The tendency and direction of crack formation in the round ingot is closely dependent on the casting speed in semi-continuous casting.The coupled thermal-stress finite element model for semi-continuous casting 7050 aluminum alloy billets has been established based on MSC.marc software

in which the hexahedral element type with eight nodes is adopted and the influence of liquid-solid transformation and solidification latent heat are considered.The effects of different casting speeds on temperature field and stress field in semi-continuous casting have been simulated with determining the complicated boundary confined condition.The simulated results indicate that the decrease of casting speed can reduce the gradient of cooling rate between inner and outer of the ingot to decrease the tensile stress in ingot surface

which is helpful for promoting the formation of the ingot and relieving the tendency of crack formation.