According to the different strength requirements, the petroleum cracking pipe can adopt several heat treatment methods such as normalization, normalization plus fire and quenching and tempering (quenching and tempering).

The key to the uneven wall thickness of the hot-rolled tube is the one-time hole in the hot rolling. The uneven wall thickness of the capillary hole is likely to be caused by the following three factors.

Precision seamless steel pipes have a hollow section and are used in large quantities as pipelines for conveying fluids, such as pipelines for conveying oil, natural gas, gas, water and certain solid materials.

Common defects in welds include porosity, slag inclusion, incomplete penetration, lack of fusion and cracks.

Longitudinal welded pipes are formed by bending steel plates or steel strips and then welding them. According to the weld form, it is divided into straight seam welded pipe and spiral welded pipe.

Generally, according to the different uses and working conditions of the steel pipe, different technical conditions should be proposed for the allowable deviation of the steel pipe size, surface quality, chemical composition, mechanical properties, process performance and other special properties.