2, precision seamless steel tube is a kind of high precision steel tube through cold rolling or cold drawing treatment; full name: cold rolled or cold drawn precision seamless steel tube. Due to the precision seamless steel tube internal and external walls without oxide layer, withstand high pressure without leakage, high precision, high finish, cold bending without deformation, flaring, flattening without cracks, etc., so it is mainly used for the production of pneumatic or hydraulic components of the product, such as cylinders or oil cylinders, are used seamless tube. The chemical composition of precision seamless steel tube has carbon C, silicon Si, manganese Mn, sulfur S, phosphorus P, chromium Cr.