Kawasaki Steel Corporation

Jfe Steel Corporation

Other

Koyo Seiko Company, Ltd.

National Institute for Materials Science

Keniti Amano

Fumimaru Kawabata

Tatsumi Kimura

Toshiyuki Hoshino

Mitsuhiro Okatsu

Tohru Hayashi

Takashi Iwamoto

Akio Ohmori

Noritsugu Itakura

Kazukuni Hase

Tomoya Koseki

Yasuhiro Omori

Kazuhiko Shiotani

Takanori Okui

Hiroki Ota

Akihiro Matsuzaki

Kimihiro Nishimura

Kiyoshi Uchida

Kenji Oi

Yasushi Morikage

Toshio Fujita

Hiroshi Murakami

Kikuo Maeda

Takahiro Kubo

Hironori Miura

Syuzo Ueda

Kazuo Hiraoka

Chiaki Shiga

Atsuhiko Ohta

Akio Okayama

Akihiko Ohta

Shozaburo Nakano

Yasuyoshi Yamane

Keizou Taoka

Hiroyuki Ookubo

Tosiyuki Hosino

Satosi Yasumoto

Michiro Hamanoue

Takuya Atsumi

Koich Yasuda

Yasuyashi Yamane

In the present invention, an iron based alloy which contains by mass %: 0.20% or less of C; 6.0 to 16.0% of Cr; 6.0 to 16.0% of Ni and whose martensitic transformation starting temperature (Ms point temperature) is in the range of 0-170&#xb0; C., inclusive of 0&#xb0; C. and exclusive of 170&#xb0; C., is used as a welding material. With respect to a weld metal, the weld metal has a iron alloy composition which contains by mass %: 0.20% or less of C; 3.0 to 13.0% of Cr; 3.0 to 13.0% of Ni and whose martensitic transformation starting temperature (Ms point temperature) is in the range of 50-360&#xb0; C., inclusive of both 50&#xb0; C. and 360&#xb0; C.

Welding material and a method of producing welded joint

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

A high-strength and high-toughness steel product having at least about 0.001% and less than about 0.030% by weight C, not more than about 0.60% by weight Si, from about 0.8 to 3.0% by weight Mn, from about 0.005 to 0.20% by weight Nb, from about 0.0003 to 0.0050% by weight B, and not more than about 0.005% by weight Al, wherein at least 90% of the product has a bainite structure. A method of making this steel product is subject to less stringent production controls because of the nature of the composition.

High-strength high-toughness steel products

Provided is a non heat-treated steel that requires no particular controls over cooling rates and no aging treatments after hot working, that can sufficiently increase tensile strength, yield strength and toughness even at lightly deformed parts, and furthermore, that has excellent material anisotropy and machinability as an alloy steel for machine structures. In other words, it is a non heat-treated steel that contains: C: more than 0.05 mass % to less than 0.10 mass %; Si: 1.0 mass % or less; Mn: more than 2.2 mass % to 5.0 mass %; S: less than 0.020 mass %; Cu: more than 1.0 mass % to 3.0 mass %; Ni: 3.0 mass % or less; Cr: 0.01 to 2.0 mass %; Al: 0.1 mass % or less; Ti: 0.01 to 0.10 mass %; B: 0.0003 to 0.03 mass %; N: 0.0010 to 0.0200 mass %; O: 0.0060 mass % or less; and the balance Fe and inevitable impurities, and that the steel structure is bainitic having block structures at 10% or more in area ratios.

Non-refined steel being reduced in anisotropy of material and excellent in strength, toughness and machinability

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.

Method of manufacturing high productive and high strength rolled H-shaped

Steel is obtained which comprises by wt %, C: 0.001-0.025%, Si: not more than 0.60%, Mn: 0.10-3.00%, P: 0.005-0.030%, S: not more than 0.01%, Al: not more than 0.10%, Cu: 0.1-1.5%, Ni: 0.1-6.0%, B: 0.0001-0.0050%, and the balance being Fe and inevitable impurities; since the steel contains C and P in small contents, stable amorphous rusts are formed on the surface thereof at an early stage; and steel simultaneously realizes excellent weather resistance, material weldability and toughness particularly in an environment such as a seashore district and the like where salt is present in a large amount.

