Cause of discoloration of excavator cylinder

Many excavator masters believe that the color of the excavator cylinder changes. The general process of discoloration of a hydraulic cylinder is such that the hydraulic cylinder turns blue first, then the color gradually darkens, turns purple, and finally turns black. The color change of the cylinder is actually a layer of colored film on the surface of the oil, rather than the problem of the cylinder itself. Next, let us analyze the cause of the cylinder discoloration.

1. The temperature difference between the inside and outside of the hydraulic cylinder is too large

If the hydraulic system temperature is too high when the excavator is working, the external connection temperature is very low, especially in winter, the temperature difference between the inside and outside of the cylinder is large, and the piston rod works at this time. It is easy to cause cylinder discoloration.

  • Use non-dedicated hydraulic oil or poor quality hydraulic oil

Many users do not have enough experience or cheap maps. When the excavator repairs and replaces the hydraulic oil, the hydraulic oil that is not used by the brand excavator is used, which may cause discoloration of the cylinder. Different grades of hydraulic oil contain different additives due to the extreme pressure anti-wear additives in the hydraulic fluid. If mixed, it will affect the cylinder.

  • Piston rods adhere to impurities

When the hydraulic cylinder is working, the piston rod is often in contact with the outside world, and it is easy to adhere to some impurities. As the impurities accumulate, the cylinder will also change color. Among them, the blue color may be caused by the adhesion of the oil seal and the additive in the hydraulic oil to the cylinder rod at a high temperature. Blackening may be due to the adhesion of the lead additive sprayed in the wear sleeve to the cylinder rod at high temperatures.

  •  Poor plating process leads to micro cracks on the surface of the piston rod

Another possibility is that the piston rod surface has a crack that is hard to see by the naked eye. The reason for this crack is that the temperature of the piston rod is not uniform enough during the electroplating process. Cracks need to be seen with a high magnification magnifier.