Improvement of Machinability of Sintered Composite-type Alloyed Steel Powder

Abstract

Composite-type alloyed steel powder has drawn great attention in recent years due to the rapid increase of high strength materials. A typical powder consisting of iron with nickel and molybdenum as an additive which adheres to the surface of iron particles is used. This type of sintered alloyed steel causes excessive tool wear. The purpose of this study is to improve the machinability of the sintered alloyed steel by adding nonmetallic materials. Experiments show that the addition of 3% glass to the sintered alloyed steel increases the tool life 100 times. In order to clarify the mechanisms of the increase of tool life, the worn face of the cutting tool is examined by an Electron Probe Microanalyzer (EPMA). The analysis shows that the glass additive acts as a protective film and lubricant when cutting with silicon nitride and tungsten carbide tools, respectively.