The Research Of Laser Cladding Hard Coating On The Surface Of 40Cr And Its Application

40 Cr steel is one of the most widely used steel in machinery manufacturing, it has good harden ability, after proper heat treatment, it have good comprehensive mechanical properties, good low temperature impact toughness, and low notch sensitivity. It always used in the manufacture of axial parts, gear and medium-sized plastic mould and other mechanical parts. But in the case of badly working condition, mechanical parts wear usually is very serious, the service life is short. Laser cladding technology is that with the action of laser beam, cladding a functional coating in the metal material surface, to achieve the effect of surface strengthening. By using laser cladding technology on the surface of 40 Cr to make alloy coatings with special properties, it can not only retain strength and toughness of 40 Cr matrix, and also can save valuable metal material, reduce the production cost, it is of great Industrial application value.The article is based on the method of experimental study, in view of the strengthen study of laser cladding on 40 Cr steel surface, and applied research results to mould manufacture of hub mould. The main contents are as follows:According to the basic theories that in the process of laser cladding, such as interaction between laser and material, metal absorption of laser light and other basic theory. And analysis convection and heat transfer of the solidification process. Combined with the design principle of laser cladding materials and the characteristics of 40 Cr steel, designed three kinds of alloy powder, and according to the actual engineering experience made the pilot scheme of laser cladding.Prepared wear-resisting cladding layer on the 40 Cr steel plates. Comparative and analysis the quality of the cladding layer under various process parameters, acquire the appropriate laser power, scanning speed, lap rate and other parameters. using XRD, metallographic microscopic analysis, micro-hardness test, compare and analysis the microcosmic performance of cladding layer; Using the impact toughness test, tensile test, friction and wear test compare and analysis the mechanical properties of cladding layer, provide experiment basis for preparation of high quality alloy cladding layer over 40 Cr Steels surface. According to the working condition of the wheel hub mould, Contrasts the hardness, impact toughness and wear resistance between Cr12 Mo V and TZ675 cladding layer, comparing the experimental data, determine the feasibility of that by using 40 Cr surface cladding TZ675 wear-resistant alloy layer instead of the whole Cr12 Mo V that in the hub mould materials. Design a feasible scheme of 40 Cr laser cladding surface strengthening, and do cladding experiments in 40 Cr wheel hub mould, demonstrates the feasibility of the laser cladding technology from the practice.