Austenitic stainless steel welding method and welded assembly

Abstract

The application discloses an austenitic stainless steel welding method and a welded assembly. The welding method comprises the following steps: assembling two welding units: each welding unit has an I-shaped groove and a U-shaped groove; the I-shaped groove is welded by laser deep penetration welding; and the U-shaped groove is welded by laser wire filling welding. By combining laser deep penetration welding and laser wire filling welding, the penetration depth of the austenitic stainless steel reaches more than 50 mm, compared with the submerged-arc welding or gas shielded welding method of the austenitic stainless steel with large thickness. Laser welding can greatly reduce the weld volume, and the heat input of laser welding is far less than that of submerged-arc welding or gas shielded welding, so that the welding deformation can be effectively controlled, the laser weld quality is high, and defects are few.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of steel welding, in particular to an austenitic stainless steel welding method and a welded assembly. BACKGROUND

[0002] For the welding seam of austenitic stainless steel with a thickness greater than 50mm, the prior art generally adopts submerged arc welding or gas shielded welding. By using the above method, the welding groove angle is generally greater than 30°, the welding seam filling volume is large, the final welding stress and welding deformation are large, and it is difficult to ensure the welding precision. At the same time, when performing large filling volume welding by submerged arc welding or gas shielded welding, defects such as pores, incomplete fusion and slag inclusion are prone to occur. SUMMARY

[0003] The purpose of the present application is to provide an austenitic stainless steel welding method and a welded assembly. The welding method of the present application adopts a laser welding method, which solves the problems of large welding deformation, easy occurrence of incomplete fusion and pores of austenitic stainless steel, especially austenitic stainless steel with a thickness greater than 50mm.

[0004] The embodiment of the present application provides an austenitic stainless steel welding method, which comprises the following steps:

[0005] Assembling two welding units: each of the welding units has an I-shaped groove and a U-shaped groove;

[0006] The I-shaped groove is welded by laser deep penetration welding;

[0007] The U-shaped groove is welded by laser wire filling welding.

[0008] In some embodiments, the I-shaped groove is provided with a step, and the steps of adjacent welding units match each other.

[0009] In some embodiments, a welding gap is arranged between adjacent I-shaped grooves, the welding gap is located on one side of the first central axis, and the welding gap extends along the welding surface direction of the I-shaped groove.

[0010] In some embodiments, the welding gap is located below the second central axis.

[0011] In some embodiments, the width of the welding gap is 0-0.5mm.

[0012] In some embodiments, the root of the U-shaped groove has a flat section and a round corner, the angle of the round corner is 85-87°, and the length of the flat section is 2-4mm.

[0013] In some embodiments, the angle of the U-shaped groove is 6-10°, and the depth of the U-shaped groove is 13-17mm.

[0014] In some embodiments, the width of the I-shaped groove is 26-34 mm.

[0015] In some embodiments, the height of the step is 1-3 mm.

[0016] In some embodiments, the parameters of the laser deep penetration welding are as follows: the power is 13-15 kW, the welding speed is 35-65 cm / min, and the defocusing amount is -15-15 mm.

[0017] In some embodiments, the parameters of the laser welding with filler wire are as follows: the power is 3-6 kW, the welding speed is 35-65 cm / min, and the defocusing amount is 30-60 mm.

[0018] Correspondingly, the application provides a welded assembly, which comprises two welded units, and the welded units have I-shaped grooves and U-shaped grooves.

[0019] In some embodiments, the I-shaped groove is provided with a step.

[0020] In some embodiments, the two welded units have a welding gap at the welding surface of the step.

[0021] The application has the beneficial effects that the application provides an austenitic stainless steel welding method and a welded assembly. The welding method of the application comprises the following steps: assembling two welded units: each welded unit has an I-shaped groove and a U-shaped groove; the I-shaped groove is welded by laser deep penetration welding; and the U-shaped groove is welded by laser welding with filler wire. The application combines laser deep penetration welding and laser welding with filler wire, and the penetration depth of the austenitic stainless steel welding reaches more than 50 mm, which is compared with the submerged-arc welding or gas shielded welding method of the large-thickness austenitic stainless steel. Laser welding can greatly reduce the weld volume, and the heat input of laser welding is much smaller than that of submerged-arc welding or gas shielded welding, which can effectively control the welding deformation, and the laser weld has high quality and few defects. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the application, the following will briefly introduce the drawings needed to be used in the embodiment description. Obviously, the drawings in the following description are only some embodiments of the application, and other drawings can be obtained by those skilled in the art without any creative effort on the basis of these drawings.

