| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for manufacturing a steel bar for a reinforced concrete structure, which has ultrahigh strength in response to a concrete strength enhanced to 200 N/mm<SP>2</SP>. SOLUTION: This manufacturing method includes: the first step of forming a deformed bar having a non-circular cross section over the entire length, by hot-rolling a cast slab having chemical components including 0.25-0.50% C, 2.00% or less Si, 2.00% or less Mn, and the balance Fe with unavoidable impurities; and the second step of sequentially quenching and tempering the deformed bar obtained in the first step. The steel bar for the reinforced concrete structure obtained in the second step has a material reference strength of a yield point or a yield strength at 0.2% in an amount of 980 N/mm<SP>2</SP>or more. Particularly, a tempering temperature during the tempering treatment is 400-750°C. COPYRIGHT: (C)2011,JPO&INPIT |
