Welding method for controlling welding deformation of stainless steel composite plate

Abstract

The invention discloses a welding method for controlling welding deformation of a stainless steel composite plate. The stainless steel composite plate comprises a base material layer and a stainless steel composite material layer. The welding method comprises the steps that an X-shaped groove symmetrical in the thickness direction is machined in the welding section of the stainless steel composite plate, the X-shaped groove comprises a central straight part, two inclined parts and two edge straight parts, the two inclined parts and the two edge straight parts are arranged on the two sides of the central straight part in the thickness direction respectively, and the inclined parts are connected with the central straight part; and the positions, corresponding to the inclined parts and the edge straight parts, of the base material layer and the stainless steel composite material layer are subjected to multi-pass welding through argon tungsten-arc welding. According to the welding method, good connection of the composite plates can be guaranteed, and meanwhile the welding deformation of the composite plates is effectively reduced.

Description

Technical Field

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

[0002] Single-sided stainless steel composite plate is a binary metal structural material. Generally, the two component metals are low-alloy steel, which is inexpensive and has good mechanical properties, and stainless steel, which has good corrosion resistance. They are combined through rolling and explosive bonding. The resulting new material has excellent comprehensive performance.

[0003] For stainless steel clad plates, the two component metals, stainless steel and carbon steel, in both the base material and the weld have significant differences in physical properties, particularly in yield strength and coefficient of thermal expansion. For example, in the widely used SUS304-Q235 clad plate, the room temperature yield strength of the cladding base material SUS304 is lower than that of the base material Q235, while the former has a higher coefficient of thermal expansion. This difference leads to inconsistent shrinkage on both sides of the base and cladding layers, ultimately resulting in increased overall welding deformation of the clad plate.

[0004] In existing technologies, existing patent literature focuses on using multi-layer, multi-pass welding methods for stainless steel composite plates, combined with the use of hybrid welding materials, to effectively ensure the performance of the weld seams in stainless steel composite plate joints. For example:

[0005] Chinese patent document CN113878204A, published on January 4, 2022, entitled "Welding Method of Stainless Steel Composite Plate", discloses a welding method for stainless steel composite plates. The method involves mechanically machining a bevel, wherein the cladding side is machined downwards to form a concave platform based on the boundary line between the cladding and the base layer; during the assembly of the composite plate welded joint, the misalignment is controlled within 0.5 to 1.5 mm; the base layer is welded using submerged arc welding, and the weld bead should be 1 mm lower than the boundary line between the cladding and the base layer; both the transition layer and the composite layer are welded using stainless steel flux-cored wire CO2 gas shielded welding.

[0006] Chinese patent document CN114888401A, published on August 12, 2022, entitled "A Welding Method for Stainless Steel Composite Plate", discloses a welding method for stainless steel composite plate. The method involves cutting and beveling the stainless steel composite plate; welding the base layer, wherein the first weld layer is welded by manual arc welding, and then the second and third weld layers are welded by submerged arc automatic welding in sequence; then the back is cleaned and ground, and the fourth weld layer is welded by submerged arc automatic welding; then the transition layer and the cladding layer are welded by submerged arc automatic welding in sequence.

[0007] However, none of the aforementioned patent documents addressed the welding deformation problem that exists in composite plates under this welding sequence. Summary of the Invention

[0008] The purpose of this invention is to provide a welding method for controlling the welding deformation of stainless steel composite plates. This method can not only ensure good fusion of the weld seam of stainless steel composite plates, but also effectively control the welding deformation of stainless steel composite plates.

[0009] To achieve the above objectives, the present invention provides a welding method for controlling welding deformation of a stainless steel composite plate, wherein the stainless steel composite plate comprises a substrate layer and a stainless steel cladding layer; the welding method includes the following steps:

[0010] A symmetrical X-shaped bevel is machined on the welding section of the stainless steel composite plate in the thickness direction. The X-shaped bevel includes a central straight section, and two inclined sections and two edge straight sections respectively provided on both sides of the central straight section in the thickness direction, wherein the inclined sections are connected to the central straight section.

