Economical welding method for stainless steel composite plate

Abstract

The invention discloses an economical welding method for a stainless steel composite plate, the stainless steel composite plate comprises a base material layer and a stainless steel composite material layer, and a transition layer is arranged at the bonding interface of the base material layer and the stainless steel composite material layer; the economical welding method comprises the steps that a composite groove is machined in the position, corresponding to a base material layer, of the welding section of the stainless steel composite plate, and the composite groove comprises a vertical inclined part, a transition arc, a horizontal inclined part and a horizontal part which are sequentially arranged; a rectangular groove is formed in the position, corresponding to the transition layer, of the welding section of the stainless steel composite plate; a groove is not machined in the position, corresponding to the stainless steel composite material layer, of the welding section of the stainless steel composite plate; laser welding is adopted for conducting self-fusion welding on the stainless steel composite layer; 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 pulse argon tungsten-arc welding.

Description

Technical Field

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

[0002] Stainless steel composite plate is a composite structural material made of stainless steel and low alloy structural steel through rolling, explosive composite and other methods. It has been gradually promoted and applied in industry because of its good mechanical properties and corrosion resistance.

[0003] Because the physical and chemical properties of the two component metals are quite different, stainless steel composite plates need to be connected by multi-layer and multi-pass welding. The composition transition of the stainless steel weld of the composite layer and the carbon steel weld of the substrate layer is achieved by adding a transition layer to avoid the decrease in the corrosion resistance of the composite layer weld (the forward welding sequence of substrate layer-transition layer-composite layer) or the deterioration of the mechanical properties of the substrate layer weld (the welding sequence of composite layer-transition layer-substrate layer). Generally speaking, no matter which welding sequence is used, stainless steel welding materials are used for the composite layer and transition layer welds. Although the filling area of ​​the transition layer and composite layer stainless steel welds is smaller than that of the substrate layer carbon steel weld, and the amount of welding materials used is relatively small, when the project volume increases and the corresponding weld length increases, its consumption is still very huge. Summary of the invention

[0004] One of the purposes of the present invention is to provide an economical welding method for stainless steel composite plates, which can use carbon steel welding materials as transition layers to complete the composition transition from stainless steel to carbon steel, thereby achieving reliable connection of stainless steel composite plates without the need for stainless steel welding materials, reducing the welding cost of stainless steel composite plates, and generating considerable economic benefits.

[0005] In order to achieve the above object, the present invention provides an economical welding method for a stainless steel composite plate, wherein the stainless steel composite plate comprises a substrate layer and a stainless steel composite layer, and a transition layer is provided at the bonding interface between the substrate layer and the stainless steel composite layer; wherein the economical welding method comprises the steps of:

[0006] A composite groove is processed at a position corresponding to the base material layer on the welding cross section of the stainless steel composite plate, wherein the composite groove sequentially includes a vertical inclined portion, a transition arc, a horizontal inclined portion and a horizontal portion; a rectangular groove is opened at a position corresponding to the transition layer on the welding cross section of the stainless steel composite plate; and no groove is processed at a position corresponding to the stainless steel composite material layer on the welding cross section of the stainless steel composite plate;

[0007] Laser welding is used to perform autogenous welding on the stainless steel composite layer;

[0008] Use carbon steel welding wire that matches the base material layer and laser welding to fill the transition layer;

[0009] The base material layer is welded by hot wire pulse swing tungsten inert gas arc welding.

[0010] In the present invention, the inventors can use carbon steel welding materials as transition layers to complete the transition of stainless steel to carbon steel composition through special design of grooves and a specific welding method, thereby realizing reliable connection of stainless steel composite plates without using stainless steel welding materials. Among them, the use of carbon steel welding materials to complete the filling of the transition layer weld can keep the transition layer weld as austenite + ferrite structure with good plasticity and toughness.

[0011] Furthermore, in the economical welding method for stainless steel composite plates described in the present invention, the single-side width w1 / 2 of the rectangular groove should be controlled within the range of the laser spot radius of laser welding -0.5 mm.

[0012] In this embodiment, rectangular grooves and horizontal extensions on both sides are opened at the transition layer weld position. When two stainless steel composite plates are laser-filled with wires for transition layer welding, the laser heat source will melt the rectangular grooves, horizontal extensions on both sides and part of the composite material layer, and finally form a transition layer weld. The groove width of the transition layer weld is greater than or equal to the laser spot diameter, which can ensure that the laser self-melting welding of the composite layer weld is completed smoothly without melting the carbon steel substrate. At the same time, by setting an upper limit of 0.5mm on the single-side width w1 / 2 of the rectangular groove, the final width of the transition layer weld can be controlled, which is helpful for the low dilution rate control of the substrate layer weld, especially the carbon steel weld in contact with the transition layer.

