微合金化高强韧钢组织控制、纳米结构及应用研究

Through compound modification treatment and microstructure control the microstructure of micro-alloy steel was fined, the fine and multi-phase structural steel was obtained. The studied steel has good integrative mechanical properties and reaches the level of high strength and toughness steel. The structure of studied steel was observed by using X-ray and high-resolution electron microscope and the size of carbide particle and phase structure are determined. The nanostructure of studied steel was observed on atom scale by using analytical electron microscope and high-resolution electron microscope. It showed that bainitic ferrite was composed of plate, subplate and subunit and their sizes were determined. Between the bainitic ferrite and retained austenite there were K-S and N-W orientation relationships. The interfacial structure of bainitic ferrite and retained austenite was observed and a series of structural steps were found. It was found that in the bainite phase transformation area existed twins after isothermal disposal and air-cooling and each twin is 2~10nm in size. In addition, the microstructure control methods and the relationship between the methods and strengthen and toughness mechanism was discussed. At present the studied steel were in the phase of elementary application experiments in factory.

采用复合变质剂和组织控制，使微合金钢得到综合强韧化，奥氏体晶粒明显减小，显微组织细化，获得微细多相组织钢。通过高分辨电镜和冷场发射枪高分辨电镜在纳米或原子尺度层次对研制钢的纳米结构（基本单元）与性能特性关系以及强韧化进行定量研究。对微量元睾虲、N、B等的赋存状态和分布进行定量测定。研制钢的强度比同类钢提高一倍以上。