Seamless steel pipes have a hollow cross-section and are widely used as pipes for transporting fluids, such as pipes for transporting oil, natural gas, gas, water, and certain solid materials. Special-shaped seamless steel pipe is a general term for seamless steel pipes with cross-sectional shapes other than round pipes. Seamless square pipes (such as a500 square tube) and seamless rectangular tubes (a500 rectangular tube) also belong to special-shaped seamless steel pipes.

Structural seamless steel pipes are seamless pipes used for general structures and mechanical structures. Mainly used in the manufacture of pipes, containers, equipment, pipe fittings, etc.

The steel sheet pile is a kind of steel structure with linkages on the edge, and the linkages can be freely combined to form a continuous and compact retaining wall or water retaining wall. Steel sheet piles can be divided into hot-rolled/tensile steel sheet piles and cold-formed steel sheet piles according to their different processing and manufacturing techniques.

Carbon steel pipes are made of steel ingots or solid round steel through perforation into capillary tubes, and then made by hot rolling, cold rolling or cold drawing. According to the production method, carbon steel pipes can be divided into two categories: seamless steel pipes and welded steel pipes. Non-metallic inclusions are non-metallic substances contained in carbon steel pipes that are different from those of the base metal. It destroys the continuity and isotropy properties of the metal matrix.

SSAW steel pipe is a welded steel pipe made of strip steel coil as raw material, extruded at regular temperature, and welded by automatic double-wire double-sided submerged arc welding process. Generally used in welding into pipelines for fluid transportation, metal structures, steel pipe pile, etc. Appearance inspection is a simple and widely used inspection method. It is an important part of the inspection of SSAW pipe products. It is mainly to find defects on the weld surface and dimensional deviations.

The results of the causal analysis of welded steel pipe waste show that the factors affecting the quality of raw materials are mainly three aspects: unstable mechanical properties of steel strips, surface defects of steel strips, and large deviations in geometric dimensions. Therefore, key control should be carried out from these three aspects.