Kabushiki Kaisha Kobe Seiko Sho

Kobe Steel, Ltd.

Masatoshi Sudo

Ichiro Tsukatani

Hiromi Hori

Shunichi Hashimoto

Toshiaki Yutori

Takehiko Kato

Yasuhiro Hosogi

Zenichi Shibata

Takafusa Iwai

Teruyuki Takahara

Denei Takai

Masanori Higashi

Tsuguaki Ohki

Akinori Ohtomo

Koji Hosomi

Shoji Kanbe

Tsuguaki Oki

Shoji Kambe

Hiromori Tsutsumi

High strength low carbon steels having good ultraworkability which comprises 0.01-0.3 wt % of C, below 1.5 wt % of Si, 0.3-2.5 wt % of Mn and the balance of iron and inevitable impurities. In the steel, a low temperature transformation product phase consisting of acicular martensite, bainite or a mixed structure thereof is uniformly dispersed in a ferrite phase in an amount by volume of 15-40%. Wire articles of these steels and methods for making the steels are also disclosed.

High strength low carbon steels, steel articles thereof and method for

There are described a high strength steel plate having a low yield ratio and improved strength-elongation balance and stretch flangeability, and a method for producing same, the steel plate containing 0.01-0.2% of C, 0.3-2.5% of Mn and 0.01-1.8% of Si and having a tripple phase of polygonal ferrite, bainite and martensite, the area ratios of the bainite and martensite phases being 4-45% and 1-15%, respectively, and the area ratio of the bainite phase being greater than that of the martensite phase.

High strength steel plate and method for manufacturing same

A cold-rolled high strength steel plate with excellent formability and baking hardenability, has the composition (% by weight) 0.2-0.15% of C, 0.02-0.7% of Mn, 0.01-0.1% of Al and 0.002-0.01% of N, optionally at least one element selected from the group consisting of 0.01-0.8% of Si, 0.01-0.1% of P, 0.0002-0.005% of B and 0.01-0.5% of V, and a microstructure comprising ferrite containing 2-30% of bainite and less than 8% of martensite. The steel plate is produced by hot and cold rolling steel of the defined composition followed by rapidly heating to a temperature between the Ac.sub.1 and Ac.sub.3 transformation points, holding at this temperature for less than 5 minutes, and quenching to a temperature below 500.degree. C. at a cooling rate between 50.degree. and 500.degree. C./sec.

Cold-rolled high strength steel plate with composite steel structure of

A high strength hot rolled steel sheet having excellent flash butt weldability, fatigue characteristic and formability, has a composite structure composed of polygonal ferrite and bainite and containing from 0.01 to 0.15% by weight of C, from 0.01 to 1.5% by weight of Si and from 0.3 to 2.0% by weight of Mn, the rest being Fe and impurities, the areal ratio of the bainite being from 3 to 60%. The steel sheet is suitable as a material for wheel rims or discs for automobiles.

Method of making high strength hot rolled steel sheet having excellent

The present invention discloses a cold-rolled ultra low carbon steel sheet with improved press-forming properties, which comprises 0.002-0.015% of C, less than 0.006% of N, less than 0.01% of O, less than 0.02% of S, 0.1-0.35% of Mn, 0.01-0.06% of acid-soluble Al, 0.02-0.15% of Ti, and 0.05-0.4% of Cr, and has a value less than 0.8 for the atomic ratio (Ti*/(C+N)) of the total titanium content except titanium of oxide form (Ti*) to the sum of carbon and nitrogen contents, with the balance Fe and incidental impurities. This steel has sufficient values of yield and tensile strengths; is excellent in various properties such as elongation, work hardening index, r value, aging index and Erichsen value; and shows good press-forming properties without any special overaging treatment.

Cold-rolled ultra low carbon steel sheet with improved press-forming

A dual phase high strength cold-rolled steel plate, comprising 0.02-0.15 weight % carbon, 1.5-2.5 weight % Mn, less than 0.2 weight % Si, 0.2-1.5 weight % Cr, 0.03-0.15 weight % P, less than 0.06 weight % Al, less than 0.02 weight % S, and the balance iron and unavoidable impurities. The steel according to the present invention permits the low-temperature transformation products to be formed in a greater proportion within a short annealing time to lower the yield ratio and zeroizes the yield point elongation without skin pass rolling. Moreover, the composition is completely free from adverse effects on tensile strength, ductility and galvanizing properties and can provide cold-rolled steel plate suitable for a wide use including motor vehicles.

Dual phase high strength cold-rolled steel plate

Maraging-steel cylinders for uranium enriching centrifugal separators are made by drawing a blank of maraging-steel into a cylindrical shape, squeezing the drawn blank, and subjecting the squeezed cylinder to aging.

Process for producing maraging-steel cylinder for uranium enriching

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Kobe, Japan

Masatoshi Sudo