| 摘要 |
The present invention discloses a cold-rolled ultra low carbon steel sheet with improved press-forming properties, which comprises 0.002-0.015% of C, less than 0.006% of N, less than 0.01% of O, less than 0.02% of S, 0.1-0.35% of Mn, 0.01-0.06% of acid-soluble Al, 0.02-0.15% of Ti, and 0.05-0.4% of Cr, and has a value less than 0.8 for the atomic ratio (Ti*/(C+N)) of the total titanium content except titanium of oxide form (Ti*) to the sum of carbon and nitrogen contents, with the balance Fe and incidental impurities. This steel has sufficient values of yield and tensile strengths; is excellent in various properties such as elongation, work hardening index, r value, aging index and Erichsen value; and shows good press-forming properties without any special overaging treatment.
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