Jfe Steel Corporation

Kawasaki Steel Corporation

Ntn Corporation

Tatsumi Kimura

Keniti Amano

Fumimaru Kawabata

Minoru Honjo

Kazukuni Hase

Nobuo Shikanai

Takanori Okui

Hideki Takahashi

Yoshikazu Yoshida

Katsuyuki Ichimiya

Keisuke Ando

Makoto Nakaseko

Shinichi Suzuki

Shinji Mitao

Yuzuru Kataoka

Rinya Kojo

Satoshi Igi

Ryo Matsuoka

Tomoo Horita

Mineyasu Takemasa

Kiyoshi Uchida

Kimihiro Nishimura

Shigeru Endo

Takashi Iwamoto

Akio Ohmori

Kiyoshi Uwai

Hironori Miura

Kazuhiko Shiotani

Moriyasu Yamaguchi

Yukio Takashima

Yasushi Morikage

Keizou Taoka

Hiroyuki Ookubo

Kazuya Tokunaga

The rail having a chemical composition containing C: 0.70-0.85 mass %, Si: 0.50-1.60 mass %, Mn: 0.20-1.00 mass %, P: 0.035 mass % or less, S: 0.012 mass % or less, Cr: 0.40-1.30 mass %, the chemical composition satisfying the formula (1)0.30&#x2264;[% Si]/10+[% Mn]/6+[% Cr]/3&#x2264;0.55&#x2003;&#x2003;(1)

Rail and method for manufacturing same

The rail having a chemical composition containing C: 0.70-1.00 mass %, Si: 0.50-1.60 mass %, Mn: 0.20-1.00 mass %, P: &#x2264;0.035 mass %, S: &#x2264;0.012 mass %, Cr: 0.40-1.30 mass %, where Ceq defined by the formula (1) is 1.04-1.25,Ceq=[% C]+([% Si]/11)+([% Mn]/7)+([% Cr]/5.8)&#x2003;&#x2003;(1)

A method for selecting a rail steel and a wheel steel comprising: selecting a rail steel and a wheel steel to be used as a rail and a wheel on an actual track, respectively, the rail steel and the wheel steel having a specific chemical composition, such that the rail comprises a head portion having a yield strength YSof 830 MPa or more, the wheel comprises a rim portion having a yield strength YSof 580 MPa or more, and a ratio YS/YSof the yield strength YSat the head portion of the rail to the yield strength YSat the rim portion of the wheel falls within a range of: 0.85&#x2264;YS/YS&#x2264;1.95 (1).

Method for selecting rail steel and wheel steel

A rail achieves a high 0.2% proof stress after straightening treatment, the high 0.2% proof stress being effective at improving rolling contact fatigue resistance of the rail, by hot rolling a steel raw material to obtain a rail, the steel raw material having a chemical composition containing C: 0.70% to 0.85%, Si: 0.1% to 1.5%, Mn: 0.4% to 1.5%, P: 0.035% or less, S: 0.010% or less, and Cr: 0.05% to 1.50% with the balance being Fe and inevitable impurities; straightening the rail with a load of 50 tf or more; and subsequently subjecting the rail to heat treatment in which the rail is held in a temperature range of 150&#xb0; C. or more and 400&#xb0; C. or less for 0.5 hours or more and 10 hours or less.

Method for producing rail

A pearlitic rail includes a composition including in % by mass: 0.70% to 0.90% of C; 0.1% to 1.5% of Si; 0.01% to 1.5% of Mn; 0.001% to 0.035% of P; 0.0005% to 0.030% of S; 0.1% to 2.0% of Cr, remainder of the composition consisting of Fe and inevitable impurities. Surface hardness of a rail top is not less than HB 430, and hardness at a depth of 25 mm from a surface of the rail top is not less than HB 410.

Pearlitic rail and method for manufacturing pearlitic rail

A rail cooling device configured to forcibly cool a rail by jetting a coolant includes a porous plate nozzle including a plurality of nozzle holes configured to jet the coolant to an underside of the base of the rail to cool the underside of the base of the rail. Ends in a width direction of the porous plate nozzle correspond to ends of the underside of the base of the rail. Nozzle holes of the porous plate nozzle at the ends of the width direction are smaller than nozzle holes of the porous plate nozzle at a central part in the width direction, and a maximum value of a distance between centers of the nozzle holes at both ends in the width direction is 30% or more of a width of the underside of the base.

Rail cooling device

A rail cooling method for forcibly cooling a rail by jetting a coolant includes jetting the coolant to a foot back part of the rail from a porous plate nozzle in which a nozzle hole at an end in a width direction is smaller than a nozzle hole at a central part in the width direction and causes a cooling capacity for the end in the width direction of the underside of the base of the rail to be lower than a cooling capacity for the central part in the width direction of the underside of the base of the rail.

Rail cooling method and rail cooling device

The present invention provides bearing steel, comprising a chemical composition including by mass %, C: 0.56%&#x2266;[% C]&#x2266;0.70%, Si: 0.15%&#x2266;[% Si]&#x3c;0.50%, Mn: 0.60%&#x2266;[% Mn]&#x2266;1.50%, Cr: 0.50%&#x2266;[% Cr]&#x2266;1.10%, Mo: 0.05%&#x2266;[% Mo]&#x2266;0.5%, P: [% P]&#x2266;0.025%, S: [% S]&#x2266;0.025%, Al: 0.005%&#x2266;[% Al]&#x2266;0.500%, O: [% O]&#x2266;0.0015%, N: 0.0030%&#x2266;[% N]&#x2266;0.015%, and remainder as Fe and incidental impurities.