[0013] Furthermore, in the economical welding method for stainless steel composite plates described in the present invention, the thickness b3 of the rectangular groove is 0.05-0.5 mm.

[0014] In this embodiment, the thickness b3 of the rectangular groove, i.e., the distance between the base material layer weld step and the bonding interface of the base material layer and the stainless steel clad material layer, can be controlled within a certain range and the smaller the better. However, if b3 is too small, the base material layer weld, especially the first layer of several welds, will be required to have a very shallow penetration during welding to avoid penetrating the base material layer to the stainless steel clad material layer. Therefore, the range of b3 can be limited to 0.05mm≤b3≤0.5mm.

[0015] Furthermore, in the economical welding method for stainless steel composite plates described in the present invention, the width w2 of the horizontal portion of the composite groove is 0.5-1 mm.

[0016] Furthermore, in order to reduce the melting of carbon steel components in the transition layer weld, a horizontal portion should be provided between the horizontally inclined portion of the composite groove of the substrate layer and the rectangular groove of the transition layer, and its single-side width is w2, and the distance from the composite plate substrate layer-composite layer bonding interface is also b3. Considering that the designed b3 is small, in order to reduce the difficulty of welding the subsequent substrate layer weld, the single-side width w2 of the horizontal portion of the composite groove of the substrate layer should not be too large, and is controlled between 0.5mm≤w2≤1mm. In this embodiment, by providing the horizontal portion w2 within the range of 0.5mm-1mm, the melting of carbon steel components in the transition layer can be reduced while reducing the difficulty of welding the subsequent substrate layer weld as much as possible.

[0017] Furthermore, in the economical welding method for stainless steel composite plates described in the present invention, the angle α2 between the vertical inclined portion and the vertical direction is ≥(1.5b1)°, where b1 represents the distance between the surface of the substrate layer and the bonding interface between it and the stainless steel composite layer, and its unit parameter is mm.

[0018] In this embodiment, the included angle α2 between the vertical inclined portion and the vertical direction is controlled to be ≥ (1.5b1)°, which can facilitate the subsequent hot wire pulse swing tungsten inert gas arc welding operation.

[0019] Furthermore, in the economical welding method for stainless steel composite plates described in the present invention, the angle α1 between the horizontal inclined portion and the horizontal direction is ≥5°.

[0020] This arrangement is beneficial to avoid melting through the base material layer parent material to the stainless steel composite material layer parent material.

[0021] Furthermore, in the economical welding method for stainless steel composite plates described in the present invention, the extension width w3 of the horizontal inclined portion is ≥ (5+0.1b1), where b1 represents the distance between the surface of the substrate layer and the bonding interface between the substrate layer and the stainless steel composite layer, and its unit parameter is mm.

[0022] In this embodiment, the extension width w3 of the horizontal inclined portion is controlled to be ≥ (5+0.1b1), so as to avoid melting through the base material layer parent material to the stainless steel composite material layer parent material.

[0023] Furthermore, in the economical welding method for stainless steel composite plates described in the present invention, the radius of the transition arc r≥0.2w3, where w3 represents the extension width of the horizontal inclined portion, and its unit parameter is mm.

[0024] For an embodiment in which a smaller rectangular groove thickness b3 is intentionally designed (for example, the embodiment in which b3 is 0.05-0.5 mm as described above), since this embodiment will greatly limit the heat input during carbon steel weld welding, in order to avoid unfused welding defects during base material layer weld welding, it is preferred to control the radius of the transition arc r≥0.2w3.

[0025] Furthermore, in the economical welding method for stainless steel composite plates described in the present invention, in the step of self-fusion welding the stainless steel composite layer by laser welding: the laser power is controlled to be 5.0-6.0KW, the welding speed is 3.5-4.0m / min, and the positive defocus is 0-5mm.

[0026] Furthermore, in the economical welding method for stainless steel composite plates described in the present invention, in the step of performing autogenous welding on the stainless steel composite layer by laser welding, the diameter of the laser spot used is ≤1 mm.

[0027] Furthermore, in the economical welding method for stainless steel composite plates described in the present invention, in the step of performing wire-filling welding on the transition layer by laser welding, the diameter of the laser spot used is ≤1 mm.

