The cylinder tube is processed by rolling, because the residual compressive stress on the outer surface is left, which helps to close the small cracks on the outer surface and prevent the expansion of the erosion effect. Then improve the appearance of anti-corrosion ability, and can delay the occurrence or expansion of fatigue cracks, thus improving the fatigue strength of the cylinder tube. Through roll forming, the rolled surface forms a cold-work hardened layer, which reduces the elasticity and plastic deformation of the grinding pair's touch surface, and then improves the wear resistance of the inner wall of the cylinder tube, and avoids burns caused by grinding. After rolling, the reduction of the surface roughness value can improve the nature of cooperation.
Rolling processing is a kind of chipless processing, which uses plastic deformation of metal at normal temperature to make the microscopic unevenness of the workpiece surface smooth and then reach the intention of changing the surface structure, mechanical properties, shape and scale. Therefore, this method can reach the two intentions of finishing and strengthening together, which cannot be achieved by grinding.
No matter what kind of processing method is used, there will always be fine uneven marks on the surface of the part, showing the appearance of intertwined peaks and valleys.