Pipe rolling – the processing of the wall thickness of the capillary is usually called pipe rolling. Pipe rolling is the most important process in the process of steel pipe forming. The main task of this link is to reduce the thick wall capillary to the extent suitable for the finished steel pipe according to the requirements of the finished steel pipe, that is, it must take into account the change of wall thickness in the subsequent sizing and reducing processes. This link also needs to improve the internal and external surface quality of capillary and the uniformity of wall thickness.
The pipe after the wall reduction and extension process of pipe rolling is generally called waste pipe. The basic feature of pipe rolling wall reduction method is to press a rigid mandrel in the capillary and compress the wall thickness of the capillary by external tools (roll or die hole). According to different deformation principles and equipment characteristics, it has many production methods. It is generally used to name the hot rolling mill according to the form of pipe mill.
The pipe mill is divided into single stand and multi stand. The single stand includes automatic pipe mill, Assel mill, ACCU-ROLL, etc. the skew pipe mill is a single stand; Continuous pipe mills are multi stand, usually 4 ~ 8 stands, such as MPM, PQF, etc. At present, continuous rolling (belonging to longitudinal rolling) and cross rolling are mainly used.
The function of hot-rolled seamless steel pipe process is to reduce and extend the hollow capillary after perforation, make its wall thickness close to or equal to the thermal size of the finished product, eliminate the uneven longitudinal wall thickness, improve the internal and external surface quality of the raw pipe, and control the outer diameter and roundness of the raw pipe.