Full penetration welding method for austenitic stainless steel zero-clearance K-type joint

Abstract

The invention provides a full penetration welding method for an austenitic stainless steel zero-clearance K-shaped joint in the field of welding. A K-shaped asymmetric welding groove with a truncated edge is machined in a machining mode, argon tungsten-arc welding is adopted for assembling and positioning, and the assembling gap is 0-1 mm; and TIG bottoming is conducted on the front face, front face TIG welding seams and back face TIG welding seams are sequentially and alternately welded, and zero-clearance full penetration welding of the fillet welds of the austenitic stainless steel plate for manufacturing the box type pressure vessel is achieved. According to the invention, zero-clearance full penetration welding for manufacturing the box type pressure vessel is realized; the procedures of assembling, removing and polishing the positioning plug blocks and repeatedly filling argon on the reverse side are omitted, the construction efficiency is improved, and the construction period is shortened; the assembly difficulty is reduced, and the assembly precision is improved; double-face welding and zero-clearance welding are adopted, the welding filling amount is reduced, welding deformation is reduced, and the structural shape and the structural size of the box type pressure container are guaranteed. The full penetration welding method is suitable for being applied to the stainless steel zero-clearance K-type joint.

Description

Technical Field

[0001] The invention relates to a welding method in the welding field, and in particular to a full penetration welding method for austenitic stainless steel zero-gap K-type joint. Background Art

[0002] In the production process of box-type pressure vessels, in order to improve the corrosion resistance and service life of the pressure vessels, austenitic stainless steels such as 06Cr18Ni11Ti, 022Cr18Ni12Mo2, and 06Cr18Ni9 are often used in the design.

[0003] In order to ensure the stability and safety of the box-type pressure vessel structure, the pressure boundary welds are designed to be full penetration welds, including the fillet welds of the box structure, and the weld quality grade is Grade I. The welds must not have welding defects such as cracks, lack of fusion, and lack of penetration, otherwise the safety, stability and reliability of the pressure vessel will be seriously affected.

[0004] However, the inventors of this application found that the above technology has at least the following technical problems in the process of implementing the technical solution of the invention in the embodiment of this application: 06Cr18Ni11Ti, 022Cr18Ni12Mo2, 06Cr18Ni9 austenitic stainless steel has austenite structure, low thermal conductivity, and large linear expansion coefficient, which leads to very large welding deformation and welding residual stress during the production process, and it is difficult to release. Especially when welding on one side with a gap (4mm~6mm) at the welding groove, the welding deformation cannot be controlled at all, and the overall size of the box structure cannot meet the design size requirements and installation accuracy requirements. Summary of the invention

[0005] In order to solve the deficiencies in the prior art, the embodiment of the present application provides a method for full penetration welding of austenitic stainless steel zero gap K-type joints in view of the problem that welding deformation cannot be controlled when welding on one side with a gap of 4mm to 6mm for austenitic stainless steel welding grooves. The method processes a K-type asymmetric welding groove with a blunt edge by mechanical processing, and uses tungsten inert gas arc welding for assembly positioning, with an assembly gap of 0 to 1mm; after assembly, TIG priming and filling are performed on the front side, and then filling welding is performed on the back side, realizing zero gap full penetration welding of austenitic stainless steel plate fillet welds in the production of box-type pressure vessels, and solving the technical problems of austenitic stainless steel welding.

[0006] The solution adopted by the embodiment of the present application to solve the technical problem is: A method for full penetration welding of austenitic stainless steel zero-gap K-type joints, comprising the following steps: The first step is to mechanically process the K-type asymmetric welding groove with blunt edges; The second step is to use positioning welding to position and assemble the joint, with the groove gap being 0 to 1 mm; the positioning welding is done by tungsten inert gas arc welding without adding welding wire; The third step is to use tungsten inert gas arc welding to perform the front weld base welding, and at the same time, argon filling protection is performed on the back side. No welding wire is added for base welding; Step 4: After the base welding is completed, weld the front TIG weld and the back TIG weld alternately.

[0007] In order to further solve the technical problems to be solved by the embodiments of the present application, in a full penetration welding method for austenitic stainless steel zero gap K-type joint provided in the embodiment of the present application, in the first step, the blunt edge length d=4mm±0.5mm of the welding groove, the blunt edge thickness e=1.8mm±0.2mm, and the blunt edge end groove angle α=45°±2.5°.

[0008] Furthermore, in the second step, the positioning welding interval is 300mm-400mm, and the welding current is 60A-70A.

[0009] Furthermore, in the third step, the welding current is 160A to 170A, and the welding speed is 100 mm / min to 150 mm / min.

[0010] Positive effect: The embodiment provides a method for full penetration welding of austenitic stainless steel zero gap K-type joint, which realizes zero gap full penetration welding in the production of box-type pressure vessels; reduces the processes of assembling, removing, grinding, and repeatedly filling argon on the back side of the positioning plugs, improves construction efficiency, and shortens the construction period; greatly reduces the difficulty of assembly and improves assembly accuracy; by adopting double-sided welding and zero gap welding, the welding filling amount is reduced, and at the same time the welding deformation is reduced, effectively ensuring the structural shape and structural size of the box-type pressure vessel.

