The main factors affecting the internal hole finish of cold-drawn seamless steel pipe are as follows:

　　1. Pungent

　　The manufacturer's experience in piercing is not mature, the piercing temperature is not controllable, the piercing equipment is short, and the uneven heating of round steel causes large temperature difference inside and outside the steel pipe, forming pits, pits, peeling, etc., And the smoothness is not good. PMC has a slender perforating furnace, and the steel pipe is evenly heated.

　　2. Cold drawing die

　　There are defects in the cold drawing die itself, resulting in poor internal finish of the finished seamless pipe. PMC adopts professional customized precision molds with high precision and good internal and external surface quality of the finished products after cold drawing.

　　3. Pickling

　　Due to the strict environmental protection requirements in recent years, many manufacturers have no pickling process and can only be processed outside without professional experience. However, there is no data accumulation on the pickling time of steel, so the processing plant is allowed to process at will. The internal impurities of the cold-drawn seamless pipe cannot be thoroughly cleaned, or there are too many acids to form pits and pits. Since its establishment, PMC has a fully closed environmental protection pickling tank. After more than ten years of data accumulation, different steel grades have different pickling methods and times, which can ensure the internal hole finish.