During the processing of seamless steel pipe
manufacturers, there are many steps to obtain such high-quality pipes. By eliminating the work hardening of seamless steel tubes, a satisfactory metallurgical structure can be obtained. The process equipment is a bright annealing furnace, which is mainly used. Heat treatment of the finished stainless steel in a protective atmosphere. When the application performance requirements of seamless steel tubes are different, the requirements of the metallographic structure after bright annealing are also different, so the process of bright heat treatment will be different.
After cold working, the residual stress of the seamless steel pipe material remains, and the residual stress is very detrimental to the stress corrosion cracking of the pipeline. Any degree of cold working will result in a significant increase in the material's resistance to stress corrosion cracking. The degree of cold working will also adversely affect the high temperature resistance of austenitic stainless steel. Generally, the higher the working temperature or the higher the fracture life requirement, the lower the cold working degree.
It can be seen from the above introduction that the heat treatment process of seamless steel pipe manufacturers is quite troublesome. In order to obtain a qualified metallographic structure, the adjustment part of the cooling section equipment of the bright annealing furnace needs to be large. Therefore, the current advanced bright annealing furnace usually uses strong convection cooling in its cooling section, and has three cooling sections, which can adjust the air volume separately. It is divided into three parts along the width of the strip.