The hydraulic rock drill is a kind of rock drilling machine that uses high-pressure oil as the power to push the piston impact drilling tool and has an independent rotary mechanism. Because of its complex structure and high matching accuracy, once there is a problem with a component, it may affect the use of the rock drill. The impact piston is the main part of the impact part of the rock drill. As long as the rock drill starts to work, the impact piston will contact the shank adapter and cause a high-level reciprocating motion. Naturally, its damage rate is higher than other parts. Therefore, today, we mainly share the reasons for the damage to the impact piston of the rock drill.

1. Impact piston face damage

A. Mechanical damage

a. Local deformation occurs on the piston impact face.

There is a top hole for processing technology at the end of the shank adapter. The impact piston and the shank adapter collide with high frequency. Over time, plastic deformation occurs, showing a mastoid shape. Keep using the same manufacturer and specification shank adapter, it will not cause more damage to the impact piston.

b. The shank adapter material or heat treatment hardness is not suitable

If the shank adapter’s hardness is low, it will be deformed during the impact process, resulting in an uneven striking surface, linear contact, and impact piston edge metal falling. If the shank adapter’s hardness is too high, it will crack or its metal will fall during the impact process.

c. Running idly for a long time.

When the rock drill is driven with no load for a long time, the rebound shock wave will cause the impact piston and the shank adapter to generate a lot of heat, accompanied by the micro-crack.

d. The shank adapter is deflected or brought in small gravels.

After the shank adapter is deflected or brought in small gravels, the two contact surfaces are not parallel when the impact piston hits the shank adapter. Because the impact is line to surface instead of surface to surface, it is easy to cause the impact piston to drop small metal pieces.

B. Corrosion

If the rock drill is exposed to corrosive substances, the exposed surface of the piston will be corroded, and the metal surface will rust or fall off. The rock drill will produce high heat during high frequency and high-speed impact, and the high heat will accelerate the corrosion rate of the exposed surface of the piston.

2. The impact piston guide area is damaged

There are two most common failure phenomena in the guide bearing area: one is with the buffer piston contact surface stuck, and the other is the impact of the piston front section fracture.

Under the action of high-frequency shock waves, tiny thermal cracks will occur locally in the impact piston, and these small thermal cracks appear with more concentrated stress, and fatigue fracture will occur.

3. impact piston cavitation

If cavitation occurs on the surface of the front and rear driving areas of the piston, small pitted pits appear, and it does not affect the use but will affect the service life. If cavitation occurs on the impact surface of the end face of the impact piston, it will not affect the use. If the cavitation rough surface occurs in the sealing area, it will cause frequent sealing replacement and serious oil leakage.

The above content is the reason why the impact piston of the rock drill is damaged. To avoid the occurrence of the above phenomenon, we can choose the shank adapter produced by regular suppliers, regular maintenance, and prevent water from entering the rock drill. Only this can improve the efficiency and prolong the rock drill service life.