In order to avoid the fracture of the longitudinally welded steel pipe, the manufacturer of the longitudinally welded pipe usually adds alloys to the material to change its properties.

The transverse cracks in the weld are caused by the central segregation during the solidification of the continuous casting slab. After rolling, the central segregation zone is located at the edge of the high-frequency welding raw material belt. During the high-frequency welding process, the weld The upper and lower surfaces form a rougher martensite structure.

In high-frequency longitudinally welded pipes, the manifestations of cracks include long cracks, partial periodic cracks, and irregular intermittent cracks.

There are many things that seamless steel pipes need to be tested, especially after they leave the factory, they need to be continuously tested for all links and models of seamless steel pipes.

Steel pipes are generally divided into seamless steel pipes and welded steel pipes according to production methods. This time we mainly introduce welded steel pipes, that is, seam steel pipes.

During the production and transportation of seamless steel pipes, oil stains will inevitably adhere to the surface of the seamless pipe, which will affect the quality of the seamless pipe rust removal and phosphating, and reduce the adhesion between the coating and the substrate.