Automatic welding method for optimizing welding seam structure of nickel-based alloy composite plate

Abstract

The invention discloses an automatic welding method for optimizing a welding seam structure of a nickel-based alloy composite board. The nickel-based alloy composite board comprises a base material layer and a nickel-based alloy composite material layer, and a transition layer is arranged at the bonding interface of the base material layer and the nickel-based alloy composite material layer; the automatic welding method comprises the steps that a trapezoidal groove is machined in the position, corresponding to the base material layer, of the welding section of the nickel-based alloy composite board; a U-shaped groove is machined in the position, corresponding to the transition layer, of the welding section of the nickel base alloy; a groove is not machined in the position, corresponding to the nickel-based alloy composite material layer, of the welding section of the nickel-based alloy composite plate; carrying out self-fusion welding on the nickel-based alloy composite material layer by adopting laser welding; a carbon steel welding wire matched with the base material layer is used, and laser welding is adopted for conducting wire filling welding on the transition layer; and welding the base material layer by adopting hot wire swing argon tungsten-arc welding.

Description

Technical Field

[0001] The invention relates to a welding method, in particular to a welding method for a composite plate. Background Art

[0002] Since bimetallic composite plates contain two different component metals, they can meet both structural and functional requirements. For example, nickel-based alloy composite plates composed of high-strength low-alloy structural steel and nickel-based alloys can provide good corrosion resistance while ensuring sufficient strength and toughness, and have been applied on a certain scale in engineering.

[0003] However, the design characteristics of multi-component metals give the materials multi-level performance while also posing challenges to the welding process. The chemical composition of the two metals can easily affect each other during welding, thereby deteriorating the mechanical or corrosion resistance of the joint. Therefore, in engineering, multi-layer and multi-pass welding is generally used for the connection of nickel-based alloy composite plates, that is, the weld is divided into a composite layer and a transition layer nickel-based alloy weld and a base carbon steel weld, and welded separately. There are two welding sequences for such a welding process, namely, the welding sequence of base-transition layer-complex layer and the welding sequence of complex layer-transition layer-base layer.

[0004] The first welding sequence is commonly used in engineering. In this welding sequence, the composition transition from carbon steel to nickel-based alloy weld is achieved by adding a transition layer weld, which can effectively avoid the decrease in corrosion resistance of the composite weld. For some special scenarios, such as closed welding of small composite components, the latter welding sequence must be adopted due to limited operating space. At this time, although the composite layer is welded first, a transition layer is still required to achieve the composition transition from nickel-based alloy to carbon steel to avoid the decrease in mechanical properties of the carbon steel weld. However, since nickel-based alloys contain very high contents of alloying elements such as Cr and Ni, carbon steel welds can easily produce hard and brittle martensitic structures due to excessive welding dilution rates. This phenomenon is discussed in the paper "Additive manufacturing of functionally graded transition joints between ferritic and austenitic alloys".

[0005] At present, the common solution to this problem in engineering is to use nickel-based alloy welding materials for all welds, but this practice greatly increases the use of nickel-based alloy welding materials, and the unit price of nickel-based alloy welding materials is often dozens of times that of carbon steel welding materials, thus greatly increasing the cost of welding materials; on the other hand, due to the low yield strength of nickel-based alloys, all-nickel-based alloy welds will reduce the overall structural strength of the joint, which is a safety hazard for some composite plate components with high strength requirements. In other words, there is a contradiction between the use of mixed welding materials and the control of joint organization and performance in the welding sequence of composite layer-transition layer-base layer of nickel-based alloy composite plates.

[0006] The Chinese patent document with publication number CN112122783A and publication date December 25, 2020, entitled "A method for laser butt welding of carbon steel-nickel alloy composite plates" discloses: the method of laser welding self-melting or wire filling welding realizes the connection of composite plates in the welding sequence of composite layer-transition layer-base layer, but the main problem to be solved by the invention is that the welding of composite plate components under closed welding conditions cannot be operated, and does not pay attention to the problem of deterioration of joint structure. Summary of the invention

[0007] One of the purposes of the present invention is to provide an automated welding method for optimizing the weld structure of a nickel-based alloy composite plate. Under the premise of using mixed welding materials, the method is based on the welding sequence of composite layer-transition layer-base material layer, and the groove and weld arrangement are specially designed. A variety of welding methods are used in combination and the process window is rationalized, thereby avoiding the martensiticization of the carbon steel weld structure of the base material layer as a whole, and realizing reliable connection of the composite plate under the welding sequence.

