Wear behaviors of cubic boron nitride tools with various binders in high-speed turning of compacted graphite irons

Abstract

Compacted graphite iron (CGI) is a promising material as diesel engines in automotive industry, but the poor machinability and low machining efficiency have further hindered the employment of CGI in the potential applications. Cubic boron nitride (cBN), possessing extreme hardness and chemical inertness, is the best candidate as tools to machine ferrous metals. In this paper, we attempt to explain the disparities in wear behaviors of cBN tool with different binders by implementing high-speed turning of CGI. The effects of various binders on cBN tool flank wear, cutting force, cutting temperature, and machined surface roughness was systematically investigated. Additionally, the response relationship among flank wear, cutting force, temperature and surface roughness was obtained. Further, the underlying reasons of the wear mechanism of cBN tool were revealed. The results indicated that the cBN tool performances strongly depend on the affinity of binders with CGI. The contributions of binder phases, cBN content, and cBN grain size under the employed machining conditions: the binders are dominated, and followed by cBN grain size or cBN content in the high-speed cutting of CGI. The small cBN grain size, and TiCN, TiC, TiN binders of cBN tools have superior cutting performance than the Co binders.