The production process of thick-walled seamless steel pipes can be divided into four basic methods: cold drawing, cold rolling, hot rolling, and thermal expansion. Uses are divided into seamless steel pipes for structure; seamless steel pipes for transportation; seamless steel pipes for boilers; high-pressure seamless steel pipes for boilers; high-pressure seamless steel pipes for fertilizer equipment; seamless steel pipes for geological drilling; seamless steel pipes for oil drilling; Seamless steel pipes for petroleum cracking; seamless steel pipes for ships; cold-drawn cold-rolled precision seamless steel pipes; various alloy pipes. Seamless steel pipes are represented by outer diameter and wall thickness. Thick-walled seamless steel pipes are mainly used for mechanical processing, coal mines, hydraulic steel, and many other purposes.