Effect of solidification path and volume shrinkage on cracking susceptibility at different cooling rates  

作　　者：Wei-an Wang Yong-kun Yang Guo-xing Qiu Jian-li Wang Guo-hua Wang Xiao-ming Li 

机构地区：[1]School of Metallurgical Engineering,Xi’an University of Architecture and Technology,Xi’an,710055,Shaanxi,China

出　　处：《Journal of Iron and Steel Research International》2025年第2期418-425,共8页钢铁研究学报(英文版)

基　　金：supported by the National Natural Science Foundation of China(No.52074207 and No.52304358);the Natural Science Basic Research Program of Shaanxi(No.2023-JC-QN-0376);Shaanxi Province Innovation Ability Support Plan(No.2023-CX-TD-53).

摘　　要：Understanding the solidification characteristics and microsegregation under varying cooling rates is essential to comprehend the formation of center cracks in large section round billets.P91 high-alloy steel was taken as the research object.The peritectic solidification process,steel solidification shrinkage and microsegregation of solute elements at different cooling rates were studied and revealed by high-temperature confocal scanning laser microscopy,Thermo-Calc thermodynamic software,hybrid laser microscopy and electron probe microanalysis.The results showed that as the cooling rate increased from 10 to 100℃/min,the percentage ofδ-Fe involved in peritectic reaction decreased from 98.6%to 36.4%,the surface roughness of the sample decreased from 8.59 to 5.14μm,and the volume shrinkage decreased from 5.92%to 2.18%.Moreover,the solidification path enters the crack sensitivity area at lower cooling rates(10 and 50℃/min),while the solidification path is far from the crack susceptibility area at higher cooling rate(100℃/min).With the increase in cooling rate,the segregation deviation parameters of the elements V,C,Mo and Cr were decreased by 9.52%,22.2%,29.4%and 70.5%,respectively.Solidification path changed and microsegregation weakened by adjusting cooling mode might be a way to improve central crack.

关 键 词：In situ observation P91 high-alloy steel Central crack Large section continuous casting round billet Surface roughness Peritectic solidification 

分 类 号：TG1[金属学及工艺—金属学]