Fix the cylinder tube surface defects before the machined surface of the cylinder tube will be a lot of pitting, which is an important factor affecting the quality of the cylinder tube, after honing in order to obtain good quality hydraulic pipes, on the need for these pits repair. So, fix hydraulic pipe surface defects, what does? 1. Increase the amount of deformation increases cold drawn cold drawing deformation passes, increase the total amount of deformation may lead to lower pitting depth, reducing the honing grinding allowance purposes. 2. Preferred hot-rolled tube blanks drawn tube pitting defects are caused by hot-rolled tubes, so the extent of corrosion by selecting a small, uniform thickness of hot-rolled tubes can reduce pitting defects and improve the cylinder timber rate. 3. Hot-rolled tube defects in the hole to clean. Product quality is a prerequisite, and only good quality, and customer service is fundamental, therefore, hydraulic tube defects surface perfect repair, is the greatest commitment to our customers several advantages a cylinder tube, to improve the surface roughness roughness can basically reach Ra≤0.08μm. 2, the amendment roundness, ovality can ≤0.01mm. 3, to improve the surface hardness, so that by eliminating deformation, hardness HV≥4 ° 4, after processing residual stress layer, improve the fatigue strength by 30%. 5, to improve with the quality and reduce wear and extend the life of parts, but the parts but lower processing costs. Rolling cylinder tube principle: it is a kind of pressure finishing, is characterized by the use of metal in the cold plastic normal condition, the use of rolling tool to exert pressure on the surface of the workpiece surface metal plastic flow, fill in the The original residual low-lying valleys in the surface roughness values ??to achieve lower. Because the surface is rolled metal plastic deformation, so cold hardening and grain tapering surface tissue, forming a dense fibrous, and the formation of residual stress layer, hardness and strength increased, thereby improving the wear resistance of the workpiece surface, corrosion and with nature. Rolling is a non-cutting plastic working method. Seamless steel tube and the difference between the cylinder 1, the main characteristics of seamless steel pipe without welding seam, can withstand greater pressure. Products can be very rough cast or cold call. 2, the cylinder tube is a product emerged in recent years, mainly in the hole, the outer dimensions with tight tolerances and roughness.