高强建筑用超细晶粒钢的开发研究

Development of Ultrafine-Grained Steel for High Strength Construction

对建筑用T8钢进行了等径弯曲通道变形(ECAP)处理,采用扫描电子显微镜、透射电子显微镜、显微硬度等手段分析了不同道次冷变形处理后T8钢的显微形貌和力学性能变化,分析了T8钢组织细化和性能强化机理。结果表明,原始态T8钢由尺寸不均、形状不规则的渗碳体颗粒组成,经过多道次冷变形后,渗碳体颗粒尺寸变小,分布更加均匀;随着冷变形道次的增加,T8钢的显微硬度呈现增加升高的趋势,且都高于原始态T8钢;随着冷变形道次的增加,建筑用T8钢的屈服强度和抗拉强度逐渐升高,而断后伸长率有所降低,冷变形后T8钢的强度都高于原始态,而塑性略低于原始态。

T8 steel was conducted by equal channel angular distortion （ECAP） treatment, the changes of microstructure and mechanical properties of the T8 steel were studied by scanning electron microscopy, transmission electron microscopy and micro hardness, the mechanism of microstructure refinement and performance enhancement of the T8 steel were analyzed. The results show that the original T8 steel is composed of irregular size and irregular shape cementite particles, after cold deformation, the cementite particle size distribution is more uniform. With the increase of cold deformation, the microhardness of the T8 steel shows an increasing trend, and both of them are higher than that of the original T8 steel. With the increase of cold deformation, the yield strength and tensile strength of the T8 steel increase gradually, while the elongation decreases. The strength of the T8 steel after cold deformation is higher than that of the original state, while the plastic is slightly lower than the original state.