US EPA

1757766 

Book/Book Chapter 

Machinability of highly alloyed powder metallurgical tool steels 

Gunnarsson, S; Kaszynski, J; Nilsson, B 

1997 

ADVANCES IN POWDER METALLURGY & PARTICULATE MATERIALS 

1559-1573 

WOS:000072572600108 

Tooling materials for powder compacting applications require
a high level of compressive strength with the ability to resist cracking and chipping. In
addition, the abrasive characteristics of some powders require tooling which can withstand high
wear conditions. Tungsten carbide tools and die inserts have been used successfully to some
degree, however, this material is very brittle and often limited to tooling of relatively simple
design. The need for a high strength, wear resistant tooling material with excellent toughness
properties has lead to the development of powder metallurgically produced tool steels. The trend
when developing new grades of powder metallurgical (P/M) tool steels has been to raise the alloy
content. The result is an increase in the percentage of hard carbide particles formed in the
matrix combined with an increase in the overall hardness level of the steel. These factors will
improve the wearability of the tool steel, however, the machinability will suffer. In this study
the machinability of some highly alloyed PIM tool steels have been evaluated. Particular
attention to the influence of sulfur additions on the machinability and mechanical properties of
the P/M steels has also been examined. The P/M tool steel grades chosen for testing, possess
excellent compressive strength properties while maintaining a high level of crack resistance. In
addition, these materials are very resistant to both adhesive and abrasive wear conditions. This
unique combination of properties make these P/M tool steels an outstanding choice for powder
compacting tooling.