Influence of the velocity mode upon alternations in ingot’s stressed state

У роботі виконано аналітичне дослідження впливу швидкісного режиму безперервного литва зливків прямокутного перетину на змінення їх пружно-деформований стан у період закінчення литва
В работе выполнено аналитическое исследование влияния скоростного режима непрерывного литья слитков прямоугольного сечения на их напряженно-деформированное состояние в период окончания разливки. Скоростной режим оказывает существенное влияние на образование дефектов в литой заготовке. Возникающие напряжения могут вызывать появление трещин и остаточных деформаций, которые ухудшают качество товарной продукции
The operation mode of continuous casting machines has a great influence on internal and surface defects of cast ingots. When a solidifying ingot passes along the process line of the continuous casting machine stress and deformations arise in its solidifying skin, it leading to cracks formation and determining the quality of production. The contemporary investigations are devoted mainly to the existing operation modes of continuous casting, in which the field of temperature distribution in ingot is stationary in the system of coordinates, linked with the crystallizer. Little attention has so far been paid to transition periods, due to difficulties of investigation and description of the processes happening during these periods. During the period of completion of continuous casting the rate of ingot’s drawing is reduced to the minimal possible value, thus ensuring trouble-free operation of continuous casting machines, the tail part of slabs being cooled down in a greater degree than the bulk of slabs. At this temperature reduction in the tail part the metal gets into the area of resilience, it greatly increasing the likeness of surface cracks formation and other defects. Due to this reason it is very important to know the ingot’s stress in its tail part. This problem can be solved by means of a mathematical model. This work presents a numerical simulation of a stressed state of a steel slab on a horizontal section of a curved continuous caster. The data, regarding temperature and stresses distribution were obtained for the surface of the bulk of continuously cast ingot and its tail part. The value of stress in ingot’s tail part can exceed its yield point, resulting in appearance of residual deformations and changes in ingot’s width. Unfavourable distribution of temperature stresses can be altered by correction of cooling in the tail part of continuously cast ingot