Silicon is the second most available element in the earth’s crust and therefore a very cost effective element for use in steel. In the paper, the microstructures, mechanical properties and hardenability of powder metallurgy (PM) alloy systems were investigated and it was demonstrated that the addition of silicon can increase strength in both the sintered and heat treated conditions. In its sintered condition, silicon strengthens the ferrite of the pearlitic microstructure by solid solution hardening. In the heat treated condition, silicon was found to increase the hardenability of low alloy steels and when used in combination with chromium, manganese or molybdenum was seen to increase hardenability over that if these elements were used alone. The increase in hardenability was such that alloys containing silicon were able to be sinter-hardened using accelerated cooling.
In 2014, Hoeganaes Corporation plans to explore this topic more fully in a paper entitled “Diffusion Behavior and Microstructural Transformations of PM Steels Containing Silicon.”
