double tungsten inert gas welding to weld the first weld pass of the base material layer. The tungsten electrode arrangement direction is parallel to the welding direction, the tungsten electrode spacing is controlled at 1-1.5mm, the welding voltage is 13.0-15.0V, the welding current is 260-300A, the welding speed is 270-300mm / min, the wire feed speed is 6.0-7.0m / min, and the welding torch is tilted 15-20° against the welding direction.

[0050] In step 500, carbon steel welding wire ER50-6, which is matched with the base material, is used to weld the other weld passes of the base layer except for the first weld pass. The welding method is single tungsten inert gas welding, the welding voltage is 13-16V, the welding current is 180-240A, the welding speed is 120-180mm / min, and the wire feed speed is 1.8-3.0m / min.

[0051] To further illustrate the preferred embodiments of this invention, Table 1 lists the characteristic parameters of the bevel used in the preferred embodiments 1-5 of this invention.

[0052] Table 1.

[0053]

[0054]

[0055] Table 2 lists the welding process parameters used in step 200 of forming the composite layer weld in preferred embodiments 1-5 of the present invention.

[0056] Table 2.

[0057]

[0058] Table 3 lists the welding process parameters used in step 300 of forming the transition layer weld in preferred embodiments 1-5 of the present invention.

[0059] Table 3.

[0060]

[0061] Table 4 lists the welding process parameters used in step 400 of forming the first weld seam of the substrate layer in preferred embodiments 1-5 of the present invention.

[0062] Table 4.

[0063]

[0064] Table 5 lists the welding process parameters used in step 500 of the present invention, which is a preferred step for filling other welds in the substrate layer.

[0065] Table 5

[0066]

[0067] In addition, to demonstrate the implementation effect of the preferred embodiment, Table 6 lists the Cr content of each layer of base material and weld in the joint of the nickel-based alloy composite plate obtained by welding according to Embodiment 1 of the present invention. By calculation, it can be found that the dilution rate of the carbon steel weld bead in direct contact with the transition layer relative to the weld bead of the composite layer is 1.95% (less than 2.0%).

[0068] Table 6.

[0069]

[0070]

[0071] Figure 2 The cross-sectional morphology of the optimized joint of the nickel-based alloy composite plate in an embodiment employing the method of the present invention is shown.

[0072] from Figure 2 As can be seen, the optimized joint of the nickel-based alloy composite plate exhibits good fusion and is free of welding defects. Furthermore, due to the application of the method of this invention, the weld area of ​​the nickel-based alloy in the transition layer and composite layer is relatively small. Therefore, compared with a full nickel-based alloy filler solution, the method of this invention can significantly reduce the amount of nickel-based alloy filler used, reduce welding costs, improve structural strength, and simultaneously increase welding efficiency.

[0073] It should be noted that the combination of the technical features in this case is not limited to the combination methods described in the claims of this case or the combination methods described in the specific embodiments. All technical features described in this case can be freely combined or combined in any way, unless they contradict each other.

[0074] It should also be noted that the embodiments listed above are merely specific embodiments of the present invention. Obviously, the present invention is not limited to the above embodiments, and similar changes or modifications made thereto are those that can be directly derived or easily conceived by those skilled in the art from the content disclosed in the present invention, and should all fall within the protection scope of the present invention.

Claims

1. A welding method for a nickel-based alloy composite plate, the nickel-based alloy composite plate comprising a substrate layer and a nickel-based alloy composite layer, wherein a transition layer is provided at the interface between the substrate layer and the nickel-based alloy composite layer; characterized in that, The welding method includes the following steps: A trapezoidal bevel is machined on the welding section of the nickel-based alloy composite plate at the position corresponding to the base material layer; the distance b4 between the bottom of the trapezoidal bevel and the interface between the base material layer and the nickel-based alloy composite layer is 1-2 mm; the single-side width w2 of the bottom of the trapezoidal bevel is ≥ (5 + 0.1b1), where b1 represents the distance from the surface of the base material layer to its interface with the nickel-based alloy composite layer, and its unit parameter is mm; a U-shaped bevel is machined on the welding section of the nickel-based alloy composite plate at the position corresponding to the transition layer; the single-side width w1 of the U-shaped bevel is 0.5-1 mm; the radius r of the arc part of the U-shaped bevel is ≥ 0.5w1, where w1 represents the single-side width of the U-shaped bevel, and its unit parameter is mm; no bevel is machined on the welding section of the nickel-based alloy composite plate at the position corresponding to the nickel-based alloy composite layer; Using a nickel-based alloy welding wire that matches the nickel-based alloy composite layer, the nickel-based alloy composite layer is welded using single tungsten inert gas welding to form a composite layer weld. Using nickel-based alloy welding wire that matches the nickel-based alloy composite layer, the transition layer is welded using single tungsten inert gas welding to form a transition layer weld. The substrate layer is welded to form a substrate layer weld. The first weld bead of the substrate layer is welded using double tungsten inert gas (TIG) welding: the tungsten electrode arrangement direction is parallel to the welding direction, the tungsten electrode spacing is controlled at 1-1.5 mm, the welding voltage is 13.0-15.0 V, the welding current is 260-300 A, the welding speed is 270-300 mm / min, the wire feed speed is 6.0-7.0 m / min, and the welding torch is tilted 15-20° against the welding direction.

2. The welding method for nickel-based alloy composite plates as described in claim 1, characterized in that, The angle α between the inclined part of the trapezoidal bevel and the vertical direction is ≥ (1.5b1)°, where b1 represents the distance from the surface of the substrate layer to the interface between it and the nickel-based alloy composite layer, and its unit parameter is mm.

3. The welding method for nickel-based alloy composite plates as described in claim 1, characterized in that, In the process of welding nickel-based alloy composite layers using single tungsten inert gas welding: a single-sided welding double-sided forming process is adopted, and the welding voltage is controlled at 10-12V, the welding current at 80-110A, the welding speed at 90-110mm / min, and the wire feeding speed at 0.4-0.8m / min.

4. The welding method for nickel-based alloy composite plates as described in claim 1, characterized in that, In the process of welding nickel-based alloy composite layers using single tungsten inert gas welding: control the assembly gap w3 = (3-2w1) mm, where w1 represents the width of one side of the U-shaped groove.

5. The welding method for nickel-based alloy composite plates as described in claim 1, characterized in that, In the process of welding the transition layer using single tungsten inert gas welding: the welding voltage is controlled at 7-10V, the welding current at 50-80A, the welding speed at 50-70mm / min, and the wire feed speed at 0.2-0.6m / min.

6. The welding method for nickel-based alloy composite plates as described in claim 1, characterized in that, In the step of welding the substrate layer, single tungsten inert gas (TIG) welding is used to weld all weld passes except the first weld pass. The welding voltage of the TIG welding is controlled at 13-16V, the welding current is 180-240A, the welding speed is 120-180mm / min, and the wire feed speed is 1.8-3.0m / min.

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