Study On Vibration Casting Experiment And Microstructure Evolution Of Q235 Thin Strip Steel

The twin-roll strip casting technology is known as the revolutionary frontier technology of the metallurgical industry in the 21 st century due to its many advantages such as short flow,high efficiency,low pollution and energy saving,and it has been widely used in the production of non-ferrous metal plates such as aluminum alloys.However,due to the high melting point,rapid heat conduction,difficult temperature measurement,and difficulty in controlling the flow of molten steel,thin strip steel casting still has problems such as broken belts and defects in the quality of the microstructure.In order to solve the practical problems of the thin strip steel casting production at the current stage and promote its industrialization and industrialization development,we team first proposed the theory of micro-vibration casting,and independently designed and developed a ?500×350 twin-roller microstrip micro amplitude cast mill using the principle of fine-grain crystals,based on this experimental platform,the experiment of vibration casting of Q235 thin strip steel was carried out,and the microstructure evolution of the rolling strip of the cast strip was studied.The main research results are as follows:(1)Through repeated vibratory casting experiments,a relatively reasonable casting temperature,casting roll speed and vibration frequency amplitude,tundish and heating temperature of the side seal plate and other casting process parameters were determined,and a continuous thin strip steel was successfully prototyped,the macro-structure and micro-structure analysis and mechanical properties of the cast strip were also studied.It was found that the vibratory cast could refine the microstructure of the strip and increase the tensile strength and yield strength of the strip.(2)The experimental equipment was improved in view of the problems such as the low heating temperature of the side seal plate and the tundish,the disorder of the cold plate at the side of the side seal plate,the disorder of the experimental operating platform,and the high stacking temperature of the thin strip,the tundish embedded silicon carbon rod and the side seal plate built-in thermal resistance wire were heated in-line,and a two-hole splitter nozzle was used to conduct the flow in the molten pool area.A new experimental operation platform and a coiler were designed.(3)The thermo-mechanical coupling model of vibration casting was established using the deactivate and reactivate element method.The secondary development was performed through the UGRAIN sub-interface to simulate the dynamic recrystallization process in the strip rolling zone with different amplitude vibration frequencies,it is found that increasing the amplitude and vibration frequency can increase the plastic strain of the blank,refine the grain structure of the blank and reduce the rolling force.