ミルスケールを含む機械構造用炭素鋼の切削における工具摩耗機構

抄録

Research on the machinability of steel materials, particularly ordinary carbon steels, has a long history, and numerous experimental data are available in textbooks and reference work. However, the majority of these studies focus on the machining characteristics of untreated base metals. In practical applications, many steel components undergo heat treatment to attain the desired mechanical properties, resulting in the formation of oxide layer (mill scale) on their surfaces. Consequently, mill scale removal becomes an essential consideration during the cutting process. Previous reports have indicated that the presence of mill scale significantly reduces tool life compared in case of only base material cutting under otherwise identical cutting conditions and leads to considerable variability in machinability. In this study, cutting experiments were conducted on high carbon steel with mill scale to experimentally evaluate the causes of instability during mill scale-affected cutting and the progression of tool wear. The results demonstrated that mill scale pieces become embedded between the tool flank and the workpiece material during cutting. Furthermore, the mill scale pieces entrapment induces an abrasive action that contributes to an increase in flank wear width.