| 摘要 |
PROBLEM TO BE SOLVED: To provide a low-cost high strength steel material for reinforcing bars with excellent balance between high strength and ductility, which allows a weld joint to have high ductility.SOLUTION: The steel material has a component composition including 0.25% or more and 0.40% or less of C, 0.15% or more and 0.50% or less of Si, 1.2% or more and 1.8% or less of Mn, 0.03% or less of P, 0.02% or less of S, less than 0.005% of Al, more than 0.15% and 0.5% or less of Cr, 0.2% or more and 0.4% or less of V, 0.003% or less of Ti, and 0.003% or less of Nb, which have predetermined relations, with the balance being Fe and unavoidable impurities. The steel material has a mixed structure which contains ferrite, perlite, and bainite. |