[0011] Tungsten inert gas (TIG) welding is used to perform multiple passes of welding on the base material layer and the stainless steel cladding layer, corresponding to the inclined and straight edge sections.

[0012] This invention employs tungsten inert gas welding (TIG) based on a multi-layer, multi-pass welding method, combined with a symmetrically designed X-shaped groove, which ensures that the weld of the stainless steel composite plate has a good fusion state and microstructure while significantly reducing welding deformation.

[0013] Furthermore, in the welding method shown in this invention, the angle α between the inclined portion and the vertical direction is 25-45°.

[0014] In this implementation, in order to reduce the weld bead area and reduce the amount of filler wire, the angle α between the inclined portion and the vertical direction is controlled between 25-45°.

[0015] Furthermore, in the welding method shown in this invention, the thickness b4 of the central straight portion is 0.5-1.5 mm.

[0016] In this implementation, in order to facilitate the assembly of the test plate and avoid burn-through and incomplete melting, the thickness b4 of the central straight section can be between 0.5-1.5 mm.

[0017] Furthermore, in the welding method shown in this invention, when the total thickness b1 of the stainless steel composite plate is greater than 16mm, it satisfies (b1-1-2b5)×tanα+w1≥15mm, where α represents the angle between the inclined part and the vertical direction, b5 represents the thickness of the straight part of the edge, and w1 represents the assembly gap.

[0018] In this implementation, in order to ensure the smooth downward movement of the tungsten inert gas welding torch and wire feeder during welding, when the total thickness b1 of the stainless steel composite plate is greater than 16mm, (b1-1-2b5)×tanα+w1≥15mm can be controlled.

[0019] Furthermore, in the welding method shown in this invention, the assembly gap w1 is 1-2 mm.

[0020] In this implementation, the assembly gap w1 can be controlled between 1-2 mm to facilitate welding.

[0021] Furthermore, in the welding method shown in this invention, the thickness b5 of the straight edge portion is less than or equal to the thickness b3 of the stainless steel composite layer.

[0022] In this implementation, in order to help reduce the weld width and shrinkage deformation, the thickness b5 of the straight edge portion is controlled to be less than or equal to the thickness b3 of the stainless steel cladding layer.

[0023] Furthermore, in the welding method shown in this invention, in the step of performing multi-pass welding on the substrate layer and the stainless steel cladding layer corresponding to the inclined portion and the straight edge portion using tungsten inert gas welding:

[0024] The first pass of the substrate layer is welded using hot-wire pulsed tungsten inert gas welding, and stainless steel welding wire is used for the filler metal.

[0025] The first pass of the stainless steel cladding layer was welded using single tungsten inert gas welding, and stainless steel welding wire was used for the filler metal.

[0026] Hot-wire oscillating tungsten inert gas welding is used to alternately fill and cover the substrate layer and the stainless steel cladding layer, with solid stainless steel welding wire as the welding material.

[0027] Furthermore, in the welding method shown in this invention, when performing root pass welding on the first weld bead of the substrate layer using hot-wire pulsed tungsten inert gas welding: the welding voltage is controlled at 11-13V, the welding current at 130-150A, the welding speed at 60-90mm / min, the wire feed speed at 0.6-1.0m / min, and the hot-wire current at 60-80A.

[0028] In this implementation, to avoid burn-through, hot-wire tungsten inert gas welding is used to perform the first weld bead on the substrate layer side. In order to reduce the difference in cooling shrinkage caused by the different types of welding materials in each layer, all the filler metal is made of stainless steel welding wire that matches the base material of the composite layer.

[0029] Furthermore, in the welding method shown in this invention, when welding the first weld pass of the stainless steel composite layer using single tungsten inert gas welding: the welding voltage is controlled at 11-12V, the welding current at 140-150A, the welding speed at 80-90mm / min, and the wire feed speed at 0.6-1.0m / min.

[0030] In this implementation, to avoid incomplete penetration, the hot wire process is eliminated, and tungsten inert gas welding is used to perform the first root pass on the composite layer side. The filler metal is made of stainless steel welding wire that matches the base material of the composite layer.

