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High quality seamless tubes require cold rolling, cold drawing or a combination of both
Seamless pipes are produced on automatic pipe mills. The solid billet is inspected and the surface defects are removed, cut to the desired length, centered on the perforated end face of the billet, and sent to a heating furnace for perforation in the perforator. At the same time as the perforation continues to rotate and advance, under the action of the roll and the head, the cavity is gradually formed inside the tube blank. It is sent to the automatic tube mill for further rolling. Finally, the entire machine is evenly wall thicknessed and sizing by the sizing machine to meet the specifications. The use of continuous rolling mills to produce hot-rolled seamless steel tubes is a more advanced method. If you want to obtain seamless tubes with smaller dimensions and better quality, cold rolling, cold drawing, or a combination of both must be used. Cold rolling is usually carried out on a two-high mill, and the steel tube is rolled in a ring-shaped pass composed of a variable-section circular hole groove and a stationary conical head. Cold drawing is usually performed on a single-chain or double-chain cold-drawing machine of 0.5 to 100T.