Machining method of hydraulic cylinder tubing
Hydraulic cylinder tube is a high-precision seamless steel tube material after cold drawing or welded tube after Drawn Over Mandrel. Since the inner and outer diameter of the precision steel pipe have no oxide layer, no leakage under high pressure, high precision, high finish, no deformation in cold bending, no cracking in flaring and flattening, it is mainly used in the production of pneumatic or hydraulic components such as penumatic cylinders or hydraulic cylinder barrels.
The chemical composition of the honed cylinder tubing contains Iron, carbon, silicon, manganese, sulfur, phosphorus and chromium.
The hydraulic cylinder barrels are usually manufactured by the method of Skiving & Roller burnishing (SRB). Due to the residual compressive stress on the surface, it helps to close the tiny cracks on the surface and hinder the expansion of erosion. Thereby improving the corrosion resistance of the surface, delaying the occurrence or expansion of fatigue cracks, and improving the fatigue strength of the honing tube. Through Roller Burnish forming, a layer of cold work hardening layer is formed on the rolling surface, which reduces the elastic-plastic deformation of the contact surface of the grinding pair, thereby improving the wear resistance of the inner wall of the grinding tube and avoiding burns caused by grinding. After Roller burnishing, the reduction in surface roughness can improve matching performance. SRB processing is a chipless processing that uses the plastic deformation of metal at room temperature to flatten the microscopic unevenness of the workpiece surface, thereby changing the surface structure, mechanical properties, shape and size.
Therefore, this method can achieve the two purposes of finishing and strengthening at the same time, but grinding cannot. No matter which processing method is used, there will always be fine and uneven knife marks on the surface of the part, and there will be staggered peaks and valleys. Rolling processing principle: It is a kind of pressure finishing processing, using the cold plasticity of metal at room temperature, applying a certain pressure on the surface of the workpiece with a rolling tool, so that the metal on the surface of the workpiece produces plastic flow and fills the original remaining depressions In the groove, thereby reducing the roughness value of the workpiece surface.
Due to the plastic deformation of the roller burnishing surface metal, the surface microstructure is cold hardened, the grains are fine, and a dense fibrous structure and residual stress layer are formed, which improves the hardness and strength, thereby improving the wear resistance and corrosion resistance of the workpiece surface and compatibility. Rolling is a plastic working method without cutting.
Several advantages of the Hydraulic cylinder tubes
- Improve the surface roughness, and the roughness can basically reach about Ra≤0.04 m.
- The roundness is correct, and the ellipticity can be ≤0.01mm
- Improve the surface hardness and make the stress and deformation disappear.
- There is a residual stress layer after processing, and the fatigue strength is increased by 30%.
- Improve the matching quality, reduce wear and prolong the service life of parts, but the processing cost of parts will be reduced instead.
