Influence of Hot Hardness and Microstructure of High-Alloyed Powder Metallurgical Tool Steels on Abrasive Wear Behavior at Elevated Temperatures

Abstract

Herein, the abrasive wear behavior of different high-alloyed powder metallurgical (PM) tool steels is investigated at elevated temperatures (400–600 °C) in a dry-pot wear tester containing Al2O3 particles. To identify the influence of the microstructure, PM tool steels with different hot hardnesses, carbide types, and carbide volume contents are selected. Wear tracks are analyzed by scanning electron microscopy (SEM) to clarify wear mechanisms. The results show that there is no direct correlation between wear resistance and only one material property such as hot hardness, carbide content, or carbide type. More important seems to be the best possible compromise between a sufficient hot hardness of the metallic matrix and a high volume content of carbides that are harder than the attacking abrasive particles at the respective temperature. When the test temperatures surpass the tempering temperature of the investigated steels, there is a pronounced change in wear behavior due to the stronger embedding of abrasive particles into the wear surface. It is thus necessary to discuss the microstructural properties as a function of temperature, considering interactions with the abrasive particles.