High-quality welding method for stainless steel composite plate

Abstract

The invention discloses a high-quality 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 high-quality welding method comprises the steps that an X-shaped groove is machined in the position, corresponding to a base material layer, of the welding section of the stainless steel composite plate, and a truncated edge is arranged in the middle of the X-shaped groove; trapezoidal grooves are formed in the positions, corresponding to the transition layer and the stainless steel composite material layer, of the welding section of the stainless steel composite plate; welding the base material layer by adopting submerged-arc welding; the transition layer is welded through double-tungsten-electrode argon arc welding; and the stainless steel composite material layer is welded through double-tungsten-electrode argon arc welding. According to the method, the width and the hardening degree of a hard and brittle micro-area on the welding interface of the transition layer and the base material layer in the welding sequence of the base material layer, the transition layer and the composite material layer are effectively controlled while the extremely low dilution rate level of the composite material layer is guaranteed, and the bonding performance of the interface is effectively improved.

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 new type of multi-component metal structural material. It uses the base material layer of carbon steel to ensure overall strength and toughness, while using the composite layer of stainless steel to achieve functional requirements such as corrosion resistance and aesthetics.

[0003] Due to the large difference in composition between stainless steel and carbon steel, multi-layer and multi-pass welding should be used when welding stainless steel composite plates in engineering (i.e., the joint welds are divided into stainless steel composite layer welds, transition layer welds, and carbon steel base layer welds, which are welded separately) to ensure the corrosion resistance and overall mechanical properties of the joint composite layer welds. In most industrial manufacturing scenarios, the welding of stainless steel composite plates adopts the welding sequence of base layer-transition layer-composite layer, because the welding operation under this welding sequence is easier to achieve, and more importantly, the composition transition from carbon steel to stainless steel (i.e., the dilution rate of the composite layer and transition layer welds) is easier to complete, and the corrosion resistance of the composite layer is easier to ensure.

[0004] But in fact, in the welding sequence of substrate layer-transition layer-composite layer, the key points of welding stainless steel composite plates are not only the composition transition of the substrate layer carbon steel to the composite layer stainless steel (dilution rate control), but also the interface control problem between the transition layer and the substrate layer.

[0005] Since the above welding is essentially a dissimilar metal connection between stainless steel and carbon steel, a transition micro-zone will inevitably be generated at the interface between the transition layer weld and the base layer weld. Since the main structure of the transition micro-zone is a martensitic structure, the interface area will be significantly hardened and brittle. Such a hard and brittle micro-zone will cause the interface area to undergo non-uniform plastic deformation when subjected to load, and then cracking and failure will occur. Therefore, the existence of a hard and brittle transition micro-zone at the welding interface between the transition layer and the base layer is a hidden danger to the service safety of the joint and needs to be controlled. However, there is no method to solve the above problem in the prior art. Summary of the invention

[0006] The object of the present invention is to provide a high-quality welding method for stainless steel composite plates. The method is based on a specially designed groove and uses a variety of arc welding methods. While ensuring an extremely low dilution rate level of the stainless steel composite layer, the width and hardening degree of the hard and brittle micro-regions on the welding interface between the transition layer and the substrate layer in the welding sequence of the substrate layer-transition layer-stainless steel composite layer are effectively controlled, and the bonding performance of the interface is effectively improved, thereby achieving high-quality connection of the stainless steel composite plate in the welding sequence of the substrate layer-transition layer-stainless steel composite layer.

[0007] In order to achieve the above object, the present invention provides a high-quality 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; the high-quality welding method comprises the steps of:

[0008] An X-shaped groove is processed at the position corresponding to the base material layer on the welding section of the stainless steel composite plate, and a blunt edge is arranged in the middle of the X-shaped groove; a trapezoidal groove is opened at the position corresponding to the transition layer and the stainless steel composite material layer on the welding section of the stainless steel composite plate;

[0009] The base material layer is welded by submerged arc welding;

[0010] The transition layer is welded by double tungsten inert gas arc welding;

[0011] Double tungsten inert gas arc welding is used to weld the stainless steel composite layer.

[0012] Furthermore, in the high-quality welding method for stainless steel composite plates described in the present invention, the angle between the inclined portion of the X-shaped groove and the vertical direction is consistent with the angle between the inclined portion of the trapezoidal groove and the vertical direction.

