Trench Inner Wall Of The Solidified Shell Of Crystalline Tin And Bismuth-tin Alloy Newborn Traits Thermal Simulation Experiments

In recent years, with the raise of the requirement to surface quality of billet, the investigation, which concerns the influence of the cooling and heat transmission of the mould on surface crack and initial solidification process of molten steel, appears more significant. The numerous findings indicated that stress of solidified shell is an important reason of surface crack, and that causes the stress of solidified shell is the uneven solidification of the shell by the change of heat transmission during the initial solidification process. That is to say, the distortion process of the initial solidified shell affects surface quality of billet directly.Consequently, in this paper, the initial solidification process of molten steel is simulated by the immersion experiment with the water-cooled copper plate and the tin, and the mathematical simulation of heat transmission is calculated with finite element software ANSYS. The influence of grooves in the mould on the shape of the initial solidified shell is investigated, the condition that could even the thickness of the initial solidified shell is searched, and the possibility that reduce surface crack of billet is researched.The result of the immersion experiment and the mathematical simulation show that the distortion of the initial solidified shell is divided by grooves, and the uneven degree of the shell is diminished; with the diminishing of grooves' spacing, the thickness of the shell is made more thin and even, and the effect is better when grooves' spacing is less than 3 millimeters. Based on this principle, while the interior wall of the mould is grooved properly, heat transmission between the initial solidified shell and the mould can be improved, the thickness and thermal stress distribution of the initial solidified shell may be made more even as well, which will reduce surface crack of billet most probably.