Causes and analysis of damage of hydraulic hammer piston

2. Reasons for damage: 1. Causes of scratch on the working surface A. Low surface hardness; B. Impurities mixed in the hydraulic oil; C. The gap between the drill sleeve guide sleeves (upper and lower bushings) is too large, and the guide sleeve fails. During the operation of the drill rod, the axis is inclined. When the piston strikes the drill rod, it is subjected to an inclined reaction force, which can decompose an axial force and a radial force, which can push the piston to one side. The original gap disappears, the oil film is damaged, and dry friction is formed between the cylinder and the piston surface, and the piston surface is scratched. 2. Breaking the piston material During the forging or heat treatment, a crack is generated, which under the action of the alternating stress causes the crack to expand until it breaks. 3. The working surface is sunken, and cracks and cracks occur around the recess. A. The carburized low alloy steel piston is the intrinsic cause of the impact end face depression and crack cracking. Through a lot of investigations, we found that the carburized low alloy steel piston failed due to impact depression, crack and cracking. B. The hardness of the piston striking part and the hardness difference of the striking part of the drill rod should be appropriate. Through years of practice, we also communicated with famous domestic and foreign suppliers, and found that the two should have a suitable hardness, and The difference should be appropriate.