Analysis of Expert Skills on Handheld Grinding Work for Metallographic Sample

Abstract

Most common heat treatment process for hardening ferrous alloy is known as carburizing. The quality assurance of carburizing process requires metallographic analysis of case depth, retained austenite, intergranular oxidation, and carbide network by means of metallographic sample. Metallographic preparation consists of sectioning, mounting, plane grinding, polishing to mirror surface, and etching. It is difficult for non-expert to prepare metallographic sample with global mirror surface because preparation skill needs long time experience in this field. There is no study on expert skills in preparation of metallographic samples. In this study, the difference of handheld plane grinding motion of metallographic specimen between expert and non-expert execution was analyzed. For this clarification, an electromyogram (EMG) of the muscle activities between expert and non-expert were investigated. As a result of investigation, we found the clear difference in the muscle activities of triceps, flexor digitorum superficialis, and abductor pollicis brevis between expert and other subjects.