Nippon Steel Sumitomo Metal Corporation

Nippon Steel Corporation

Other

Honda Motor Co., Ltd.

Honda Giken Kogyo Kabushiki Kaisha

Chuo Hatsujo Kabushiki Kaisha

Toho Kinzoku Co., Ltd.

Suzuki Metal Industry Co., Ltd.

Nippon Hardmetal Co., Ltd.

Masayuki Hashimura

Hiroshi Hagiwara

Kei Miyanishi

Atsushi Mizuno

Masafumi Miyazaki

Takashi Fujita

Tatsuro Ochi

Shuji Kozawa

Hideaki Yamamura

Takanari Miyaki

Manabu Kubota

Hiroshi Hirata

Takayuki Kisu

Kohichi Isobe

Shinya Teramoto

Ikuo Ochiai

Hiroaki Hayashi

Kenichiro Naito

Hajime Saitoh

Shoichi Suzuki

Daisuke Hirakami

Noriyuki Yamada

Takahisa Suzuki

Makoto Okonogi

Hideo Kanisawa

Kazumi Mizukami

Toshimi Tarui

Seiichi Koike

Atsushi Murakami

Toshiharu Aiso

Naotsugu Yoshida

Kenichiro Miyamoto

Toshio Ozone

Tetsushi Chida

Ken-ichiro Naito

Takashi Otowa

Taisuke Nishimura

Hitoshi Demachi

Katsuaki Shiiki

Sakae Katayama

Hiroto Imamura

Hiroshi Yarita

Keiichi Maekawa

Masaaki Mikura

Junya Yamamoto

Kouichi Yamazaki

Shouich Suzuki

Seiji Ito

Kenji Fukuyasu

Jun Aoki

Toshio Banno

Shuuji Kozawa

Tetsuo Sawashima

Motonobu Suehiro

Jun Kawaguchi

Masato Yanase

Takanori Miyaki

Tatsurou Ochi

A spring steel includes a predetermined chemical composition and a composite inclusion having a maximum diameter of 2 &#x3bc;m or more that TiN is adhered to an inclusion containing REM, O and Al, in which the number of the composite inclusion is 0.004 pieces/mmto 10 pieces/mm, the maximum diameter of the composite inclusion is 40 &#x3bc;m or less, the sum of the number density of an alumina cluster having the maximum diameter of 10 &#x3bc;m or more, MnS having the maximum diameter of 10 &#x3bc;m or more and TiN having the maximum diameter of 1 &#x3bc;m to 10 pieces/mm.

Spring steel with excellent fatigue resistance and method of manufacturing the same

A spring steel according to the present embodiment has a chemical composition consisting of, in mass %, C: 0.4 to 0.7%, Si: 1.1 to 3.0%, Mn: 0.3 to 1.5%, P: 0.03% or less, S: 0.05% or less, Al: 0.01 to 0.05%, rare earth metal: 0.0001 to 0.002%, N: 0.015%, O or less: 0.0030% or less, Ti: 0.02 to 0.1%, with the balance being Fe and impurities. In the spring steel, the number of oxide inclusions having an equivalent circular diameter of equal to or greater than 5 &#x3bc;m is equal to or less than 0.2/mm, the oxide inclusions each being one of an Al-based oxide, a complex oxide containing REM, O and Al, and a complex oxysulfide containing REM, O, S, and Al. Further, a maximum value among equivalent circular diameters of the oxide inclusions is equal to or less than 40 &#x3bc;m.

Spring steel and method for producing the same

The present invention provides spring steel used for spring steel wire achieving both high strength and cold coilability and spring steel wire, that is, spring steel containing, by mass %, C: 0.45 to 0.70%, Si: 1.0 to 3.0%, Mn: 0.05 to 2.0%, P: 0.015% or less, S: 0.015% or less, N: 0.0015 to 0.0200%, and t-O: 0.0002 to 0.01 and further limiting Al&#x2264;0.01% and Ti&#x2264;0.003%. Further, it is characterized by satisfying the following regarding the cementite-based spherical carbides present at an observed plane, an occupied area ratio of grains with a circle equivalent diameter of 0.2 &#x3bc;m or more of 7% or less, a density of presence of grains with a circle equivalent diameter of 0.2 to 3 &#x3bc;m of 1/&#x3bc;mor less, and a density of presence of grains with a circle equivalent diameter 3 &#x3bc;m or more of 0.001/&#x3bc;mor less, having an prior austenite grain size number of #10 or higher and a residual austenite of 15 mass % or less, and having an area ratio of poor regions with a small density of presence of cementite-based carbides of a circle equivalent diameter of 2 &#x3bc;m or more of 3% or less.

