Stainless steel industrial welded pipes sometimes require preheating. What is the principle of preheating stainless steel pipes and what purpose is it?

The purpose of the preheating treatment of the stainless steel industrial welded pipe is to eliminate the inhomogeneity of the microstructure caused by ingot casting and forging, to improve the morphology and distribution characteristics of the carbides, and to prepare the necessary raw materials for the final heat treatment. In the cold roller, if the size of the carbide particles is too large, the shape is poor or the segregation is serious, the final heat treatment will cause uneven matrix structure and hardness, resulting in an increase in the probability of spalling of the working layer of the roller and decrease the thermal shock resistance of the cold roller. .