Research On The Edm Surface Strengthening Of Stainless Steel 1Cr13

Electrical discharge machining (EDM) surface strengthening is a processing method that makes the workpiece surface hardened by using the energy density of electric energy derectly. By the spark discharge effect, the conductive electrode materials melt and infiltrate into the surface of the workpiece, then become the alloying surface strengthening layer, which can make the physical, chemical and mechanical properties of the workpiece surface improved, and repair the workpiece surface damage with maintaining the properties of the workpiece matrix. In this paper, for the abrasion phenomenons of the turbine flowing-passage components are very serious, the study on the EDM surface strengthening of stainless steel 1Cr13 is carried out. As a result, this research work has a great significance for improving the anti-abrasion property and extending the service life of the turbine blades.In this paper, the background and the development status of the research issue are comprehensively reviewed, the formation laws and the influencing factors of EDM surface strengthening layer are researched deeply, and the variation laws of the electrode-workpiece weight, the strengthening layer thickness, and the surface morphology with enhancing time, electrode materials, and electrical parameters are obtained. The results show that, in the premise of ensuring the strengthening layer thickness, the qualities of the strengthening layer and the efficiency of the strengthening process can be improved by selecting and controling the process parameters (discharge voltage, capacitance, pulse frequency, peak current, pulse width and enhanced time).The latent heat problem of EDM surface strengthening process was dealt with by method of equivalent specific heat, and the time-varying and unequal amplitude heat flux of single-pulse electric spark discharge was loaded by APDL Programing. The finite element simulation model of the electrode melting drops coating process on the workpiece was established, and the numerical simulation of the temperature field and thermal stress field of the single-pulse electric spark discharge strengthening region was carried out. Thus the variation laws of the temperature field and thermal stress field with the time are detailedly analysised, which provides the theoretical basis for selecting and controling the process parameters.The microstructure, the elements distribution, and the phase structure of the strengthening layer are analysised by using scanning electron microscopy and X-ray diffraction, the hardness and the wearing resistance of the strengthening layer are studied by micro-hardness test and wear test. The results show that, the hardness and the wearing resistance of the strengthening layer are significantly higher than that of the workpiece matrix. The strengthening layer with high hardness and high wearing resistance can be obtained by selecting high hardness, high alloying electrode materials and reasonable electrical parameters. The hardness of the EDM surface strengthening layers generated by YG6 and WC electrodes is 2 to 3 times more than that of the workpiece matrix, and the wearing resistance of the strengthening layers is also improved significantly.