Abstract: At least one of the inner race, the outer race and rolling elements in the improved ball-and-roller bearing is made of an alloy steel that contains 0.1-1.2 wt % of C, 3.0-18.0 wt % of Cr, 0.01-1.5 wt % of Si, 0.3-1.5 wt % of Mn, up to 2.5 wt % of Mo, up to 0.002 wt % of O.sub.2 and up to 0.015 wt % of S and which is subjected to plasma-assisted carburization to such an extent that the relative surface carbon area is at least 15% the surface carbon concentration is in the range of 1.6-3.5 wt % and the amount of surface retained austenite is in the rang of 20 vol %-45 vol %. The bearing can work effectively for a prolonged lifetime even if it is placed under hostile conditions as exemplified by an increased areal pressure of load and entrance of foreign matter into lubricating oils.

Abstract: A rolling member used as an outer race, inner race, a ball or roller of a bearing contains a metal flow in the structure formed by plastic working (fold forging). The angle of metal flow determined by a tangent line of the metal flow and the axis of rotation of the rolling member is 10.degree. or larger to improve the service line against rolling fatigue.

Abstract: A rolling bearing comprise a bearing ring having inner and outer rings, and rolling elements. At least one of the inner and outer rings and the rolling elements is formed of a sintered alloy steel and has pores and carbides present therein. The largest one of the pores has a diameter equal to or smaller than 3 .mu.m in terms of a diameter assued if the largest pore were converted to a spherical shape. The largest one of the carbides has a diameter equal to or smaller than 12 .mu.m in terms of a diameter assumed if the largest carbide were converted to a spherical shape. The at least one of the inner and outer rings and the rolling elements has hardness higher than 64 and lower than 69 in terms of HRC.