Abstract: The effects of silicon content on microstructure and mechanical properties of the test 1 250 MPa grade Nb- V microaUoyed Si-Mn-Cr-Mo bainite rail steel (/% ：0.25 C,0.38～1.56 Si,1.69～1.76 Mn,1.34～1.37 Cr,0.32～0. 33 Mo,0.034 ～0.036 Nb,0. 11 ～0. 12 V) are studied. The test results show that by test steel air cooling after hot-rolling, with the increase of silicon content, the ferrite + pearlite phase transformation test steel is suppressed, and the content of bainite and martensite in the room temperature structure increases to afiect the strength and hardness of steel. With silicon content increasing from 0.38% to 1.56% , the test steel % yield strength increases from 846 MPa to 903 MPa, the tensile strength increases from 1 280 MPa to 1 355 MPa, and the HBW hardness value increases from 353 to 411.

摘要： 研究了1250 MPa级Nb-V微合金化Si-Mn-Cr-Mo系贝氏体轨钢(/%:0.25 C,0.38-1.56 Si,1.69～1.76 Mn,1.34～1.37 Cr,0.32～0.33 Mo,0.034～0.036 Nb,0.11～0.12 V)硅含量对试验钢显微组织和力学性能的影响。试验结果表明:试验钢热轧后空冷,随着硅含量的增加,试验钢的铁素体+珠光体相变被抑制,室温组织中贝氏体、马氏体含量增加,影响钢的强度和硬度,硅含量由0.38%提高到1.56%时,试验钢的屈服强度由846 MPa增至903 MPa,抗拉强度由1 280 MPa增至1 355 MPa,HBW硬度值由353增至411。

关键词: Nb-V微合金化, Si-Mn-Cr-Mo贝氏体钢轨钢, 硅, 组织, 力学性能,