High strength spring steel and steel wire

A steel for induction hardening includes as a chemical composition, by mass %, C: 0.45% to 0.85%, Si: 0.01% to 0.80%, Mn: 0.1% to 1.5%, Al: 0.01% to 0.05%, REM: 0.0001% to 0.050%, O: 0.0001% to 0.0030%. Ca: 0.0050% or less as necessary, Ti: less than 0.005%, N: 0.015% or less, P: 0.03% or less, S: 0.01% or less, and the balance consists of Fe and impurities. The steel for induction hardening also includes a composition inclusion which is an inclusion containing REM, O, S, and Al, or an inclusion containing REM, Ca, O, S, and Al, to which TiN is adhered.

Steel for induction hardening with excellent fatigue properties

A case hardening steel includes as a chemical composition, by mass %, C: 0.10% to 0.40%, Si: 0.01% to 0.80%, Mn: 0.1% to 1.5%, Cr: 0.35% to 2.0%, Al: 0.01% to 0.05%, REM: 0.0001% to 0.050%, O: 0.0001% to 0.0030%, Ca: 0.0050% or less as necessary, Ti: less than 0.005%, N: 0.015% or less, P: 0.03% or less, S: 0.01% or less, and the balance consists of Fe and impurities. The case hardening steel also includes a composition inclusion which is an inclusion containing REM, O, S, and Al, or an inclusion containing REM, Ca, O, S, and Al, to which TiN is adhered.

Case hardening steel with excellent fatigue properties

The present invention is steel for surface hardening for machine structural use which contains, by mass %, C: 0.3 to 0.6%, Si: 0.02 to 2.0%, Mn: 0.35 to less than 1.5%, and Al: 0.01 to 0.5%, is restricted to B: less than 0.0003%, S: 0.0001 to 0.021%, N: 0.003 to 0.0055%, P: 0.0001 to 0.03%, and O: 0.0001 to 0.0050%, has a ratio Mn/S of Mn and S satisfying 70 to 30,000, has a balance of Fe and unavoidable impurities, and, when nitrided, then induction hardened, has a surface hardenability of a Vicker's hardness when tempered at 300&#xb0; C. of 650 or more.

Steel for surface hardening for machine structural use and part for machine structural use

A bearing steel includes, as a metallographic structure, inclusions which contain complex oxysulfides including Rare Earth Metal, Ca, O, S, and Al, TiN, MnS, AlO, and complex oxides including Al and Ca, wherein, a number fraction of the complex oxysulfides in a total number of the inclusions is 50% to less than 100% and a number of complex oxysulfides having a major axis of 5 &#x3bc;m or more is 0.001 pieces to 2 pieces in an observed section of 1 mm, and a number of TiN existing independently from the complex oxysulfides and having a major axis of 5 &#x3bc;m or more is 0.001 pieces to less than 1.0 piece in an observed section of 1 mm.

Bearing steel and method for producing same

This invention provides a forging steel excellent in forgeability, which forging steel comprises, in mass %, C: 0.001 to less than 0.07%, Si: 3.0% or less, Mn: 0.01 to 4.0%, Cr: 5.0% or less, P: 0.2% or less, S: 0.35% or less, Al: 0.0001 to 2.0%, N: 0.03% or less, one or both of Mo: 1.5% or less (including 0%) and Ni: 4.5% or less (including 0%), and a balance of iron and unavoidable impurities; wherein Di given by the following Equation (1) is 60 or greater:=5.41&#xd7;(Si)&#xd7;(Mn)&#xd7;(Cr)&#xd7;(Mo)&#xd7;(Ni)&#xd7;(Al)&#x2003;&#x2003;(1)

