Jfe Steel Corporation

Saiichi Murata

Tomohiro Ishii

Hiroki Ota

Chikara Kami

Mitsuyuki Fujisawa

Keisuke Nakazono

Yukio Kimura

Masataka Yoshino

Yukihiro Matsubara

Ayako Ta

Sumio Kaiho

Nobukazu Kitagawa

Genichi Ishibashi

A ferrite-martensite dual-phase stainless steel has satisfactory corrosion resistance and workability for a material for the body of a freight car and excellent low-temperature toughness. The ferrite-martensite dual-phase stainless steel has a specified chemical composition, in which inequalities (I) and (II) below are satisfied, and a steel microstructure including a dual phase of a ferrite phase and a martensite phase, in which the content of the martensite phase is 5% or more and 95% or less in terms of vol. %:10.5&#x2264;Cr+1.5&#xd7;Si&#x2264;13.5&#x2003;&#x2003;(I)1.5&#x2264;30&#xd7;(C+N)+Ni+0.5&#xd7;Mn&#x2264;6.0&#x2003;&#x2003;(II),

Ferrite-martensite dual-phase stainless steel and method of manufacturing the same

Provided is a material for a cold-rolled stainless steel sheet having a chemical composition containing, by mass %, C: 0.01% to 0.05%, Si: 0.02% to 0.75%, Mn: 0.1% to 1.0%, P: 0.04% or less, S: 0.01% or less, Cr: 16.0% to 18.0%, Al: 0.001% to 0.10%, N: 0.01% to 0.06% and the balance being Fe and inevitable impurities. The material has a metallographic structure including a martensite phase having an area ratio of 5% to 50% and the balance being a ferrite phase. A ferrite phase in portions extending from surface layers of front and back surfaces of a steel sheet has an average grain diameter of 20 &#x3bc;m or more and 50 &#x3bc;m or less, and a ferrite phase in a central portion of the sheet includes an unrecrystallized ferrite phase.

Material for cold-rolled stainless steel sheet

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Tokyo, Japan

Saiichi Murata