[0031] Furthermore, in the welding method shown in this invention, when hot-wire oscillating tungsten inert gas welding is used to alternately fill and cover the substrate layer and the stainless steel cladding layer: the welding voltage is controlled at 11-13V, the welding current at 130-160A, the welding speed at 50-70mm / min, the wire feed speed at 0.6-1.2m / min, the hot-wire current at 70-80A, and the oscillation amplitude at 0.5-3mm; and the number of weld passes applied to the substrate layer and the stainless steel cladding layer is controlled to be equal.

[0032] In this implementation, to achieve good forming while reducing interlocking with the base material to minimize welding shrinkage deformation, hot-wire oscillating tungsten inert gas welding is used. Filling and capping welding are performed alternately on the base material and cladding material sides of the composite plate weld. All welding materials used are solid welding wires with performance no lower than that of the stainless steel base material of the cladding layer. Furthermore, to reduce the difference in welding shrinkage caused by the inconsistent number of weld passes on both sides of the X-groove, the number of weld passes applied to both the base material and cladding material sides must be controlled to be equal.

[0033] The welding method for controlling welding deformation of stainless steel composite plates described in this invention has the following advantages and beneficial effects compared with the prior art:

[0034] The welding method described in this invention can ensure a good connection of stainless steel composite plates, while the weld fusion is good and free of defects.

[0035] The welding method described in this invention can effectively reduce the welding deformation of stainless steel composite plates.

[0036] The welding method described in this invention uses the most common tungsten inert gas (TIG) welding equipment. The equipment has low cost requirements, the welding process is parameterized and windowed, the assembly requirements are low, and the welding method does not need to be changed throughout the welding process. It is very friendly to actual industrial production conditions and has good scalability. Attached Figure Description

[0037] Figure 1 The diagram schematically illustrates the bevel used in the welding method for controlling welding deformation of stainless steel composite plates according to the present invention.

[0038] Figure 2 The cross-sectional morphology of the welded joint of the stainless steel composite plate of Embodiment 1 of the present invention is shown.

[0039] Figure 3 The image shows a metallographic structure inside the joint weld of the stainless steel composite plate of Embodiment 1 of the present invention. Detailed Implementation

[0040] The welding method for controlling welding deformation of stainless steel composite plates according to the present 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 improper limitation on the technical solution of the present invention.

[0041] Figure 1 The image shows two stainless steel composite panels, A and B, welded together to form weld 6. The stainless steel composite panel includes a base layer 1 (e.g., a carbon steel base layer) and a stainless steel cladding layer 2. Figure 1 In the diagram, "b1" indicates the total thickness of the stainless steel composite plate, "b2" indicates the thickness of the base material layer, and "b3" indicates the thickness of the stainless steel composite layer.

[0042] In one specific embodiment, a stainless steel composite plate with the grade SUS304-Q235 can be used, that is, the base material is Q235 and the stainless steel composite layer is SUS304. The thickness b1 of the stainless steel composite plate is 10mm, wherein the thickness b2 of the base material layer is 8mm and the thickness b3 of the stainless steel composite layer is 2mm.

[0043] In some embodiments, the welding method for controlling welding deformation of stainless steel composite plates may include the following steps:

[0044] 100: Processing is performed at the welding position of the two spliced ​​stainless steel composite plates A and B as follows. Figure 1 The X-shaped bevel shown is symmetrical in the thickness direction. It includes a central straight section 3, and two inclined sections and two edge straight sections located on either side of the central straight section 3 in the thickness direction. The inclined sections 4 connect to the central straight section 3, and the edge straight sections 5 connect to the inclined sections 4. The inclined sections and edge straight sections on the stainless steel composite layer side can be referred to as the "stainless steel composite layer side bevel," and the inclined sections and edge straight sections on the substrate layer side can be referred to as the "substrate layer side bevel."

[0045] The thickness of the central straight section 3 is Figure 1 The thickness of the central straight section 3, represented by "b4", is controlled between 0.5 and 1.5 mm to facilitate the assembly of the test plate and avoid burn-through and incomplete melting.

