Study of Crack Formation and Resolidified Layer in EDM Process on T90Mn2W50Cr45 Tool Steel

This article is concerned with analysis of crack formation and spherical form of resolidified layer on T90Mn2W50Cr45 tool steel surface, which is processed in electrical discharge machine (EDM). Crack and resolidified layer are examined by scanning electron microscope (SEM) with different magnification. Experiments were conducted on the T90Mn2W50Cr45 tool steel surface for different combination of process parameters like pulse: on time, off time, and current. The crack formation is influenced by the base material (T90Mn2W50Cr45 tool steel) properties, electrode wear, and resolidified layer. SEM with lower magnification will show the crack formation on the surface, while higher magnification will show the structure of the resolidified layer. It was found that the pulse current is directly proportional with resolidified layer thickness and crack density.