[0013] Furthermore, in the high-quality welding method for stainless steel composite plates described in the present invention, the angle between the inclined portion of the X-shaped groove and the vertical direction and the angle between the inclined portion of the trapezoidal groove and the vertical direction are both α≥(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.

[0014] In this embodiment, the groove design can facilitate the subsequent operation of the welding gun for submerged arc welding and double tungsten electrode argon arc welding.

[0015] Furthermore, in the high-quality welding method for stainless steel composite plates described in the present invention, the thickness b3 of the blunt edge of the X-shaped groove is controlled within the range of 2-4 mm, and zero-gap assembly is maintained, which is combined with the process parameter window of the base submerged arc welding to achieve good forming while avoiding the first base weld from melting through.

[0016] Furthermore, in the high-quality welding method for stainless steel composite plates described in the present invention, the single-side width of the step of the trapezoidal groove w2≥(2+0.1b1), 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.

[0017] Furthermore, in the high-quality welding method for stainless steel composite plates described in the present invention, the distance w1 between the step plane of the trapezoidal groove and the bonding interface between the substrate layer and the stainless steel composite layer is controlled within the range of 0.5b2-0.8b2, where b2 represents the distance between the surface of the stainless steel composite layer and the bonding interface between it and the substrate layer, and its unit parameter is mm.

[0018] In this embodiment, due to the special arc characteristics of dual tungsten electrode argon arc welding, the surface flatness of the workpiece to be welded is required to be relatively high, so a step can be provided in the groove of the carbon steel substrate layer. Considering the large volume of the dual tungsten electrode argon arc welding torch, the distance w1 between the step plane of the trapezoidal groove and the bonding interface between the carbon steel substrate layer and the stainless steel composite layer and the single-side width w2 of the step of the trapezoidal groove can be controlled to facilitate subsequent torch operation.

[0019] Furthermore, in the high-quality welding method for stainless steel composite plates described in the present invention, in the step of welding the substrate layer using submerged arc welding: use a carbon steel welding wire that matches the substrate layer, control the welding current to 400-600A, the welding voltage to 25-35V, and the welding speed to 0.5-1.0m / min.

[0020] In this embodiment, the above embodiment can ensure that the carbon steel substrate layer weld has sufficiently good forming, especially the excess height of the carbon steel substrate layer weld can be kept flush with the step, and the higher surface flatness will be beneficial to the forming control of double tungsten electrode argon arc welding.

[0021] Furthermore, in the high-quality welding method for stainless steel composite plates described in the present invention, in the step of welding the transition layer using double tungsten electrode argon arc welding: a stainless steel welding wire with performance not lower than that of the stainless steel composite layer is used.

[0022] Furthermore, in the high-quality welding method for stainless steel composite plates described in the present invention, in the step of welding the transition layer using double tungsten electrode argon arc welding: the welding voltage is controlled to be 14-15V, the welding current is 360-420A, the welding speed is 300-340mm / min, the wire feeding speed is 4.6-5.0m / min, and the gap between the two tungsten electrodes is 0.5-1.5mm.

[0023] Furthermore, in the high-quality welding method for stainless steel composite plates described in the present invention, in the step of welding the stainless steel composite layer using double tungsten electrode argon arc welding: using a stainless steel welding wire matching the stainless steel composite layer, controlling the welding voltage to 14-15V, the welding current to 360-420A, the welding speed to 300-340mm / min, the wire feeding speed to 4.6-5.0m / min, and the gap between the two tungsten electrodes to 0.5-1.5mm.

[0024] In this embodiment, when the above embodiment is adopted, in combination with a specially designed stepped composite groove, the dilution rates of the transition layer weld and the stainless steel composite layer can be controlled below 15% and 3%, respectively, while greatly reducing the width of the martensitic hardened layer at the interface between the transition layer and the carbon steel substrate layer, and controlling the hardening degree of the weld to below 30% compared to the carbon steel substrate layer weld, thereby ensuring that the interface area does not undergo uneven plastic deformation when subjected to a large load, thereby improving the interface reliability.

[0025] The high-quality welding method for stainless steel composite plates described in the present invention has the following advantages and beneficial effects compared with the prior art:

[0026] The welding method described in the present invention can effectively control the width and hardening degree of the hard and brittle micro-regions on the welding interface between the transition layer of the stainless steel composite plate and the carbon steel substrate layer in the welding sequence of the carbon steel substrate layer-transition layer-stainless steel composite layer while ensuring an extremely low dilution rate level of the stainless steel composite layer, thereby effectively improving the bonding performance of the interface, thereby achieving high-quality connection of the stainless steel composite plate in the welding sequence of the carbon steel substrate layer-transition layer-stainless steel composite layer.

