To ensure that the L245 pipeline steel pipe has higher fatigue strength, compressive strength, surface hardness, and longer service life, various non-metallic inclusions such as oxide inclusions, sulfide inclusions, and point inclusions in the steel must be strictly controlled Within the range; the inhomogeneity of various carbides in steel (such as carbide liquefaction, strip carbide, band carbide, and network carbide, etc.) should be controlled within the level.

The thickness of the decarbonized layer on the surface of the finished bearing steel after hot processing should be minimized; the macroscopic low-magnification structure of the steel should be generally loose. The center loses, and the level of segregation should be small. Subcutaneous bubbles, shrinkage holes, Inclusions, and cracks. The annealed steel is required to have a uniform and fine spherical pearlite structure.

1. Surface requirements

To ensure that the surface of the bearing is free of defects, the surface of the bearing steel product should be smooth and free of defects such as cracks, scars, folding, pitting, and scratches.

2. Size requirements

In the finishing of bearing steel, to accurately cut the raw materials and process them into the required part size, the dimensional accuracy of the bearing steel product is also strictly required, and the shape of the finished product is also required to be straight.