Research On Flow And Temperature Field And The Formation Mechanism Of Oblique Cracks During The TRC Strip

Twin-roll strip casting technology is one of the most revolutionary frontier technology.It combines with the rapid solidification technology and the thermal forming technology,with a short process,high efficiency,energy saving and environmental protection,and it is potential to improve the quality of casting strip.However,the twin-roll strip casting process is a highly coupled complicated problem,involving the flow field,temperature field and solidification,the process parameters are difficult to control,subtle change of process parameters are likely to lead to serious defect of casting strip.Hence,for the oblique cracks in the strip during the twin-roll strip casting process,the numerical simulation is carried out,analyzed the formation mechanism of the oblique cracks.This paper developed a numerical model coupled with flow field,temperature field and solidification.The heat transfer law obtained by the interface heat transfer model of twin-roll strip casting weld pool based on the Kiss point position is added as the heat transfer boundary condition,which makes the convective heat transfer of the weld pool with the casting rollers more realistic.According to the numerical simulation,the flow field characteristic of the weld pool is analyzed,and the flow field distribution of the weld pool is obtained by the flow chart.At the same time,the influence of different process parameters(casting speed,casting temperature and heat transfer coefficient)on the flow field and temperature field and the Kiss point position in the weld pool were studied,and got the casting process parameters range.Meanwhile,due to the irregularity of the weld pool flow field,the Kiss curve is distributed during the process of twin-roll strip casting process.So,based on the solidified Kiss curve,the initiation and expansion mechanism of the strip oblique cracks was analyzed,and obtained the causes and preventive measures.Taking use of the casting process parameters range,the experimental scheme of casting Q235 steel strip was designed independently by using the twin-roll strip caster in lab,the experiment has proved the feasibility of twin-roll casting Q235 steel strip and the best processing parameters has also been confirmed.This paper provides a valuable research result for the future research and the actualproduction of the twin-roll strip caster,and provides reference and guiding significance for the future research work.