Simulation Of Steel Flow Heat Transfer And Stress For Incoloy800 Superalloy Slab Vertical Continuous Casting Process

Incoloy800 super alloy known as heat resistant alloy or super alloy, as it has a high temperature strength, oxidation and corrosion resistance, mechanical properties, making the high-temperature alloys occupies a pivotal position in the power, petrochemical, transportation, aviation and aerospace industry, thus it has became an indispensable material between building national defense and national industrialization. In continuous casting process, the super alloy has easily leaded to crack due to its special mechanical properties. In this paper, the author established a super alloy slab continuous casting mode based on the high temperature mechanical properties of the material, considering the steel flow, heat transfer and stress field, applying electromagnetic stirring for continuous casting process, the solidification process and stress distribution of super alloy slab have been simulated.The development and application of super alloy, the application of the electromagnetic stirrer in continuous casting process and the continuous casting technology are reviewed. Also the crack generation mechanism and preventive measures are analyzed, at last, several brief analysis about the formation of thermal cracking and the current theory of judgment are made. According to super alloy high temperature mechanical properties, for a high-temperature alloy casting solidification process, three-dimensional mathematical model of heat transfer and elastic-plastic model is established. Based on ANSYS commercial software, coupled flow field with temperature field and stress field, then electromagnetic stirring for continuous casting process is considered. Thermal cracking theory coupled with user program is used to simulate solidification and stress. The effects of some different parameters on the distribution of temperature and thermal cracking are discussed.The results showed that:(1) The distribution of vortex flow field will accelerate the solidification at the center of the wide face. The higher the temperature is, the thinner the solidified shell will be. As a result, the billet is easily damaged by the relatively large superheat. The casting speed plays more impacts on the temperature field than the superheat and heat flux. The greater the casting speed is, the thinner the solidified shell thickness is. (2) The distribution of stress-strain field is similar to the temperature field, and the crack sensitive locations are located near the corner of slab. As the equivalent stress gradient is caused by temperature gradient, it easily leads to surface longitudinal cracks at the wide face of the slabs. (3) The stress and strain at the corner and wide face of slab have a significant improvement with EMS, with a reasonable stirring intensity and decreasing stirring position could reduce the probability of cracks at the corner and wide face of slab. (4) Heat flux have a great influence on the hot cracks near the slab's corner, the larger the heat flux is, the larger the hot tearing indicator is at the corner of slab. The larger casting speed is, the easier hot cracks will happen.