an antifriction bearing includes a fixed ring which comprises a steel containing up to about 10 % of residual austenite . an alternator for vehicles includes a stator mounted on a frame , a rotor having its rotary shaft rotatably supported by a pair of bearings on the frame and a drive pulley mounted on one end of the shaft projecting outward from the frame . the outer ring of at least the bearing toward the pulley comprises a steel containing up to about 10 % of residual austenite .