Hydrogen diffusion in slab for stacking slowcooling
WANG Weihua1,2,LI Zhanjun1,2,CHU Rensheng1,2,CHEN Xia1,2
(1. Research Institute of Technology, Shougang Group Co., Ltd.， Beijing 100043,China;
2. Beijing Key Laboratory of Green Recyclable Process for Iron and Steel Production Technology, Beijing 100043, China)
Abstract： In order to investigate the removal effect of hydrogen element in the slab slow cooling process of a medium plate plant, and finally to prevent the occurrence of white spots and improve the qualified rate of flaw detection, eight slabs with 250 mm×1 600 mm cross section were selected as the research objects according to the Fick′s second law unsteady mass transfer equation, and a twodimensional hydrogen diffusion model for the stacking slowcooling process of medium and heavy slabs was established using the software ABAQUS. The calculation results show that the stacking slowcooling of continuous casting slab is a powerful dehydrogenation measure by utilizing the dehydrogenation peak effect during phase transformation. After 24 to 48 h of the stacking cooling, the dehydrogenation rate of offline continuous casting slab can reach over 84.6% when the stacking slowcooling conditions are reasonable. If the average w (H)= 0.000 1% is taken as the criterion to prevent the occurrence of "white spots", the hydrogen content in the slab can be considered to be in the safe range after 24 h of stacking cooling. If the maximum w (H)= 0.000 1% is taken as the criterion to prevent the occurrence of "white spots", the w (H) in the slab is considered to be in the safe range after 36 h of stacking.
2019, Vol. 54 
