1. It is not the color of the cylinder itself that the oil cylinder is discolored.

The oil cylinder turns black, blue or purple phenomenon, actually is the oil cylinder surface coating a layer of color film, is not the problem of the oil cylinder itself. In general, the oil cylinder turns blue first, then the color deepens, turns purple, and finally becomes black.

2. There are many reasons for the discoloration of the oil cylinder:

1. There are high temperature phenomena in the hydraulic system. In the work, the piston rod is frequently exposed to low-temperature environment (especially during cold seasons).

2. During the maintenance cycle, the special hydraulic oil of the non-brand excavator is replaced. This phenomenon usually occurs in the first few days after changing the oil product. The reason is that there is an extreme pressure anti-wear additive in the hydraulic oil and the quality and performance are different;

3, the piston rod caused by uneven temperature control in the process of plating coating on the surface of the electricity in the later work appear crack, a magnifying glass to observe with high multiple irregular surface of the piston rod can see tiny crack.

4, blue is the oil seal and hydraulic oil additives at high temperature within the attachment on the cylinder rod, black cup "(that is, the wear-resisting set) is in the lead in the spraying material additives under the high temperature caused by adhesion on the cylinder rod.

Generally, the hydraulic oil temperature is too high, and this phenomenon occurs in the first half of the bucket oil cylinder with more use, it is recommended that the gray soil in the radiator part should be cleaned regularly to ensure the heat dissipation effect.

Iii. How to deal with the discoloration of oil cylinder?

If the oil cylinder appears in a very small part of the blue, you can ignore it, over time will automatically disappear;

If the color 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 return to normal after a period of time.