Study on a Piling Mechanisms in a High-Speed Surface Modification Process by EDM

Abstract

The Surface Modification by Electrical Discharge Machining, which is developed as substitute for PVD, CVD, has been applied to cutting tools and mold dies. This process was realized with the TiC powder composite structure electrode. This process is a high-speed method that a hard layer of about several microns can be formed faster than a previous CVD and PVD in a few minutes. Some experiments of surface modification were performed with two types of composite structure electrodes (TiH2 green compact and TiC semi-sintered types)on carbon steel. The results of experiment were shown as follows ; (1) There are two types, one of them shows piling pattern and the other shows a piling and machining pattern. (2) The TiC layer made by green compact electrode is porosity construction in microstructure, then the other by semi-sintered shows very a hard and precise microstructure. (3) It is considered to be dependent on the difference in a electrode wear rate that the structures of a hard layer differ greatly.