Hot-rolling seamless pipe is generally produced in the automatic rolling machine. After inspection and removal of surface defects, the solid tube is cut into required length, end to end in the perforated tube surface centering, and then sent to the furnace heating, piercing the piercer. While continuing to rotate the perforation and forward, under the action of the roll and the head of the tube gradually formed an internal cavity, said capillary. Continue rolling and then sent to the automatic rolling machine. Finally, after all the Leveling machine leveling the wall thickness and the sizing mill sizing, to meet the specifications.
The solid tube into a hollow capillary; we can understand stereotypes, both the rolling section as an annular; their equipment is called puncher.
Usually, Cold drawing is carried out on 0.5 ~ 100T single chain or double chain drawing machine. Cold rolling is performed below the recrystallization temperature, and hot rolling is rolling at a temperature above the recrystallization conducted. Cold-drawing seamless steel pipe is often small diameter while hot-rolling seamless steel pipe is often a large diameter.