Surface Integrity in Micromilling of Hardened AISI D2 Tool Steel

This paper presents workpiece surface integrity of micromilling hardened tool steel AISI D2. These include 3D mapping of surface texture, analysis of microstructure and microhardness variation. The results indicate no evidence of major surface damage such as microcracks, un-tempered/over-tempered martensite, phase transformations or white layer formation was detected in any of the specimens analysed. No discernible deformation of the material grain structure beneath the machined surface was observed. This was mainly attributed to the comparatively low levels of mechanical force and temperatures generated during the micro milling operation.