Ti＋Nb超低碳烘烤硬化钢的组织和性能研究  

Research on Microstructure and Properties of Ti+Nb Ultra-low Carbon Bake-hardening Steel

作　　者：陈继平[1] 康永林[1] 郝英敏[1] 刘光明[1,2] 

机构地区：[1]北京科技大学材料科学与工程学院,100083 [2]首钢技术研究院,北京100041

出　　处：《热加工工艺》2009年第6期13-16,共4页Hot Working Technology

基　　金：“十一五”国家科技支撑计划项目(2006BAE03A13)

摘　　要：采用光学显微镜和透射电镜分别对Ti+Nb超低碳烘烤硬化退火钢板的金相显微组织以及析出、位错和亚结构进行观察,在MTS拉伸试验机和X射线衍射仪上分别对退火钢板的力学性能、烘烤硬化值以及热轧、冷轧和退火板织构进行研究。结果表明,Ti+Nb超低碳BH钢退火板的组织主要为饼形的再结晶铁素体晶粒和一些伸长的饼形晶粒。退火板中析出物分布比较细小弥散,对位错产生钉扎,起到了强化超低碳BH钢基体的作用。退火板的铁素体晶界附近区域出现了无析出物区,有利于退火板的屈服变形在较低应力状态下开始。Ti+Nb超低碳BH钢板经连续退火后获得了较为优良的伸长率和r值以及较高的BH值和n值。有利于深冲性能的{111}织构在热轧、冷轧和退火织构组分中的含量逐渐增加,在退火织构组分中含量达到最大值16.83%。The microstructure, precipitation, dislocation and sub-structure of Ti＋Nb ultra-low carbon bake-hardening annealed steel sheets were observed using optical microscopy and transmission electron microscopy. The mechanical properties and bake-hardening value （BH） of annealed steel sheet, as well as the hot-rolled, cold-rolle.d and annealed texture were investigated using MTS tensile test machine and X-ray difffactometer respectively. The results show that the microstructure of Ti＋Nb ultra-low carbon bake hardening annealed steel sheet is mainly pancake-like recrystallized ferrite grains and a few elongated pancake grains. Fine precipitates which are dispersively distributed in the annealed steel sheets make dislocations pin. The dislocation pinning strengthens the matrix of the ultra-low carbon BH steel. Precipitation-free zone appears nearby the ferrite grain boundary, which is advantageous to the beginning of yield deformation for annealed steel sheet under relative low stress condition. Relatively superior elongation rate and r value, as well as higher BH value and n value of Ti ＋Nb ultra-low carbon bake-hardening steel sheet are obtained after continuous annealing. The { 111 } textures which are favorable to the deep-drawing performance increase gradually in the content of hot-rolled, cold-rolled and annealed texture component, it achieves the maximum of 16.83%.

关 键 词：超低碳 烘烤硬化 组织性能 织构 

分 类 号：TG113[金属学及工艺—物理冶金]