Process for producing strips of high strength and good formability

摘要

The invention relates to a method for producing a highly resistant (at least 900MPa), very ductile steel strip. The steel, containing (in mass per cent); 0.10 to 0.20 % C; 0.30 to 0.60 % Si; 1.50 to 2.00 % Mn; max. 0.08 % P; 0.30 to 0.80 % Cr; up to 0.40 % Mo; up to 0.20 % Ti and/or Zr; up to 0.08 % Nb; the remainder being Fe and unavoidable impurities, is melted, cast in slabs and then rolled out into a hot rolled strip. The roll end temperature is above 800C, the cooling speed on the delivery roller table is at least 30C/s and the reel temperature is 300 to 600C.