[0028] Furthermore, in the economical welding method for stainless steel composite plates described in the present invention, in the step of using laser welding to filler wire weld the transition layer: the laser power is controlled to be 6.0-8.0KW, the welding speed is 5.0-6.0m / min, the positive defocus is 10-15mm, the wire feeding speed is 0.2-0.5m / min, and the wire feeding angle is 45-60°.

[0029] In this embodiment, by cooperating with a specially designed groove form, the transition layer weld will melt part of the stainless steel composite layer weld downward, and ultimately ensure that the ratio of the carbon steel component (including carbon steel parent material and carbon steel welding wire) melted into the transition layer weld does not exceed 25%, thereby the transition layer weld can still maintain a parent phase austenite + ferrite structure with good toughness.

[0030] Furthermore, in the economical welding method for stainless steel composite plates described in the present invention, in the step of welding the substrate layer using hot wire pulse swing tungsten inert gas arc welding: the welding voltage is controlled to be 13.0-15.0V, the peak current is 180-220A, the base current is 70-120A, the duty cycle is 40-70%, the pulse frequency is 3-8Hz, the hot wire current is 60-80A, the welding speed is 150-180mm / min, the wire feeding speed is 2.2-2.6m / min, and the swing width is 1-2mm.

[0031] In this embodiment, when the hot wire pulse tungsten inert gas arc welding is used to complete the filling of the base layer weld, the oscillation can be added to further reduce the penetration depth and dilution rate. The use of this welding method in combination with the specially designed groove form can ensure that the dilution rate of the base layer weld, especially the carbon steel weld directly in contact with the transition layer weld, is controlled below 4.0% without penetrating the base layer weld step.

[0032] The economical welding method of the stainless steel composite plate of the present invention has the following advantages and beneficial effects compared with the prior art:

[0033] The welding method described in the present invention can use carbon steel welding materials as a transition layer to complete the composition transition from stainless steel to carbon steel, thereby realizing reliable connection of stainless steel composite plates without using stainless steel welding materials, reducing the welding cost of stainless steel composite plates and generating considerable economic benefits. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 The schematic diagram of the groove used in the economical welding method of the stainless steel composite plate described in the present invention is schematically shown.

[0035] Figure 2 The figure shows the morphology of the welded joint of the stainless steel composite plate prepared by the economical welding method of Example 1 of the present invention after being corroded by nitric acid.

[0036] Figure 3 The metallographic structure photograph of the transition layer / carbon steel substrate layer weld joint cross section of the stainless steel composite plate welded joint prepared by the economical welding method of Example 1 of the present invention after being corroded by nitric alcohol is shown. DETAILED DESCRIPTION

[0037] The economical welding method of the stainless steel composite plate of the present invention will be further explained and illustrated below in conjunction with specific embodiments and the accompanying drawings of the specification. However, such explanation and illustration do not constitute an improper limitation on the technical solution of the present invention.

[0038] The object of the present invention is to provide an economical welding method for stainless steel composite plates. Figure 1 Shows two joined stainless steel composite panels A and B. Figure 1 The dotted line O in the figure represents a joint. The stainless steel composite plate comprises a carbon steel substrate layer 1 and a stainless steel composite material layer 2, and a transition layer is provided at the bonding interface between the carbon steel substrate layer 1 and the stainless steel composite material 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 stainless steel composite layer, and the symbol "b2" represents the distance between the surface of the stainless steel composite layer and the bonding interface between it and the carbon steel substrate layer.

[0039] In a specific embodiment, a stainless steel composite plate with a grade of SUS304 / Q235 can be used, that is, the base material is Q235, and the stainless steel composite material is SUS304. The thickness of the stainless steel composite plate is 10 mm, wherein b2 of the stainless steel composite plate is 2 mm, and b1 is 8 mm.

[0040] In some embodiments, an economical welding method for stainless steel clad plates comprises the steps of:

[0041] 100: Processing at the welding position of two spliced ​​stainless steel composite plates A and B as follows Figure 1 The groove shown. A composite groove is processed at a position corresponding to the base material layer on the welding section of the stainless steel composite plate. The composite groove includes a vertical inclined portion 6, a transition arc 7, a horizontal inclined portion 8 and a horizontal portion 9 arranged in sequence. The width (single side) of the horizontal portion 9 is Figure 1 Indicated by "w2"; a rectangular groove 10 is opened at the position corresponding to the transition layer on the welding section of the stainless steel composite plate, and the single-side width of the rectangular groove is w1 / 2; no groove is processed at the position corresponding to the stainless steel composite layer on the welding section of the stainless steel composite plate, that is, the welding surface of the stainless steel composite layer is a vertical plane.

[0042] 200: The stainless steel composite layer is self-welded by laser welding to form a composite layer weld 3.

