Advanced powder metal technology is capable of producing carburized, low alloy steel bearings and gears that deliver mechanical performance comparable to conventional steel. This quantum leap in PM technology has been accomplished by applying cold work densification to surfaces that require enhanced durability in the application.
Using various test methods, core and surface properties are compared for the PM and conventional steel materials; namely tensile, impact toughness, bending fatigue, and contact fatigue. A back to back durability test for automotive manual transmission gears has been used to compare PM gears with conventional steel gears. Test data shows that PM gear teeth can endure equivalent contact stress and, by employing design benefits which are exclusive to PM tooling related gear tooth manufacture, similar tooth loading as conventional gears.
PM manufacturing can achieve AGMA 10 gear quality. Along with the economic design benefits of PM gears, the design limitations, namely component size and tooth geometry, are reviewed.