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Laser quenching technology of steel and its application

time��2017/9/26 9:50:09��source����visits��

Laser quenching technology is the process of rapidly heating the surface of iron and steel by focusing the laser beam to form a martensitic hardened layer. Laser quenching has the advantages of high power density, fast cooling rate, no cooling medium such as water or oil. It is a clean and fast quenching process. Compared with the carburizing process, flame quenching, induction hardening, laser hardened uniform, high hardness (general than induction quenching high 1-3HRC), the deformation of the workpiece is small, the heating layer depth and the heating track is easy to control, easy to realize automation, without induction hardening so as to size parts design of induction coil accordingly. The processing of large parts, nor by carburizing chemical heat treatment furnace when the size is limited, so many industries are gradually replacing the traditional process of induction hardening and chemical heat treatment etc.. Especially, the deformation of the workpiece before and after laser quenching stainless steel tube is almost negligible, so it is especially suitable for the surface treatment of high precision parts. The depth of the laser hardened layer is generally between 0.3~2.0mm range according to the composition, size and shape of the component as well as the parameters of the laser process. The surface of the large gear and the shaft journal of large shaft are quenched, the surface roughness is basically unchanged, without the subsequent mechanical processing, the actual working conditions can be met. Laser remelting hardening technology is a process that uses laser beam to heat up the substrate surface to the melting temperature, and cools the surface of molten layer rapidly because of the heat conduction and cooling of the substrate. The obtained quenched and quenched structures are very dense, and the microstructures in the depth direction are melting solidified layer, phase change hardened layer, heat affected zone and base material. The laser hardening layer has higher hardening depth, higher hardness and better wear resistance than the laser hardening layer. The defect of this technology is that the roughness of the workpiece surface is destroyed to a certain extent. In order to reduce the surface roughness of the parts after laser remelting treatment and reduce the amount of subsequent processing, a special laser hardening coating has been prepared by Huazhong University of Science and Technology, which can greatly reduce the surface roughness of the fused layer. At present, the surface roughness of various materials, such as roll, guide and so on, in the metallurgical industry which is subjected to laser remelting treatment, is close to the level of laser quenching. The laser quenching has been successfully applied to the surface of vulnerable parts of strengthen the metallurgical industry, machinery industry, petroleum chemical industry, especially in improving the roll, guide, gear, blade and the service life of wearing parts, the effect is significant, has achieved great economic and social benefits. In recent years, the surface strengthening of parts such as moulds and gears has also been applied more and more widely. The characteristics of laser quenching technology application material quality advantage of the practical application of the 1. hardened parts deformation of laser quenching process of thermal cycling fast steel large shaft 2. almost without damaging the surface roughness of the anti oxidation protective thin coating on die steel mold 3. laser quenching cracking precision to determine the amount of NC quenching cold die steel mold, cutting tool 4. on the local channel, precise positioning of the quenching NC quenching of medium carbon alloy steel damper 5. laser quenching clean and efficient without water or oil cooling medium iron engine cylinder 6. quenching hardness higher than the conventional method of quenching layer fine microstructure, good toughness of high carbon alloy steel large roller type HGL-V laser laser quenching equipment 5kW transverse flow CO 2 laser, the maximum output power of 5.5kw. The basic size of the laser processing machine for large multi-function machining machine tools is 5.5 meters long and 2.6 meters in diameter. Special workpieces can be machined in larger size range. The laser machining machine tool is a double cantilever machining system, which can be used in multi position laser processing. Six axis four linkage CNC system, the machine tool is equipped with six axis four linkage CNC system, which can be used for precise laser machining of complex workpieces. In laser quenching industry, laser hardening technology can strengthen the surface of all kinds of rails, big gear, journal, cylinder wall, mould, shock absorber, friction wheel, roller and roller parts. Applicable materials are medium, high carbon steel, cast iron. Application of laser hardening: laser hardening of the cast iron engine cylinder, its hardness increased by HB230 to HB680, the service life increased by 2~3 times.