The general process of changing the color of the hydraulic cylinder is as follows: the cylinder will first become blue, then the color will gradually deepen, become purple, and finally become black. The discoloration of the oil cylinder is actually a color film on the surface of the oil, not the problem of the oil cylinder itself. What causes the discoloration of the cylinder?
1. The temperature difference between the inside and outside of the hydraulic cylinder is too large: If the temperature of the hydraulic system is too high during the excavator's work, and the external temperature is very low, especially in winter, the temperature difference between the inside and outside of the hydraulic cylinder will be very large. In this case, the piston rod can easily cause the cylinder to change color.
2. Use of non-dedicated hydraulic oil or inferior hydraulic oil: Many users, due to insufficient experience or cheap maps, use hydraulic oil other than that of the brand's excavator for maintenance of the excavator and replacement of hydraulic oil, which can easily cause oil cylinders. Discoloration. Because there is an extreme pressure anti-wear additive in hydraulic oil, the additives contained in different brands of hydraulic oil are different, and if used in combination, it will affect the cylinder.
3. Impurities attached to the piston rod: When the hydraulic cylinder is working, the piston rod is often in contact with the outside world, and it is easy to attach some impurities. As the impurities accumulate, the cylinder will also change color. Among them, the blue may be caused by the additives in the oil seal and hydraulic oil attached to the cylinder rod at high temperatures. The blackening may be due to the lead additive contained in the spray coating in the wear sleeve attaching to the cylinder rod at high temperatures.
In addition, there is also a possibility that cracks on the surface of the piston rod are difficult to see with the naked eye, and the reason for this crack is that the temperature control of the piston rod is not uniform during the electroplating process, and the cracks that occur need the help of a high-power magnifying glass. see.