The cylinder barrel is the main component of the oil cylinder, mining single pillar, hydraulic support, gun barrel and other products. The quality of its processing directly affects the life and reliability of the entire product. The cylinder has high processing requirements, and its inner surface roughness is required to be Ra0.4 ~ 0.8µm, and the requirements for coaxiality and wear resistance are strict. The basic feature of the cylinder barrel is deep hole machining, which has always troubled the processing personnel.

The rolling process, because the surface layer has residual compressive stress on the surface, helps to seal the tiny cracks on the surface and hinders the expansion of erosion. Thereby, the corrosion resistance of the surface can be improved, and the generation or expansion of fatigue cracks can be delayed, thereby improving the fatigue strength of the cylinder. Through rolling forming, a layer of cold work hardening layer is formed on the rolling surface, which reduces the elastic and plastic deformation of the contact surface of the grinding pair, thereby improving the wear resistance of the inner wall of the cylinder and avoiding burns caused by grinding. After rolling, the reduction of surface roughness value can improve the fit properties.

As the control hub of the hydraulic system, the hydraulic valve moves frequently, and has very high requirements on the precision, sealing and reliability of each component device. Most foreign companies use rolling to improve the precision coordination.

Rolling processing is a chip-free processing that uses the plastic deformation of metal at room temperature to flatten the microscopic unevenness of the workpiece surface to achieve the purpose of changing the surface structure, mechanical properties, shape and size. Therefore, this method can achieve two purposes of finishing and strengthening at the same time, which cannot be achieved by grinding. No matter what kind of processing method is used for processing, there will always be fine uneven knife marks on the surface of the part, and the phenomenon of staggered peaks and valleys will appear.

The principle of rolling processing: it is a pressure finishing process, which uses the cold plastic characteristics of metal at room temperature, and applies a certain pressure to 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 residue. In the low concave trough, the roughness value of the workpiece surface is reduced. Due to the plastic deformation of the rolled surface metal, the surface structure is cold hardened and the grains are thinned, forming a dense fibrous shape, and forming a residual stress layer, the hardness and strength are improved, thereby improving the wear resistance and corrosion resistance of the workpiece surface. Sex and cooperation. Rolling is a non-cutting plastic processing method. The non-cutting processing technology is safe and convenient, and can accurately control the accuracy. Several major advantages:

1. Improve the surface roughness, the roughness can basically reach Ra≤0.08µm.

2. Correct the roundness, the ellipticity can be ≤0.01mm.

3. Improve surface hardness, eliminate stress and deformation, and increase hardness by HV≥4°

4. There is a residual stress layer after processing, which improves the fatigue strength by 30%.

5. Improve the quality of fit, reduce wear, and prolong the service life of parts, but the processing cost of parts is reduced.

The oil cylinder is the most important part of construction machinery. The traditional processing method is: broaching cylinder block - fine boring cylinder block - grinding cylinder block. The rolling method is: broaching cylinder block - fine boring cylinder block - rolling cylinder block, more technology can be consulted:

The process is 3 parts, but the time is compared: it takes about 1-2 days to grind 1 meter of cylinder block, and about 10-30 minutes to roll 1 meter of cylinder block. Input comparison: grinder or quilting machine (tens of thousands - millions), rolling knives (1 thousand - tens of thousands). The way of hydraulic equipment

After rolling, the surface roughness of the hole is reduced from Ra3.2～6.3µm before rolling to Ra0.4～0.8µm, the surface hardness of the hole is increased by about 30%, and the fatigue strength of the inner surface of the cylinder is increased by 25% . The service life of the oil cylinder is increased by 2 to 3 times if only the influence of the cylinder is considered, and the efficiency of the boring and rolling process is about 3 times higher than that of the grinding process. The above data shows that the rolling process is efficient and can greatly improve the surface quality of the cylinder.

After the cylinder is rolled, there are no sharp tiny edges on the surface, and long-term motion friction will not damage the seal ring or seal, which is particularly important in the hydraulic industry.