对一种低碳Si-Mo合金钢在连续空冷条件下得到的粒状贝氏体,经不同回火温度处理后的显微组织与机械性能作了研究。结果表明:粒状贝氏体中的小岛为马氏体和残留奥氏体的混合组织,残留奥氏体的含量约为10%;由于回火过程中,小岛内的大量残留奥氏体发生了转变,使韧性相A_R明显减少,所以粒状贝氏体组织有回火脆倾向;空冷粒状贝氏体经适当的低温回火处理后,可得到良好的强韧性配合。 The microstructure and mechanical properties of granular low-carbon Si-Mo alloyed steel obtained under continuous air cooling conditions were studied by different tempering temperature. The results show that the islets in the granular bainite are a mixture of martensite and retained austenite, and the content of retained austenite is about 10%. Due to the tempering process, a large amount of retained austenite A change occurred, the toughness phase A_R significantly reduced, so granular bainite temper brittle tend to; air-cooled granular bainite after appropriate low-temperature tempering, can be a good combination of toughness.