[0008] In order to achieve the above object, the present invention provides an automated welding method for optimizing the weld structure of 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 bonding interface between the substrate layer and the nickel-based alloy composite layer; the automated welding method comprises the steps of:

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

[0010] Laser welding is used to perform autogenous welding on the nickel-based alloy composite layer;

[0011] Use carbon steel welding wire that matches the base material layer and laser welding to fill the transition layer;

[0012] The base material layer is welded by hot wire swing tungsten inert gas arc welding.

[0013] In the present invention, the inventors have achieved reliable connection of nickel-based alloy composite plates in the welding sequence of composite layer-transition layer-substrate layer by using a special groove design, comprehensively using a variety of welding methods and rationalizing the process. Among them, the automated welding method for optimizing the weld structure of nickel-based alloy composite plates described in the present invention can effectively avoid the overall martensiticization of the carbon steel weld structure of the substrate layer of the nickel-based alloy composite plate in the welding sequence of composite layer-transition layer-substrate layer, thereby improving the connection reliability of the joint. Compared with the prior art, the automated welding method for optimizing the weld structure of nickel-based alloy composite plates described in the present invention can greatly reduce the use of nickel-based alloy welding materials, while reducing welding costs and improving the structural strength of the joint. In addition, the composite plate welding method proposed in the present invention adopts both automated welding technology and parameterized welding processes, which are less dependent on the welding qualifications and skill levels of welding operators, and show good scalability.

[0014] Furthermore, in the automated welding method for optimizing the weld structure of the nickel-based alloy composite plate described in the present invention, the angle α between the inclined portion of the trapezoidal groove and the vertical direction is ≥(1.5b1)°, where b1 represents the distance from the surface of the substrate layer to the bonding interface between it and the nickel-based alloy composite layer, and its unit parameter is mm.

[0015] Furthermore, in the automated welding method for optimizing the weld structure of the nickel-based alloy composite plate described in the present invention, the single-side bottom width w2 of the trapezoidal groove is ≥ (5+0.1b1), where b1 represents the distance from the surface of the substrate layer to the bonding interface between it and the nickel-based alloy composite layer, and its unit parameter is mm.

[0016] Furthermore, in the automated welding method for optimizing the weld structure of the nickel-based alloy composite plate described in the present invention, the distance b4 between the bottom of the trapezoidal groove and the bonding interface between the substrate layer and the nickel-based alloy composite layer is 1-2 mm.

[0017] In this embodiment, the base weld position can be processed into a trapezoidal groove. Considering the operability of hot wire swing tungsten inert gas arc welding of the base weld, the angle α between the inclined portion of the trapezoidal groove and the vertical direction can be controlled to α≥(1.5b1)°, the single-side bottom width w2 of the trapezoidal groove can be controlled to w2≥(5+0.1b1), and the distance b4 between the bottom of the trapezoidal groove and the bonding interface between the substrate layer and the nickel-based alloy composite layer can be controlled to be between 1-2 mm.

[0018] Furthermore, in the automated welding method for optimizing the weld structure of the nickel-based alloy composite plate described in the present invention, the single-side width w1 / 2 of the U-shaped groove is 1-1.5 mm.

[0019] Furthermore, in the automated welding method for optimizing the weld structure of the nickel-based alloy composite plate described in the present invention, the radius r of the arc portion of the U-shaped groove is ≥ 0.25w1, where w1 represents twice the single-side width of the U-shaped groove, and its unit parameter is mm.

[0020] In this embodiment, in order to ensure that the laser self-melting welding of the composite layer is smoothly performed without melting the carbon steel, and because the nickel-based alloy molten pool has high viscosity and poor fluidity, in order to ensure that no unfused defects are generated, the transition layer weld position can be processed into a U-shaped groove. At the same time, in order to ensure that the composite layer weld can be smoothly welded without melting the carbon steel parent material, the width w1 of the U-shaped groove should be greater than the laser spot diameter. In order to allow the molten pool gas to be discharged smoothly, the straight edge angle of the U-shaped groove can be maintained at 90 degrees, and w1 should not be too small while being greater than the laser spot diameter, and should be controlled within the range of 2-3mm, that is, the single-side width w1 / 2 of the U-shaped groove is controlled between 1-1.5mm, and the radius r of the arc portion of the U-shaped groove is controlled to r≥0.25w1.