[0011] The invention is suitable for application as a full penetration welding method for zero-gap K-type joints of austenitic stainless steel. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0013] Figure 1 Schematic diagram of zero gap welding between bottom plate and outer plate for 06Cr18Ni11Ti water tank; Figure 2Make a zero-gap K-type welding groove element diagram for the bottom plate and outer plate of the 06Cr18Ni11Ti water tank.

[0014] In the figure, 1. bottom plate; 2. outer plate; 3. front TIG weld; 4. back TIG weld; blunt edge length d = 4mm ± 0.5mm; blunt edge thickness e = 1.8mm ± 0.2mm; blunt edge end groove angle α = 45° ± 2.5°; groove gap c = 0 ~ 1mm. DETAILED DESCRIPTION

[0015] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments. Although the embodiments of the present invention have been shown and described, it can be understood by those of ordinary skill in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of the present invention is defined by the attached claims and their equivalents. Based on the embodiments in the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative work are within the scope of protection of the present invention.

[0016] As shown in the figure, a method for full penetration welding of austenitic stainless steel zero gap K-type joint includes the following steps: The first step is to use mechanical processing to process a K-type asymmetric welding groove with a blunt edge, with a blunt edge length d=4mm±0.5mm, a blunt edge thickness e=1.8mm±0.2mm, and a blunt edge end groove angle α=45°±2.5°.

[0017] The second step is to use positioning welding to position and assemble the joint, with the groove gap c=0~1mm; positioning welding uses tungsten inert gas arc welding, without adding welding wire, the positioning welding spacing is 300mm~400mm, and the welding current is 60A~70A.

[0018] The third step is to use tungsten inert gas arc welding to perform the base welding of the front weld, and at the same time, fill the back side with argon for protection. No welding wire is added for the base welding. The welding current is 160A~170A, and the welding speed is 100mm / min~150mm / min.

[0019] Step 4: After the base welding is completed, alternately weld the front TIG weld 3 and the back TIG weld 4. The inter-pass temperature is controlled below 100°C.

[0020] The working process of this embodiment: See also Figure 1Taking the production of the bottom plate 1 and the outer plate 2 of a 06Cr18Ni11Ti water tank as an example, the implementation steps and production process of the full penetration welding method of the austenitic stainless steel zero gap K-type joint are specifically described.

[0021] The first step is to use mechanical processing to process the welding groove of the bottom plate, and the groove form is a K-type asymmetric groove with a blunt edge; The second step is to use positioning welding to position and assemble the joint, with the groove gap being 0mm; the positioning welding adopts tungsten inert gas arc welding, without adding welding wire, the positioning welding spacing is 350mm, and the welding current is 65A; The third step is to use tungsten inert gas arc welding to perform the front weld base welding, and at the same time, argon protection is performed on the back side. No welding wire is added for base welding. The welding current is 160A and the welding speed is 120mm / min. Step 4: After the base welding is completed, alternately weld the front TIG weld 3 and the back TIG weld 4 in sequence, and control the interpass temperature below 100°C.

[0022] See also Figure 2 , blunt edge length d = 4 ± 0.5mm, blunt edge thickness e = 1.6 ± 0.2mm, blunt edge end groove angle α = 45° ± 2.5°, groove gap c = 0 ~ 1mm.

[0023] Finally, it should be noted that the above is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the aforementioned embodiments, it is still possible for those skilled in the art to modify the technical solutions described in the aforementioned embodiments or to make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for full penetration welding of austenitic stainless steel zero gap K-type joints, characterized by: The steps include: The first step is to mechanically process the K-type asymmetric welding groove with blunt edges; The second step is to use positioning welding to position and assemble the joint, with the groove gap being 0 to 1 mm; the positioning welding is done by tungsten inert gas arc welding without adding welding wire; The third step is to use tungsten inert gas arc welding to perform the front weld base welding, and at the same time, argon is filled for protection on the back side. No welding wire is added for base welding; Step 4: After the base welding is completed, alternately weld the front TIG weld (3) and the back TIG weld (4).

2. The method for full penetration welding of austenitic stainless steel zero gap K-type joint according to claim 1, characterized in that: In the first step, the blunt edge length of the welding groove is d=4mm±0.5mm, the blunt edge thickness is e=1.8mm±0.2mm, and the blunt edge end groove angle α is 45°±2.5°.

3. The method for full penetration welding of austenitic stainless steel zero gap K-type joint according to claim 1 is characterized by: In the second step, the positioning welding spacing is 300mm~400mm, and the welding current is 60A~70A.

4. The method for full penetration welding of austenitic stainless steel zero gap K-type joint according to claim 1, characterized in that: In the third step, the welding current is 160A to 170A, and the welding speed is 100 mm / min to 150 mm / min.

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