High-temperature steel for boiler making

US5573605A · kind A · utility

Assignee

• Mannesmann AG · DE

Inventors

• Walter Bendick · Duisburg, DE
• Klaus H. Haarmann · Frisco, US
• Ingo von Hagen · Krefeld, DE

Key dates

• Filing date: Mar 7, 1995
• Grant date: Nov 12, 1996
• Expiry date: Mar 7, 2015

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C22C38/28
• WIPO field: Materials, metallurgy
• WIPO sector: Chemistry

Abstract

A high-temperature steel for boiler making having improved creep strength and low tendency to hardening in welded condition, having the following melt analysis (wt. %): C 0.050 to 0.100% Si 0.15 to 0.45% Mn 0.30 to 0.70% P .ltoreq.0.020% S .ltoreq.0.010% Al .ltoreq.0.020% Cr 2.20 to 2.60% Mo 0.90 to 1.10% V 0.20 to 0.30% Ti 0.05 to 0.10% B 0.0015 to 0.0070% N .ltoreq.0.01% The balance of the steel is comprised of iron and ordinary impurities. The steel is annealed for a period of about 30 to about 60 minutes at about 980.degree. C. to about 1040.degree. C., thereupon cooled in air, and then tempered for at least one hour at about 730.degree. C. to about 760.degree. C.