[0021] Furthermore, in the automated welding method for optimizing the weld structure of the nickel-based alloy composite plate described in the present invention, in the step of using laser welding to perform self-fusion welding on the nickel-based alloy composite layer: the laser spot diameter used is ≤1mm, the laser power is controlled to be 3.0-4.0KW, the welding speed is 2.0-2.5m / min, and the positive defocus is 0-5mm.

[0022] Furthermore, in the automated welding method for optimizing the weld structure of the nickel-based alloy composite plate described in the present invention, in the step of performing wire welding on the transition layer by laser welding, the diameter of the laser spot used is ≤1 mm.

[0023] Furthermore, in the automated welding method for optimizing the weld structure of the nickel-based alloy composite plate described in the present invention, in the step of using laser welding to fill the transition layer with wire: the laser power is controlled to be 4.0-5.0KW, the welding speed is 2.0-3.0m / min, the positive defocus is 5-10mm, the wire feeding speed is 1.5-2.0m / min, and the wire feeding angle is 30-45°.

[0024] In this embodiment, the top width of the transition layer weld, which is approximately the width w1 of the U-shaped groove, can be controlled below 3 mm by matching a specially designed groove form to promote low dilution rate control of the carbon steel weld, especially the carbon steel weld in direct contact with the transition layer weld.

[0025] Furthermore, in the automated welding method for optimizing the weld structure of the nickel-based alloy composite plate described in the present invention, in the step of welding the substrate layer using hot wire swinging tungsten inert gas arc welding: the welding voltage is controlled to be 12.0-14.0V, the welding current is 140-180A, the welding speed is 120-150mm / min, the wire feeding speed is 1.8-2.6m / min, the hot wire current is 60-100A, and the swing width is 1-4mm.

[0026] In this embodiment, due to the high alloying degree of nickel-based alloy, it is very difficult to control the dilution rate of carbon steel welds, especially carbon steel welds in direct contact with transition layer welds. Therefore, on the basis of special groove design and transition layer laser wire welding process application, hot wire swing tungsten inert gas arc welding is also required when welding the base weld. At the same time, in the application of this welding process, it can be ensured that the penetration depth is effectively reduced on the basis of good welding forming, and with the obtained narrow width transition layer weld, the dilution rate of carbon steel welds, especially carbon steel welds in direct contact with transition layer welds, can be controlled below 2.0% relative to the composite weld, thereby avoiding martensitication of the carbon steel weld structure as a whole.

[0027] The automated welding method for optimizing the weld structure of the nickel-based alloy composite plate of the present invention has the following advantages and beneficial effects compared with the prior art:

[0028] The automated welding method for optimizing the weld structure of the nickel-based alloy composite plate described in the present invention can effectively avoid martensiticization of the carbon steel weld structure of the nickel-based alloy composite plate in the composite layer-transition layer-base layer welding sequence, thereby improving the connection reliability of the composite plate components.

[0029] Compared with the current practice of filling with all nickel-based alloy materials in the industry to address this problem, the automated welding method for optimizing the weld structure of the nickel-based alloy composite plate described in the present invention not only greatly reduces the welding cost, but also effectively improves the structural strength of the joint.

[0030] In the automated welding method for optimizing the weld structure of the nickel-based alloy composite plate described in the present invention, each layer of weld is welded using an automated welding method, and the process specifications are highly parameterized, so the operation process is simple and reliable, which makes the welding process less dependent on senior welding practitioners and has good scalability. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 The groove schematic diagram used in the automated welding method for optimizing the weld structure of the nickel-based alloy composite plate described in the present invention is schematically shown.

[0032] Figure 2The cross-sectional morphology of a nickel-based alloy composite plate joint prepared by the automated welding method for optimizing the weld structure of a nickel-based alloy composite plate according to Example 1 of the present invention is shown.

[0033] Figure 3 A metallographic structure photograph of the transition layer / carbon steel substrate layer weld joint section of a nickel-based alloy composite plate welded joint after being corroded by nitric alcohol using the automated welding method for optimizing the weld structure of a nickel-based alloy composite plate according to Example 1 of the present invention is shown. DETAILED DESCRIPTION

[0034] The automated welding method for optimizing the weld structure of the nickel-based alloy composite plate described in the present invention will be further explained and illustrated below in conjunction with specific embodiments and drawings of the specification. However, such explanation and illustration do not constitute an improper limitation on the technical solution of the present invention.

