Seamless pipes are widely used. Seamless pipes for general purposes are rolled by ordinary carbon structural steel, low alloy structural steel or alloy structural steel, with the largest output, and are mainly used as pipes or structural parts for conveying fluid.
Supply is divided into three types according to different purposes: a. Supply according to chemical composition and mechanical properties; B. Supply according to mechanical properties; C. Supply according to hydraulic test. The steel pipes supplied according to category a and b shall also be subjected to hydraulic test if they are used to bear liquid pressure.
There are many kinds of seamless pipes for special purposes, such as boiler seamless pipes, geological seamless pipes and petroleum seamless pipes.