Ti-Nb微合金化对低碳高强度钢组织和性能的影响

0.153Ti-0.038Nb和0.080Ti-0.062Nb两种Ti-Nb微合金化低碳钢(/%:0.061～0.075C、0.22Si、1.76～1.77Mn、0.002～0.003S、0.006P、0.003Als、0.003 8～0.004 2N、0.004 0～0.004 5O)由50 kg真空感应炉冶炼,轧成10 mm板,终轧温度880℃,水冷至630℃。试验结果表明,两种Ti-Nb微合金化钢的析出物均为(Nb,Ti)(C,N)复合析出物;当Ti含量由0.080%增加至0.153%,同时Nb含量由0.062%降至0.038%时,钢屈服和抗拉强度分别从558 MPa和653 MPa提高至633 MPa和756 MPa,屈强比、伸长率和断面收缩率变化较小。表明,添加Ti代替部分Nb进行复合微合金化可提高钢材强度,降低生产成本。

Effect of Ti-Nb Microalloying on Structure and Properties of Low Carbon High Strength Steel

0. 153Ti-0. 038Nb and 0. 080Ti-0. 062Nb two kind of Ti-Nb microalloying low carbon steel (/% : 0. 061 ~0. 075C, 0. 22Si, 1.76 〜1.77Mn, 0. 002 〜0. 003S, 0. 006P, 0.003Als, 0.003 8 ~0. 004 2N, 0.004 0 ~0. 004 50) are melted by a 50 kg vacuum induction furnace and rolled to 10 mm plate with finishing rolling at 880 ℃ , water cooling to 630 ℃.Test results show that the precipitates in both Ti-Nb microalloying steels are ( Nb, Ti) ( C, N) compound precipitates； with increasing Ti content from 0. 080% to 0. 153% and decreasing Nb content from 0. 062% to 0. 038% , the yield and tensile strength of steel respectively increase from 558 MPa and 653 MPa to 633 MPa and 756 MPa, besides, the variations in ratio between yield and tensile strength, elongation and reduction of area of steels are minor. It indicates the strength of steel products could be increased by adding Ti to replace part of Nb to carry out compound microalloying and the production cost is decreased.