[0035] The purpose of the present invention is to provide an automated welding method for optimizing the weld structure of a nickel-based alloy composite plate. Figure 1 Shows two spliced ​​nickel-based alloy composite plates A and B. Figure 1 The dotted line O in the figure represents a joint. The nickel-based alloy composite plate comprises a carbon steel substrate layer 1 and a nickel-based alloy composite layer 2, and a transition layer is provided at the interface between the carbon steel substrate layer 1 and the nickel-based alloy composite layer 2. Figure 1 The symbol "b1" represents the distance between the surface of the carbon steel substrate layer and the bonding interface between it and the nickel-based alloy composite layer, and the symbol "b2" represents the distance between the surface of the nickel-based alloy composite layer and the bonding interface between it and the carbon steel substrate layer.

[0036] In a specific embodiment, a nickel-based alloy composite plate with the grade of Incoloy825 / X52 can be used, that is, the carbon steel substrate layer material is X52, and the nickel-based alloy composite layer material is Incoloy825. The plate thickness of the nickel-based alloy composite plate is 13 mm, wherein b2 of the nickel-based alloy composite plate is 3 mm, and b1 is 10 mm.

[0037] In some embodiments, an automated welding method for optimizing the weld structure of a nickel-based alloy clad plate comprises the steps of:

[0038] 100: Processing at the welding position of two spliced ​​nickel-based alloy composite plates A and B as follows Figure 1 The groove shown. A trapezoidal groove is processed at a position corresponding to the base material layer on the welding cross section of the nickel-based alloy composite plate. The trapezoidal groove includes a vertical inclined portion 6 and a horizontal portion 7 arranged in sequence. The extension width of the horizontal portion 7 (i.e., the single-side bottom width of the trapezoidal groove) is Figure 1 In the figure, “w2” is used to represent that the distance between the horizontal portion 7 and the interface between the substrate layer 1 and the nickel-based alloy composite layer 2 is Figure 1Indicated by "b4" in the figure; a U-shaped groove 8 is opened at the position corresponding to the transition layer on the welding section of the nickel-based alloy composite plate, the single-side width of the U-shaped groove is w1 / 2, and the radius of the bottom arc of the transition layer U-shaped groove is r. No groove is processed at the position corresponding to the nickel-based alloy composite layer on the welding section of the nickel-based alloy composite plate, that is, the welding surface of the nickel-based alloy composite layer is a vertical plane, and the thickness of the groove is Figure 1 It is represented by "b3", b3=b2-r.

[0039] 200: Laser welding is used to perform autogenous welding on the nickel-based alloy composite layer to form a composite layer weld 3.

[0040] 300: Use carbon steel welding wire that matches the base material layer and use laser welding to fill the transition layer with wire to form a transition layer weld 4.

[0041] 400: Use carbon steel welding wire that matches the carbon steel substrate layer, and adopt hot wire swing tungsten inert gas arc welding to perform wire welding on the carbon steel substrate layer to form a substrate layer weld 5.

[0042] Preferably, in some embodiments, the angle α between the vertical inclined portion 6 of the trapezoidal groove and the vertical direction can be controlled to be α≥(1.5b1)°, where b1 represents the distance between the surface of the substrate layer and the bonding interface between the substrate layer and the nickel-based alloy composite layer, and its unit parameter is mm. In this embodiment, the welding operability of the subsequent hot wire swing tungsten inert gas arc welding can be facilitated by controlling the angle α.

[0043] Preferably, in some embodiments, the single-side bottom width of the trapezoidal groove (i.e., the extended width of the horizontal portion 7) w2 can be controlled to be w2≥(5+0.1b1), where b1 represents the distance from the surface of the substrate layer to the bonding interface between the substrate layer and the nickel-based alloy composite layer, and its unit parameter is mm. In this embodiment, the subsequent hot wire swing tungsten inert gas arc welding can be facilitated by controlling w2.

[0044] Preferably, in some embodiments, the distance b4 between the bottom of the trapezoidal groove and the bonding interface between the substrate layer and the nickel-based alloy composite layer can be controlled to be between 1 and 2 mm. In this embodiment, the welding operability of the subsequent hot wire swing tungsten inert gas arc welding can be facilitated by controlling b4.

