Color recognition and handling skills of excavator cylinder

Many excavator users have encountered the problem of discoloration of the cylinder. They think it is a problem with the quality of the cylinder. They are often in a hurry. Actually, the discoloration of the excavator cylinder is a very common phenomenon. The identification techniques are as follows: Under normal circumstances, the cylinder will first Turns blue, then darkens, turns purple, and finally becomes black.

First, the discoloration of the excavator cylinder is not a discoloration of the cylinder itself

The cylinder becomes black, blue, or purple. In fact, the surface of the cylinder is covered with a colored film, not the cylinder itself. Under normal circumstances, the cylinder will turn blue first, then the color will deepen, turn purple, and finally become black.

Second, there are many reasons for the discoloration of excavator cylinders:

1. There is a high temperature phenomenon in the hydraulic system. During work, the piston rod is in frequent contact with the low-temperature environment (especially in the cold season) (the temperature suddenly dips);

2. In the maintenance cycle, non-exclusive hydraulic oil for the excavator was replaced. This phenomenon generally occurs when the piston rod is discolored within a few days after the oil has been changed. The reason is that there is a difference in the quality and performance of an extreme pressure antiwear additive in the hydraulic oil;

3, the piston rod plating process due to uneven temperature control in the later work in the plating layer surface cracks, with a high magnification magnifying glass observation of the surface of the piston rod can see irregular small cracks.

4. Blue is the result of the oil seal and the additives in the hydraulic oil being attached to the cylinder rod at high temperature. The blackening is caused by the lead additive in the spray inside the cup (ie wear sleeve) attached to the cylinder rod at high temperature. .


Generally, the hydraulic oil temperature is too high, and this phenomenon often occurs in the first half of the bucket cylinder that is used more frequently. It is recommended that the ash soil of the radiator part be cleaned frequently to ensure the heat dissipation effect.

Third, how to deal with excavator cylinder discoloration?

If the cylinder has a very subtle blue color, you can leave it alone and it will disappear after a while;

If the discoloration is more serious, you need to replace the oil seal and wear sleeve, and try to avoid the high temperature of the hydraulic oil, and it will return to normal after a while.