Investigation on non-uniform friction behaviors of slab during continuous casting based on an inverse algorithm

The non-uniform friction and lubrication are key factors that affect the slab quality during continuous casting. In order to present the complicated friction behavior of slab in the mold, a friction calculation model was built based on a full-scale heat transfer model. An inverse algorithm was applied to calculate the real heat flux by measuring temperatures from thermocouples buried in various locations of the mold. ANSYS software was used to solve the finite-element equations. The results showed that the friction state of the slab surface progressed from a liquid friction zone to a mixed friction zone, and then to a solid friction zone from the meniscus. In the casting direction, the liquid frictional stress gradually increased, which was between 0 and 1 kPa; the mixed frictional stress rapidly increased from 1 to 15 kPa; the solid frictional stress increased linearly, reaching 28.4 kPa at the exit. The slag solidification temperature, slag crystallization temperature and superheat could affect the states of liquid, solid or mixed friction.