1. Technology Center, Xinyu Iron and Steel Group Co., Ltd., Xinyu 338001, Jiangxi, China; 2. National Engineering Research Center for Continuous Casting Technology, Center Iron and Steel Research Institute, Beijing 100081, China; 3. No.1 Steelmaking Plant, Xinyu Iron and Steel Group Co., Ltd., Xinyu 338001, Jiangxi, China
Abstract：In order to study and discuss the formation mechanism of typical defects of steel plate and provide theoretical reference for the stability control of steel plate quality, the causes of typical defects such as surface crack, unqualified center flaw detection and unqualified impact performance of extra thick steel plate were studied by means of metallographic microscope and scanning electron microscope. The results show that there are two causes for surface cracks of steel plate, one is the hot embrittlement caused by high harmful elements in steel, the other is the continuous casting billet crack caused by high inclusions and spread during rolling. The reason for the unqualified inspection of steel plate is the large Nb, Ti and V carbonitride precipitated from the steel plate core, accompanied by large MgO and Al2O3 inclusions. The main reasons for the poor impact performance are the banded structure of the rolled plate, the upper martensite/austenitic structure containing carbon in the banded structure, the coarse grain and mixed grain.
2020, Vol. 39 
