Talking about seamless steel pipe, we cannot ignore the discussion about stress relief annealing of it. And our main topic today would be the temperature for the producing of the steel pipe. So discussing here if you have any troubles for steel pipe. Temperature of process of stress relief annealing would be category as followed list: First of all, the workpiece was slowly heated to Ac 1 or less 100 ~ 200 (500 ~ 600 ); Then, holding a certain time (1 ~ 3h) followed by slow furnace cooling to 200 , baked and then cooled. And for steel, it is generally 500 ~ 600 ,Iron is generally 500 ~ 550 likely to cause pearlite graphitization than 550. Finally, weldment generally 500 ~ 600