Numerical simulation of the deformation risk in thin slab continuous casting process with liquid core reduction

The application of liquid core reduction (LCR) technology in thin slab continuous casting can refine the internal microstructure of slab and improve production efficiency. In order to avoid the crack risk caused by large deformation during LCR process, and to minimize the thickness of the slab in bending segments, it is essential to determine the maximum theoretical reduction amount and corresponding reduction scheme for LCR process. With the SPA-H weathering steel as specific research steel grade, the distribution of temperature and deformation fields of the slab with LCR process were analyzed based on a three-dimensional (3D) thermal-mechanical finite element model. The high-temperature tensile test was designed to determine the critical strain of corner crack propagation and intermediate crack initiation with various strain rates and temperature, and the prediction model of the critical strain for two typical cracks, combining the effects of strain rate and temperature, were proposed by incorporating the Zener-Hollomon parameter. The crack risk with different LCR schemes were calculated based on the crack risk prediction model, and the maximum theoretical reduction amount for SPA-H slab with a transverse section of 145mm × 1600 mm is 41.8 mm, corresponding reduction amounts of segment 0 to segment 4 are 15.8mm, 7.3mm, 6.5mm, 6.4mm and 5.8mm, respectively.