SEDL / STP / STP1195-EB / STP24828S

High-Hardness, High-Density Powder Metal Bearing Applications

Chidester, AJ
Senior project metallurgist, chief metallurgist, and Needle Bearing Division metallurgist, Advanced Technology Center, The Torrington Company, Torrington, CT

Green, WB
Senior project metallurgist, chief metallurgist, and Needle Bearing Division metallurgist, Advanced Technology Center, The Torrington Company, Torrington, CT

Corbo, K
Senior project metallurgist, chief metallurgist, and Needle Bearing Division metallurgist, Advanced Technology Center, The Torrington Company, Torrington, CT

Pages: 15    Published: Jan 1993

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Abstract

A unique, assembled camshaft, where the lobes are made from high-density powder metal 4680 steel, has been developed for automotive applications. The development was motivated by weight reduction, reduced costs, and the increased stress levels created by the use of tappet roller followers. We will present rolling contact fatigue test data on the lobe material using a ball-on-rod tester and a Unisteel-type flat washer tester. Density levels from 7.6 g/cc to 7.8 g/cc were tested in this program. Other properties such as yield strength, tensile strength, elongation, fracture toughness, fatigue crack growth rate, and rotating beam fatigue life of high-density 4680 powder metal hardened and tempered to HRC 58-62 will be presented. Other powder metal bearing applications requiring high hardness and density, such as slider blocks for automotive air conditioners and square linear bearings for automotive constant velocity joints, will be discussed.