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对C-Si-Mn系TRIP钢采用等温退火工艺,得到具有TRIP效应贝氏体基高强钢。结果表明,TBF钢的组织主要由无碳化物贝氏体板条束、块状残余奥氏体、板条束间的薄膜状残余奥氏体及少量的回火马氏体组成。在连退过程中,贝氏体等温温度对TBF钢的组织和性能影响显著,当贝氏体等温温度为300℃时,TBF钢具有低屈服强度(789 MPa)、高抗拉强度(1241 MPa)以及良好的伸长率(16.6%)。等温300℃时,屈服强度的降低主要是因为80~190 nm的无碳化物贝氏体板条的生成。经过XRD测定,其残余奥氏体含量为12.04%,残奥含碳量经过测算为1.4%。稳定的块状残余奥氏体和无碳化物贝氏体板条有利于韧性的提高,相反,马氏体应该减少或避免。
The isothermal annealing process of C-Si-Mn TRIP steel was used to obtain bainite-based high strength steel with TRIP effect. The results show that the microstructure of TBF steel is mainly composed of carbide-free bainite lath, massive retained austenite, thin-film retained austenite between laths and a small amount of tempered martensite. In continuous annealing process, the isothermal temperature of bainite has a significant effect on the microstructure and properties of TBF steel. When bainite isothermal temperature is 300 ℃, TBF steel has low yield strength (789 MPa), high tensile strength (1241 MPa ) And good elongation (16.6%). At 300 ℃, the decrease of yield strength is mainly attributed to the formation of carbide-free bainite slats of 80-190 nm. After XRD measurement, the residual austenite content of 12.04%, Paralympic carbon content was calculated as 1.4%. Stable blocky retained austenite and carbide-free bainite lath contribute to the improvement of toughness, on the contrary, martensite should be reduced or avoided.