[0046] The thickness of the straight edge 5 is Figure 1 The thickness of the straight edge 5, represented by "b5", can be reduced by controlling the thickness of the stainless steel cladding layer to be less than or equal to the thickness of the cladding layer, thus reducing the weld width and shrinkage deformation.

[0047] Assembly gap at Figure 1 The assembly gap w1 is indicated by "w1". In some more specific implementations, the assembly gap w1 can be 1-2 mm to facilitate welding.

[0048] In some more specific embodiments, the angle α between the inclined portion 4 and the vertical direction can be between 25-45°, which can improve welding efficiency, reduce welding costs and reduce the weld bead filling area.

[0049] In some more specific embodiments, in order to ensure the smooth downward movement of the tungsten inert gas welding torch and the wire feeder, when the thickness b1 of the stainless steel composite plate is greater than or equal to 16mm, (b1-1-2b5)×tanα+w1≥15mm can be controlled, where α represents the angle between the inclined part 4 and the vertical direction, b5 represents the thickness of the straight edge part 5, and w1 represents the assembly gap.

[0050] 200: Tungsten inert gas welding is used to perform multi-pass welding on the substrate layer side bevel and the stainless steel composite layer side bevel.

[0051] In some specific implementations, step 200 includes:

[0052] The first weld bead (located near the core of the composite plate in the thickness direction) of the substrate layer side bevel is welded using hot-wire pulsed tungsten inert gas welding. The filler metal can be made entirely of stainless steel welding wire compatible with the base material of the composite layer. The welding voltage can be controlled at 11-13V, the welding current at 130-150A, the welding speed at 60-90mm / min, the wire feed speed at 0.6-1.0m / min, and the hot-wire current at 60-80A. In some more specific embodiments, the filler metal can be made of 309L solid welding wire compatible with the stainless steel of the composite layer.

[0053] The first weld bead (located near the core of the composite plate in the thickness direction) of the stainless steel cladding layer's side bevel is welded using single tungsten inert gas (TIG) welding. The filler metal can be a stainless steel welding wire compatible with the cladding layer's base material. The welding voltage can be controlled at 11-12V, the welding current at 140-150A, the welding speed at 80-90mm / min, and the wire feed speed at 0.6-1.0m / min. In some more specific embodiments, 309L stainless steel welding wire with performance no less than that of the cladding layer's stainless steel base material can be used.

[0054] The composite plate is welded in multiple passes from core to surface using hot-wire oscillating tungsten inert gas (TIG) welding, alternately filling and capping welds within the bevels on the substrate layer and stainless steel cladding layer sides. The filler metal can be made with solid welding wire of at least equal performance to the stainless steel base material of the cladding layer. The welding voltage can be controlled at 11-13V, welding current at 130-160A, welding speed at 50-70mm / min, wire feed speed at 0.6-1.2m / min, hot-wire current at 70-80A, and oscillation amplitude at 0.5-3mm. The number of weld passes on the substrate layer and stainless steel cladding layer sides is controlled to be equal. In some more specific embodiments, solid welding wire 309L of at least equal performance to the stainless steel base material of the cladding layer can be used.

[0055] To further demonstrate the technical effects of 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.

[0056] Table 1.

[0057]

[0058] Table 2 lists the welding process parameters used in the preferred embodiments 1-5 of the present invention when performing root pass welding on the first weld bead of the substrate layer.

[0059] Table 2.

[0060]

[0061] Table 3 lists the welding process parameters used in the preferred embodiments 1-5 of the present invention when welding the first weld pass of the composite layer.

[0062] Table 3.

[0063]

[0064] Table 4 lists the welding process parameters used in the preferred embodiments 1-5 of the present invention for filling and capping welding of the substrate layer and the stainless steel composite layer.

[0065] Table 4.

[0066]

[0067] Figure 2 The cross-sectional morphology of the welded joint of the stainless steel composite plate of Embodiment 1 of the present invention is shown.

[0068] from Figure 2 It can be seen that the stainless steel composite plate of Example 1 prepared by the method of the present invention has a good joint bonding, and there are no welding defects such as incomplete fusion or incomplete penetration. At the same time, the overall deformation of the joint is effectively controlled, and the deformation angle β is less than 5 degrees.