[0045] Preferably, in some embodiments, the single-side width of the U-shaped groove can be controlled to be w1 / 2≥the laser spot radius of laser welding, that is, the total width w1 of the two U-shaped grooves formed by the two spliced ​​nickel-based alloy composite plates A and B≥the laser spot diameter of laser welding. This design can ensure that the laser autogenous welding of the nickel-based alloy composite layer weld is completed smoothly without melting the carbon steel substrate.

[0046] Preferably, in some embodiments, in order to allow the molten pool gas to be discharged smoothly, the straight edge angle of the U-shaped groove can be maintained at 90 degrees, and w1 should not be too small while being larger than the laser spot diameter, and is controlled within the range of 2-3 mm, that is, the single-side width w1 / 2 of the U-shaped groove is controlled between 1-1.5 mm, and the radius r of the arc portion of the U-shaped groove is controlled at r≥0.25w1.

[0047] Preferably, in some embodiments, in step 200, laser autogenous welding is used to form the composite layer weld 3, and the laser spot diameter can be controlled to be ≤1 mm, the laser power to be 3.0-4.0 KW, the welding speed to be 2.0-2.5 m / min, and the positive defocus to be 0-5 mm.

[0048] In step 300, laser wire welding is used to weld the transition layer weld 4. The filler metal can be ERNiCrMo-3. The laser spot diameter is ≤1mm, the laser power is controlled to be 4.0-5.0KW, the welding speed is 2.0-3.0m / min, the positive defocus is 5-10mm, the wire feeding speed is 1.5-2.0m / min, and the wire feeding angle is 30-45°.

[0049] In this embodiment, the top width of the transition layer weld, which is approximately the width w1 of the U-shaped groove, can be controlled below 3 mm by matching a specially designed groove form to promote low dilution rate control of the carbon steel weld, especially the carbon steel weld in direct contact with the transition layer weld.

[0050] In step 400, the carbon steel weld 5 is welded using carbon steel welding wire ER50-6 that matches the base parent material. The welding method uses hot wire swing tungsten inert gas arc welding, and the welding voltage is controlled to be 12.0-14.0V, the welding current is 140-180A, the welding speed is 120-150mm / min, the wire feeding speed is 1.8-2.6m / min, the hot wire current is 60-100A, and the swing width is 1-4mm.

[0051] In this embodiment, due to the high alloying degree of nickel-based alloy, it is very difficult to control the dilution rate of carbon steel welds, especially carbon steel welds in direct contact with transition layer welds. Therefore, on the basis of special groove design and transition layer laser wire welding process application, hot wire swing tungsten inert gas arc welding is also required when welding the base layer weld. At the same time, in the application of this welding process, it can be ensured that the penetration depth is effectively reduced on the basis of good welding forming, and with the obtained narrow width transition layer weld, the dilution rate of carbon steel welds, especially carbon steel welds in direct contact with transition layer welds, relative to the composite layer weld can be controlled to less than 2.0%, thereby avoiding martensitication of the carbon steel weld structure as a whole.

[0052] In order to further reflect the preferred implementation of this case, Table 1 lists the characteristic parameters of the grooves used in the preferred embodiments 1-5 of the present invention.

[0053] Table 1.

[0054] <![CDATA[b3(mm)]]> α(°) <![CDATA[w1(mm)]]> r(mm) <![CDATA[w2(mm)]]> <![CDATA[b4(mm)]]> Example 1 2 15 2 1 6 1 Example 2 2.5 15 2 0.5 8 2 Example 3 1.5 18 2 1.5 7 1 Example 4 2 20 3 1 7 2 Example 5 1.5 25 3 1.5 6 1.5

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

[0062] Table 4.

[0063]

[0064] In addition, in order to prove the implementation effect of the preferred embodiment, Table 5 lists the Cr element content of each layer of the base material and the weld in the joint of the nickel-based alloy composite plate obtained by welding in Example 1 of the present invention. By calculation, it can be obtained that the dilution rate of the carbon steel weld directly contacting the transition layer relative to the composite weld is 1.86% (lower than 2.00%), thereby avoiding the formation of martensitic structure in the carbon steel weld of the base layer.

[0065] Table 5.

[0066]

[0067] Figure 2 The cross-sectional morphology of a nickel-based alloy composite plate joint prepared by the automated welding method for optimizing the weld structure of a nickel-based alloy composite plate according to Example 1 of the present invention is shown.

[0068] from Figure 2 It can be seen that the nickel-based alloy composite plate joints prepared by the present invention are well fused, which proves that the method of the present invention can achieve good connection of nickel-based alloy composite plates.

