冷却制度对铸态先进高强度钢组织及断裂韧性的影响  

Effect of cooling process on microstructure and fracture toughness of as-cast advanced high strength steel

作　　者：吴战芳 车立达 刘振宇 李向阳 WU Zhan-fang;CHE Li-da;LIU Zhen-yu;LI Xiang-yang(School of Materials Science and Engineering,Northeastern University,Shenyang 110819,China;CISRI HIPEX Technology Co Ltd,Beijing 100081,China;China Iron&Steel Research Institute Group,Beijing 100081,China)

机构地区：[1]东北大学材料科学与工程学院,辽宁沈阳110819 [2]钢研昊普科技有限公司,北京100081 [3]中国钢研科技集团有限公司,北京100081

出　　处：《材料热处理学报》2020年第11期94-102,共9页Transactions of Materials and Heat Treatment

摘　　要：通过设计一套可开模的水冷铜模装置,研究了不同连续冷却工艺对先进高强度钢显微组织和断裂韧性的影响。为研究试验钢的裂纹形成及扩展机理,对试样中不同类型夹杂物在基体中所产生的径向应力进行了计算以及应用了一种新方法来表征试验钢裂纹的扩展行为。结果表明:试验钢在固相线附近进行缓慢冷却有利于形成更多的MnS+Al2O3复合夹杂物,与单一的Al2O3夹杂相比,复合夹杂周围的径向应力明显降低。试验钢在临界铁素体转变温度以下缓慢冷却,有助于获得更多的晶内多边形铁素体,晶内多边形铁素体对裂纹扩展有抑制作用,因此试验钢的断裂韧性更高。Effect of different continuous cooling process on microstructure and fracture toughness of advanced high strength steel was studied by designing a water-cooled copper mold device with open mold. In order to study the crack formation and propagation mechanism of the tested steel, the radial stress produced by different types of inclusions in the sample was calculated and a new method was applied to characterize the crack propagation behavior of the tested steel. The results show that the slow cooling of the tested steel near the solid line is beneficial to the formation of more MnS+Al2O3 composite inclusions, and the radial stress around the composite inclusions is obviously reduced compared with the single Al2O3inclusions. The slow cooling of the tested steel below the critical ferrite transition temperature is helpful to obtain more intragranular polygonal ferrite, which can inhibit the crack growth, so the fracture toughness of the tested steel is higher.

关 键 词：先进高强度钢(AHSS) 断裂韧性 裂纹扩展 夹杂物 铁素体 

分 类 号：TG142.3[一般工业技术—材料科学与工程]