Research Of Cam Contour Surface Hardening Technology Based On Magnetron Ion Sputtering Deposition

As a new surface engineering technology, hard coating technology develop rapidly inrecent years, and is widely used in aerosPace, military, machinery manufacturing and otherfields. In this article, a study of cam contour surface hardening technology based on themagnetron ion sputtering deposition was made.40Cr of the cam material was used as the basematerial for depositing TiAlN hard coating on its surface with the method of magnetronsputtering deposition. Thereby the friction coefficient was reduced between the roller and cam,and the anti-friction and wear properties of the cam contour surface were improved. For thelower temperatures of this kind of surface hardening technology, it can be effective alternativeto traditional heat treatment process, eliminating workpiece deformation of cam due to heattreatment. So it can be significant savings in manufacturing costs. SEM, X-ray diffraction(XRD), scratch test and friction test were used to investigate the composition，microstructure,components, phases and properties of the TiAlN hard coatings. In order to determine theoptimum coating thickness and the failure mechanism of TiAlN hard coating in the camengaging process, finite element simulation analysis of cam and roller engaging model wasconducted by the finite element software LS-DYNA.Firstly, a cam and roller engaging model was built by the three-dimensional modelingsoftware according to the actual size. A mathematical model was built by the basic theory offinite element. The material model was built according to the experimental data and theconstraints of the models were built according to the actual working conditions. stressdistribution of Hertz contact theory and finite element analysis were comPared to verify thecorrectness of the model. And it proves that the model is correct and reliable for the samerange of stress distribution. The theoretical stress values calculated by the formula of theHertz stress and the stress obtained by the finite element simulation were comPared to verifythe correctness of the model. And the differences between the two stress values were small, soit proves that the model is correct and reasonable too.Friction tests of different thickness of TiAlN hard coatings under different loads anddifferent speeds were conducted to verify the performance of the friction. The bestdistribution interval of the coefficient of friction was obtained by analyzing the relationship between the friction performance and coating thickness as well as the load and speed. at theshort deposition time, the coating thickness is thin and coating surface quality is poor,resulting in a low interfacial bonding strength of the film base and more seriously influencedby the load and speed; with the increase in the thickness of the coating, the surface quality andinterfacial bonding strength of the film base were both improved, and thus the influence ofload and speed becomes weak. At a certain preParation process case, the thickness of thecoating becomes a decisive indicator of the coating performance.By Data aggregation of values of the stress and strain from the simulation of the modelunder different loads and thicknesses and combined with actual TiAlN hard coating preParedexperience, the most optimum coating thickness range of the TiAlN hard coating wasdetermined at a thickness interval of5~7um. This thickness range of the TiAlN hard coatingwas relatively easy to prePare and had good performance. The TiAlN coating failuremechanism was summed up through the analysis of the stress distribution and the coatingfailure theory summarized from the literature. The conclusion in this article will play a certaintheoretical guidance for future production.