Stainless steel welded pipe, referred to as welded pipe, is a steel pipe made of commonly used steel or steel strips after being curled and formed by a unit and a mold. The production process of welded steel pipes is simple, the production efficiency is high, there are many varieties and specifications, and the equipment investment is low, but the general strength is lower than that of seamless steel pipes. Since the 1930s, with the rapid development of continuous rolling production of high-quality striped steel and the advancement of welding and inspection technology, the quality of welds has continued to improve, and the using and specifications of welded steel pipes have increased day by day, and heat used in more and more fields, especially in Heat exchange equipment uses pipes, decorative pipes, medium and low pressure fluid pipes, etc. to replace seamless steel pipes.

Advantages of stainless steel welded steel pipe
(1) Uniform wall thickness - the base material is a formed strip, with good wall thickness consistency and high surface finish, reaching industrial clean surface level 2B
(2) Low residual stress - after forming, the steel pipe is bright annealed at a high temperature higher than 1040 degrees to eliminate stress.
(3) High welding seam strength - fusion welding is used for welding, and the material composition remains unchanged. After high temperature heat treatment, the weld seam and the base metal have the same intergranular structure. When performing destructive tests such as flattening, reverse bending, and flaring on the weld, there will be no problems such as cracking, cracking strength, and burrs at the weld. In addition, eddy current testing and water pressure or gas test are also required to ensure the quality of the pipe.
(4) Good consistency - the outer diameter, wall thickness, length and straightness of the pipe are consistent, and the processing precision is high.

Cutting and stamping of stainless steel welded pipe:
Since stainless steel welded pipes are stronger than ordinary materials, higher pressure is required for stamping and shearing. Only when the gap between the knife and the knife are accurate can there be no poor shearing and work hardening. Use plasma or laser cutting. When gas cutting or arc cutting has to be used, the heat-affected zone should be ground and heat treated as necessary.

Process flow of welding stainless steel pipes:
1. Cut the plate into materials as required, with a length of 6 m;
2. Immediately after unloading, use an oxygen acetylene flame to clean the cut area.
3. Before welding the pipe, check whether the steel pipe is under pressure and whether there are cracks and other defects;
4. Prepare the argon arc welding machine and corresponding gas protection equipment and auxiliary materials;
5. According to the required wall thickness, draw the docking marking line on the steel pipe to facilitate accurate positioning during centering installation;
6. Use manual tungsten arc welding to make the base layer, and then automatically submerge arc welding to repair the surface layer.

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