Nippon Steel Sumitomo Metal Corporation

Shuuji Yoshida

Hideya Kaminaka

Junko Imamura

Kouichi Takeuchi

Masayuki Shibuya

Junichi Higuchi

Hayato Kita

Katsuhiko Taketsu

Yoshiaki Yamade

Tomoyuki Sukawa

Shinnya Yamamoto

A high-Si content austenitic stainless steel, which exhibits stable acid resistance and excellent corrosion resistance in high-temperature and concentrated nitric acid, has a chemical composition comprising: C: at most 0.04%; Si: 2.5-7.0%; Mn: at most 10%; P at most 0.03%; S: at most 0.03%; N: at most 0.035%; sol. Al: at most 0.03%; Cr: 7-20%; Ni: 10-22%; optionally, one or more types selected from Nb, Ti, Ta and Zr: 0.05-0.7% in total; and the remainder being Fe and impurities, wherein a total amount of Btype inclusions measured by a method according to JIS G0555 (2003) Annex 1 'Microscopic Testing for the Non-Metallic Inclusions on the Point Counting Principle' is not more than 0.03% by area %.

Method for manufacturing high-Si austenitic stainless steel

The present invention provides a duplex stainless steel having excellent resistance to alkalis and particularly corrosion resistance against high-temperature concentrated alkali solutions and excellent weldability. The duplex stainless steel has a chemical composition comprising, in mass %, C: at most 0.03%, Si: at most 0.5%, Mn: at most 2.0%, P: at most 0.04%, S: at most 0.003%, Cr: at least 25.0% to less than 28.0%, Ni: at least 6.0% to at most 10.0%, Mo: at least 0.2% to at most 3.5%, N: less than 0.5%, W: at most 3.0%, and a remainder of Fe and impurities.

Duplex stainless steel having excellent alkali resistance

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Joetsu, Japan

Shuuji Yoshida