As the main components of hydraulic cylinder, mining single pillar, hydraulic support, gun barrel and other products, the processing quality of cylinder directly affects the service life and reliability of the whole product. The processing requirements of the cylinder barrel are high, and the inner surface roughness is required to be ra0.4-0.8 & um, and the coaxiality and wear resistance are strict. The basic feature of cylinder barrel is deep hole machining, which has always troubled the machining personnel.
By rolling processing, the surface residual compressive stress is left on the surface layer, which helps to close the micro cracks on the surface and hinders the expansion of erosion. So as to improve the corrosion resistance of the surface and delay the generation or expansion of fatigue cracks, thus improving the fatigue strength of the cylinder. Through rolling forming, a 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 the burn caused by grinding. After rolling, the reduction of surface roughness can improve the fitting property.
Oil cylinder is the most important part of construction machinery. The traditional machining 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. The process is three parts, but the time comparison: grinding cylinder block 1 meter takes about 1-2 days, and rolling cylinder block 1 meter takes about 10-30 minutes. Input comparison: grinding machine or quilting mill (tens of thousands to millions), rolling knife (1000 to tens of thousands). After rolling, the surface roughness of the hole is reduced from ra3.2 ~ 6.3um to Ra0.4 ~ 0.8 & um before rolling, the surface hardness of the hole is increased by about 30%, and the fatigue strength of the inner surface of the cylinder barrel is increased by 25%. The service life of the oil cylinder can be increased by 2-3 times if only the influence of the cylinder barrel is considered, and the efficiency of the boring and rolling process can be increased by about 3 times compared with the grinding process. The above data show that the rolling process is efficient and can greatly improve the surface quality of the cylinder.
After the oil cylinder is rolled, there is no sharp edge on the surface, and the long-term movement friction will not damage the sealing ring or seal. This is particularly important in the hydraulic industry.
