Spur gears, bevel gears, splined hubs, and cams are ideal components for production using powder metallurgy. Induction hardening is a method to make these parts locally hard and wear-resistant with a tougher ductile matrix.
Localized hardening of the piece helps maintain dimensions, and induction hardening is commonly specified for these applications. The inductance of PM materials is typically less than that of wrought material of similar composition due to porosity, therefore a higher power setting is normally required to reach a given depth of hardening. Furthermore, because the heat is rapidly dissipated, a fast transfer to the quench is mandatory. As with wrought steels, the response to hardening by induction is dependent on combined carbon content, alloy content, and surface decarburization.
For more information, click on the link below (subscription required). Then scroll to Figure 34.
Joseph W. Newkirk, Heat Treatment of Powder Metallurgy Steels, Heat Treating of Irons and Steels, Vol 4D, ASM Handbook, Edited By Jon L. Dossett, George E. Totten, ASM International, 2014, p 253-273, https://doi.org/10.31399/asm.hb.v04d.9781627081689
