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. ...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.展开更多
40Cr steel is laser quenched by the NEL-2500A rapidly axial flow CO2 laser. Then the martensite induced by laser quenched is shocked by Nd：YAG laser again. Through comparing and analyzing the appearance and size of m...40Cr steel is laser quenched by the NEL-2500A rapidly axial flow CO2 laser. Then the martensite induced by laser quenched is shocked by Nd：YAG laser again. Through comparing and analyzing the appearance and size of martensite, the dislocation density in microstmcture between the treated zones by laser quenched and by laser quenched plus laser shock, the following results are shown： The second martensite obtained by laser compound treatment is more fmer compared with those obtained by laser quenched; In the hardened zones obtained by compound treatment, a lot of slender second twin crystal martensites are induced; A lot of more high density dislocation tangles and cellular dislocations are generated. From the transmission electron microscope （TEM） micrograph after compound treatment, there are not only long lath and short nubbly martensites arranged in cross direction, but also massive nubbly and small short nubbly martensites arranged in longitudinal direction. Some martensites look like the broken blocks of quenched martensites. These new martensites are inserted transversely in the quenched martensites with large tangle. And they make quenched martensites break into pieces. Compared with the quenched martensites, the size of fresh martensites are smaller, about 0.3-0.5 μm.展开更多
基金Funded by the National Natural Science Foundation of China(50901089)
文摘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.
基金This project is supported by National Natural Science Foundation of China (No. 50451004)Talent Foundation of Jiangsu University, China.
文摘40Cr steel is laser quenched by the NEL-2500A rapidly axial flow CO2 laser. Then the martensite induced by laser quenched is shocked by Nd：YAG laser again. Through comparing and analyzing the appearance and size of martensite, the dislocation density in microstmcture between the treated zones by laser quenched and by laser quenched plus laser shock, the following results are shown： The second martensite obtained by laser compound treatment is more fmer compared with those obtained by laser quenched; In the hardened zones obtained by compound treatment, a lot of slender second twin crystal martensites are induced; A lot of more high density dislocation tangles and cellular dislocations are generated. From the transmission electron microscope （TEM） micrograph after compound treatment, there are not only long lath and short nubbly martensites arranged in cross direction, but also massive nubbly and small short nubbly martensites arranged in longitudinal direction. Some martensites look like the broken blocks of quenched martensites. These new martensites are inserted transversely in the quenched martensites with large tangle. And they make quenched martensites break into pieces. Compared with the quenched martensites, the size of fresh martensites are smaller, about 0.3-0.5 μm.
