Problems in High-Speed Steel Manufacture and Use: A Challenge for Economic Powder Metallurgy Processing

The role of high-speed steel as a cutting tool material is described. The choice of grades for various applications is strongly influenced by economic considerations as affected by alloy availability and cost. While the heat treatment applied to the finished tool is critical in achieving the desired properties, many factors affecting tool manufacture and use are dependent upon proper control of steel production. The coarse structure of cast ingots necessitates heavy hot-working reductions to achieve an adequate breakdown of primary carbides. Lengthy and expensive process routes are involved. Powder metallurgy techniques can provide an ideal distribution of carbides and many potential benefits are outlined, as are some of the problems encountered. Exploitation appears to have been limited, due to the expensive plant and processes required; consequently, in many applications, use of the products cannot be justified economically. At present, the most significant benefit lies in increasing the availability of highly alloyed high-speed steel grades for high duty. A wider range of applications could result from introducing a more economic process, or from developing a powder metallurgy route towards tool materials having a lower content of strategically vulnerable alloying elements. PM/0183