According to the Metal Powder Industries Federation (MPIF) Standard 35, sinter hardening is quench hardening during the cooling cycle of the sintering furnace. Accelerated cooling is applied to the part to achieve a microstructure optimized for strength and improved tolerance capabilities. While conventional sintering requires regulation of time, temperature, and atmosphere within the sintering furnace, sinter hardening further requires careful regulation of the cooling curve to yield the desired physical and mechanical properties.
That is the technical definition of sinter hardening, but the part designers need to know is that sinter hardening offers some compelling engineering advantages. It eliminates the time, cost, and potential for defects that come with a separate heat treating step. During sinter hardening, components are quenched in the sintering atmosphere instead of a traditional oil quench, rendering the part surface clean and free of oil residue.