Stainless steel 316 seamless pipe production process

Stainless steel seamless pipes are made by perforating steel ingots or solid tubes into rough tubes, and then hot-rolled, cold-rolled or cold-drawn. The specifications of stainless steel seamless pipes are expressed by outer diameter * wall thickness in millimeters. The outer diameter of hot-rolled seamless pipes is generally greater than 32mm, and the wall thickness is 2.5-200mm. The outer diameter of cold-rolled seamless steel pipes can reach 6mm, and the wall thickness can reach 0.25mm. The outer diameter of thin-walled pipes can reach 5mm and the wall thickness is less than 0.25mm. Cold rolling has higher dimensional accuracy than hot rolling.

The production process of cold-rolled stainless steel seamless pipes is generally more complicated than hot rolling. The tube billet must first be rolled with three rollers, and then sizing tests must be performed after extrusion. If there is no response crack on the surface, the round tube must be cut by a cutting machine and cut into a billet of about one meter in length. Then enter the annealing process. Annealing requires pickling with acidic liquid. When pickling, pay attention to whether there is a large amount of bubbling on the surface. If there is a large amount of bubbling, it means that the quality of the steel pipe does not meet the corresponding standards. In appearance, cold-rolled stainless steel seamless pipes are shorter than hot-rolled stainless steel seamless pipes. The wall thickness of cold-rolled stainless steel seamless pipes is generally smaller than that of hot-rolled stainless steel seamless pipes, but the surface looks brighter than thick-walled stainless steel seamless pipes, and the surface is not too rough, and the diameter does not have too many burrs.

The delivery state of hot-rolled stainless steel seamless pipes is generally hot-rolled and heat-treated before delivery. After quality inspection, hot-rolled stainless steel seamless pipes must be strictly hand-selected by staff, and the surface must be oiled after quality inspection, followed by multiple cold drawing tests. After hot rolling treatment, perforation tests must be carried out. If the perforation diameter is too large, straightening and correction must be carried out. After straightening, the conveyor device will be transported to the flaw detector for flaw detection, and then labeled, arranged in specifications, and placed in the warehouse.