Research of steel strips microstructure and properties after symmetric and asymmetric cold rolling

Symmetric and asymmetric cold rolling of steel strips was carried out. There were 5 passes at 1700 mill to obtain 0.5 mm strip thickness from 2 mm initial strip thickness. The asymmetric rolling technique—with different roll radii and equal circumferential speeds of rolls—was applied on an industrial mill for the first time: rolls have different diameters and equal circumferential speeds. The research on the microstructure and mechanical properties was carried out after each of the rolling types. It was established that steel's strength is 11–13% higher after asymmetric rolling compared to symmetric one. High shear strains were revealed after asymmetric rolling. Computer simulation of experimental rolling was done using DEFORM finite element method (FEM) software in two-dimensional mode. The stress state of the strips was examined as a result of computer simulation. The computer simulation results showed that the absolute maximum shear stress at the exit of the deformation zone value is 1.6 times higher at asymmetric rolling than at symmetric one.