[0069] Figure 3 The image shows a metallographic structure inside the joint weld of the stainless steel composite plate of Embodiment 1 of the present invention.

[0070] from Figure 3 It can be seen that the metallographic structure of the weld of the stainless steel composite plate of Example 1 prepared by the method of the present invention is the microstructure of austenitic stainless steel base material, specifically austenite + δ ferrite. This indicates that the weld is not affected by the base material, and the weld quality is high from the perspective of microstructure.

[0071] Therefore, the welding method for welding deformation of stainless steel composite plates described in this invention can achieve good fusion connection of stainless steel composite plate welds, ensure that the joint has good microstructure and mechanical properties, and effectively control the welding deformation of the joint.

[0072] 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.

[0073] 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 controlling welding deformation of a stainless steel composite plate, wherein the stainless steel composite plate comprises a substrate layer and a stainless steel cladding layer; characterized in that, The welding method includes the following steps: A symmetrical X-shaped bevel is machined on the welding section of the stainless steel composite plate in the thickness direction. The X-shaped bevel includes a central straight section, and two inclined sections and two edge straight sections respectively provided on both sides of the central straight section in the thickness direction, wherein the inclined sections are connected to the central straight section. Tungsten inert gas (TIG) welding is used to perform multiple passes of welding on the base material layer and the stainless steel cladding layer, corresponding to the inclined and straight edge sections.

2. The welding method as described in claim 1, characterized in that, The angle α between the inclined part and the vertical direction is 25-45°.

3. The welding method as described in claim 1, characterized in that, The thickness b4 of the central straight section is 0.5-1.5 mm.

4. The welding method as described in claim 1, characterized in that, When the total thickness b1 of the stainless steel composite plate is greater than 16mm, it satisfies (b1-1-2b5)×tanα+w1≥15mm, where α represents the angle between the inclined part and the vertical direction, b5 represents the thickness of the straight part of the edge, and w1 represents the assembly gap.

5. The welding method as described in claim 1, characterized in that, The assembly clearance w1 is 1-2mm.

6. The welding method as described in claim 1, characterized in that, The thickness b5 of the straight edge portion is less than or equal to the thickness b3 of the stainless steel composite layer.

7. The welding method as described in claim 1, characterized in that, In the step of performing multi-pass welding on the substrate layer and stainless steel cladding layer corresponding to the inclined and straight edge sections using tungsten inert gas welding: The first pass of the substrate layer is welded using hot-wire pulsed tungsten inert gas welding, and stainless steel welding wire is used for the filler metal. The first pass of the stainless steel cladding layer was welded using single tungsten inert gas welding, and stainless steel welding wire was used for the filler metal. Hot-wire oscillating tungsten inert gas welding is used to alternately fill and cover the substrate layer and the stainless steel cladding layer, with solid stainless steel welding wire as the welding material.

8. The welding method as described in claim 7, characterized in that, When performing the first pass of the substrate layer using hot-wire pulsed tungsten inert gas welding: control the welding voltage to be 11-13V, the welding current to be 130-150A, the welding speed to be 60-90mm / min, the wire feed speed to be 0.6-1.0m / min, and the hot wire current to be 60-80A.

9. The welding method as described in claim 7, characterized in that, When welding the first pass of a stainless steel cladding layer using single tungsten inert gas welding: control the welding voltage to be 11-12V, the welding current to be 140-150A, the welding speed to be 80-90mm / min, and the wire feed speed to be 0.6-1.0m / min.

10. The welding method as described in claim 7, characterized in that, When using hot-wire oscillating tungsten inert gas welding to alternately fill and cover the substrate layer and the stainless steel cladding layer: control the welding voltage to be 11-13V, the welding current to be 130-160A, the welding speed to be 50-70mm / min, the wire feed speed to be 0.6-1.2m / min, the hot wire current to be 70-80A, and the oscillation amplitude to be 0.5-3mm; and control the number of weld passes on the substrate layer and the stainless steel cladding layer to be equal.

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