Abstract
The surface roughness of cold rolled steel sheet is an important quality because it affects the press formability and image clarity after coating of steel sheet. The surface roughness is obtained by imprinting a roll surface onto a steel sheet surface in temper rolling process with or without lubricant. In the recent paper, we demonstrated that the surface imprinting is greatly affected by dull-finishing methods and lubricants using laboratory scale 4-high rolling mills. Various numerical analyses of surface imprinting have been performed, however imprinting mechanism has not been clarified. Because the roll surface textures depend on roll surface finishing methods and the deformation behaviors of rolled material are complicated.
In this paper, sheet coining analysis by three dimensional elastic–plastic finite element method have been conducted to clarify the effects of roll surface texture and lubrication state on surface imprinting. Then, the results are compared with those obtained by temper rolling experiments, as follows: The tool of modeling the electric-discharged dull roll results in a better surface imprinting than the tool of modeling the shot dull roll. A small friction coefficient between the tool and the steel are results in better surface imprinting. This indicate that agree with the soluble lubricant with small friction coefficient is better surface imprinting than dry condition in the rolling experiment. Those results from the 3D FEM analysis agree with those obtain in the rolling experiment.
