A rolling bearing is a tapered roller bearing, a cylindrical roller bearing, or a deep groove ball bearing including an inner ring, an outer ring, and a rolling element, each of the inner ring, the outer ring, and the rolling element being composed of a steel, the rolling bearing having a quench-hardened layer in at least one of an inner ring raceway surface of the inner ring, an outer ring raceway surface of the outer ring, and a rolling contact surface of the rolling element. A ratio of a total area of a plurality of martensite crystal grains in the quench-hardened layer is more than or equal to 70%. The plurality of martensite crystal grains are classified into a first group and a second group. An average grain size of the martensite crystal grains belonging to the first group is less than or equal to 0.97 μm.

A rolling bearing is a tapered roller bearing, a cylindrical roller bearing, or a deep groove ball bearing including an inner ring, an outer ring, and a rolling element, each of the inner ring, the outer ring, and the rolling element being composed of a steel, the rolling bearing having a quench-hardened layer in at least one of an inner ring raceway surface of the inner ring, an outer ring raceway surface of the outer ring, and a rolling contact surface of the rolling element. A ratio of a total area of a plurality of martensite crystal grains in the quench-hardened layer is more than or equal to 70%. The plurality of martensite crystal grains are classified into a first group and a second group. An average grain size of the martensite crystal grains belonging to the first group is less than or equal to 0.97 μm.

The present invention provides a method of heat treating a steel component including the sequential steps of: (a) carbonitriding the steel component; (b) quenching the steel component; (c) optionally tempering the steel component; and (d) ferritically nitrocarburizing the steel component.

The present invention provides a method of heat treating a steel component including the sequential steps of: (a) carbonitriding the steel component; (b) quenching the steel component; (c) optionally tempering the steel component; and (d) ferritically nitrocarburizing the steel component.

The invention relates to a method for producing a rolling bearing ring featuring an improved robustness against the formation of white etching cracks (WEC), wherein the rolling bearing component, which is made of a hypo-eutectoid heat-treated steel containing C in an amount of 0.4-0.55% and Cr in an amount of 0.5-2.0% in order to form a hardened boundary layer, is inductively heated, then quenched and subsequently tempered.

An improved grinding ball may include a carbon content of 1.1 to 1.4 wt %, a chromium content of 10 to 14 wt %, a manganese content of 0.8 to 1.5 wt %, a silicon content of 0.6 to 1 wt %, a molybdenum content of less than 1 wt %, a nickel content of less than 1 wt %, any impurities with a total content of less than 0.5 wt %, the balance to obtain 100% being iron. The grinding ball includes a discrete distribution of chromium carbides as opposed to a network distribution.

An improved grinding ball may include a carbon content of 1.1 to 1.4 wt %, a chromium content of 10 to 14 wt %, a manganese content of 0.8 to 1.5 wt %, a silicon content of 0.6 to 1 wt %, a molybdenum content of less than 1 wt %, a nickel content of less than 1 wt %, any impurities with a total content of less than 0.5 wt %, the balance to obtain 100% being iron. The grinding ball includes a discrete distribution of chromium carbides as opposed to a network distribution.

The invention provides a heat treatment method for a steel product. The steel product includes at least 0.5-0.7% of Si by weight; the method provides the following steps: step 1) putting the steel product under an Austenitizing temperature of 830-890° C. and lasting for a first time to Austenitize the steel product, step 2) immersing the Austenitized steel product in a salt bath at an isothermal temperature of 200-350° C. and lasting for the second time. The method of the invention improves the toughness and elongation of the steel product, keeps the wear resistance of the product, and can be well applied to the fields of thin section ring of bearings and the like. The invention also provides a steel product and a bearing ring.

A method for heat treating a steel component, the method comprising steps of: (a) carbonitriding the steel component and (b) ferritically nitrocarburizing the steel component.

A method for heat treating a steel component, the method comprising steps of: (a) carbonitriding the steel component and (b) ferritically nitrocarburizing the steel component.