| 摘要 |
<P>PROBLEM TO BE SOLVED: To reduce an in-plane anisotropy of r value in a steel sheet having low content of C or Mn. <P>SOLUTION: The steel sheet has a chemical compositions composed, by mass, of (1) 0.04%-0.25% C, 0.60%-<1.5% Mn or (2) 0.25%-1.00% C, 0.30%-<0.60% Mn and one or both of 0.05%-<0.50% Si, 0.005%-0.080% sol.Al and has a mechanical properties, so that ▵r1 regulated in the following formula (1) is ≥-0.20 and ≤0.20 and ▵r2 regulated in the following formula (2) is ≤0.42. The steel sheet is manufactured with a hot-rolled sheet annealing, cold-rolling and a finish-annealing under the specific conditions. The above formulas are the followings: ▵r1=(r<SB POS="POST">0</SB>-2r<SB POS="POST">45</SB>+r<SB POS="POST">90</SB>)/2...(1), and ▵r2=r<SB POS="POST">max</SB>-r<SB POS="POST">min</SB>...(2). <P>COPYRIGHT: (C)2013,JPO&INPIT |
