氮含量对500E抗震钢筋20MnVN组织和性能的影响

Effect of Nitrogen Content on Structure and Mechanical Properties of 500E Anti-Quake Reinforced Bar Steel 20MnVN

研究的Ф6．5mm500E抗震钢筋20MnVN（／％：0．19～0．20C，0．23～0．26Si，1．26—1．31Mn，0．016～0．023P，0．006—0．012S，0．10～0．11V，0．0038—0．0163N）的生产流程为50t顶底复吹转炉-LF-160mm×160mm方坯连铸-控轧控冷工艺。结果表明，随着钢中氮含量增加，500E20MnVN钢盘条拉伸断口的韧窝变深，口径增大，组织中铁素体含量由63．6％增加至74．8％；增加氮含量有助于20MnVN钢盘条屈服强度、抗拉强度和伸长率的提高，当氮含量由0．0038％增加到0．0163％时，该钢屈服强度、抗拉强度和伸长率分别由513MPa、650MPa和10．5％提高到571MPa、703MPa和13．0％。分析了V—N微合金化和V（C，N）析出的强韧化机理。

The production flowsheet for studied Ф6. 5 mm 500E anti-quake reinforced bar steel 20MnVN （/%： 0. 19 -0. 20C, 0.23 -0. 26Si, 1.26 - 1.31Mn, 0. 016 -0. 023P, 0.006 -0. 012S, 0. 10-0. 11V, 0.0038 -0.016 3N） is 50 t top and bottom combined blowing converter-LF-160 mm× 160 mm billet casting-rod control rolling and control cooling process. The results show that with increasing the nitrogen content in steel, the tough dimples of tensile fracture of 500E 20MnVN steel coil become deeper and their diameters become larger, and the ferrite content in structure increases from 63.6% to 74. 8% ; increasing nitrogen content is available to increase the yield strength, tensile strength and elongation of 20MnVN steel coil, and with increasing the nitrogen content in steel from 0.003 8% to 0.016 3%, the yield strength, tensile strength and elongation of steel increases respectively from 513 MPa, 650 MPa and 10. 5% to 571 MPa, 703 MPa and 13.0%. The V-N microalloying and V（ C, N） precipitated strengthening-toughing mechanism is analyzed.