Service life of hard alloy tools in the machining of porous sintered materials

Abstract

1. Investigations of the machinability of new, low-machinability materials, including sintered porous ones, indicate that cutting speeds for 20-min life of tools from the existing materials cannot meet the more and more stringent technical and economic requirements. More effective special-purpose tool materials are needed. 2. In order to formulate new tool materials for specific uses, it is necessary to know the causes of wear of the existing tool materials in concrete applications. The availability of newer refractory compounds will help to meet new specifications for tool materials. 3. It was established that tool life relations for the machining of porous iron with VK8 and T15K6 hard alloys and TsM-332 ceramic have a nonmonotonic character. The inflections on the tool life curves indicate changes of the factors governing the nature of cutting tool wear. 4. It would be very difficult to explain the shape of the tool life curves obtained in the machining of porous sintered materials in terms of adhesion and diffusion processes alone. It is possible that abrasive, thermal, oxidation, and fatigue forms of wear also manifest themselves during the machining of porous iron, but special investigations will be required to establish their presence. 5. It is found that single-carbide VK hard alloys are the best tool materials for machining porous iron. TsM-332 ceramic is altogether unsuitable for this purpose because of the short life of tools made from it.