热轧工艺对390 MPa级高铁转向架用钢组织性能影响

高铁转向架的服役要求其屈服强度不低于390 MPa，抗拉强度不低于510 MPa，-40 ℃低温冲击功不低于34 J，满足30年服役寿命。研究设计了一种具有高韧性、耐腐蚀和易焊接的试验钢化学成分，通过控制轧制和控制冷却方法，调整其组织和力学性能。经过拉伸试验、冲击试验、扫描电镜对试验钢的力学性能和显微组织进行了检测与分析。结果表明，390 MPa高铁转向架用耐候钢的成分设计合理，各项力学性能符合要求，其中当终轧温度为850 ℃、以7 ℃/s的冷速冷却至550 ℃时综合性能最好，屈服强度为487 MPa，抗拉强度为596 MPa，-40 ℃低温冲击功为216 J。

Effect of hot rolling process on microstructure and properties #br# of 390 MPa grade steel used for EMU bogie

The service requirements of high speed railway bogies were that the yield strength, the tensile strength and the low temperature impact energy of -40 ℃ were not less than 390 MPa, 510 MPa and 34 J, respectively, meeting the service life of 30 years. The chemical composition of the test steel with high toughness, corrosion resistance and easy welding was designed. The microstructure and mechanical properties were adjusted by controlling the rolling and the cooling method. The mechanical properties and microstructure of the experimental steel were tested and analyzed by the tensile test, impact test and scanning electron microscope. The results showed that the composition of the weathering steel for 390 MPa high speed railway bogie was reasonable, and the mechanical properties met the requirements. When the finishing temperature was 850 ℃ and the cooling rate was 7 ℃/s to 550 ℃, the overall performance was best. At this time, the yield strength was 487 MPa, the tensile strength was 596 MPa, and the low temperature impact energy of -40 ℃ was 216 J.