Q345B低碳高强度钢的高温塑性  

Hot ductility of low carbon high strength steel Q345B

作　　者：刘伟建[1] 王春苗[2] 余璐[1] 祁永峰[1] 

机构地区：[1]北京科技大学钢铁冶金新技术国家重点实验室,北京100083 [2]河北联合大学轻工学院,河北唐山063000

出　　处：《有色金属科学与工程》2015年第3期61-66,87,共7页Nonferrous Metals Science and Engineering

基　　金：国家自然科学基金资助项目(51274032)

摘　　要：使用Gleeble3500热/力模拟机对Q345B低碳高强度钢的高温塑性进行了测定.通过透射电镜、扫描电镜及金相显微镜对析出物形貌、断口形貌和断口组织进行了观察,分析了Q345B钢的断裂机理.结果表明,在1 350-650℃范围内,明显存在3个区间,第I区温度范围为熔点到1 307℃,断裂形式是由S、O等元素偏析引起的沿晶断裂;第II区温度范围为1 307-920℃,由于动态再结晶的发生,断裂形式为穿晶塑性断裂;第III区温度范围为920-650℃,断裂形式是由析出物钉扎晶界以及先共析铁素体析出引起的沿晶断裂.分析结论可为连铸生产提供理论依据.The hot ductility of low carbon high strength Q345 B was determined using thermal analogue machine Gleeble-3500. The precipitates, fracture surface and microstructure of tested samples were observed by transmission electron microscopy（TEM）, scanning electron microscopy（SEM）, and optical microscopy（OM）.The fracture mechanisms were analyzed. The results show that there are three regions between 1 350 ℃ and650 ℃. The temperature range of region I is from melting point to 1 307 ℃. The fracture mode is intergranular fracture caused by the segregation of S and O. The temperature range of region II is from 1 307 ℃ to 920 ℃.The occurrence of dynamic recrystallization leads to the intragranular fracture. The temperature range of region III is from 920 ℃ to 650 ℃. The fracture mode is intergranular fracture caused by the pinning effect of precipitates and the precipitation of pro-eutectoid ferrite along the austenite grain boundaries. The results provide the theoretical basis for the production of continuous casting.

关 键 词：高温塑性 析出物 沿晶断裂 穿晶断裂 先共析铁素体 

分 类 号：TF142.12[冶金工程—冶金物理化学] TF701