Welded stainless steel pipe refers to a steel pipe with seams on the surface that is welded by bending and deforming a steel strip or steel plate into a circular, square or other shape. How can we make steel strips or steel plates welded together, and what are the welding skills?
1. According to the use, the welded stainless steel welded pipe has general use and high temperature and high pressure, etc. The latter pipe is often made of special alloy steel, and the shrinkage crack of the weld during the welding process and the heat affected zone pipe machinery must be considered and dealt with. The performance is not greatly changed due to the influence of welding operation.
2. According to the thickness of the pipe wall, pipes made of relatively thin materials such as steel strips can be welded by high frequency, and some thin-walled pipes can be welded by shielding gas method; pipes with a wall thickness exceeding 2mm can be welded by hand arc welding.
3. According to the diameter of the pipe, the small diameter can only be welded on one side and the technician can drill into the pipe to perform double-sided welding. The single-sided welding requires the skills of the welders to be able to weld two people on one side. After the steel ball experiment, it is ensured that the cross-sectional area passing ability and the welding seam forming meet the planning requirements.
4. As long as the pipe material is high-strength alloy steel, including temperature-resistant, pressure-resistant, wear-resistant, and low-temperature-resistant alloy steel pipes, the welding process must be emphasized to avoid martensite formation and cracks due to high temperature welding operations. The general requirement in the process is that the electrode should be selected well, and it should be baked and sent to the welder according to the requirements. Before welding both ends of the weld, remove oil, water, rust, and debris, clean and clean, and use the energy of the welding line. Maybe smaller, to minimize shaking during the welding process, and the arrangement of the final weld should have an annealing effect on the heat affected zone as much as possible. Slow cooling after welding, cover with asbestos cloth, etc.
5. In order to ensure the welding quality of the pipes, the welders must be trained and tested, and qualified for work. The welder needs to weld the steel pipe well. In addition to the basic theory, it is necessary to ponder the operation skills. The welding process of the pipe may include several postures of down welding, vertical welding and overhead welding (in the case where the pipe cannot be rolled). The forming of welding and overhead welding (some tubes are not very large, one forming, and the current cannot be adjusted halfway), control the stability and forming of the arc during the process, can shake properly, and combine the forming with the necessary shaking.