1 State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004, Hebei, China; 2 Technical Center, Tianjin Pipe (Group) Co., Ltd., Tianjin 300301, China; 3 National Engineering Research Center for Equipment and Technology of Cold Strip Rolling, Yanshan University, Qinhuangdao 066004, Hebei, China
Effect of welding heat input on microstructure and impact toughness in CGHAZ of X100Q steel
1 State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004, Hebei, China; 2 Technical Center, Tianjin Pipe (Group) Co., Ltd., Tianjin 300301, China; 3 National Engineering Research Center for Equipment and Technology of Cold Strip Rolling, Yanshan University, Qinhuangdao 066004, Hebei, China
摘要 The coarse-grained heat-affected zones (CGHAZs) of X100Q steel were reproduced via simulating their welding thermal cycles with the varying heat input (Ej) from 10 to 55 kJ/cm in Gleeble3500 system. The microstructures were characterized, and the impact toughness was estimated from each simulated sample. The results indicate that the microstructure in each simulated CGHAZ was primarily constituted of lath-like bainite. With the decreased heat input and accordingly the lowered Ar3 (the onset temperature for this transition), the prior austenite grain and the bainitic packet/block/lath substructure were refined remarkably, and the impact toughness was enhanced due to the microstructure refinement. The bainitic packet was the microstructural unit most effectively controlling the impact properties in CGHAZ of X100Q steel, due to their close correlation with the 50% fracture appearance transition temperatures, their size equivalent to the cleavage facet and their boundaries impeding the crack propagation.
Abstract:The coarse-grained heat-affected zones (CGHAZs) of X100Q steel were reproduced via simulating their welding thermal cycles with the varying heat input (Ej) from 10 to 55 kJ/cm in Gleeble3500 system. The microstructures were characterized, and the impact toughness was estimated from each simulated sample. The results indicate that the microstructure in each simulated CGHAZ was primarily constituted of lath-like bainite. With the decreased heat input and accordingly the lowered Ar3 (the onset temperature for this transition), the prior austenite grain and the bainitic packet/block/lath substructure were refined remarkably, and the impact toughness was enhanced due to the microstructure refinement. The bainitic packet was the microstructural unit most effectively controlling the impact properties in CGHAZ of X100Q steel, due to their close correlation with the 50% fracture appearance transition temperatures, their size equivalent to the cleavage facet and their boundaries impeding the crack propagation.
Hui-bin Wang,Fei-long Wang,Gen-hao Shi, et al. Effect of welding heat input on microstructure and impact toughness in CGHAZ of X100Q steel[J]. Journal of Iron and Steel Research International, 2019, 26(6): 637-646.