Cold drawing and cold extrusion are two different methods of cold processing for square pipes, and the two are not the same concept. Cold drawing refers to the method of applying tensile force at both ends of the metal material to cause tensile deformation; cold extrusion refers to the method of applying extrusion force at one end of the material so that the material is extruded through a mold hole, the diameter of the mold hole is smaller than the diameter of the material. In addition to tensile deformation, cold extrusion also causes compressive deformation in the material, and cold extrusion is generally carried out on special cold extrusion machines. Materials processed by cold extrusion have better properties than those processed by cold drawing. The process of cold extrusion (rolling) stainless steel seamless square pipe: round pipe blank heating piercing capping annealing acid washing oil coating (copper plating) multi-pass cold extrusion (cold rolling) blank pipe heat treatment straightening hydraulic test (flaw detection) marking storage. So-called cold-extruded stainless square pipe means that the metal stainless square pipe is stretched without heating using a cold extrusion machine. The advantage is that it does not need to be performed at high temperatures, like drainage boards. The disadvantage is that there is a larger residual stress, and it cannot be pulled too long. Cold extrusion can improve toughness and tensile strength to achieve better mechanical properties. by: http://www.zdjm.cn/