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研究了TMCP和回火工艺参数对含Nb无碳化物贝氏体/马氏体钢组织与力学性能的影响。结果表明,轧后空冷可获得超高强无碳化物贝氏体/马氏体复相钢,屈服强度高于1000 MP,抗拉强度高于1800 MP;贝氏体含量略高,钢的回火稳定性较好。空冷有利于微合金元素Nb第二相粒子析出,发挥细晶强化作用,提高钢的强韧性。回火过程中,随着回火温度的升高,抗拉强度逐渐降低,冲击性能呈现“W”型变化趋势。350~400℃回火时,强韧性最优,450℃回火时,发生回火脆性。
The effects of TMCP and tempering process parameters on microstructure and mechanical properties of Nb-free carbides bainite / martensitic steel were studied. The results show that ultra-high strength carbide-free bainite / martensite duplex steel can be obtained after rolling and air cooling. The yield strength is higher than 1000 MP and the tensile strength is higher than 1800 MP. The content of bainite is slightly higher and the tempering of steel Stability is better. Air cooling is conducive to micro-alloying elements Nb second phase particles precipitation, play fine grain strengthening effect, improve the toughness of steel. Tempering process, with the tempering temperature increases, the tensile strength decreased, the impact performance showed “W ” type trend. Tempering at 350 ~ 400 ℃, the best toughness, tempering at 450 ℃, the occurrence of temper brittleness.