Abstract: A sintered friction material is formed by pressure sintering mixed powder at 800° C. or above, the mixed powder consisting of, in mass %, Cu and/or Cu alloy: 40.0 to 80.0%, Ni: 0% or more and less than 5.0%, Sn: 0 to 10.0%, Zn: 0 to 10.0%, VC: 0.5 to 5.0%, Fe and/or Fe alloy: 2.0 to 40.0%, lubricant: 5.0 to 30.0%, metal oxide and/or metal nitride: 1.5 to 30.0%, and the balance being impurity.

Abstract: A sintered friction material is formed by pressure sintering mixed powder at 800° C. or above, the mixed powder consisting of, in mass %, Cu and/or Cu alloy: 40.0 to 80.0%, Ni: 0% or more and less than 5.0%, Sn: 0 to 10.0%, Zn: 0 to 10.0%, VC: 0.5 to 5.0%, Fe and/or Fe alloy: 2.0 to 40.0%, lubricant: 5.0 to 30.0%, metal oxide and/or metal nitride: 1.5 to 30.0%, and the balance being impurity.

Abstract: A heat-treated steel material includes: a chemical composition expressed by, in mass %: C: 0.16% to 0.38%; Mn: 0.6% to 1.5%; Cr: 0.4% to 2.0%; Ti: 0.01% to 0.10%; B: 0.001% to 0.010%; Si: 0.20% or less; P: 0.05% or less; S: 0.05% or less; N: 0.01% or less; Ni: 0% to 2.0%; Cu: 0% to 1.0%; Mo: 0% to 1.0%; V: 0% to 1.0%; Al: 0% to 1.0%; Nb: 0% to 1.0%; REM: 0% to 0.1%; and the balance: Fe and impurities; and a structure expressed by: retained austenite: 1.5 volume % or less; and the balance: martensite.

Abstract: Provided is a rail vehicle axle having an excellent fatigue limit and notch factor. A rail vehicle axle according to the present embodiment has a chemical composition consisting of, in mass %, C: 0.20 to 0.35%, Si: 0.20 to 0.65%, Mn: 0.40 to 1.20%, P: 0.020% or less, S: 0.020% or less, Cu: 0 to 0.30%, Ni: 0 to 0.30%, Cr: 0 to 0.30%, Mo: 0 to 0.08%, Al: 0 to 0.100%, N: 0.0200% or less, V: 0 to 0.060%, and Ti: 0 to 0.020%, with the balance being Fe and impurities, and satisfying Formulae (1) and (2): 0.58?C+Si/8+Mn/5+Cu/10+Cr/4+V?0.67??(1) Si+0.9Cr?0.50??(2) where, each element symbol in Formulae (1) and (2) is substituted by the content (mass %) of a corresponding element.

Abstract: Provided is a rail vehicle axle having an excellent fatigue limit and notch factor. A rail vehicle axle according to the present embodiment has a chemical composition consisting of, in mass %, C: 0.20 to 0.35%, Si: 0.20 to 0.65%, Mn: 0.40 to 1.20%, P: 0.020% or less, S: 0.020% or less, Sn: 0.07 to 0.40%, N: 0.0200% or less, Cu: 0 to 0.30%, Ni: 0 to 0.30%, Cr: 0 to 0.30%, Mo: 0 to 0.08%, Al: 0 to 0.100%, V: 0 to 0.060%, and Ti: 0 to 0.020%, with the balance being Fe and impurities, and satisfying Formulae (1) and (2): 0.58?C+Si/8+Mn/5+Cu/10+Cr/4+V?0.67??(1) Si+0.9Cr?0.50??(2) where, each element symbol in Formulae (1) and (2) is substituted by the content (mass %) of a corresponding element.

Abstract: Provided is a rail vehicle axle having an excellent fatigue limit and notch factor. A rail vehicle axle according to the present embodiment has a chemical composition consisting of, in mass %, C: 0.20 to 0.35%, Si: 0.20 to 0.65%, Mn: 0.40 to 1.20%, P: 0.020% or less, S: 0.020% or less, Cu: 0 to 0.30%, Ni: 0 to 0.30%, Cr: 0 to 0.30%, Mo: 0 to 0.08%, Al: 0 to 0.100%, N: 0.0200% or less, V: 0 to 0.060%, and Ti: 0 to 0.020%, with the balance being Fe and impurities, and satisfying Formulae (1) and (2): 0.58?C+Si/8+Mn/5+Cu/10+Cr/4+V?0.67??(1) Si+0.9Cr?0.50??(2) where, each element symbol in Formulae (1) and (2) is substituted by the content (mass %) of a corresponding element.

Abstract: A heat-treated steel material includes: a chemical composition expressed by, in mass %: C: 0.16% to 0.38%; Mn: 0.6% to 1.5%; Cr: 0.4% to 2.0%; Ti: 0.01% to 0.10%; B: 0.001% to 0.010%; Si: 0.20% or less; P: 0.05% or less; S: 0.05% or less; N: 0.01% or less; Ni: 0% to 2.0%; Cu: 0% to 1.0%; Mo: 0% to 1.0%; V: 0% to 1.0%; Al: 0% to 1.0%; Nb: 0% to 1.0%; REM: 0% to 0.1%; and the balance: Fe and impurities; and a structure expressed by: retained austenite: 1.5 volume % or less; and the balance: martensite.

Abstract: A high tensile strength, hot or cold rolled steel sheet having improved ductility and hole expandability consists essentially, on a weight basis, of: C: 0.05-0.3%, Si: 2.5% or less, Mn: 0.05-4%, Al: greater than 0.10% and not greater than 2.0% wherein 0.5.ltoreq.Si(%)+Al(%).ltoreq.3.0, optionally one or more of Cu, Ni, Cr, Ca, Zr, rare earth metals (REM), Nb, Ti, and V, and a balance of Fe and inevitable impurites with N being limited to 0.01% or less. The steel sheet has a structure comprising at least 5% by volume of retained austenite in ferrite or in ferrite and bainite. A hot rolled steel sheet is produced by hot rolling with a finish rolling end temperature in the range of 780.degree.-840.degree. C., cooling to a coiling temperature in the range of 300.degree.-450.degree. C. either by rapid cooling to the coiling temperature at a rate of 10.degree.-50.degree. C./sec or by initial rapid cooling to a temperature range of 600.degree.-700.degree. C.