Effects of V-Nb Micro-alloying on the Microstructure and Property of Non-quenched and Tempered Steel
The effect of V,V-Nbmicroalloying on structure and properties of non-quenched and tempered steel were examined in this study.The microstructures of the V-Nbmicroalloyed steel and the V alloyed steel were characterized by the transmission electron microscopy (TEM).The mechanical properties and the impact toughness were measured by uniaxial tensile test and the impact toughness tester.It was found that the composite addition of Nb and V could result in an increasing of the intragranular ferrite volume fraction and its much more uniform distribution,the refinement of the microstructure of the ferrite and pearlite comparing with that of the single V-microalloyed steel.Also interestingly,with the addition of Nb,the lamellar structure of the pearlite becomes bending,broken and granular,which reduces the length-width ratio greatly.The measurements of the mechanical properties and the impact toughness indicates that the composite addition of Nb and V could result in a 3 times improvement of the impact toughness without losing the tensile strength.Based on the analysis of the relationship between microstructure and properties,it is proposed that the improved toughness with the composite addition of Nb and V in the non-quenched and tempered steels could be ascribed to the refinement of the pearlite microstructure due to the precipitation induced pining on the austenite growth during hot forging process and the formation of the intragranular ferrite during cooling process,which provides a feasible way to the industrial production of the non-quenched and tempered steels with high impact toughness.
non-quenched and tempered steel composite microalloying grain refinement high toughness
BAO Yaozong CHEN Shaohui ZHENG Lihui TAN Li LIU Pan XU Haifeng CAO Wenquan DONG Han
Central Iron & Steel Research Institute, Beijing 100081, China Sha Gang Group Huai Gang Special Steel Co.,Ltd, Huaian 223002, Jiangsu, China Great Wall Motor Company Limited, Baoding 071000, Hebei, China Central Iron & Steel Research Institute, Beijing 100081, China; School of Materials Science and Engi
国际会议
成都
英文
694-697
2016-11-16（万方平台首次上网日期，不代表论文的发表时间）