Maraging steel and process for manufacturing a strip or a part cut out of a strip of cold-rolled maraging steel

US6663730B2 · kind B2 · utility

Assignee

• Imphy Ugine Precision · FR

Inventor

• Lucien Coutu · London, GB

Key dates

• Filing date: Nov 19, 2001
• Grant date: Dec 16, 2003
• Expiry date: Nov 19, 2021

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C21D2201/00
• WIPO field: Materials, metallurgy
• WIPO sector: Chemistry

Abstract

A maraging steel strip or part and process for manufacture of a strip or of a part cut out of a strip of cold-rolled maraging steel and hardened by a hardening heat treatment. In the process, before the hardening heat treatment is performed, the strip or the part is subjected to cold plastic deformation with a degree of working greater than 30% and the strip or the part is subjected to recrystallization annealing in order to obtain a fine-grained structure with ASTM index higher than 8. The composition by weight of the maraging steel is: 12%≦Ni≦24.5%; 2.5%≦Mo≦12%; 4.17%≦Co≦20%, Al %≦0.15%; Ti≦0.1%; N≦0.003%; Si≦0.1%; Mn≦0.1%; C≦0.005%; S≦0.001%; P≦0.005%; H≦0.0003%; O≦0.001%; iron and impurities resulting from smelting, the chemical composition also satisfying the relationships: 20%≦Ni+Mo≦27%; 50≦Co×Mo≦200; Ti×N≦2×10−4.