Nkk Corporation

Jfe Steel Corporation

Ntn Corporation

Mitsubishi Aluminum Company, Ltd.

Jfe Bars & Shapes Corporation

Shinji Mitao

Takeshi Fujita

Kohei Hasegawa

Minoru Honjo

Masataka Suga

Tatsumi Kimura

Kiyoshi Uwai

Shinichi Suzuki

Takashi Iwamoto

Kazukuni Hase

Mitsuhiro Okatsu

Kunikazu Tomita

Yoshihiro Yazawa

Tomoyuki Yokota

Kuninori Minakawa

Keisuke Ando

Yoshiaki Murakami

Seiji Nabeshima

Kimihiro Nishimura

Nobuo Shikanai

Masayoshi Nakamura

Yasuhiro Omori

Seishi Tsuyama

Yuzuru Kataoka

Yota Kuronuma

Masakazu Niikura

Ryo Matsuoka

Mineyasu Takemasa

Koichi Ohori

Shunichi Tachibana

Hiroyasu Yokoyama

Keiichiro Kishi

Hiroshi Saitoh

Yoshiko Takeuchi

Keiji Ueda

The present invention provides a steel for nitrocarburizing having excellent mechanical workability before nitrocarburizing, and showing excellent fatigue properties after nitrocarburizing, which is suitable for applying in mechanical structural components for automobiles etc. prepared by adjusting the composition so that it contains in mass %, C: 0.01% or more and less than 0.10%, Si: 1.0% or less, Mn: 0.5% to 3.0%, P: 0.02% or less, S: 0.06% or less, Cr: 0.3% to 3.0%, Mo: 0.005% to 0.4%, V: 0.02% to 0.5%, Nb: 0.003% to 0.15%, Al: 0.005% to 0.2%, and Sb: 0.0005% to 0.02%, and the balance including Fe and incidental impurities, and setting the area ratio of bainite phase to the whole microstructure to more than 50%.

Steel for nitrocarburizing and nitrocarburized component, and methods for producing said steel for nitrocarburizing and said nitrocarburized component

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

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

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

A pearlitic steel railroad rail which comprises 0.75 to 0.84% C, 0.10 to 1.0% Si, 0.4 to 2.5% Mn, 0.035% or less P, 0.035% or less S, and 0.05 to 0.6% Nb, by weight. This rail has better wear resistance than the heretofore used pearlitic steel rail and sufficient ductility so cracks do not appear due to thermal dilation and contraction caused by a change of temperature. The rail is consequently very suitable for the use in a mine railroad.

Pearlitic steel railroad rail

Disclosed is an aluminum alloy sheet having a chemical composition of an Si-containing Al--Mg--CU alloy. The aluminum alloy sheet exhibits a streak-shaped modulated structure at a diffraction grating points of an Al--Cu--Mg--system compound in the electron beam diffraction grating image. The above mentioned streak can be generated efficiently when the alloy essentially consists of 1.5 to 3.5% by weight of Mg, 0.3 to 1.0% by weight of Cu, 0.05 to 0.6% by weight of Si, and the balance of Al and inevitable impurities, and the ratio of Mg/Cu is in the range of 2 to 7. The alloy contains 0.01-0.50% of at least one element selected from the group consisting of Sn, Cd, and In.

Low baking temperature hardenable aluminum alloy sheet for press-forming

A method manufacturing an aluminum alloy sheet comprising preparing an aluminum alloy ingot essentially consisting of 1.5 to 3.5% by weight of Mg, 0.3 to 1.0% by weight of Cu, 0.05 to 0.6% by weight of Si, and a balance of Al, in which the ratio of Mg/Cu is in the range of 2 to 7, homogenizing the ingot in one step or in multiple steps, performed at a temperature within a range of 400 to 580.degree. C., preparing an alloy sheet having a desired sheet thickness by subjecting the ingot to a hot rolling and a cold rolling, subjecting the alloy sheet to heat treatment including heating the sheet up to a range of 500.degree. to 580.degree. C. at a heating rate of 3.degree. C./sec. or more, keeping it for 0 to 60 seconds at the temperature reached, and cooling it to 100.degree. C. or less at a looking rate of 2.degree. C./sec. or more, and keeping the alloy sheet at a temperature within a range of 180.degree. to 300.degree. C. for 3 to 60 seconds. Thus, a natural aging-retardated aluminum alloy sheet is obtained.

Method of manufacturing natural aging-retardated aluminum alloy sheet

Disclosed is a method manufacturing an aluminum alloy sheet comprising preparing an aluminum alloy ingot essentially consisting of 1.5 to 3.5% by weight of Mg, 0.3% to 1.0% by weight of Cu, 0.05 to 0.35% by weight of Si, 0.03 to 0.5% by weight of Fe, 0.005 to 0.15% by weight of Ti, 0.0002 to 0.05% by weight of B and a balance of Al, in which the ratio of Mg/Cu is in the range of 2 to 7, homogenizing the ingot in one step or in multiple steps, performed at a temperature within the range of 400.degree. to 580.degree. C., preparing an alloy sheet having a desired sheet thickness by subjecting the ingot to a hot rolling and a cold rolling, subjecting the alloy sheet to a heat treatment including heating the sheet up to a range of 500.degree. to 580.degree. C. at a heating rate of 3.degree. C./second or more, keeping it at the temperature reached for 0 to 60 seconds, and cooling at a cooling rate of 2.degree. C./second or more, subjecting the alloy sheet to a preliminary aging treatment performed at a temperature within the range of 45.degree. to 100.degree. C. for 2 to 48 hours after keeping at room temperature or immediately after the heat treatment, and subjecting the alloy sheet to a restoring treatment performed at a temperature within the range of 180.degree. to 300.degree. C. for 3 to 60 seconds. Thus, a natural aging-retardated aluminum alloy sheet exhibiting excellent formability and excellent bake hardenability is obtained.

A heat-resistant TiAl alloy having excellent room-temperature fracture toughness, high-temperature oxidation resistance and high-temperature strength is disclosed. Said alloy consists essentially of from 29 to 35 wt. % aluminum, from 0.5 to 20 wt. % nobium, and at least one element selected from the group consisting of from 0.1 to 1.8 wt. % silicon, and from 0.3 to 5.5 wt. % zirconium, the balance being titanium and incidental impurities. Preferably impurities are limited to 0.6 wt.-% oxygen, 0.1 wt.-% nitrogen and 0.5 wt.-% hydrogen.

Heat-resistant TiAl alloy excellent in room-temperature fracture

Growing community of inventors

Tokyo, Japan

Shinji Mitao