Weatherable steel material

N&mdash;V(nitrogen-vanadium) containing continuous casting slab with no surface cracks suitable for the manufacture of non-tempered high tensile steel materials has a tensile strength of 490 MPa or more and excellent toughness. A method of manufacturing non-tempered high tensile steel materials uses the casting slab as the raw material. Compatibility between the desired properties of the materials utilizing VN and inhibition of the surface cracks of test pieces, can be attained by controlling the steel composition and the relationship between each of components of the steel thereby controlling precipitation of VN and MnS. A continuous casting slab with no surface cracks contains C, Si, Mn, P, S, Al, V, N, Ti, B, Ca and REM each within a specified range, and satisfies an equation for the relationship between V and N and a relationship between Mn and S.

Continuous casting slab suitable for the production of non-tempered high tensile steel material

A high tensile strength steel product for high heat input welding having excellent toughness in the heat-affected zone and having a tensile strength of at least 490 MPa contains, in terms of percent by weight, from about 0.05% to about 0.18% of C, 0.6% or less of Si, from about 0.80% to about 1.80% of Mn, 0.005% or less of Al, 0.030% or less of P, 0.004% or less of S, 0.005% or less of Nb, from about 0.04% to about 0.15% of V, from about 0.0050% to about 0.00150% of N, and from about 0.010% to about 0.050% of Ti, the ratio of the Ti content to the Al content, Ti/Al, satisfying 5.0 or more, and further contains at least one of from about 0.0010% to about 0.0100% of Ca and from about 0.0010% to about 0.0100% of REM, and the balance being Fe and incidental impurities. In the steel product, oxide inclusions containing, in terms of percent by weight, 20% to about 95% of a titanium oxide, 70% or less of Al O , 5% to about 50% in total of at least one of calcium oxide and a REM oxide, and 15% or less of MnO are dispersed.

High tensile strength steel product for high heat input welding, having excellent toughness in heat-affected zone

In a rolling bearing having a rolling bearing ring and a rolling element of at least 20 mm in diameter, at least one of the rolling bearing ring and the rolling element consists of carburized or carbonitrided steel containing at least 0.2 wt % and not more than 0.35 wt % of carbon and at least 2.2 wt % and not more than 3.6 wt % of Ni. Thus obtained is a rolling bearing capable of reducing the material cost and increasing the fatigue life or reducing the carburizing time by ensuring surface hardness and optimizing the case depth.

Rolling bearing

A high-strength and high-toughness steel product having at least about 0.001% and less than about 0.030% by weight C, not more than about 0.60% by weight Si, from about 0.8% to 3.0% by weight Mn, from about 0.005 to 0.20% by weight Nb, from about 0.0003 to 0.0050% by weight B, and not more than about 0.005% by weight AL wherein at least 90% of the product has a bainite structure. A method of making this steel product is subject to less stringent production controls because of the nature of the composition.

Method of producing a bainite steel product

High-strength and high-toughness non heat-treated steel having excellent

The invention provides a steel product having superior weathering which is coated with a rust layer containing 50 or more weight % of non-crystalline rust, a method of producing the steel product, and a method of forming weathering protective rust on a material surface of the steel product. A material of a steel product is placed in an atmosphere in which the dew point is kept constant and the temperature of the steel product material is repeatedly varied between a temperature range of 5.degree. C. or more higher than the dew point and a temperature range of 5.degree. C. or more lower than the dew point. Weathering protective rust is thereby formed on the material surface of the steel product and a steel product having superior weathering is obtained. Preferably, the atmosphere contains 15 to 50 volume % of oxygen gas, and the temperature of the steel product is varied at a rising rate of 0.1 to 2.degree. C./minute and a lowering rate of 0.01 to 2.degree. C./minute. Alternatively, a desired steel product can also be obtained by placing a material of the steel product in an atmosphere containing 15 to 50 volume % of oxygen gas, keeping constant the dew point in the atmosphere, and keeping the temperature of the steel product material in the atmosphere at a certain value in a temperature range between a temperature 5.degree. C. lower than the dew point and a temperature 20.degree. C. lower than the dew point; or by placing a material of the steel product in an atmosphere containing 15 to 50 volume % of oxygen gas, and forming and keeping a water film with a thickness not more than 500 .mu.m but not less than 50 .mu.m on a material surface of the steel product.

Steel products having superior weathering, method of producing the steel

Growing community of inventors

Okayama, Japan

Keniti Amano