[0043] 300: Use carbon steel welding wire that matches the base material layer and use laser welding to fill the transition layer to form a transition layer weld 4, that is, Figure 1 In this step, when laser wire welding is performed, the laser heat source melts the rectangular groove, the horizontal portions extending on both sides, and melts part of the composite material layer downward, finally forming a transition layer weld 4.

[0044] 400: Use carbon steel welding wire that matches the carbon steel substrate layer, and adopt hot wire pulse swing tungsten inert gas arc welding to perform wire welding on the carbon steel substrate layer to form a substrate layer weld 5.

[0045] Preferably, in some embodiments, the single-side width w1 / 2 of the rectangular groove should be controlled within the range of the laser spot radius of laser welding -0.5 mm, that is, the total width w1 of the two rectangular grooves formed by the two spliced ​​stainless steel composite plates A and B is controlled within the range of the laser spot diameter of laser welding -1 mm. This design can ensure that the laser autogenous welding of the stainless steel composite layer weld is successfully completed and the carbon steel substrate is not melted to obtain a smaller width transition layer weld.

[0046] Preferably, in some embodiments, the thickness b3 of the rectangular groove may be limited to a range of 0.05 mm ≤ b3 ≤ 0.5 mm.

[0047] Preferably, in some embodiments, the included angle α2 between the vertical inclined portion 6 and the vertical direction is ≥(1.5b1)°, where b1 represents the distance between the surface of the substrate layer and the bonding interface between the substrate layer and the stainless steel composite layer, and its unit parameter is mm. In this embodiment, the subsequent hot wire pulse swing tungsten inert gas arc welding operation can be facilitated by controlling the included angle α2.

[0048] Preferably, in some embodiments, the angle α1 between the horizontal inclined portion 8 and the horizontal direction is ≥5°, and the extension width w3 of the horizontal inclined portion 8 is ≥(5+0.1b1). In this embodiment, melting through the carbon steel substrate layer parent material to the stainless steel composite layer parent material can be avoided.

[0049] Preferably, in some embodiments, the radius r of the transition arc 7 is ≥ 0.2w3, wherein w3 represents the extension width of the horizontal inclined portion 8, and its unit parameter is mm.

[0050] Preferably, in some embodiments, in step 200, laser autogenous welding is used for welding, and the laser spot diameter used is ≤1mm to form the composite layer weld 3. The laser power can be controlled to be 5.0-6.0KW, the welding speed to be 3.5-4.0m / min, and the positive defocus amount to be 0-5mm.

[0051] In step 300, laser wire welding is used to weld the transition layer weld 4. The filler metal can be ER50-6. The laser spot diameter is ≤1mm, the laser power is controlled to be 6.0-8.0KW, the welding speed is 5.0-6.0m / min, the positive defocus is 10-15mm, the wire feeding speed is 0.2-0.5m / min, and the wire feeding angle is 45-60°.

[0052] By adopting this preferred embodiment, with the specially designed groove form, the transition layer weld will melt part of the composite layer weld downwards, and ultimately ensure that the ratio of carbon steel components (including carbon steel base material and carbon steel welding wire) melted into the transition layer weld does not exceed 25%.

[0053] 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 adopts hot wire pulse tungsten inert gas arc welding, and the welding voltage is controlled to be 13.0-15.0V, the peak current is 180-220A, the base current is 70-120A, the duty cycle is 40-70%, the pulse frequency is 3-8Hz, the hot wire current is 60-80A, the welding speed is 150-180mm / min, the wire feeding speed is 2.2-2.6m / min, and the swing width is 1-2mm.

[0054] In this embodiment, when hot wire pulse oscillating tungsten inert gas arc welding is used to complete the filling of the base layer weld, the special groove form designed in the present invention can ensure that the dilution rate of the carbon steel weld, especially the carbon steel weld in direct contact with the transition layer weld, is controlled below 4.0% on the basis of the non-penetrating carbon steel weld step.

[0055] 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.

[0056] Table 1.

[0057]

[0058] 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.

[0059] Table 2.

[0060]

[0061] 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.

[0062] Table 3.

[0063]

[0064] 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.

[0065] Table 4

[0066]

[0067] 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 stainless steel composite plate obtained by welding in Example 1 of the present invention. By calculation, it can be obtained that the dilution rate of the transition layer weld relative to the composite layer weld is 82.10%, and the dilution rate of the carbon steel weld directly in contact with the transition layer relative to the composite layer weld is 3.25% (lower than 4.0%), thereby avoiding the formation of martensitic structure in the carbon steel weld.

[0068] Table 5.