[0027] At the same time, since the welding method described in the present invention adopts automated welding technology and parameterized welding process, it is less dependent on the welding qualifications and experience of the welding personnel, and therefore has good scalability.

[0028] In addition, the welding methods adopted by the method of the present invention are all high-efficiency welding methods, which have the characteristics of fast welding speed and high deposition efficiency, and can greatly reduce the on-site construction time. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 The schematic diagram of the groove used in the high-quality welding method for stainless steel composite plates described in the present invention is schematically shown.

[0030] Figure 2 The cross-sectional morphology of a composite plate joint prepared by the high-quality welding method for stainless steel composite plates according to Example 1 of the present invention after being corroded by a stainless steel corrosive agent - Carlin's reagent is shown.

[0031] Figure 3 The metallographic structure photograph of the composite plate joint prepared by the high-quality welding method of the stainless steel composite plate of Example 1 of the present invention is shown at the interface between the transition layer and the carbon steel weld in the composite plate joint after being corroded by the stainless steel corrosive agent - Carlin's reagent.

[0032] Figure 4The composite plate joint prepared by the high-quality welding method of the stainless steel composite plate of Example 1 of the present invention is shown, and the plastic deformation at the interface between the transition layer and the carbon steel weld in the stainless steel composite plate joint is shown under the action of a large load indentation of 30Kgf. DETAILED DESCRIPTION

[0033] The high-quality 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 drawings of the specification, however, such explanation and illustration do not constitute an improper limitation on the technical solution of the present invention.

[0034] Figure 1 Shows two joined stainless steel composite panels A and B. Figure 1 The dotted line O in the figure represents a joint seam. The stainless steel composite plate comprises a stainless steel composite material layer 1 and a carbon steel substrate layer 2, and a transition layer is provided at the bonding interface between the stainless steel composite material layer 1 and the carbon steel substrate 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.

[0035] In a specific embodiment, a stainless steel composite plate with a grade of SUS304 / Q235 can be used, that is, the carbon steel substrate layer material is Q235, and the stainless steel composite layer material is SUS304. The plate thickness of the stainless steel composite plate is 19 mm, wherein b1 of the stainless steel composite plate is 16 mm, and b2 is 3 mm.

[0036] In some embodiments, the high quality welding method of the stainless steel composite plate of the present invention may include the steps of:

[0037] 100: Processing at the welding position of two spliced ​​stainless steel composite plates A and B as follows Figure 1 The groove shown in FIG. Among them, an X-shaped groove is processed at the position corresponding to the carbon steel substrate layer on the welding section of the stainless steel composite plate, and a blunt edge 6 is provided in the middle of the X-shaped groove, and the thickness of the blunt edge is Figure 1 It is represented by "b3" in the text.

[0038] A trapezoidal groove is opened on the welding section of the stainless steel composite plate at the position corresponding to the transition layer and the stainless steel composite layer. The single-side width of the step of the trapezoidal groove is Figure 1 In some more specific embodiments, the step width w2 of the trapezoidal groove can be controlled to be greater than or equal to (2+0.1b1); the distance between the step plane of the trapezoidal groove and the bonding interface between the carbon steel substrate layer and the stainless steel composite layer is about 1 / 4 of the distance between the step plane of the trapezoidal groove and the bonding interface between the carbon steel substrate layer and the stainless steel composite layer. Figure 1In some more specific embodiments, the distance w1 between the step plane of the trapezoidal groove and the bonding interface between the substrate layer and the stainless steel composite layer can be controlled within the range of 0.5b2-0.8b2. b3 is controlled within the range of 2-4mm, and the two welding test plates are assembled with zero gap.

[0039] In this embodiment, due to the special arc characteristics of dual tungsten electrode argon arc welding, it has a high requirement for the flatness of the surface of the workpiece to be welded, so a step can be opened in the groove of the carbon steel substrate layer. Considering the large volume of the dual tungsten electrode argon arc welding torch, the distance w1 between the step plane of the trapezoidal groove and the bonding interface between the carbon steel substrate layer and the stainless steel composite layer and the single-side width w2 of the step of the trapezoidal groove can be controlled to facilitate the subsequent welding gun operation. At the same time, the blunt edge design and zero-gap assembly can ensure that the first base weld will not be melted through and is well formed.

