Study On Surface Strengthening Of H13 Steel By EDM

Electrical discharge machining (EDM) is a material removal process by using thermal energy to machine electrically conductive parts. Because of its machining speciality, it has been extensively applied in lots of industries, such as avigation, spaceflight, micro-electronics, etc. With the deep research of EDM technology, it is also being used for surface strengthening successfully and favorable benefit has been obtained.This article uses the DM7132 precise electric spark shaper, selects the silicon as the electrode material to carry on superficial strengthening processing to the H13 steel work piece. It has carried on the discussion on the electric spark machining mechanism, it has also thoroughly discussed the mechanism and the formation rule of the strengthened level which the electric spark surface forms. It has analyzed and studied the organization, the ingredient, and the performance of the strengthened level ,so that the union intensity between the strengthened level and the substrate is improved. Through the machining heat treatment of H13 steel by the electric spark, the article has done the research of the impact of silicon to the H13 steel in work piece surface strength, degree of hardness as well as the improvement of wear resistant.By means of detection and analyses of the X-ray diffraction and EPMA, strengthening layer contains Si, Fe, C, Cr, Mn, Mo, V and so on. The content of Silicon and Ferro is much more than that of substrate material and it is also distributed gradient from the surface to substrate of work piece. The results show that the electro-spark deposition is not a process of the position electrodes' overlaying on the matrix materials, but a complicate alloying and metallurgy process of the elements coming from the positive electrodes, specimen and working liquid.Experiments of micro-hardness, wearing resistance and corrosion resistance show that all properties are much higher than those of the workpiece material.