After mechanical processing, stainless steel pipes will deform due to the redistribution of internal stress, and stress is prone to remain inside them. To reduce hardness and enhance plasticity; Refine the grain size, homogenize the composition of the steel, and eliminate the residual internal stress in the steel to prevent deformation and cracking. Therefore, all stainless steel pipes must undergo stress relief annealing after rough machining.
The common equipment for stress relief annealing of stainless steel pipes is the continuous bright annealing furnace for stainless steel pipes. This is a Muffle type bright annealing furnace. The protective gas source adopts an ammonia decomposition furnace and is equipped with a gas purification device. The transmission method can be selected as "stainless steel mesh belt" or "stainless steel steel belt" according to the user's requirements for conveying. This equipment features advanced control, significant energy conservation and convenient maintenance. The entire heating zone adopts PID automatic multi-zone temperature control.
The stainless steel pipes are evenly arranged on the feeding frame and sent to the annealing furnace by the conveyor belt. Under the protection of a controlled atmosphere, they are heated to 1050-1080℃ and then maintained for a relatively short period of time. This can dissolve all the carbides in the austenite. Then, they are rapidly cooled to below 350℃ to obtain a supersaturated solid solution, which is uniform unidirectional austenite.