The invention relates to a surface-hardened, rotationally symmetrical workpiece, to a hardening method and to a hardening apparatus. The proposed hardening apparatus comprises a machine frame on which two coaxially arranged rotary bearings designed to support a rotationally symmetrical workpiece are arranged, at least one rotary bearing being operatively connected to a drive device to generate rotation of the workpiece; and at lease one laser apparatus for generating focused, high-energy radiation is arranged on said rotary bearing, said laser apparatus being movable in the axial direction, and the radiation being directed toward the workpiece.

A method for controlling carbide network in a bearing steel wire rod by controlling cooling and rolling, comprises the following steps: rapidly rolling a bar to a wire rod and spinning it into a loose coil, controlling the rolling temperature at 780° C.-880° C.; and the spinning temperature at 750° C.-850° C.; carrying out on-line controlling cooling of continuous loose coils using EDC water bath austempering cooling process, controlling the cooling rate at 2.0° C./s-10° C./s, and controlling the final cooling temperature within 620-630° C.; after EDC water bath austempering cooling, using slow cooling under a cover, and the temperature is controlled to be 400° C.-500° C. when being removed out of the cover; after slow cooling, collecting coils, and cooling in air to the room temperature.

A centrifugally cast composite roll for hot rolling comprising an outer layer made of an Fe-based alloy having a chemical composition comprising by mass 2.6-3.6% of C, 0.1-3% of Si, 0.3-2% of Mn, 2.3-5.5% of Ni, 0.5-3.2% of Cr, 0.3-1.6% of Mo, 1.8-3.4% of V, and 0.7-2.4% of Nb, 1.4 ≤V/Nb ≤2.7, a V equivalent (Veq=V+0.55 Nb) being 2.60-4% by mass, and the balance being Fe and impurities, and an inner layer made of an iron-based alloy and integrally fused to the outer layer.

There is provided a centrifugally cast composite roll for rolling having excellent wear resistance and surface deterioration resistance at levels of a high-speed steel cast iron roll and having rolling incident resistance at a level of a high alloy grain cast iron roll. Its outer layer includes chemical components by mass ratio: C: 1.5 to 3.5%; Si: 0.3 to 3.0%; Mn: 0.1 to 3.0%; Ni: 1.0 to 6.0%; Cr: 1.5 to 6.0%; Mo: 0.1 to 2.5%; V: 2.0 to 6.0%; Nb: 0.1 to 3.0%; B: 0.001 to 0.2%; N: 0.005 to 0.070%; and the balance being Fe and inevitable impurities, wherein: a chemical composition of the outer layer satisfies Formula (1) and has 5 to 30% of M.sub.3C carbide by area ratio; an outer layer Shore hardness (A) of a roll surface satisfies Formula (2); and a residual stress (B) of the roll surface satisfies Formula (3),
2×Ni+0.5×Cr+Mo>10.0  (1)
Hs 75≤A≤Hs 85  (2)
100 MPa≤B≤350 MPa  (3).

There is provided a centrifugally cast composite roll for rolling having excellent wear resistance and surface deterioration resistance at levels of a high-speed steel cast iron roll and having rolling incident resistance at a level of a high alloy grain cast iron roll. Its outer layer includes chemical components by mass ratio: C: 1.5 to 3.5%; Si: 0.3 to 3.0%; Mn: 0.1 to 3.0%; Ni: 1.0 to 6.0%; Cr: 1.5 to 6.0%; Mo: 0.1 to 2.5%; V: 2.0 to 6.0%; Nb: 0.1 to 3.0%; B: 0.001 to 0.2%; N: 0.005 to 0.070%; and the balance being Fe and inevitable impurities, wherein: a chemical composition of the outer layer satisfies Formula (1) and has 5 to 30% of M.sub.3C carbide by area ratio; an outer layer Shore hardness (A) of a roll surface satisfies Formula (2); and a residual stress (B) of the roll surface satisfies Formula (3),
2×Ni+0.5×Cr+Mo>10.0  (1)
Hs 75≤A≤Hs 85  (2)
100 MPa≤B≤350 MPa  (3).

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.

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.

In the present there is presented a method to manufacture multimaterial rolls, comprising method to produce base material containing part of the roll, joining of special material containing part for that, hot working at least part of the length of the roll ingot containing base material and special material, —so that at least requested roll ingot length and diameter are achieved as well as final treatment of the roll ingot—to manufacture finished roll. This method enables manufacture of large rolls, for example having length more than 3 meters as one integrated component without welding or mechanical joint—so, that in the working surfaces of the rolls is used steel with high amount of alloying elements and carbide forming alloying elements.

In the present there is presented a method to manufacture multimaterial rolls, comprising method to produce base material containing part of the roll, joining of special material containing part for that, hot working at least part of the length of the roll ingot containing base material and special material, —so that at least requested roll ingot length and diameter are achieved as well as final treatment of the roll ingot—to manufacture finished roll. This method enables manufacture of large rolls, for example having length more than 3 meters as one integrated component without welding or mechanical joint—so, that in the working surfaces of the rolls is used steel with high amount of alloying elements and carbide forming alloying elements.