连铸恒温出坯电磁感应加热温度场分布与演变

连铸恒温出坯是实现连铸直轧的有效手段,为了实现圆坯恒温出坯的目的,依据感应加热原理提出在连铸坯切割段变功率感应加热恒温出坯的方法,通过数值模拟研究了恒温出坯方法的可行性。研究发现,通有交流电的感应线圈在铸坯内部产生磁场和感应电流,上述物理场主要集中在铸坯表面。此外,感应电流产生的焦耳热对连铸坯起到均温作用,均温效果随着电流频率或铸坯移速的增大先增强后减弱。研究表明,变功率感应加热实现圆坯连铸恒温出坯的方案是可行的。为了优化感应加热功率,建立了感应线圈加热功率计算模型。根据感应线圈加热功率计算模型,实现恒温出坯的加热功率与连铸坯几何尺寸、物性参数、初始温度、运动速度和线圈长度密切相关。

Distribution and evolution of temperature in constant temperature billet of continuous casting process by induction heating

Constant temperature billet of continuous casting is an effective means to realize direct rolling process. In order to achieve the purpose of constant temperature casting of round billet, a method of constant temperature casting by variable power induction heating in the cutting section of continuous casting billet was put forward according to the principle of induction heating. Feasibility study on the method was performed by numerical simulations. The numerical results showed that magnetic flux density and induced electric current are induced inside the billet by applying alternating current into coils. Magnetic flux density and induced electric current are assembled in the vicinity of the billet surface. In addition, Joule heating induced by induced electric current is beneficial to a uniform distribution of temperature in round billet. The effect of induction heating on constant temperature round billet first increases and then decreases with the increase of frequency or the velocity of billet. It indicated that a constant temperature round billet can be obtained by induction heating with a variable power. In order to optimize induction heating power, a theoretical model on induction heating power was established. According to the theoretical model, induction heating power achieving constant temperature billet is related to geometric dimensions, material properties, initial temperature and velocity of billet and the length of coils.