AUSTENITE-FERRITE DUPLEX STAINLESS STEEL SHEET

• Main Authors: MIZUTANI AKITO, FUJISAWA MITSUYUKI
• Format: Patent
• Language: English; Japanese
• Published: 22.02.2021
• Subjects: ALLOYS; CHEMISTRY; FERROUS OR NON-FERROUS ALLOYS; METALLURGY; TREATMENT OF ALLOYS OR NON-FERROUS METALS

To provide an austenite-ferrite duplex stainless steel sheet which has both high yield strength and excellent microbial corrosion resistance necessary for application to structural members of an underwater structure.SOLUTION: The austenite-ferrite duplex stainless steel sheet contains, by mass%, C: 0.100% or less, Si: 1.00% or less, Mn: 2.0-7.0%, P: 0.07% or less, S: 0.030% or less, Cr: 18.0-24.0%, Ni: 0.1-3.0%, Mo: 0.01-1.00%, Cu: 0.1-3.0%, Ag: 0.010-0.120% and N: 0.15-0.30%, and contains one or two kinds selected from B: 0.0010-0.0100% and REM: 0.010-0.100% and the balance is composed of Fe and inevitable impurities and the content (mass%) of Ag, B and REM is set to [%Ag], [%B] and [%REM], respectively, (30×[%B]+1.2×[%REM])/[%Ag]≥1.00 is satisfied.SELECTED DRAWING: Figure 1 【課題】水中構造物の構造部材へ適用する上で必要な高い耐力と優れた耐微生物腐食性とを兼備した、オーステナイト・フェライト系二相ステンレス鋼板を提供する。【解決手段】質量％で、Ｃ：０．１００％以下、Ｓｉ：１．００％以下、Ｍｎ：２．０〜７．０％、Ｐ：０．０７％以下、Ｓ：０．０３０％以下、Ｃｒ：１８．０〜２４．０％、Ｎｉ：０．１〜３．０％、Ｍｏ：０．０１〜１．００％、Ｃｕ：０．１〜３．０％、Ａｇ：０．０１０〜０．１２０％およびＮ：０．１５〜０．３０％を含有するとともに、Ｂ：０．００１０〜０．０１００％およびＲＥＭ：０．０１０〜０．１００％のうちから選ばれる１種または２種を含有し、残部がＦｅおよび不可避的不純物からなり、Ａｇ、ＢおよびＲＥＭの含有量（質量％）をそれぞれ［％Ａｇ］、［％Ｂ］および［％ＲＥＭ］とした時、（３０×［％Ｂ］＋１．２×［％ＲＥＭ］）／［％Ａｇ］≧１．００を満足する。【選択図】図１