Tubing/short-circuit thickening/pier roughening process: after heating the tubing end, it is sent to the thickening equipment for upsetting. Plastic deformation occurs at the end of the oil pipe (the inner diameter of the pipe end does not change, and the wall thickness of the pipe end and the effective length of the thick wall section are increased). So as to achieve the purpose of thickening the pipe end. The external thickening process is a complex composite process of upsetting, expanding and extruding. The purpose of thickening is to enhance the strength of the threaded connection of the oil pipe, improve the use time of the threaded connection, avoid the fracture, and extend the life of the oil pipe and prevent accidents!