せん断帯分布形態に基づく板圧延における反り発生機構

抄録

This study focuses on the warpage behavior in strip rolling, particularly on the formation of shear bands, that potentially give reasonable account of the warpage behavior. Rolling experiments and rigid-plastic finite element analyses were conducted to clarify the effect of each factor on the equipment one and the material one to the control of warpage, yielding the following results:

(1) As the experimental and analytical conditions, two asymmetrical rolling factors adopted together, strip entering the roll-bite with an angle ±8°, and a single roll driven condition. As a result, direction of warpage is determined by the shape factor Γ (contact arc length / thickness). Γ ≤ 1.6; direction of warpage is mainly influenced by the strip's inclination. Γ ≥ 1.9; direction of warpage is mainly influenced by the driving conditions. The strip's inclination significantly affects the shear stress distribution and the form of shear bands, especially when Γ ≤ 1.6. On the other hand, the driving conditions of rolls have a greater influence when Γ ≥ 1.9.

(2) To investigate the effect of work hardening index (n value) of the rolled material on the warpage behavior, single driven rolling experiments and analyses were conducted using materials with different n values. N value of the rolled material affects the concentration of shear bands, which in turn influences the warpage behavior. A larger n value, i.e. great work hardening material that tends to broad the strain concentration, results in lower concentration of shear bands, and smaller warpage curvature.