| 摘要 |
PURPOSE:To produce titled steel for high strength reinforcing bar by heating a steel ingot contg. specific contents of C, Si, Mn, Al, Nb at temps. higher than specific temps. then subjecting the same to rough rolling at reduction rate of area higher than specific values in a specific temp. range then to intermediate and finish rolling at reduction rate of area higher than specific values at temps. lower than specific temps. CONSTITUTION:A steel ingot is made to contain, by wt%, 0.2-0.4 C, <0.5 Si, 0.6-2 Mn, <0.1 Al, 0.01-0.1 Nb. After this ingot is heated to >=1,200 deg.C, the ingot is subjected to rough rolling at >=60% reduction rate of area at 900- 1,200 deg.C then to intermediate and finish rolling at >=60% reduction rate of area at <=875 deg.C. If necessary, 0.03-0.2V is further added thereto. Thus, the steel for reinforcing bars of high yield point elongation ratios having high strength of >=50kg/mm.<2> upper yield point is obtained. |