[0023] Figure 1 The structure of a welded assembly provided in the embodiments of the application;

[0024] Figure 2 The structure of another welded assembly provided in the embodiments of the application;

[0025] Figure 3 Another structure of a welding assembly provided in the embodiments of the present application;

[0026] Figure 4 A weld structure of an austenitic stainless steel plate welded by the welding method of the embodiments of the present application;

[0027] In the figure, 100-welding unit, 101-I groove, 102-U groove, 103-step, 104-welding gap, 105-flat section. DETAILED DESCRIPTION

[0028] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, but not all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of the present application. In addition, in the description of the present application, the term “comprising” means “including but not limited to”. The terms first, second, third, etc. are only used as labels and do not impose numerical requirements or establish sequences. Various embodiments of the present application can exist in a range form; it should be understood that the description in a range form is only for the convenience and brevity, and should not be understood as a hard limit to the scope of the present application; therefore, it should be considered that the described range has been specifically disclosed all possible sub-ranges and single values in the range. For example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single numbers in the range, such as 1, 2, 3, 4, 5 and 6, regardless of the range. In addition, whenever a numerical range is indicated in this document, it refers to any cited number (fraction or integer) in the indicated range.

[0029] In the welding of large-thickness stainless steel plates, especially steel plates thicker than 50 mm, the welding groove angle is generally greater than 30°, the weld filling volume is large, the welding stress and welding deformation are large, and it is difficult to ensure the welding precision. In order to solve the problems in the prior art, such as Figure 1 As shown in the figure, the embodiments of the present application provide an austenitic stainless steel welding method, comprising the following steps: assembling two welding units 100: each welding unit has an I groove 101 and a U groove 102; the I groove 101 is welded by laser deep penetration welding, and the U groove 102 is welded by laser wire filling welding.

[0030] This application utilizes a combination of double-sided laser deep penetration welding and laser filler wire welding to achieve a laser welding penetration depth of over 50mm in austenitic stainless steel, enabling the welding of austenitic stainless steel plates with a thickness exceeding 50mm. Furthermore, this welding method results in a smaller weld bevel, less filler material, and lower welding stress and deformation. Moreover, compared to submerged arc welding or gas shielded welding methods for thick austenitic stainless steel, this laser weld method produces higher quality welds with fewer defects.

[0031] like Figure 2 As shown, in order to improve the assembly accuracy, this application further improves the structure of the welding unit 100. The welding surfaces of adjacent welding units 100 adopt stepped welding surfaces. Specifically, the I-bevel 101 is provided with a step 103. The steps 103 of adjacent welding units 100 match each other. By providing matching steps in the I-bevel 101, this application improves the assembly accuracy of the two welding units 100 and avoids the situation of misalignment of welding units 100. In addition, the weld strength of the I-bevel 101 with the step 103 structure after laser deep penetration welding is higher.

[0032] When the welding unit 100 has a stepped structure 103, the welding method includes the following steps:

[0033] First, laser deep penetration welding is performed on the blunt edge of the I-groove 101 on the higher side;

[0034] Then perform laser deep penetration welding on the lower side of the I-groove 101 blunt edge.

[0035] The above welding method avoids the weld shrinkage that would cause the gap on the higher side to become larger when laser deep penetration welding is performed on the lower side with the I-groove 101 blunt edge first.

[0036] like Figure 3 As shown, to further reduce welding stress, a welding gap 104 is provided between adjacent I-grooves 101. The welding gap 104 is located on one side of the first central axis O1 and extends along the welding surface direction of the I-grooves 101. In a specific embodiment, the welding gap 104 is located below the second central axis O2, and the width of the welding gap 104 is 0-0.5 mm. This application provides an assembly gap at the lower I-grooves 101. After welding on the higher side, the welded part shrinks, and the lower I-grooves fit snugly, reducing the stress on the welded part.