[0040] In some embodiments, the angle between the inclined portion 7 of the X-shaped groove and the vertical direction is consistent with the angle between the inclined portion 8 of the trapezoidal groove and the vertical direction.

[0041] In some more specific embodiments, the angle between the inclined portion 7 of the X-shaped groove and the vertical direction and the angle between the inclined portion 8 of the trapezoidal groove and the vertical direction can be controlled to be α≥(1.5b1)°.

[0042] In this embodiment, the welding gun operation of subsequent submerged arc welding and double tungsten inert gas welding can be facilitated.

[0043] 200: The carbon steel substrate layer is welded by submerged arc welding to obtain a carbon steel substrate layer weld 3. During welding, one inner and one outer weld are performed (inner weld first and then outer weld). A carbon steel welding wire matching the carbon steel substrate layer is used, such as CHW-S1 welding wire. The welding process parameters can be controlled as follows: welding current is 400-600A, welding voltage is 25-35V, and welding speed is 0.5-1.0m / min.

[0044] The above welding process can ensure that the weld of the carbon steel substrate layer has a sufficiently good forming, especially the excess height of the weld of the carbon steel substrate layer can be kept flush with the step, and the higher surface flatness will be beneficial to the subsequent forming control of double tungsten electrode argon arc welding.

[0045] 300: The transition layer is welded by double tungsten electrode argon arc welding to obtain a transition layer weld 4, and the welding performance is not lower than that of the stainless steel composite layer of the stainless steel welding wire, such as the stainless steel welding wire ER309L; the welding process parameters can be controlled as follows: welding voltage is 14-15V, welding current is 360-420A, welding speed is 300-340mm / min, wire feeding speed is 4.6-5.0m / min, and the gap between the two tungsten electrodes is 0.5-1.5mm. In some specific embodiments, the angle ε between the tungsten electrode arrangement direction and the welding direction can be controlled to be 0 degrees.

[0046] 400: The stainless steel composite layer is welded by double tungsten electrode argon arc welding to obtain a stainless steel composite layer weld 5, and a stainless steel welding wire matching the stainless steel composite layer is used for welding, such as stainless steel welding wire ER309L; the welding process parameters can be controlled as follows: welding voltage is 14-15V, welding current is 360-420A, welding speed is 300-340mm / min, wire feeding speed is 4.6-5.0m / min, and the gap between the two tungsten electrodes is 0.5-1.5mm. In some specific embodiments, the angle ε between the tungsten electrode arrangement direction and the welding direction can be controlled to be 0 degrees.

[0047] By adopting the above welding process and combining it with a specially designed stepped composite groove, the dilution rates of the transition layer weld and the stainless steel composite layer weld can be controlled below 15% and 3% respectively. At the same time, the width of the martensitic hardened layer at the interface between the transition layer and the carbon steel substrate layer can be greatly reduced, and the degree of hardening can be controlled below 30% compared to the carbon steel substrate layer weld, thereby ensuring that the interface area will not undergo uneven plastic deformation when subjected to large loads, thereby improving interface reliability.

[0048] In order to further reflect the technical effects of 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.

[0049] Table 1.

[0050]

[0051]

[0052] Table 2 lists the welding process parameters used in the steps of forming the carbon steel substrate layer weld 3 in preferred embodiments 1-5 of the present invention.

[0053] Table 2.

[0054]

[0055] Table 3 lists the welding process parameters used in the step of forming the transition layer weld 4 in the preferred embodiments 1-5 of the present invention.

[0056] Table 3.

[0057]

[0058] Table 4 lists the welding process parameters used in the steps of forming the composite material layer weld 5 in preferred embodiments 1-5 of the present invention.

[0059] Table 4.

[0060]

[0061] 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 welded joint of the stainless steel composite plate obtained by welding in Example 1 of the present invention, and the dilution rate D1 of the transition layer weld and the dilution rate D2 of the stainless steel composite layer weld can be calculated. It can be seen from Table 5 that the dilution rate level of the transition layer weld D1 is lower than 15.00%, and the dilution rate D2 of the stainless steel composite layer weld is lower than 3%, thereby ensuring that the composite layer weld has good corrosion resistance.

[0062] Table 5.

[0063]

[0064] Figure 2 The cross-sectional morphology of a composite plate joint prepared by the high-quality welding method for stainless steel composite plates according to Example 1 of the present invention after being corroded by a stainless steel corrosive agent - Carlin's reagent is shown.

