Abstract: Low carbon carburizing (surface hardening) and higher carbon through hardening steels primarily containing molybdenum, vanadium and nickel and, to a lesser amount, chromium used for rolling contact bearings, gears and other similar applications where high hardness at elevated temperatures is required. The alloy steel includes, in % by weight: 0.05% to 1.25% C; up to 1.25% Cr; 0.40% to 4% Mn; up to 4.0% Mo; up to 2.0% V; 1.0% to 3.0% Ni; 4% to 8% (Mo+V+Ni+Cr); less than 0.20% Si; and balance Fe plus incidental additions and impurities. The method for providing a steel having improved hardness at elevated temperatures includes the steps of: (a) providing an alloy including, in % by weight: less than 1.25% Cr, 0.4% to 4% Mn, up to 4% Mo, up to 2% V, 1 to 3% Ni, 4% to 8% (Mo+V+Ni+Cr), less than 0.2% Si, a C content selected from one of 0.05% to 0.40% C defining a carburizing steel or greater than 0.40% to 1.

Abstract: High speed steel (HSS) compositions having less C and Cr contents than standard grades of HSS to permit carburization using conventional techniques. The alloys contain less than 0.40 wt. % C and less than 2% Cr. The low Cr content is a critical factor in enhancing the ease of carburizing the present steels. The resulting HSS compositions possess high hardness and fracture resistance. More particularly, the steels include, in % by weight: 0-0.4% C; 0.5-1.5% Cr; 1.5-3.5% Ni; 0.1-0.6% M; 0.15-0.65% Si; 0.03 max % P; 0.03 max % S; one or more members selected from the group consisting of 4.0-15.3% Mo; 1.0-5.7% V; up to 13% Co and up to 28% W, and wherein the aggregate amount of %Cr+%Mo+%V+%W+%Co is between 7.5-35% and balance essentially Fe and incidental impurities. A method for treating the above alloy includes the steps of carburizing at about 960° C. followed by quenching, preheating to about 870° C. followed by austenitizing at 1125° C.-1225° C.

Abstract: High speed steel (HSS) compositions having less C and Cr contents than standard grades of HSS to permit carburization using conventional techniques. The alloys contain less than 0.40 wt. % C and less than 2% Cr. The low Cr content is a critical factor in enhancing the ease of carburizing the present steels. The resulting HSS compositions possess high hardness and fracture resistance. More particularly, the steels include, in % by weight: 0-0.4% C; 0.5-1.5% Cr; 1.5-3.5% Ni; 0.1-0.6% M; 0.15-0.65 % Si; 0.03 max % P; 0.03 max % S; one or more members selected from the group consisting of 4.0-15.3% Mo; 1.0-5.7% V; up to 13% Co and up to 28% W, and wherein the aggregate amount of %Cr+%Mo+%V+%W+%Co is between 7.5-35% and balance essentially Fe and incidental impurities. A method for treating the above alloy includes the steps of carburizing at about 960° C. followed by quenching, preheating to about 870° C. followed by austenitizing at 1125° C.-1225° C.

Abstract: A steel machine component, such as a bearing race, has a critical surface of generally circular configuration. Here the steel of the machine component exists in a state of compression to improve the physical characteristics of the surface. To this end, high speed steel is melted along the full circumference of the surface. Upon cooling to room temperature some of the austenite in the steel transforms into martensite. Tempering converts much of the remaining austenite into martensite, so that the machine component at the surface is almost entirely martensite. Martensite normally occupies a greater volume than austenite, but since the layer of martensite so formed is confined by the underlying core of the machine component, the layer exists in a state of compression. The high speed steel is melted with a laser beam that makes a trace over the full surface of the machine component.

Abstract: A machine component which is formed from a high alloy steel has, along a surface where the component is subjected to cyclic loading, a glaze in which the steel has a refined microstructure that resists spalling. Whereas the microstructure of the core underlying the glaze contains carbides of relatively large particle size, the microstructure of the glaze contains carbides of a much smaller particle size. For the most part the microstructure of the glaze comprises martensite and retained austenite in a fine dendritic network. The glaze is acquired by directing a laser beam at the surface, with the beam having sufficient energy and intensity to melt the component where it illuminates the surface, thus creating a puddle. Relative motion between the beam and the component advances the puddle over the surface. The molten metal in the previously illuminated region loses its heat to the underlying core of the component and solidifies, in effect undergoing a self-quench.