Bearing steel and ingot material for bearing having excellent rolling contact fatigue life characteristics and method for manufacturing the same

The invention provides a high-strength pearlitic steel rail, which is inexpensive, and has a tensile strength of 1200 MPa or more, and is excellent in delayed fracture properties. Specifically, the rail contains, in mass percent, C of 0.6 to 1.0%, Si of 0.1 to 1.5%, Mn of 0.4 to 2.0%, P of 0.035% or less, S of 0.0005 to 0.010%, and the remainder is Fe and inevitable impurities, wherein tensile strength is 1200 MPa or more, and size of a long side of an A type inclusion is 250 mm or less in at least a cross-section in a longitudinal direction of a rail head, and the number of A type inclusions, each having a size of a long side of 1 mm to 250 mm, is less than 25 per observed area of 1 mmin the cross-section in the longitudinal direction of the rail head.

High-strength pearlitic steel rail having excellent delayed fracture properties

A steel rail including a composition of, in mass percent, C of 0.6% to 1.0%, Si of 0.1% to 1.5%, Mn of 0.4% to 2.0%, P of 0.035% or less, S of 0.010% or less, Ca of 0.0010% to 0.010%, and the remainder being Fe and inevitable impurities, wherein the tensile strength is 1200 MPa or more, and the size of a long side of a C type inclusion is 50 &#x3bc;m or less in at least a cross-section in a longitudinal direction of a rail head, and the number of Ca type inclusions, each having a size of a long side of 1 &#x3bc;m to 50 &#x3bc;m, is 0.2 to 10 per observed area of 1 mmin the cross-section in the longitudinal direction of the rail head.

An internal high hardness type pearlitic rail that has a composition containing 0.73% to 0.85% by mass C, 0.5% to 0.75% by mass Si, 0.3% to 1.0% by mass Mn, 0.035% by mass or less P, 0.0005% to 0.012% by mass S, 0.2% to 1.3% by mass Cr, and the balance being Fe and incidental impurities, in which the value of [% Mn]/[% Cr] is greater than or equal to 0.3 and less than 1.0, where [% Mn] represents the Mn content, and [% Cr] represents the Cr content, and in which the internal hardness of a rail head that is defined by the Vickers hardness of a portion located from a surface layer of the rail head to a depth of at least 25 mm is greater than or equal to 380 Hv and less than 480 Hv.

Internal high hardness type pearlitic rail with excellent wear resistance and rolling contact fatigue resistance and method for producing same

When manufacturing a straight steel section having a joint comprising a ball claw and a curved claw by hot-rolling a bloom vertically symmetrically to make a section blank having a flange A at a web end (first step), vertically asymmetrically hot-rolling the section blank to adjust the size of the web and form the flange into a rough joint B including a projection A (second step), and subjecting the projection to hot bend rolling into a curved claw (third step), wherein the bloom has a chemical composition comprising, in mass percentage, from 0.01 to 0.20% C, up to 0.8% Si, up to 1.8% Mn, up to 0.030% P, and up to 0.020% S; and therein the claw bending start temperature in the third step is a temperature of over Ar or up to Ar -50&deg; C., thereby achieving a depth of wrinkle flaws present on the inner surface side of the curved claw of up to 0.5 mm.

Linear shape steel excellent in joint fatigue characteristics and production method therefor

A steel material excellent in weathering resistance by defining the chemical ingredients in the steel each to a predetermined range and setting an ingredient parameter formula in accordance with the working circumstance thereby reducing the flow rust and, particularly, forming stable rust with good protective property even in a salty circumstance such as in coast districts is provided. Further, also considering the amount of A type inclusions and B type inclusions according to JIS G 0555, a steel material of excellent earthquake proofness and weathering proofness also including weld heat affect zone is provided.

Method of manufacturing corrosion resistant steel materials

The present invention relates to an H-shaped steel used as a building structure such as a column material or the like for highrise and super highrise building structures. In the bainite structure of extra-low-carbon steel, diffusive &agr; is finely dispersed in &agr; to ensure tensile strength at the 590-MPa level and significantly improve toughness in the direction of the flange thickness. Fine dispersion of &agr; is achieved by controlling Mn and Cu in proper ranges. In other word, the present invention provides 590MPa class heavy gauge H-shaped steel with excellent as-rolled toughness in the direction of the flange thickness, containing 0.001 to 0.025 wt % of C, 0.6 wt % or less of Si, 0.4 to 1.6 wt % of Mn, 0.025 wt % or less of P, 0.010 wt % or less of S, 0.1 wt % or less of Al, 0.6 to 2.0 wt % of Cu, 0.25 to 2.0 wt % of Ni, 0.001 to 0.050 wt % of Ti, and 0.0002 to 0.0030 wt % of B, wherein Mn/Cu&lE;2.0 and 250&lE;117 Mn (wt %)&plus;163 Cu (wt %)&lE;350 are satisfied.

590MPa class heavy gauge H-shaped steel having excellent toughness and method of producing the same

Rolled H-shapes having high strength and high toughness, and which can be produced using cheaper alloy components than conventional products and which can be manufactured with a high productivity, are disclosed. A method for manufacturing the H-shapes is also disclosed. The rolled H-shapes include 0.03 to 0.1 wt. % of Nb and 0.005 to 0.04 wt. % of Ti. The method includes a rough universal rolling process in which an accumulated reduction at a rolling temperature of 950&deg; C. or lower is 5% or larger, and reverse operation is conducted fast; and a finishing universal rolling, in which the rolling temperature is 750&deg; C. or higher. Preferably, in the rough universal rolling, the accumulated reduction at a rolling temperature of 950&deg; C. or lower is 50% or more.

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Tokyo, Japan

Tatsumi Kimura