Behaviour of Longitudinal Cracks on Slab Surfaces in V-H Rolling Processes

摘要

The behaviour of longitudinal cracks on slab surfaces in multi-pass vertical-horizontal rolling processes was simulated by the finite element method (FEM). The influence of friction coefficients and fillet radii of grooved edge rolls on the closure and growth of cracks were analysed in regard to crack shape and crack length elongation ratio. The results indicate that the crack width increases both with increasing friction coefficient and with increasing fillet radii of the grooved edger rolls; the crack length increases as the fillet radii increase in Vi and Hi passes, and decreases as the fillet radii increase in V_2 approx H_3 rolling. Moreover, the cracks become longer under a higher friction coefficient. Experiments of the behaviour of longitudinal cracks on slab surfaces in multi-pass V-H rolling processes were investigated taking lead as model material for the hot rolling of steel. The calculated results showed similar deformation variations compared to the experimental ones.