New Grade “SUMIBORON BN7115” for Finishing Sintered Ferrous Alloys and Cast Iron

摘要

The cubic boron nitride (cBN) cutting tool “SUMIBORON” is mainly composed of cBN particles that have low activity with iron, and has high hardness and high thermal conductivity next to diamond, contributing to productivity improvement and cost reduction in the finishing of difficult-to-cut ferrous materials. In the past decade, the automotive industry has strongly driven the shift to hybrid electric vehicles and electric vehicles, which requires higher precision and higher efficiency in machining of sintered ferrous alloys and cutting tools with stable performance and longer tool life for cast iron. The authors have successfully developed a new grade “SUMIBORON BN7115” for finishing these materials. BN7115 employs a high-purity cBN particles and new binder consisting of Co-Al-Cr-WC to improve the bonding strength between cBN particles, thereby achieving good resistance to wear and breakage. BN7115 is expected to solve problems such as a degradation of the cuting surface of sintered ferrous alloys caused by the dropout of cBN particles and chipping of edges caused by thermal shock during cutting cast iron.