Abstract
In order to study the key factors which predominate over the machinability of steel, the fundamentals of the wear phenomena of metal cutting tool was investigated. The electron micro-probe X-ray analyzer was used to uncover the wear characteristics of carbide tools in turning of mild steel and leaded-free-cutting-steel at a cutting speed of 150 m/min. Tool surfaces and the internal sections were subjected to the X-ray micro analysis after 40 minutes of machining.
The experimental data shows that only iron and its compounds adhered at the crater of the tool, and aluminum and manganese were detected at the leading land and the trailing surface behind the crater. At the flank wear surfaces, iron, aluminum and manganese coexisted. At the worn surfaces, including the flank wear and crater wear, cobalt was detected with much less intensity than inside the tool material.
Concerning the action of lead included in free-cutting-steel, it was concluded that a portion of the lead melted at the tool-chip interface and acted as a lubricant; whereas, the lead particles which were included inside the chip did not melt but acted as notches reducing the toughness of the chip.
