HIGH-SPEED CUTTING OR HIGH HARDNESS STEEL CUTTING FOR END MILLS MADE OF CEMENTED CARBIDE WITH ULTRA MICRO GRAIN

摘要

In this study, tool materials for end milling which have long tool life were examined. In the mold machining, already high-speed machining or highly hardness materials are often applied. In these cases, long life of end mills is expected. Relations of material characteristic and their cutting performance were investigated. Cemented carbide material for end mills is suitable for high-speed cutting or high hardness steel cutting. In general, we know hard materials of end mills have high performance of tool life, but such too hard materials as 93HRA or harder tool materials are easy to occur chipping. By this reason, we could not use super hard materials. I produced end mills made of cemented carbide with ultra micro grain. WC grain size of ultra micro grain cemented carbide is under 0.3 μm. These materials have a good balance of toughness and wear resistance. Ultra micro grain cemented carbide end mills have a high performance on tool life for high-speed cutting or milling of hardened steels. The influences of the composition and grain size of cemented carbide on hardness and toughness were examined.