Investigation On Internal Cracks Of Bayi Steel's Continuous Casting Billet

This paper analyzed the effects of steel compositions, the operating Parade tars and equipments on the deformation and the fracture caused by internal cracks of the products made by the LD-steelmaking plant of Xinjiang Bayi iron and steel company. We adopted the methods of the sulphur print, the low multiple inspection and SEM analysis to research of the reasons that produced and increased the cracks of the continuous casting billet. And then, we separately measured the strand temperature from the meniscus to straightening point and the molten steel temperature in the tundish by using the advanced on-line measuring technology and the continuously measuring technologyIt's shown that the factors which caused central cracks inside the Q235 casting billet at Bayi No 1 square billet are: continuous caster not aiming at the rollers of secondary cooling zone; the higher sulfur content of steel and the lower ratio of Mn/S; the higher superheated metal at tapping the higher speed of pulling the casting billet and the overcooling of the secondary cooling zone is during CCM runsTherefore, controlling and adjusting the ratio of Mn/S, casting temperature, cooling degree and roller gap were the efficient methods to prevent and eliminate internal cracks of the billet of Bayi Steel's continuous casting billet...