摘要
进行了Ti和Ti+Nb超低碳BH钢的铁素体区热轧以及冷轧、退火实验。结果表明,两种超低碳BH钢铁素体区热轧后纵截面晶粒均明显拉长成纤维状,接近冷轧态组织,只有少量等轴晶粒。经后续冷轧和高温盐浴连续退火后均发生了再结晶,形成了等轴铁素体晶粒。两种超低碳BH钢的热轧、冷轧和退火织构均在{111}<121>和{111}<112>处具有峰值,Ti-ULC-BH钢退火板纤维织构组分在{111}<112>处强度最大为16,Ti+Nb-ULC-BH钢退火板纤维织构组分在{111}<121>处强度最大为11,这与反映深冲性能的r值高低相一致。EBSD微观取向分析结果表明,两种超低碳BH钢退火板的铁素体晶粒间微观取向主要是以大角度晶界(>15°)为主,晶界取向差均主要分布在25°～60°;Ti-ULC-BH钢退火板织构中<111>织构占到了75.7%;Ti+Nb-ULC-BH钢退火板织构中<111>织构占60.5%。
Ti and Ti＋Nb ultra-low carbon bake hardening steels hot-rolled in the ferrite region was studied by following cold-rolling and annealing.The results show that the ferrite grains on the longitudinal plane of the hot-rolled steel sheets for two ULC-BH steels have been elongated into fiber-like microstructures.The hot-rolled microstructure is closed to the cold-rolled microstructure with a small number of equiaxed ferrite grains.Through subsequent cold rolling and salt bath continuous annealing processes,all the cold-rolled microstructures are recrystallized into equiaxed ferrite grains.The intensity peak values of hot-rolled texture,cold-rolled texture and continuously annealed texture all exist at {111}121 and {111}112.The maximum intensity of fiber texture at {111}112 for Ti-ULC-BH continuously annealed steel is 16,while for Ti＋Nb-ULC-BH annealed steel,the maximum intensity of fiber texture at {111}121 is 11.It corresponds to the r values which can reflect the deep drawability of ultra-low carbon bake hardening steel sheet hot-rolled in the ferrite region.It has been shown from the results of EBSD micro-orientation analysis that the orientations among neighboring ferrite grains are mainly high angle grain boundaries（15°） for two ULC-BH steels.The misorientation distribution for the two ULC-BH steels is in the range of 25°～60°.The volume fraction of 111 fiber texture for Ti-ULC-BH annealed steel sheet is 75.7%,while for the Ti＋Nb-ULC-BH annealed steel sheet,the volume fraction of 111 fiber texture is 60.5%.
出处
《热加工工艺》
CSCD
北大核心
2012年第10期31-34,38,共5页
Hot Working Technology
基金
“十一五”国家科技支撑计划项目(2006BAE03A13)
关键词
超低碳
烘烤硬化钢
铁素体区轧制
微观取向
ultra-low carbon
bake hardening steel
ferrite region rolling
micro-orientation
