Welded pipes are generally completed through cold rolling, high-frequency welding, forming and other processes. It is a kind of seamed pipe.

Seamless steel pipes are divided into hot-rolled seamless pipes and cold-drawn seamless pipes. Hot-rolled pipes are made through blank forging, perforation, rolling, shaping and other processes. Generally, large-diameter, thick-walled seamless pipes adopt this form; cold-drawn pipes are cold-drawn from tube blanks. The material strength is relatively low, and the appearance and internal control surfaces are smooth. Small-diameter, thin-walled seamless pipes are mostly of this type.