Improving the processing efficiency of high-strength cast irons with vermicular graphite

Abstract

The article, based on the analysis of literature sources, describes the existing ideas about the structural features of high-strength cast irons with vermicular graphite (CGI), when compared with gray cast irons (GCI) and high-strength cast irons with spheroidal graphite. The influence of chemical composition and structure on their machinability, as well as the operational properties and condition of the surface layer of the workpiece, and the possibilities of its improvement, are considered. It has been found that tools made of superhard materials based on cubic boron nitride (CBN) and cermets do not provide such high efficiency when machining cast irons with vermicular graphite as when machining gray cast irons. The best machinability in the CGI-CBN pair was achieved with intermittent milling at a speed of 800 m/min. The absence of MnS in the composition of the CBN and the vermicular shape of graphite inclusions are the main factors that complicate their processing. In addition, the vermicular morphology of cast irons contributes to the rapid diffusion wear of tools made of superhard materials. This paper presents the results of the durability of tools made of superhard and carbide materials when machining the surfaces of parts made of vermicular graphite cast iron (CGI) and gray cast iron (GC) with end mills. Also, the nature of wear, which is present in this case.

Keywords

• resistance
• machinability
• chemical composition
• structure
• cast iron with vermicular graphite