Process for producing an easily shaped cold-rolled sheet or strip

US6162308A · kind A · utility

Assignee

• Thyssen Stahl AG · DE

Inventors

• Ilse Heckelmann · Xanten, DE
• Ullrich Heidtmann · Bottrop, DE
• Rolf Bode · Wesel, DE

Key dates

• Filing date: Oct 27, 1998
• Grant date: Dec 19, 2000
• Expiry date: Oct 27, 2018

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C21D8/0436
• WIPO field: Materials, metallurgy
• WIPO sector: Chemistry

Abstract

A method for producing a cold-rolled steel sheet or strip with good formability, especially stretch formability, for making pressings with a high buckling resistance from a steel comprising (in % by mass): 0.01 to 0.08% C, 0.10 to 0.80% Mn, maximum 0.15% Si, 0.015 to 0.08% Al, a maximum 0.005% N, 0.01 to 0.04% Ti and/or Nb, whose contents exceeding the quantity necessary for stoichiometric binding of the nitrogen, ranges from 0.003 to 0.015% Ti or 0.0015 to 0.008% Nb, and a maximum 0.15% in total of one or several elements from the group copper, vanadium, nickel, the remainder being iron, including unavoidable impurities, including a maximum 0.08% P and a maximum 0.02% S, comprises preheating the cast slab to a temperature exceeding 1050.degree. C., hot-rolling at a final temperature ranging from over the Ar.sub.3 temperature to 950.degree. C., coiling the hot-rolled strip at a temperature ranging from 550 to 750.degree. C., cold-rolling at a total cold-rolling degree of deformation from 40 to 85%, recrystallization annealing of the cold strip in a continuous furnace at a temperature of at least 720.degree. C., subsequent cooling at 5 to 70 K/s; and skin passing.