[0037] In a specific embodiment, the root of the U-shaped groove 102 has a flat section 105 and a rounded corner R1, the angle of which is 85° to 87°; the length D1 of the flat section 105 is 2 to 4 mm. This application improves the size of the U-shaped groove 102 to prevent the root of the U-shaped groove 102 from being too narrow, which would result in poor surface formation of the laser deep penetration weld.

[0038] In specific embodiments, the angle a of the U-shaped groove 102 is 6-10°, so as to avoid the U-shaped groove 102 from forming a negative angle due to the shrinkage of the weld during welding, which affects the welding implementation.

[0039] In specific embodiments, the depth W2 of the U-shaped groove 102 is 13-17 mm. The width W1 of the I-shaped groove 101 is 26-34 mm. When the welding unit 100 has a stepped structure, the widths W3 of the two steps 103 are the same, and the width W3 of the step 103 is 13-17 mm.

[0040] In order to avoid the height of the step from being too high to affect the quality of the weld, in specific embodiments, the height D2 of the step 103 is 1-3 mm.

[0041] In specific embodiments, the parameters of the laser deep penetration welding are as follows: the power is 13-15 kW, the welding speed is 35-65 cm / min, the defocusing amount is -15-15 mm, the protective gas is N2 (≥99.99%), and the flow rate is 30-70 L / min.

[0042] In specific embodiments, the parameters of the laser welding with filler wire are as follows: the power is 3-6 kW, the welding speed is 35-65 cm / min, the defocusing amount is 30-60 mm, the protective gas is N2 (≥99.99%), and the flow rate is 30-70 L / min. The laser welding with filler wire uses an austenitic stainless steel welding wire with a diameter of φ1.2 mm, and the wire feeding speed is 160-280 cm / min.

[0043] The embodiments of the present application provide a welded assembly, as shown in Figure 1 The welded assembly includes two welding units 100, and each welding unit 100 has an I-shaped groove 101 and a U-shaped groove 102. The width W1 of the I-shaped groove 101 is 26-34 mm, the depth W2 of the U-shaped groove 102 is 13-17 mm, the root of the U-shaped groove 102 has a flat section 105 and a round corner R1, the angle of the round corner R1 is 85°-87°, and the length D1 of the flat section 105 is 2-4 mm.

[0044] As shown in Figure 2 The welding unit 100 of the welded assembly has a step 103 structure, which improves the assembly precision of the two welding units 100. In specific embodiments, the step 103 is distributed on both sides of the first central axis O1, each welding unit 100 forms a concave-convex step structure with the same width and height on both sides of the first central axis O1, and the step 103 structures formed at the welding surfaces of the I-shaped grooves 101 of adjacent welding units 100 match with each other. In specific embodiments, the width W3 of the step 103 is 13-17 mm, and the height D2 of the step 103 is 1-3 mm.

[0045] As shown in Figure 3 In order to further reduce the welding stress, the assembly body of the present application adopts a structure with a welding gap 104 between the step 103 welding surfaces of adjacent welding units 100, and the welding gap 104 is located on one side of the first central axis O1 and extends along the Y-axis direction. In the specific embodiment, the X-axis extension direction is defined as the up-to-down direction in the present application, the welding gap 104 is located below the second central axis O2, and the width of the welding gap 104 is 0-0.5 mm. The assembly gap is provided at the I-shaped groove 101 on the lower side, and after welding on the higher side, the welding part shrinks, the I-shaped groove on the lower side is tightly attached, and the welding part stress is reduced.

[0046] The assembly of the assembly body and welding are completed by the following methods:

[0047] (1) Position the welding unit 100 by clamping, welding temporary accessories and spot welding;

[0048] (2) First, complete the laser deep penetration welding of the higher side of the fillet (step 103 welding surface), adjust the tooling, remove the temporary accessories, and then perform the laser deep penetration welding of the lower side of the fillet;

[0049] (3) Perform laser wire filling welding on the U-shaped groove 102 with a narrow gap on both sides.

