Nippon Steel Corporation

Sumitomo Metal Industries, Inc.

Fine Sinter Co., Ltd

Nippon Steel Sumitomo Metal Corporation

Naomitsu Mizui

Yutaka Wakasu

Taizo Makino

Yukiteru Takeshita

Manabu Kubota

Kazuo Hikida

Yuichiro Yamamoto

Shinichiro Tabata

Nobusato Kojima

Kazutaka Asabe

Takeshi Nakano

Tomoki Fukagawa

Takayuki Kamimura

Satoru Nakano

Shigeki Nomura

Isao Shimazoe

Kazumichi Kawasaki

Kazutoshi Kunishige

Fumio Ishimoto

Kiyonobu Sugae

Nozomi Komatsubara

Osamu Kanda

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)

Rail vehicle axle

A sintered friction material is formed by pressure sintering mixed powder at 800&#xb0; 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.

Sintered friction material

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.

Heat-treated steel material and method of manufacturing the same

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&#x2264;C+Si/8+Mn/5+Cu/10+Cr/4+V&#x2264;0.67&#x2003;&#x2003;(1)Si+0.9Cr&#x2265;0.50&#x2003;&#x2003;(2)

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., then air-cooling for 2-10 seconds, and final rapid cooling to the coiling temperature. A cold rolled steel sheet is produced by hot rolling, cooling to a coiling temperature in the range of 300.degree.-720.degree. C., descaling, cold rolling with a reduction of 30-80%, and annealing. Annealing is performed by heating between the Ac.sub.1 point and the Ac.sub.3 point and cooling such that the temperature is either kept for at least 30 seconds in the range of 550.degree. C. to 350.degree. C. or slowly decreased at a rate of 400.degree. C./min or less in that temperature range.

High tensile strength steel sheet having improved formability

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Tokyo, Japan

Naomitsu Mizui