FERRITIC STAINLESS STEEL MATERIAL

• Main Authors: TAI ZENICHI, WAKAMURA MAI
• Format: Patent
• Language: English; Japanese
• Published: 08.07.2022
• Subjects: ALLOYS; CHEMISTRY; FERROUS OR NON-FERROUS ALLOYS; METALLURGY; TREATMENT OF ALLOYS OR NON-FERROUS METALS

To provide a ferritic stainless steel material that has excellent corrosion resistance and designability.SOLUTION: The inventive ferritic stainless steel material includes a ferritic stainless steel as a base, which contains, in mass%, C, Si, Mn, P, S, Cr, Ni, Cu, Mo, N, Al, Ti, Nb specified quantities, with a total content of Nb and Ti being 6(C+N) or more, and the balance being Fe and impurities. On a base surface, a pattern is formed by an oxide film part provided with a black oxide film satisfying a brightness index of L*≤45.0, chromatic indices of -5.0≤a*≤5.0 and -5.0≤b*≤5.0, and a gloss GS(60°)≤40.0, and an exposed-base portion with the oxide film not formed. The difference in brightness index between the oxide film part and the exposed-base portion satisfies ΔL*≥30.0 and the difference in gloss between them satisfies ΔGS(60°)≥130.0. A passive-state film formed on the exposed-base portion satisfies a Cr fraction≥30%.SELECTED DRAWING: Figure 1 【課題】耐食性及び意匠性に優れるフェライト系ステンレス鋼材を提供する。【解決手段】質量％で、Ｃ、Ｓｉ、Ｍｎ、Ｐ、Ｓ、Ｃｒ、Ｎｉ、Ｃｕ、Ｍｏ、Ｎ、Ａｌ、Ｔｉ、Ｎｂを所定量含有し、かつＮｂ及びＴｉの合計含有量が６（Ｃ＋Ｎ）以上あり、残部がＦｅ及び不純物からなる組成を有するフェライト系ステンレス鋼を素地として、素地の表面には、明度指数Ｌ＊≦４５．０、クロマネチックス指数－５．０≦ａ＊≦５．０、－５．０≦ｂ＊≦５．０、光沢度ＧＳ（６０°）≦４０．０を満たす黒色の酸化皮膜が形成された酸化皮膜部と、酸化皮膜が形成されていない素地露出部とにより模様が形成されており、酸化皮膜部と素地露出部とにおいて明度指数の差ΔＬ＊≧３０．０及び光沢度の差ΔＧＳ（６０°）≧１３０．０を満たし、かつ素地露出部表面に形成された不働態皮膜がＣｒ分率≧３０％を満たす、フェライト系ステンレス鋼材。【選択図】図１