A Study on Finished Surface Roughness of a Nitriding Spheroidal Graphite Cast Iron

Abstract

This paper describes finished surface roughness when an orthogonal cutting operation for a spheroidal graphite cast iron, whose surface is hardened by a plasma nitriding, is carried out. It is generally known that cutting operations of a plasma nitriding workpieces is very difficult due to hard surface. High-precision and high-efficiency cutting for normal spheroidal graphite cast iron have not been obtained by changing a cutting tool rake angle and a cutting velocity in our conventional experiments, so far. In other words, the high-precision and the high-efficiency cutting for normal spheroidal graphite cast iron is very difficult with only changing tool shape and cutting conditions. Therefore, a new method, which is a treatment to the workpiece is applied before the cutting, is introduced instead of improving the cutting tool. That is to say the cutting with small depth of cut after the nitriding treatment can improve the surface roughness.