[0065] from Figure 2 It can be seen that the joints prepared by the high-quality welding method of the stainless steel composite plate described in the present invention are well combined and the welds are beautifully formed.

[0066] Figure 3 The metallographic structure photograph of the composite plate joint prepared by the high-quality welding method of the stainless steel composite plate of Example 1 of the present invention is shown at the interface between the transition layer and the carbon steel weld in the composite plate joint after being corroded by the stainless steel corrosive agent - Carlin's reagent.

[0067] from Figure 3 It can be seen that the width of the hardened micro-zone is effectively suppressed to below 8 mm, and the degree of hardening is effectively controlled. The hardness within the layer is 315 HV, which is only 28.6% of the hardening degree of the carbon steel weld.

[0068] Figure 4 The composite plate joint prepared by the high-quality welding method of the stainless steel composite plate of Example 1 of the present invention is shown, and the plastic deformation at the interface between the transition layer and the carbon steel weld in the stainless steel composite plate joint is shown under the action of a large load indentation of 30Kgf.

[0069] from Figure 4 It can be seen that when the interface structure of the joint prepared by the method of the present invention is subjected to heavy load, the three layers of transition layer weld, substrate layer weld and hardened micro-area show good plastic deformation coordination, no significant plastic deformation mismatch, no cracking failure, and the interface bonding quality is stable and reliable.

[0070] 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.

[0071] 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. A high-quality 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 high quality welding method comprises the steps of: An X-shaped groove is processed at the position corresponding to the base material layer on the welding section of the stainless steel composite plate, and a blunt edge is arranged in the middle of the X-shaped groove; a trapezoidal groove is opened at the position corresponding to the transition layer and the stainless steel composite material layer on the welding section of the stainless steel composite plate; The base material layer is welded by submerged arc welding; The transition layer is welded by double tungsten inert gas arc welding; Double tungsten inert gas arc welding is used to weld the stainless steel composite layer.

2. The high quality welding method for stainless steel composite plate according to claim 1, characterized in that: The angle between the inclined portion of the X-shaped groove and the vertical direction is consistent with the angle between the inclined portion of the trapezoidal groove and the vertical direction.

3. The high quality welding method for stainless steel composite plate according to claim 2, characterized in that: The angle between the inclined portion of the X-shaped groove and the vertical direction and the angle between the inclined portion of the trapezoidal groove and the vertical direction are both α≥(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.

4. The high quality welding method for stainless steel composite plate according to claim 1, characterized in that: The thickness b3 of the blunt edge at the middle of the X-shaped groove is 2-4 mm.

5. The high quality welding method for stainless steel composite plate according to claim 1, characterized in that: The step single side width w2 of the trapezoidal groove is ≥ (2+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.

6. The high quality welding method for stainless steel composite plate according to claim 1, characterized in that: The distance w1 between the step plane of the trapezoidal groove and the bonding interface between the substrate layer and the stainless steel composite layer is controlled in the range of 0.5b2 to 0.8b2, where b2 represents the distance between the surface of the stainless steel composite layer and the bonding interface between it and the substrate layer, and its unit parameter is mm.

7. The high quality welding method for stainless steel composite plate according to claim 1, characterized in that: In the step of welding the substrate layer by submerged arc welding: use a carbon steel welding wire that matches the substrate layer, control the welding current to 400-600A, the welding voltage to 25-35V, and the welding speed to 0.5-1.0m / min.

8. The high quality welding method for stainless steel composite plate according to claim 1, characterized in that: In the step of welding the transition layer by using double tungsten electrode argon arc welding: a stainless steel welding wire matching the stainless steel composite material layer is used.

9. The high quality welding method for stainless steel composite plate according to claim 1, characterized in that: In the step of welding the transition layer using double tungsten electrode argon arc welding: control the welding voltage to 14-15V, the welding current to 360-420A, the welding speed to 300-340mm / min, the wire feeding speed to 4.6-5.0m / min, and the gap between the two tungsten electrodes to 0.5-1.5mm.

10. The high quality welding method for stainless steel composite plate according to claim 1, characterized in that: In the step of welding the stainless steel composite layer by double tungsten electrode argon arc welding: use a stainless steel welding wire that matches the stainless steel composite layer, control the welding voltage to 14-15V, the welding current to 360-420A, the welding speed to 300-340mm / min, the wire feeding speed to 4.6-5.0m / min, and the gap between the two tungsten electrodes to 0.5-1.5mm.

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