INFLUENCE OF CHEMICAL COMPOSITION AND AUSTENITIZING TEMPERATURE ON HARDENABILITY OF PM STEELS

摘要

The hardenability of powder metallurgy (PM) steels is an important measure of how well certain alloy systems can be used for sinter hardening. Several options are now available for sinter-hardening applications as new alloys have been developed over the last few years. Alloy composition has been optimized to take advantage of rapid cooling in sinter-hardening furnaces while addressing the cost of alloying elements. One of the most widely used tests for hardenability is the Jominy end-quench, where samples are heated into the austenite range and water quenched on one end of the sample, producing a wide range in cooling rate within one sample. The hardenability of different alloy systems was examined by way of Jominy tests and sintering studies. Austenitizing temperature has an important effect on the measured Jominy hardenability of higher molybdenum containing steels. Selection of the austenitizing temperature for these alloy grades therefore has a profound effect on the predicted hardenability of different alloy systems.