During the manufacturing process of the piston rod, rolling processing can be used. To some extent, residual compressive stress may be left on the surface layer, which helps to seal small surface cracks and hinder the expansion of erosion. Thereby improving the surface corrosion resistance, the piston rod can also delay the generation or expansion of fatigue cracks, thereby enhancing the fatigue strength of the oil cylinder rod.
The piston rod is formed by rolling, and a cold work hardening layer is formed on its rolling surface, which can reduce the elastic and plastic deformation of the contact surface of the grinding pair, thereby improving the wear resistance of the cylinder rod surface and avoiding burns caused by grinding.
After rolling the piston rod, the surface roughness value is reduced, which can effectively improve the fitting properties. At the same time, it reduces the friction damage to the sealing ring or seal during the movement of the cylinder rod piston, and improves the overall service life of the cylinder. Rolling technology is a high-quality process measure.
Basic requirements for piston rods
1. The piston rod requires sufficient strength, stiffness, and stability to a certain extent.
2. The piston rod has good wear resistance and requires high machining accuracy and surface roughness.
3. Minimize the impact of stress concentration on the structure as much as possible.
4. Ensure reliable connection and prevent looseness.
5. The design of the piston rod structure should facilitate the disassembly and assembly of the piston.
In general, the blank of the piston rod is suitable to choose 38CrMoAlAn alloy structural steel. After quenching and surface nitriding treatment, high core strength, excellent wear resistance, and fatigue resistance can be obtained. If the piston rod is produced in small batches, in order to effectively improve production efficiency, free forging should be used to make the blank. However, when using free forging to produce blanks, it is necessary to determine the size and shape of the blanks.
In general, if producing piston rods in small quantities, cylindrical blanks should be selected. However, due to the varying precision requirements for processing different components, it is necessary to set the dimensional tolerance level of forgings at 8-12.
