Effects of Grain Size on the Groove Depths in Microlaser Cutting of Austenitic Stainless Steel SUS304

Abstract

Over the last decade, developments of fine grained materials and investigations of the effects of grain size on mechanical processing at the micro scale have been reported. There are several papers and reports on the function improvements achieved due to enhanced edge quality. However, it is difficult to identify the studies about the effects of grain size on the processed surface in laser processing because ultrafine grain materials were not supplied in the market. In this study, the effect of grain size on the depth of groove by laser processing is investigated. Microgrooves are produced using a picosecond laser machine. The grooves are observed with a non-contact 3D measuring machine, and the depth and surface conditions are determined. There are obvious differences on the depth between the different grain sizes. Specimens were cut to allow the observation of the phase transformation of grains in the cross section using scanning electron microscope (SEM) and electron back scatter diffraction (EBSD). There are several obstacles when producing deeper grooves. As a result, smaller grained stainless steels are suitable for producing microparts by microlaser cutting.