[0069] Figure 3A metallographic structure photograph of the transition layer / carbon steel substrate layer weld joint section of a nickel-based alloy composite plate welded joint after being corroded by nitric alcohol using the automated welding method for optimizing the weld structure of a nickel-based alloy composite plate according to Example 1 of the present invention is shown.

[0070] from Figure 3 It can be seen that the metallographic structure at the transition layer weld / carbon steel weld interface after nitric alcohol corrosion shows that the transition layer weld is not corroded, which means that it still maintains the austenite structure of the base material. A large number of ferrite grains can be seen in the carbon steel weld, and no obvious martensite structure appears. This shows that the application of the method of the present invention can successfully achieve a good transition of the weld structure of the nickel-based alloy composite plate connection joint in the composite layer-transition layer-base welding sequence.

[0071] It should be noted that the combination of the various technical features in this case is not limited to the combination described in the claims of this case or the combination described in the specific embodiments. All technical features recorded in this case can be freely combined or combined in any way unless there is a contradiction between them.

[0072] It should also be noted that the above-listed embodiments are only specific embodiments of the present invention. Obviously, the present invention is not limited to the above embodiments, and similar changes or modifications made therewith can be directly derived or easily associated with by those skilled in the art from the contents disclosed in the present invention, and all should belong to the protection scope of the present invention.

Claims

1. An automated welding method for optimizing the weld structure of 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 bonding interface between the substrate layer and the nickel-based alloy composite layer; characterized in that: The automated welding method comprises the steps of: A trapezoidal groove is processed at the position corresponding to the base material layer on the welding section of the nickel-based alloy composite plate; a U-shaped groove is processed at the position corresponding to the transition layer on the welding section of the nickel-based alloy; and no groove is processed at the position corresponding to the nickel-based alloy composite material layer on the welding section of the nickel-based alloy composite plate; Laser welding is used to perform autogenous welding on the nickel-based alloy composite layer; Use carbon steel welding wire that matches the base material layer and laser welding to fill the transition layer; The base material layer is welded by hot wire swing tungsten inert gas arc welding.

2. The automated welding method according to claim 1, characterized in that: The angle α between the inclined portion of the trapezoidal groove and the vertical direction is ≥(1.5b1)°, where b1 represents the distance from the surface of the substrate layer to the bonding interface between the substrate layer and the nickel-based alloy composite layer, and its unit parameter is mm.

3. The automated welding method according to claim 1, characterized in that: The single-side bottom width w2 of the trapezoidal groove is ≥(5+0.1b1), where b1 represents the distance from the surface of the substrate layer to the bonding interface between the substrate layer and the nickel-based alloy composite layer, and its unit parameter is mm.

4. The automated welding method according to claim 1, characterized in that: The distance b4 between the bottom of the trapezoidal groove and the bonding interface between the substrate layer and the nickel-based alloy composite layer is 1-2 mm.

5. The automated welding method according to claim 1, characterized in that: The single side width w1 / 2 of the U-shaped groove is 1-1.5 mm.

6. The automated welding method according to claim 1, characterized in that: The radius r of the arc portion of the U-shaped groove is ≥0.25w1, where w1 represents twice the single-side width of the U-shaped groove, and its unit parameter is mm.

7. The automated welding method according to claim 1, characterized in that: In the step of using laser welding to perform self-melting welding on the nickel-based alloy composite layer: the laser spot diameter used is ≤1mm, the laser power is controlled to be 3.0-4.0KW, the welding speed is 2.0-2.5m / min, and the positive defocus is 0-5mm.

8. The automated welding method according to claim 1, characterized in that: In the step of performing wire welding on the transition layer by laser welding, the diameter of the laser spot used is ≤1 mm.

9. The automated welding method according to claim 1, characterized in that: In the step of using laser welding to filler wire welding the transition layer: control the laser power to 4.0-5.0KW, the welding speed to 2.0-3.0m / min, the positive defocus to 5-10mm, the wire feeding speed to 1.5-2.0m / min, and the wire feeding angle to 30-45°.

10. The automated welding method according to claim 1, characterized in that: In the step of welding the substrate layer by hot wire swing tungsten inert gas arc welding: control the welding voltage to 12.0-14.0V, the welding current to 140-180A, the welding speed to 120-150mm / min, the wire feeding speed to 1.8-2.6m / min, the hot wire current to 60-100A, and the swing width to 1-4mm.

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