Forging steel

The present invention provides hot forging use non heat-treated steel where controlled cooling after shaping by hot forging is used to make the main structure of the steel martensite even without subsequent reheating and heat treatment by quenching and tempering and thereby give a steel part with a high strength and high toughness and superior machineability and a hot forged non heat-treated steel part made of that steel, in particular provides a martensite type hot forging use non heat-treated steel characterized by containing, by mass %, C: 0.10 to 0.20%, Si: 0.10 to 0.50%, Mn: 1.0 to 3.0%, P: 0.001 to 0.1%, S: 0.005 to 0.8%, Cr: 0.10 to 1.50%, Al: over 0.1 to 0.20%, and N: 0.0020 to 0.0080% and having a balance of substantially Fe and unavoidable impurities and a hot forged non heat-treated steel part made of such steel and characterized in that the steel structure of the entire cross-section at part or all of that part is substantially a martensite structure with an effective crystal grain size of 15 &#x3bc;m or less.

Hot forging use non-heat-treated steel and hot forged non-heat-treated steel part

Steel for machine structure use for surface hardening containing, by mass %, C: 0.3 to 0.6%, Si: 0.02 to 2.0%, Mn: 1.5% to 3.0%, W: 0.0025 to 0.5%, Al: 0.001 to 0.5%, N: 0.003 to 0.02%, S: 0.0001 to 0.025%, P: 0.0001 to 0.03%, and O: 0.0001 to 0.0050%, having an Mn/S of 70 to 30000, and having a balance of substantially Fe and unavoidable impurities.

Steel for machine structure use for surface hardening and steel part for machine structure use

Provided is a hot-working steel excellent in machinability and impact value comprising, in mass %, C: 0.06 to 0.85%, Si: 0.01 to 1.5%, Mn: 0.05 to 2.0%, P: 0.005 to 0.2%, S: 0.001 to 0.35%, and Al: 0.06 to 1.0% and N: 0.016% or less, in contents satisfying Al&#xd7;N&#xd7;10&#x2266;96, and a balance of Fe and unavoidable impurities, total volume of AlN precipitates of a circle-equivalent diameter exceeding 200 nm accounting for 20% or less of total volume of all AlN precipitates.

Hot-working steel excellent in machinability and impact value

This case hardening steel has a chemical composition including, by mass %: C: 0.1 to 0.6%; Si: 0.02 to 1.5%; Mn: 0.3 to 1.8%; P: 0.025% or less; S: 0.001 to 0.15%; Al: over 0.05 to 1.0%; Ti: 0.05 to 0.2%; N: 0.01% or less; and O: 0.0025% or less, and further including, by mass %, one or more of Cr: 0.4 to 2.0%, Mo: 0.02 to 1.5%, Ni: 0.1 to 3.5%, V: 0.02 to 0.5%, and B: 0.0002 to 0.005%, and the balance consisting of iron and unavoidable impurities.

Case hardening steel, carburized component, and manufacturing method of case hardening steel

The present invention provides a steel for nitriding with a composition including, by mass %: C: 0.10% to 0.20%; Si: 0.01% to 0.7%; Mn: 0.2% to 2.0%; Cr: 0.2% to 2.5%; Al: 0.01% to less than 0.19%; V: over 0.2% to 1.0%; Mo: 0% to 0.54%; N: 0.001% to 0.01%; P limited to not more than 0.05%; S limited to not less than 0.2%; and a balance including Fe and inevitable impurities, the composition satisfying 2&#x2266;[V]/[C]&#x2266;10, where [V] is an amount of V by mass % and [C] is an amount of C by mass %, in which the steel for nitriding has a microstructure containing bainite of 50% or more in terms of an area percentage.

Steel for nitriding and nitrided part

The present invention provides spring use heat treated steel which is cold coiled, can achieve both sufficient atmospheric strength and coilability, has a tensile strength of 2000 MPa or more, and can improve the performance as a spring by heat treatment after spring fabrication, that is, high strength spring-use heat treated steel characterized by containing, by mass %, C: 0.45 to 0.9%, Si: 1.7 to 3.0%, and Mn: 0.1 to 2.0%, restricting N: to 0.007% or less, having a balance of Fe and unavoidable impurities, and satisfying, in terms of the analyzed value of the extracted residue after heat treatment, [amount of Fe in residue on 0.2 &#x3bc;m filter/[steel electrolysis amount]&#xd7;100&#x2266;1.1.

High strength spring-use heat treated steel

Growing community of inventors

Tokyo, Japan

Masayuki Hashimura