High frequency welded pipe is generally completed by cold rolling, high frequency welding, forming and other processes. This is a slotted pipe.

Seamless steel pipes can be divided into hot-rolled seamless pipes and cold-drawn seamless pipes. The heat pipe is made of blank forging, piercing, rolling, shaping and other processes. Generally, large-diameter thick-walled seamless pipes adopt this form; Cold-drawn pipe is made of tube blank, with relatively low material strength and smooth internal and external control surfaces. Small-caliber thin-walled seamless pipes are mostly of this kind.