The cold drawn tube is subjected to rolling processing, and the surface layer has residual surface compressive stress, which contributes to the sealing of the surface micro crack and hinders the expansion of the erosion effect. Thereby, the surface corrosion resistance is improved, and the generation or expansion of the fatigue crack can be delayed, thereby improving the fatigue strength of the cold drawn tube. Through roll forming, the rolling surface forms a cold hardening layer, which reduces the elastic and plastic deformation of the grinding contact surface, thereby improving the wear resistance of the inner wall of the cold drawn tube and avoiding burns caused by grinding. . After rolling, the surface roughness value is reduced to improve the compounding property.
Cold drawn tube
Rolling processing is a kind of chipless processing, which utilizes plastic deformation of metal at normal temperature to flatten the microscopic unevenness of the surface of the workpiece to achieve the purpose of changing the surface structure, mechanical properties, shape and size. Therefore, this method can achieve both the finishing and strengthening purposes at the same time, which is impossible for grinding. No matter what kind of processing method is used, there will always be fine uneven surface marks on the surface of the part, and there will be staggered peaks and valleys. The principle of rolling processing: it is a kind of pressure finishing, which uses metal at normal temperature. The cold plasticity of the state uses a rolling tool to apply a certain pressure to the surface of the workpiece to cause plastic flow of the surface metal of the workpiece, and fill it into the original residual low concave valley, and the surface roughness of the workpiece is reduced. Due to the plastic deformation of the rolled surface metal, the surface layer is cold hardened and the grain is thinned to form a dense fibrous shape, and a residual stress layer is formed, and the hardness and strength are improved, thereby improving the wear resistance and corrosion resistance of the surface of the workpiece. Sex and fit. Rolling is a non-cutting plastic working method.