Laser Quenehing and Ion Sulphidizing Complex Surface Treat Technology for Diesel Engine Cylinder

In order to solve the problem of wear-out-failure of diesel engine cylinder, the laser-quenching and low temperature ion sulfurizing complex surface treatment technology was operated on the surface of 42MnCr52 steel. And the tribological properties of the complex layer were investigated. The experimental results indicated that the complex layer was composed of soft surface sulphide layer and sub-surface laser- quenching harden layer, and showed excellent friction-reduction and wear-resistance performance at high temperature. The synergistic effect of the complex layer resulted in 20% increase in hardness, 10% reduction in friction coefficient and 50% reduction in wear weight loss, respectively, compared with those of the standard samples. The bench-test further demonstrated that this technology can improve the lubricating condition between cylinder and piston ring, and reduce both abnormity wear when the lubricating oil is deficiency at the time of start-up and sticking wear at high temperature during the operating period, and then prolong the service life of engine.