Kawasaki Steel Corporation

Nippon Steel Corporation

Tomoya Koseki

Takaaki Toyooka

Kenji Ichino

Mitsuo Kimura

Keniti Amano

Yoshitaka Sawa

Yukio Miyata

Fumio Murase

Hiroki Ota

Mitsuhiro Okatsu

Fumimaru Kawabata

Noritsugu Itakura

Tohru Hayashi

Kenji Oi

Ryota Yamaba

Yoshihiro Okamura

Syuzo Ueda

Shozaburo Nakano

Ichiro Nakagawa

Kohji Yuda

A high-Cr martensite steel pipe having excellent pitting resistance and method for manufacturing the same, which involves forming a pipe of steel including C: about 0.03 wt % or less, Si: about 0.5 wt % or less, Mn: about 0.5-3.0 wt %, Cr: about 10.0-14.0 wt %, Ni: about 0.2-2.0 wt %, Cu: about 0.2-1.0 wt % and N: about 0.03 wt % or less with the balance being Fe and incidental impurities, and having a value X shown as defined in the following formula (1) of about 12.2 or more. The pipe is quenched after austenitizing it at a temperature substantially equal to an A.sub.C3 point or higher, and the pipe is annealed in a temperature range from about 550.degree. C. or higher to a temperature lower than an A.sub.C1 point.

Method of manufacturing high chromium martensite steel pipe having

Roll for hot rolling having enhanced abrasion resistance and reduced

A martensitic steel for a line pipe having excellent corrosion resistance and weldability is disclosed. The martensitic steel contains about:

Martensitic steel for line pipe having excellent corrosion resistance

This invention provides bainite steel materials having a less scattering of properties in a thickness direction or between steel materials by using a chemical composition of C: not less than 0.001 wt % but less than 0.030 wt %, Si: not more than 0.60 wt %, Mn: 1.00-3.00 wt %, Nb: 0.005-0.20 wt %, B: 0.0003-0.0050 wt % and Al: not more than 0.100 wt % and rendering not less than 90% of the material into a bainite texture in steel materials such as thick steel plates, steel sheets, section steels, rod steels and the like.

Bainitic steel materials having a less scattering of properties and

A high-Cr martensitic steel pipe having excellent pitting resistance and method for manufacturing the same, which involves forming a pipe of steel including C: about 0.03 wt % or less, Si: about 0.5 wt % or less, Mn: about 0.5-3.0 wt %, Cr: about 10.0-14.0 wt %, Ni: about 0.2-2.0 wt %, Cu: about 0.2-1.0 wt % and N: about 0.03 wt % or less with the balance being Fe and incidental impurities, and having a value X shown as defined in the following formula (1) of about 12.2 or more. The pipe is quenched after austenitizing it at a temperature substantially equal to an Ac.sub.3 point or higher, and the pipe is tempered in a temperature range from about 550.degree. C. or higher to a temperature lower than an Ac.sub.1 point.

High chromium martensitic steel pipe having excellent pitting resistance

A roll outer layer material for hot rolling includes, as analyzed in weight percent, of 2.5-4.0% C, 6.0-20% Cr, 3.0-10.0% V, 0.6-5.0% Nb, 2.0-15% Mo, 3.0% or below Si, 3.0% or below Mn, C, V, Nb and Cr satisfying a following formula (1),

Method of manufacturing roll for hot rolling

An extra high tensile steel having an excellent stress corrosion cracking resistance in sea water and a yield strength of 1080 MPa or more is provided. A slab comprising, in terms of % by weight, 0.04 to 0.09% of C, 0.01 to 0.10% of Si, 0.05 to 0.65% of Mn, 8.0 to 11.0% of Ni, 0.5 to 1.5% of Mo, 0.2 to 1.5% of Cr, 0.02 to 0.20% of V and 0.01 to 0.08% of Al with the balance consisting of iron and unavoidable impurities is heated to a temperature between 1000.degree. C. and 1250.degree. C., hot rolled at a temperature of Ar' point or above, air-cooled, reheated at a rate of 120.degree. C./min or less to a temperature region of from (A.sub.C3 point--40.degree. C.) to (A.sub.C3 point+40.degree. C.), quenched and subsequently tempered at a temperature of the A.sub.C1 point or below.

Process for producing extra high tensile steel having excellent stress

Method of producing bainitic steel materials having a less scattering of

Centrifugal cast roll shell material

A roll outer layer material for hot rolling consists essentially, as analyzed in weight percent, of 2.5-4.0% C, 6.0-20% Cr, 3.0-10.0% V, 0.6-5.0% Nb, 2.0-15% Mo, 3.0% or below Si, 3.0% or below Mn, C, V, Nb and Cr satisfying a formula where 10.5.ltoreq.6.5.C(%)--1.3.V(%)--0.7.Nb(%).ltoreq.2.Cr(%)--2, and the balance being Fe and incidental impurities. A method of manufacturing a roll for hot rolling comprises the steps of centrifugally casting an outer layer material having the above composition, centrifugally casting graphite steel containing 0.5% or above of C as an intermediate layer, and casting an axis material which is a spheroidal graphite cast iron, a flake graphite cast iron or a graphite steel. Carbon is present in the intermediate layer in an amount which satisfies a formula, C (intermediate layer).gtoreq.2.0-0.5�C(%)--0.2.V(%)--0.11.Nb(%)! (outer layer).

Roll outer layer material for hot rolling and method of manufacturing

Steel having excellent vibration-damping properties and weldability includes about 0.02 wt % or less of C, about 0.02 wt % or less of Si, and about 0.08 wt % or less of Mn. This steel also includes about 0.05 to 1.5 wt % of Cu, about 1.0 to 7.0 wt % of Al, about 0.008 wt % or less of N, and Fe and incidental impurities which together constitute the remaining wt %.

Steel having excellent vibration-dampening properties and weldability

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Aichi, Japan

Tomoya Koseki