低Al含量Fe-C-Si-Mn轻量化高强钢的微观组织与力学性能研究

Microstructure and mechanical properties of lightweight high strength low-Al Fe-C-Si-Mn steel

从工业化应用角度出发,本文设计了两种不同Al含量(分别为1%和2%)的Fe-C-Si-Mn轻量化高强钢,研究了奥氏体化温度对钢微观组织和力学性能的影响。结果表明,添加一定量Al元素后,钢密度相较于普通碳素钢有所降低。Al含量为1.0%时,钢经淬火-回火处理后组织为回火马氏体板条,当奥氏体化温度为1050℃时,钢的综合力学性能最佳,其性能较锻态钢有显著提升。而当Al含量为2.0%时,不同奥氏体化温度热处理后钢组织为回火马氏体板条+铁素体,力学性能较锻压态无明显改善,表明2.0%Al钢不宜进行淬火-回火热处理。

From an industrial application perspective,two light-weight high-strength steels with 1.0%and 2.0%Al,respectively,were designed,and the effects of austenitizing temperature and Al content on the microstructure and mechanical properties were investigated.The results indicate that by adding a certain amount of Al element,the density of steel is reduced compared to ordinary carbon steel.After quenching-tempering heat treatment,the microstructure of 1.0%Al-bearing steel is tempered martensite.The optimal comprehensive mechanical properties of the steel can be obtained by austenitizing at 1050℃,resulting in a significant performance improvement compared to the as-forged steel.After heat treatment at various austenitizing temperatures,the microstructure of 2.0%Al-bearing steel consistently comprises tempered martensite and ferrite.Its mechanical properties show no significant im-provement compared with those of the forged state,indicating that 2.0%Al-bearing steel is not sui-table for quenching-tempering heat treatment.