Ni-based heat resistant alloy

US9328403B2 · kind B2 · utility

Assignee

• NIPPON STEEL & SUMITOMO METAL CORPORATION · JP

Inventors

• Hiroyuki Semba · Tokyo, JP
• Hirokazu Okada · Kobe, JP
• Hiroyuki Hirata · Tokyo, JP
• Mitsuru Yoshizawa · Amagasaki, JP
• Atsuro Iseda · Kobe, JP

Key dates

• Filing date: Jul 31, 2012
• Grant date: May 3, 2016
• Expiry date: Aug 14, 2032

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C22C19/051
• WIPO field: Materials, metallurgy
• WIPO sector: Chemistry

Abstract

A Ni-based heat resistant alloy as pipe, plate, rod, forgings and the like consists of C≦0.15%, Si≦2%, Mn≦3%, P≦0.03%, S≦0.01%, Cr: 15% or more and less than 28%, Mo: 3 to 15%, Co: more than 5% and not more than 25%, Al: 0.2 to 2%, Ti: 0.2% to 3%, Nd: fn to 0.08%, and O≦0.4Nd, further containing, as necessary, at least one kind of Nb, W, B, Zr, Hf, Mg, Ca, Y, La, Ce, Ta, Re and Fe of specific amounts, the balance being Ni and impurities, wherein, fn=1.7×10−5d+0.05{(Al/26.98)+(Ti/47.88)+(Nb/92.91)}. In the formula, d denotes an average grain size (μm), and each element symbol denotes the content (mass %) of that element. If the alloy contains W, Mo+(W/2)≦15% holds. The alloy has improved ductility after long-term use at high temperatures, and cracking due to welding can be avoided.