JI Yuan1,2,MIN Yun- feng1,2,LI Peng- shan1,2,LIU Hua- song1,2,ZHANG Jia- quan1,2
1. State Key Laboratory of Advance Metallurgy, University of Science and Technology Beijing, Beijing 100083, China 2. School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083, China
Abstract：Banding phenomena is a common interior structural defect in steels which is harmful to the processability and usability of steel. The research status and understandings of the formation mechanism of banded structure in hypoeutectoid steels, the harm to mechanical properties of steels, the way to eliminate banded structure and the method of rating banded structure were systematically formulated. The analysis showed that the residual interdendritic microsegregation was the fundamental reason of banding, and reasonable controls of the alloy composition, dendrite morphology and hot working process were also the important ways to eliminate banded structure. The bigger the difference of the Ar3 transformation temperature between the interdendritic regions and the dendritic regions caused by microsegregation is, the easier banded structure formed. The cooling rate in an austenitic transformation and the austenitic grain size were the main factors to form the banded structure. Both the higher cooling rate and the bigger austenitic grain size can eliminate banded structure. The main effects of primary carbide and secondary carbide on the formation of banded structure in hypereutectoid steel were also formulated. To make the alloy elements distribute equality and reduce the amounts of micrcosegregation were the main ways to alleviate or eliminate the banded structure. There may be a long strip of inclusions in banded structures, however, the effects of the size, morphology, and distribution of inclusions in steel on the formation of banded structure were not clear. How to carry on the quantitative analysis of banded structurein steel was a key problem to be solved. In addition, the influences of heating system of slabs on the banded structure and grain size were needed to study further.
2016, Vol. 26 
