Abstract: The production process flowsheet of Φ22~25 mm steel reinforced bar HRB400 (/% : 0.20~0.25 C, 0.25~0.43Si, 0.90~1.15Mn) and Φ18~28 mm high strength steel reinforced bar HRB500 (/% : 0.20~0.25C, 0.50~0.65Si, 1.38 ~ 1.53Mn, 0.05~0.07V) is 100 t top and bottom combined blowing converter-deoxidizing and alloying during tapping-ladle bottom argon blowing- 160 mm X 160 mm billet casting-continuous rolling. By observation on structure of reinforced bar HRB400 and high strength reinforced bar HRB500 the precipitation behavior and the effect of V and Nb carbide precipitation on properties of steel are analyzed, and the strengthening measures including to control the self-tempering structure layer at surface of HRB400 steel reinforced bar less than 1 mm and using V-Nb composite micro-alloying for HRB500 steel reinforced bar are put forward. With controlling carbon content in steel 0. 18% ~0. 23% , increasing steel bar temperature after water cooling to 700 ℃from original 650 ℃ , and using V + Nb =0.05%〜0.07% to com- posite-strengthen for HRB500 steel bar, the yield and tensile strength of Φ22 ~25 mm bar of HRB400 steel decreases respectively from 460~510 MPa and 580 ~610 MPa to 440~490 MPa and 570~620 MPa, and the yield and tensile strength of of Φ18~28 mm bar of HRB500 steel increases respectively from 560~610 MPa and 670~700 MPa to 570~620 MPa and 680~710 MPa obviously to increase the comprehensive mechanical properties of steel.

摘要： Φ22~25mmHRB400（/%:0.20~0.25C,0.25~0.43Si,0.90~1.15Mn）钢筋和Φ18~28 mm HRB500（/%:0.20~0.25C，0.50~0.65Si，1.38~1.53Mn，0.05~0.07V）高强度钢筋的生产工艺流程为100 t顶底复吹转炉-出钢脱氧合金化-钢包底吹氩气-160 mm×160 mm方坯连铸-连轧。通过对HRB400钢筋和HRB500高强度钢筋的组织观察,分析了V和Nb碳化物在钢中的析出行为及对性能的影响,提出了HRB400钢筋的表面淬火自回火组织层宜控制在1 mm以下和HRB500钢筋采用V-Nb复合微合金化强化改进措施。通过控制钢中C含量0.18%~0.23%,钢筋水冷后温度从650℃提高到700℃,HRB500钢筋采用V+Nb含量0.05%~0.07%复合强化等工艺措施。Φ22~25mm HRB400钢筋屈服和抗拉强度分别从460~510 MPa和580~610 MPa下降至440~490MPa和570~620 MPa,Φ18~28mm HRB500钢筋屈服和抗拉强度分别从560~610 MPa和670~700 MPa提高至570~620 MPa和680~710 MPa,显著提高了钢筋的综合力学性能。

关键词: HRB400, HRB500, 高强度钢筋, 组织, 力学性能, 强化措施