[0050] Application example: using the welding unit 100 shown in Figure 3 to weld 60 mm thick austenitic stainless steel plates, the structural parameters of the welding unit 100 are: the width W1 of the I-shaped groove 101 is 30 mm (the width W3 of the step 103 is 15 mm, and the height D2 of the step 103 is 2 mm), the depth W2 of the U-shaped groove 102 is 15 mm, the root of the U-shaped groove 102 has a flat section 105 and a round corner R1, the angle of the round corner R1 is 86°, the length D1 of the flat section 105 is 3 mm, and the width D2 of the welding gap 104 is 0.5 mm.

[0051] The welding parameters are: the laser deep penetration welding parameters are: power is 14 kW, welding speed is 50 cm / min, defocusing amount is 10 mm, protective gas is N2 (≥99.99%), and flow rate is 50 L / min.

[0052] The laser wire filling welding parameters are: power is 5 kW, welding speed is 50 cm / min, defocusing amount is 30 mm, protective gas is N2 (≥99.99%), and flow rate is 50 L / min. The laser wire filling welding uses austenitic stainless steel welding wire with a diameter of φ1.2 mm, and the wire feeding speed is 220 cm / min.

[0053] The weld structure after welding is as shown inFigure 4 As shown, the welded joint is qualified by the radiographic inspection and the tensile test, the tensile strength of the welded joint is equivalent to that of the base material.

[0054] In the above embodiments, the description of each embodiment has its own focus, and the parts not described in detail in a certain embodiment can be referred to the relevant description of other embodiments.

[0055] The above describes in detail the austenitic stainless steel welding method and the welded assembly provided by the embodiments of the present application, the principles and implementation manners of the present application are described by applying specific examples, the above embodiment description is only used to help understand the method of the present application and its core idea; meanwhile, for the person skilled in the art, according to the idea of the present application, the specific implementation manner and application range will have changes, and the above description should not be understood as the limitation of the present application.

Claims

1. An austenitic stainless steel welding method, characterized by, The method comprises the following steps: two welding units (100) are assembled: each welding unit (100) has an I-shaped groove (101) and a U-shaped groove (102), the I-shaped groove (101) is provided with a step (103), the steps (103) of adjacent welding units (100) match each other, there is a welding gap (104) between adjacent I-shaped grooves (101), the welding gap (104) is located on one side of a first central axis (O1), and the welding gap (104) extends along the welding surface direction of the I-shaped groove (101), and the welding gap (104) is located below a second central axis (O2); first, laser deep penetration welding of the root face of the I-shaped groove (101) on the higher side is performed; then, laser deep penetration welding of the root face of the I-shaped groove (101) on the lower side is performed; the U-shaped groove (102) is welded by laser welding with a filler wire; the parameters of the laser deep penetration welding are as follows: the power is 13-15 kW, the welding speed is 35-65 cm / min, and the defocusing amount is -15-15 mm; the parameters of the laser welding with a filler wire are as follows: the power is 3-6 kW, the welding speed is 35-65 cm / min, and the defocusing amount is 30-60 mm.

2. The austenitic stainless steel welding method according to claim 1, characterized by, the width of the welding gap (104) is 0-0.5 mm.

3. The austenitic stainless steel welding method according to claim 1, characterized by, the root of the U-shaped groove (102) has a flat section (105) and a round corner (R1), the angle of the round corner (R1) is 85-87°, and the length of the flat section (105) is 2-4 mm.

4. The austenitic stainless steel welding method according to claim 1, characterized by, the angle of the U-shaped groove (102) is 6-10°, and the depth of the U-shaped groove (102) is 13-17 mm.

5. The austenitic stainless steel welding method according to claim 1, characterized by, the width of the I-shaped groove (101) is 26-34 mm.

6. The austenitic stainless steel welding method according to claim 1, characterized by, the height of the step (103) is 1-3 mm.

7. A solder assembly characterized by, the welding assembly comprises two welding units (100), and the welding unit (100) has an I-shaped groove (101) and a U-shaped groove (102); the I-shaped groove (101) is provided with a step (103), and the steps (103) of adjacent welding units (100) match each other; the two welding units (100) have a welding gap (104) at the welding surface of the step (103), the welding gap (104) is located on one side of a first central axis (O1), and the welding gap (104) extends along the welding surface direction of the I-shaped groove (101).

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