Nisshin Steel Co., Ltd.

Nippon Steel Nisshin Co., Ltd.

Junichi Katsuki

Takashi Yamauchi

Naoto Hiramatsu

Satoshi Suzuki

Sadayuki Nakamura

Ryoji Hirota

Hiroyasu Matsubayashi

Teruyoshi Iida

Hanji Ishikawa

Tomoharu Shigetomi

Masato Otsuka

Hideki Tanaka

Takafumi Kawagoe

Provided is a martensitic stainless-steel sheet having a reduced anisotropy in workability and fatigue resistance which are attributable to oxide based inclusions. A martensitic stainless-steel sheet which has a steel composition that contains, in terms of mass %, 0.030 to 0.300% C, 0.20 to 2.50% Si, 0.15 to 4.00% Mn, 0.01 to 1.00% Ni, 11.00 to 15.00% Cr, 0.001 to 0.100% N, 0.0001 to 0.0350% Al, 0 to 0.50% V, 0 to 0.50% Nb, 0 to 0.50% Ti, 0 to 0.020% B, and a balance of Fe and unavoidable impurities, and that has a value of &#x3b3;max, determined by the following equation (1), of 80.0 or greater, and in which oxide based inclusions are observed in the metallographic structure, the oxide based inclusions having a converted composition comprising up to 30 mass % or less AlO, 20 to 60 mass % SiO, and 15 to 70 mass % MnO.

Martensitic stainless-steel sheet and metal gasket

A hot rolled austenitic stainless steel sheet contains 0.030 to 0.300% of C, from 0.30 to 3.20% of Si, from 0.90 to 17.00% of Mn, from 1.00 to 8.00% of Ni, from 14.00 to 19.00% of Cr, from 0.50 to 3.50% of Cu, from 0.045 to 0.250% of N, from 0.0001 to 0.0300% of Al, from 0 to 0.50% of V, from 0 to 0.50% of Nb, from 0 to 0.30% of Ti, and from 0 to 0.010% of B, all in terms of percentage by mass, with the balance of Fe and unavoidable impurities, has a converted average composition of an oxide based inclusion that contains 30% by mass or less of AlO, 60% by mass or less of SiO, and 15% by mass or more of MnO, and satisfies MnO&#x2014;3SiO+110. Anisotropy of workability and fatigue resistance characteristics caused by an oxide based inclusion is decreased.

Austenitic stainless steel sheet and metal gasket

A stainless steel plate is manufactured by performing temper rolling using a dull roller after the finish cold rolling and bright annealing. The stainless steel plate has an arithmetic mean roughness Ra of 0.2 to 1.2 &#x3bc;m in a direction perpendicular to the rolling direction of the steel plate surface. Furthermore, the stainless steel plate has a transfer ratio of 15 to 70% which is an area ratio of a portion onto which a dull pattern is transferred relative to the steel plate surface. In addition, the micro-pits being formed in the steel plate surface, having a depth of 0.5 &#x3bc;m or more, and having an opening area of 10 &#x3bc;mor more, have an existing density in the steel plate surface of 10.0 or less per 0.01 mm, and an opening area ratio in the steel plate surface of 1.0% or less.

Stainless steel plate

A new austenitic stainless steel containing approximately 0.1-1.0 mass % of Si and not more than approximately 0.003 mass % of Al. Nonmetallic inclusions dispersed in a steel matrix are converted to MnO&#x2014;SiO&#x2014;AlOcontaining not less than approximately 15 mass % of SiOand not more than approximately 40 mass % of AlO. During steel making, molten steel is covered with basic slag and heavily deoxidized with a Si alloy whose Al content is controlled to not more than approximately 1.0 mass % in a vacuum or non-oxidizing atmosphere. The austenitic stainless steel sheet can be formed to an objective shape without the occurrence of cracking due to its decrease in susceptibility to cracking and its good formability.

Method of manufacturing austenitic stainless steel having less susceptibility to cracking during forming

A new austenitic stainless steel containing approximately 0.1-1.0 mass % of Si and not more than approximately 0.003 mass % of Al. Nonmetallic inclusions dispersed in a steel matrix are converted to MnO&mdash;SiO &mdash;Al O containing not less than approximately 15 mass % of SiO and not more than approximately 40 mass % of Al O . During steel making, molten steel is covered with basic slag and heavily deoxidized with a Si alloy whose Al content is controlled to not more than approximately 1.0 mass % in a vacuum or non-oxidizing atmosphere. The austenitic stainless steel sheet can be formed to an objective shape without the occurrence of cracking due to its decrease in susceptibility to cracking and its good formability.

Austenitic stainless steel less susceptible to cracking during forming and a manufacturing method thereof

Soft stainless steel sheet excellent in workability

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Yamaguchi, Japan

Junichi Katsuki