Method of continuously heat-treating steel sheet or strip

US4191600A · kind A · utility

Assignee

• Centre De Recherches Metallurgiques-Centrum Voor Research in De Metallurgie · BE

Inventors

• Philippe Paulus · Liège, BE
• Marios Economopoulos · Liège, BE

Key dates

• Filing date: May 2, 1978
• Grant date: Mar 4, 1980
• Expiry date: May 2, 1998

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C21D1/26
• WIPO field: Materials, metallurgy
• WIPO sector: Chemistry

Abstract

Cold-rolled steel sheet or strip (e.g. containing max. 0.15% C., max. 0.60% Mn, max. 0.020% Si, and 0.001-0.050% B) is heated to a temperature higher than its recrystallization temperature and then cooled by immersion in an aqueous bath at above 75.degree. C. The cooling by immersion consists of two successive stages, in the first of which cooling occurs at a rate of 25.degree.-180.degree. C./s to 200.degree.-425.degree. C., the product of the cooling rate v in .degree. C./s times the sheet or strip thickness e in mm being greater than 25, and in the second of which v is 90.degree.-500.degree. C./s and v times e is at least 35. Optionally a further annealing or overageing step comprises holding at 275.degree.-525.degree. C. for 30-250 s.