Excavator pump plunger and cylinder "killed" fault handling

Excavator pump plunger and cylinder "killed" Troubleshooting: a HE-280 excavator, overhaul and replace the hydraulic pump cylinder and plunger, the hydraulic pump does not work and accompanied by abnormal sound. Disassembly found that the plunger and cylinder stick together, was "killed" state. Metallographic analysis of the cylinder block and the plunger confirmed that retained austenite was transformed into martensite, and the lower the temperature, the greater the amount of change. In the cold season, the residual transformation is completed in a very short period of time, causing the piston to "bite to death" due to its instantaneous increase in volume. To this end, the measuring tool can be used to measure the hydraulic cylinder and plunger at room temperature with the gap; the cylinder and the plunger were cold, that is placed in -50 ~ -60 ℃ place, 30min after removal; with a grinder On the piston grinding to room temperature with the size; on the plunger surface laser quenching; with a special polishing paste on the piston surface and then polished, loaded after the troubleshooting.