Papers by Keyword: Laser Quenching

Abstract: The surface of 45 steel is quenched by CO₂ laser with scanning speed 1000 mm/min and different laser power 1000W, 1200W, 1400W, 1600W and 1800W. Experiments are carried out to analyze microstructure, friction and wear properties of quenched 45 steel. The results show that the quenching layer thickness increases gradually with the increase of laser power,and the maximum value of quenching layer hardness increases first and then decreases. When the laser power is 1600W, the maximum hardness value is 883HV_0.5. But when the laser power is 1800W, the hardness of quenching layer becomes to decrease. The reason is the surface of 45 steel becomes to melt. The wear volume increases first and then decreases too. When laser power is 1600W, the minimum wear volume is 0.08mm³, which is 6.4% to the wear volume of 45 steel matrix without laser quenching. Therefore, better microstructure and properties of 45 steel can be obtained when laser scanning speed is 1000mm/min and laser power is 1600W.

Abstract: Have studied microstructure of the gas nitriding layer and the laser quenching/ nitriding layer using the X-ray diffractometer and the transmission electron microscope to the brittl of nitriding layer. The results show that the content of Fe3N in composite nitrided layer increased from 14.74% to the 69.45%, while the crisp hard ξ-Fe2N content dropped from 79.95%to 25.03%, Especially the Cr2N particles are much finer and the depth of the nitrided layer increases. There have phase relation, coherence and compatibility between γ'-Fe4N and α-Fe. spherical particles of cementite was formed in lower strip bainite, while the γ′ of gas nitriding diffusion layer is big, the carbide assumes the long strip off and with distributing certain directivity. Brittleness of laser hardening/ nitriding layer reduces.

Abstract: In this paper, a temperature field model of 45 steel shafts during the laser quenching was built and simulated by using ANSYS software. Its surface temperature distribution of the shaft during the laser beams scanning was simulated. Their effects of different laser power, laser beams spot size and scan speed on part’s quenching performance were analyzed.

Abstract: Generally, the welding HAZ is more sensitive to corrosion. In order to increase the corrosion resistance of the welding HAZ in aircraft structures, the laser surface treatment technology was used to treat the welding HAZ. In this study, the processing parameters of the laser surface treatment were optimized. According to our study, the laser quenching can increase the corrosion resistance property obviously. The laser surface treatment new technique has been used in the maintenance of the airplane structures, which has better application outlook.

Abstract: Laser quenching is a kind of advanced surface heat treatment technology,which is widely used in automotive, aerospace, and other industrial fields. The present laser quenching machines are general use the nc machine tools most. These kinds of machine have greatly limited the processing ability and the range of processing has been very restricted too. During this paper,first according to the theory study,we put forward the technical requirements about how to acqurie even hardened laye in laser quenching process. Then, the paper list the shortcomings of present numerical control machine tool in the aspects of realizating the laser quenching. At last according to the condition in practical production, the paper come to the total solution to realize CNC laser quenching, doing some theoretical exploration for the realization of the laser quenching.

Abstract: 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。Experimental results indicated that the complex layer is composed of soft surface sulphide layer and sub-surface laser-quenching harden layer, represents excellent friction-reduction and wear-resistance performance at high temperature. The synergistic effect of the laser quenching-sulphide 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.