[0069]

[0070]

[0071] Figure 2The figure shows the morphology of the welded joint of the composite plate prepared by the economical welding method of Example 1 of the present invention after being corroded by nitric acid.

[0072] from Figure 2 It can be seen from the figure that the welded joint is well bonded, indicating that the method of the present invention can be used to connect stainless steel composite plates.

[0073] Figure 3 The metallographic structure photograph of the transition layer / carbon steel weld joint section of the welded joint of the composite plate prepared by the economical welding method of Example 1 of the present invention after being corroded by nitric alcohol is shown.

[0074] from Figure 3 It can be seen that the transition layer weld cannot be corroded by nitric acid, indicating that it still retains the base material austenite corrosion-resistant structure, and the carbon steel weld adjacent to the transition layer has a structure of ferrite + pearlite, without martensite, which means that the purpose of the present invention is achieved, that is, the carbon steel welding material is used to complete the structure / composition transition from the transition layer of the stainless steel composite plate to the carbon steel weld, and the composite plate joint connection is reliable.

[0075] 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.

[0076] 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 the contents disclosed by those skilled in the art from the present invention, and all should belong to the protection scope of the present invention.

Claims

1. An economical welding method for a stainless steel composite plate, wherein the stainless steel composite plate comprises a substrate layer and a stainless steel composite layer, wherein a transition layer is provided at a bonding interface between the substrate layer and the stainless steel composite layer; It is characterized in that The economical welding method comprises the steps of: Processing a composite groove at a position corresponding to the base material layer on the welding cross section of the stainless steel composite plate, wherein the composite groove includes a vertical inclined portion, a transition arc, a horizontal inclined portion and a horizontal portion arranged in sequence; opening a rectangular groove at a position corresponding to the transition layer on the welding cross section of the stainless steel composite plate; and not processing a groove at a position corresponding to the stainless steel composite material layer on the welding cross section of the stainless steel composite plate; Laser welding is used to perform autogenous welding on the stainless steel 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 pulse swing tungsten inert gas arc welding.

2. The economical welding method for stainless steel composite plate according to claim 1, characterized in that: The single-side width w1 / 2 of the rectangular groove is ≥ the laser spot radius of laser welding and ≤ 0.5 mm.

3. The economical welding method for stainless steel composite plate according to claim 1, characterized in that: The thickness b3 of the rectangular groove is 0.05-0.5 mm.

4. The economical welding method for stainless steel composite plate according to claim 1, characterized in that: The width w2 of the horizontal portion of the composite groove is 0.5-1 mm.

5. The economical welding method for stainless steel composite plate according to claim 1, characterized in that: The included angle α2 between the vertical inclined portion 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 stainless steel composite layer, and its unit parameter is mm.

6. The economical welding method for stainless steel composite plate according to claim 1, characterized in that: The included angle α1 between the horizontal inclined portion and the horizontal direction is ≥5°.

7. The economical welding method for stainless steel composite plate according to claim 1, characterized in that: The extension width w3 of the horizontal inclined portion 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 stainless steel composite layer, and its unit parameter is mm.

8. The economical welding method for stainless steel composite plate according to claim 1, characterized in that: The radius r of the transition arc is ≥ 0.2w3, where w3 represents the extension width of the horizontal inclined portion, and its unit parameter is mm.

9. The economical welding method for stainless steel composite plate according to claim 1, characterized in that: In the step of self-fusion welding the stainless steel composite layer by laser welding: the laser power is controlled to be 5.0-6.0KW, the welding speed is 3.5-4.0m / min, and the positive defocus is 0-5mm.

10. The economical welding method for stainless steel composite plate according to claim 1, characterized in that: In the step of self-fusion welding the stainless steel composite layer by laser welding, the diameter of the laser spot used is ≤1 mm.

11. The economical welding method for stainless steel composite plate 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.

12. The economical welding method for stainless steel composite plate 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 6.0-8.0KW, the welding speed to 5.0-6.0m / min, the positive defocus to 10-15mm, the wire feeding speed to 0.2-0.5m / min, and the wire feeding angle to 45-60°.

13. The economical welding method for stainless steel composite plate according to claim 1, characterized in that: In the step of welding the substrate layer using hot wire pulse swing tungsten inert gas arc welding: control the welding voltage to 13.0-15.0V, the peak current to 180-220A, the base current to 70-120A, the duty cycle to 40-70%, the pulse frequency to 3-8Hz, the hot wire current to 60-80A, the welding speed to 150-180mm / min, the wire feeding speed to 2.2-2.6m / min, and the swing width to 1-2mm.

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