HIGH CORROSION RESISTANT Ni-Cr-Mo STEEL EXCELLENT IN WELDABILITY AND SURFACE PROPERTY, AND METHOD FOR MANUFACTURING THE SAME

• Main Authors: HIRATA SHIGERU, OKAZAKI KENJI
• Format: Patent
• Language: English; Japanese
• Published: 01.03.2021
• Subjects: ALLOYS; CHEMISTRY; FERROUS OR NON-FERROUS ALLOYS; METALLURGY; METALLURGY OF IRON; PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OFWROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS

To provide a Ni-Cr-Mo steel that has excellent corrosion resistance, weldability and surface quality.SOLUTION: Provided is a Ni-Cr-Mo steel having C: 0.005 to 0.035%, Si: 0.02 to 0.25%, Mn: 0.03 to 0.40%, P: ≤0.030%, S: 0.0001 to 0.0020%, Ni: 32.0 to 38.0%, Cr: 21.0 to 25.0%, Mo: 6.0-8.0%, W: 0.01-2.0%, Cu: 2.0 to 5.0%, N: 0.18 to 0.30%, B≤0.0005%, Ca≤0.0015%, REM≤0.0020%, Al: 0.005 to 0.150%, Ti: 0.002 to 0.200% and O≤35 ppm, and the balance consisting of Fe and unavoidable impurities, and satisfying the following equations (1) to (3). 1.3×Mo+1.0×W-1.3×Cu-52.7×Al-17.9×Ti<6.5 --- equation (1), 8.4×Si+Cu<4.70 --- equation (2), Ti+0.625×Si<0.26 --- equation (3).SELECTED DRAWING: Figure 1 【課題】優れた耐食性、溶接性および表面性状にも優れたＮｉ−Ｃｒ−Ｍｏ鋼を提供する。【解決手段】Ｃ：０．００５〜０．０３５％、Ｓｉ：０．０２〜０．２５％、Ｍｎ：０．０３〜０．４０％、Ｐ：≦０．０３０％、Ｓ：０．０００１〜０．００２０％、Ｎｉ：３２．０〜３８．０％、Ｃｒ：２１．０〜２５．０％、Ｍｏ：６．０〜８．０％、Ｗ：０．０１〜２．０％、Ｃｕ：２．０〜５．０％、Ｎ：０．１８〜０．３０％、Ｂ≦０．０００５％、Ｃａ≦０．００１５％、ＲＥＭ≦０．００２０％、Ａｌ：０．００５〜０.１５０％、Ｔｉ：０．００２〜０．２００％、Ｏ≦３５ｐｐｍ、残部がＦｅおよび不可避的不純物からなり、かつ、次式（１）〜（３）を満足するＮｉ−Ｃｒ−Ｍｏ鋼。１．３×Ｍｏ＋１．０×Ｗ−１．３×Ｃｕ−５２．７×Ａｌ−１７．９×Ｔｉ＜６．５...式（１）、８．４×Ｓｉ＋Ｃｕ＜４．７０...式（２）、Ｔｉ＋０．６２５×Ｓｉ＜０．２６...式（３）【選択図】図１