Jfe Steel Corporation

Ntn Corporation

Konami Digital Entertainment Co., Ltd.

Nhk Spring Co., Ltd.

Sumihatsu Co., Ltd.

Minoru Honjo

Akira Tange

Shinichi Suzuki

Takashi Iwamoto

Tatsumi Kimura

Kazukuni Hase

Nobuo Shikanai

Katsuyuki Ichimiya

Kiyoshi Uwai

Hideto Kimura

Shigeru Endo

Kimihiro Nishimura

Shinji Mitao

Yuzuru Kataoka

Mineyasu Takemasa

Takashi Kumabe

Shigeo Okamoto

Ryo Matsuoka

Naoki Iizuka

Keiichi Fujie

Koei Tsuru

Katsutoshi Yamashita

Kazuya Tokunaga

Provided is a method for producing a rail, with which the sweep in the height direction of a rail before straightening can be suppressed when producing standard rails specified in JIS E 1101. The method includes subjecting a bloom having a chemical composition containing, in mass %, C: 0.60% or more and 0.85% or less, Si: 0.10% or more and 1.00% or less, and Mn: 0.10% or more and 1.30% or less, with the balance being Fe and inevitable impurities, to hot rolling to obtain a rail, subjecting the rail to accelerated cooling under conditions where a cooling start temperature T1 of rail head is 750° C. or higher and 850° C. or lower, a cooling stop temperature T2 of rail head is higher than 700° C., and T1−T2 is 20° C. or more, and then allowing the rail to be naturally cooled.

Method for producing rail

Proposed are the welding conditions under which welds are always stably formed such that the difference in hardness between flash-butt welds and rail base metal and the deflection in a bending test are in better ranges. A plurality of pieces of rail base metal are joined via welds formed by flash-butt welding, where the rail base metal has a chemical composition containing C: 0.60 to 1.20 mass %, Si: 0.10 to 1.50 mass %, Mn: 0.10 to 1.50 mass %, and Cr: 0.10 to 1.50 mass %, with the balance being Fe and inevitable impurities, and the flash-butt welding is performed with an amount of welding heat input of 1.50×10kA×sec or more and 4.50×10kA×sec or less.

Method for manufacturing rail, and rail

Provided is a rail that is effective in improving wear resistance and rolling contact fatigue (RCF) resistance. The rail has a metallic structure including a pearlitic structure and a structure other than the pearlitic structure in a surface layer from a surface of a rail head to a depth of at least 0.5 mm, where the pearlitic structure has Vickers hardness of 420 HV or more and 520 HV or less, and the structure other than the pearlitic structure has Vickers hardness of 350 HV or more and 420 HV or less.

Rail

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.

Provided is high strength steel for springs that, compared to conventional high strength steel for springs, has excellent decarburization resistance and scale exfoliation property, by optimization of the added amounts of C, Si, Mn, and Cr as well as of Sb and Sn. The steel for springs contains C: more than 0.45 mass % and less than 0.65 mass %, Si: 0.15 mass % or more and 0.70 mass % or less, Mn: 0.10 mass % or more and 1.00 mass % or less, Cr: 0.20 mass % or more and 1.50 mass % or less, P: 0.025 mass % or less, S: 0.025 mass % or less, O: 0.0015 mass % or less, Sb: 0.010 mass % or more and less than 0.030 mass %, and Sn: 0.010 mass % or more and 0.030 mass % or less, under predetermined conditions.

Steel for spring, and method for producing spring

A method is provided with which a bearing steel, even when obtained from an ingot, is made to have a segregation part reduced in the degree of segregation and maximum inclusion diameter. The ingot contains 0.56-0.70 mass % C, 0.15-0.50 mass %, excluding 0.50 mass %, Si, 0.60-1.50 mass % Mn, 0.50-1.10 mass % Cr, 0.05-0.5 mass % Mo, up to 0.025 mass % P, up to 0.025 mass % S, 0.005-0.500 mass % Al, up to 0.0015 mass % O, and 0.0030-0.015 mass % N, with the remainder comprising Fe and incidental impurities. The ingot has a degree of segregation of 2.8 or less and a predicted value of the maximum diameter of inclusions present in 30,000 mmof the ingot, as calculated by extreme value statistics, of 60 &#x3bc;m or less.

Ingot for bearing and production process

Disclosed is high strength spring steel that can limit the depth of pitting occurring when corroded and therefore possesses high strength as well as excellent pitting corrosion resistance and corrosion fatigue property, with a composition containing: C: greater than 0.35 mass % and less than 0.50 mass %; Si: greater than 1.75 mass % and less than or equal to 3.00 mass %; Mn: 0.2 mass % to 1.0 mass %; Cr: 0.01 mass % to 0.04 mass %; P: 0.025 mass % or less; S: 0.025 mass % or less; Mo: 0.1 mass % to 1.0 mass %; and O: 0.0015 mass % or less, under a condition that a PC value calculated by PC=4.2&#xd7;([C]+[Mn])+0.1&#xd7;(1/[Si]+1/[Mo])+20.3&#xd7;[Cr]+0.001&#xd7;(1/[N]) is greater than 3.3 and equal to or less than 8.0. Also disclosed is a preferred method for manufacturing the same.

Spring steel and method for manufacturing the same

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

Disclosed is high strength spring steel that can limit the depth of pitting occurring when corroded and therefore possesses high strength as well as excellent pitting corrosion resistance and corrosion fatigue property, with a composition containing: C: greater than 0.35 mass % and less than 0.50 mass %; Si: greater than L75 mass % and less than or equal to 3.00 mass %; Mn: 0.2 mass % to 1.0 mass %; Cr: 0.01 mass % to 0.04 mass %; P: 0.025 mass % or less; S: 0.025 mass % or less; Mo: 0.1 mass % to 1.0 mass %; and 0: 0.0015 mass % or less, under a condition that a PC value calculated by PC=4.2&#xd7;([C]+[Mn])+0.1&#xd7;(1/[Si]+1/[Mo])+20.3&#xd7;[Cr]+0.001&#xd7;(1/[N]) is greater than 3.3 and equal to or less than 8.0. Also disclosed is a preferred 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

The present invention provides a vending machine that converts a force applied from a manual operation means into an electric power, and operates by utilizing the electric power as a source of power. A drive force generation/transmission mechanism includes a generator () that generates the electric power by utilizing the force applied from the manual operation means () and motors (-) driven by the electric power generated by the generator (). Article moving mechanisms (-) are constructed to operate by utilizing the output of the motors (-) as the operation source.

Automatic vending machine

The invention provides a method of determining completion of coin insertion capable of easily and reliably determining whether or not a number of coins required for purchasing an article has been inserted. A coin holding portion () is constructed such that coins are retained in row in the coin holding portion () being electrically connected to each other in series. Further, a first electrode () that comes into contact with the coin located at one end side of the row is provided in the coin holding portion (); and a second electrode () that comes into contact with the coin located at the other end side of the row is provided in the coin holding portion (). The coin holding portion () is constructed to detect an electric current between the first electrode () and the second electrode () to determine whether or not the required number of coins has been inserted.

Growing community of inventors

Tokyo, Japan

Minoru Honjo