Nisshin Steel Co., Ltd.

Sanoh Kogyo Kabushiki Kaisha

Takashi Igawa

Yoshihiro Uematsu

Katsuhisa Miyakusu

Hiroshi Fujimoto

Masayuki Kinugasa

Toshihiko Takemoto

Teruo Tanaka

Kazuo Hoshino

Yukio Oda

Naoto Hiramatsu

Satoshi Suzuki

Akira Sakakura

Naoto Okubo

Yukito Nomura

Juichi Ozawa

Koichi Satake

An austenitic stainless steel comprising (C+&#xbd;N) up to 0.060 mass %, Si up to 1.0 mass %, Mn up to 5 mass %, S up to 0.003 mass %, S/Mn ratio up to 0.003, 15&#x2013;20 mass % Cr, 5&#x2013;12 mass % Ni, Cu up to 5 mass %, 0&#x2013;3.0 mass % Mo and the balance being Fe except inevitable impurities under the condition that a value Md(representing a ratio of a strain-induced martensite) defined by the under-mentioned formula is controlled within a range of &#x2212;60 to &#x2212;10. Hardness increase of the steel sheet after being cold-rolled is preferably 20% or more as Vickers hardness. A metallurgical structure of the steel sheet is preferably adjusted to grain size number of #8 to #11 in a finish annealed state. The steel sheet is blanked with high dimensional accuracy, and a die life is also prolonged.Md=551&#x2212;462(C+N)&#x2212;9.2Si&#x2212;29(Ni+Cu)&#x2212;8.1Mn&#x2212;13.7Cr&#x2212;18.5Mo.

Austenitic stainless steel excellent in fine blankability

Duplex structure stainless steel having high strength and elongation and

A multifold pipe made by multiple rolling up and turning of a copper coated steel sheet into a multifold pipe, characterized in that said steel sheet is a cold rolled sheet of a super soft austenitic stainless steel comprising by weight: up to 0.05% of C, up to 1.0% of Si, up to 5.0% of Mn, from 9.0% to 15.0% of Ni, from 15.0% to 20.0% of Cr, up to 0.04% of N, up to 5.0% of Cu, the balance being Fe and unavoidable impurities, wherein the alloying elements are further adjusted so that both the two relations (1) and (2) noted below are satisfied:

Stainless steel multifold pipe

A high strength chromium containing steel sheet having a tensile strength of at least 40 kgf/mm.sup.2, and excellent in corrosion resistance and workability, comprising, by weight, C:up to 0.030%, Si:up to 2.30%, Mn:up to 3.0%, P:more than 0.0005% and not more than 0.150%, S:up to 0.010%, Ni:up to 2.0%, Cu:more than 0% and not more than 2.0%, Cr:not less than 5.0% and less than 10.0%, N:up to 0.030%, V:not less than 0.01% and not more than 0.10%, and optionally at least one of 0.01 to 0.30% of Ti, 0.01 to 0.30% of Nb, 0.01 to 0.30% of Zr, 0.01 to 0.20% of Al and 0.0002 to 0.0200% of B, the amounts of Si, Mn, P, Ni and Cu being adjusted so that the relation:Si+Mn+10P+Ni+Cu&gt;1.0% may be satisfied, the balance being iron and unavoidable impurities.

Chromium containing high strength steel sheet excellent in corrosion

A high strength steel belt having an excellent flatness and a duplex structure of austenite and martensite has been prepared by a process which comprises providing a cold rolled or cold rolled and annealed strip of a martensitic structure from low carbon martensitic stainless steel containing from 10 to 17% by weight of Cr and having a carbon content of not exceeding 0.15% by weight, connecting ends of the strip or ends of a plate cut from said strip to provide an endless belt, causing the endless belt to circularly move between rolls under tension and to pass through a heating furnace where the belt is heated to a temperature within a range from (As point of the steel+30.degree. C.) to Af point of the steel and not higher than 900.degree. C. so that a part of the martensitic phase may be changed to a reversed austenitic phase and a desired surface flatness may be obtained after cooling.

Process for producing high strength endless steel belt having a duplex

Pipe joint made of stainless steel and method of making the same

Shape memory stainless steel excellent in stress corrosion cracking

A chromium containing steel sheet excellent in corrosion resistance and workability, comprising, by weight, C:up to 0.030%, Si:up to 0.5%, Mn:up to 0.5%, P:up to 0.040%, S:up to 0.010%, Ni:up to 0.3%, Cu:up to 0.3%, Cr: not less than 5.0% and less than 11.0%, N:up to 0.030%, V:not less than 0.01% and not more than 0.10%, and optionally at least one of 0.01 to 0.30% of Ti, 0.01 to 0.30% of Nb, 0.01 to 0.30% of Zr, 0.01 to 0.20% of Al and 0.0002 to 0.0200% of B, the amounts of Si, Mn, P, Ni and Cu being adjusted so that the relation:Si+Mn+10P+Ni+Cu.ltoreq.1.0% may be satisfied, the balance being iron and unavoidable impurities.

Chromium containing steel sheet excellent in corrosion resistance and

A high strength steel strip excellent in shape having a duplex structure of austenite and martensite has been prepared by a process which comprises providing a cold rolled or cold rolled and annealed strip of a martensitic structure from low carbon martensitic stainless steel containing from 10 to 17% by weight of Cr and having a carbon content of not exceeding 0.15% by weight, causing the strip to continuously pass through a continuous heat treatment furnace under tension where the strip is heated to temperatures within the range from (the As point of the steel+30.degree. C.) to the Af point of the steel and not higher than 900.degree. C. so that a part of the martensitic phase may be changed to a reversed austenitic phase, and cooling the heated strip to ambient temperature, wherein the As point of the steel is a temperature of the steel of which temperature is being raised at which the transformation of martensite to austenite begins and the Af point of the steel is a temperature of the steel of which temperature is being raised at which the transformation of martensite to austenite is finished.

Process for producing high strength stainless steel strip excellent in

A stainless steel which exhibits substantially martensitic structure at room temperature was heated at a temperature of 550.degree. to 675.degree. for 1 to 30 hours. Then a reverse-transformed austenite phase appeared and a stainless steel having high strength and high elongation and being free from weld softening was obtained.

Process for preparing a high strength stainless steel having excellent

A process for the production of an electrical steel sheet having the ideal (100) [001] cube texture of iron of iron alloy, comprising cold rolling a sheet of a single crystal or large grained crystals of iron or iron alloy, in which said single crystal is or a majority of said large grained crystals are oriented so that the pole of the {114} plane may form an angle not greater than 15.degree. with the normal direction of the plane of the sheet, and the &lt;401&gt; direction may form an angle of not greater than 15.degree. with a single direction in the plane of the sheet, in said single direction at a rolling reduction of at least 40%, and annealing the rolled sheet to form a primary recrystallization texture of fine grains of an average grain size of not larger than 5 mm under conditions preventing the occurrence of secondary recrystallization.

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Yamaguchi, Japan

Takashi Igawa