Research On The Technology And Application Of Laser Strengthening In Steel Surface

With the development of modern laser technology, laser processing have develop a process technology with more universal and a variety of purposes to a special-purpose processing technology. Laser surface hardening is a very important field of technology among these. The research on the technology of laser surface hardening and exploiting, which can improve component performance of the product over a long service life and expand the application area of technology, up to promote the manufacture technical level.The paper study the temperature field of laser surface hardening by numerical simulation method, then study the technology of the laser melting and the laser cladding about 45# steel and Cr5 steel, and analyze the relevant organization and performance. At the same time, carry out the research on the technology of laser surface hardening of laser cladding with the product of chopping knife and the legs of hydraulic support. The researches indicate the laser surface hardening is a process of drastic and nonequilibrium thermal effect, heating speedy to gasification temperature for moment, and high temperature reside short time, but cooling time is short of T8/5. In contrast, the speed of heating is faster than the speed of cooling. So, reasonable select of the technology has an obvious effect to improve the steel surface properties. In single pass laser fused, the surface hardness of 45# steel can reach HV750, and Cr5 steel can reach HV 800, the depth of harden zone can reach more than lmm. In multi-channel laser melting, laser fused after processing exist the effect of back to hot for laser melting before processing. This effect show relatively obvious in 45# steel, Cr5 steel fused layer have more thermostability. The wear-resisting property of 45# steel increases 0.5 times in comparison with the based metal. And Cr5 can reach 10 times, the fused scanning interval(overlapping ratio) have a relatively optimal values in both property of the fused lay and production efficiency. It can form the area of cladding layer, transition layer and the based metal by laser cladding Ni60 on surface for 45# steel and Cr5 steel. The microhardness of 45# steel cladding layer can average reach HV 800, and the properties of friction and wear can improve nearly 4 times in comparison with based metal. The microhardness of Cr5 steel cladding layer can average reach Hv850, and the properties of friction and wear can improve nearly 10 times in comparison with the based metal. The wear resistance and thermal stability of Cr5 steel has good engineering significance by laser surface strengthening treatment.The research results can apply to the laser cladding of the kitchen knife blade and the legs of hydraulic support. We have carried out preliminarily studied, and got preferably effect of cladding. All these can provide the basis of the experimental data and technical support for the development of the latter project and base construction.