Abstract：In the casting process of calcium-treated steel, alumina carbon stopper head and spinel carbon stopper head are easily corroded by the free [Ca] in molten steel. Using magnesia carbon refractory can reduce the corrosion of [Ca] and increase the service life of the stopper head. The influence of SiC powder amount on properties of magnesia carbon stopper head was studied, the composite structure of magnesia carbon stopper head was designed and the thermal shock resistance of the product was tested. The conventional properties and steel mill test results of magnesia carbon stopper head and spinel carbon stopper head were compared. Research indicates that, with the increase of SiC powder amount, the strength of materials at room temperature and high temperature are increased, while the thermal expansion coefficient is decreased. The composite structure improves the physical matching between the stopper head and the stopper body and improves stability of stopper head. The specific performance is that magnesia carbon stopper head test sample has no cracks on the surface and inside after thermal shock cycles at 1 100 ℃ for 3 times. Although the mechanical strength of magnesia carbon stopper head is slightly weaker than spinel carbon stopper head, the performance of casting calcium-treated steel for the former is better. The analysis finds that the direct cause of spinel carbon stopper head damage is the corrosion of free [Ca].
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2023, Vol. 33 
