【摘要】 研究了等温温度对低碳低合金奥氏体-贝氏体铸钢组织和力学性能的影响。结果表明,在280℃时,组织由细针状下贝氏体、残余奥氏体和少量马氏体组成;在300℃时,得到完全由贝氏体铁素体和富碳残余奥氏体组成的奥贝组织,无碳化物相,硬度稍有下降,冲击韧度大幅度提高,此时综合性能最佳;在320℃贝氏体逐渐分成枝叉状,360℃时,形成带有羽毛状的上贝氏体组织,冲击韧度进一步提高,但硬度较低,材料的综合性能较差。更多还原

【Abstract】 The influence of austempering temperature on the microstructure and mechanical properties of low-alloy and low carbon (LALC) austenitic-bainitic cast steel was investigated. The results show that the microstructure consists of fine acicular bainite, retained austenite and few martensite at 280 ℃, and a pure ausferrite structure consists of typical bainitic ferrite and carbon-rich retained austenite without carbide at 300 ℃.The hardness of the steel decreases slightly and impact toughness increases sharply with increase of the isothermal temperature. The optimal mechanical properties can be obtained at 300 ℃. The morphology of bainite gradually changes from fork shape to feather upper bainite when temperature increases from 320 ℃ to 360 ℃, and the toughness further increases, but the hardness decreases, the combination of properties is poor.更多还原