摘要 The effect of the strain hardening exponent (n) of a material on the changes in shape, strain inhomogeneity, and contact pressure was investigated during wire flat rolling to understand its effect on the deformation behavior of a flat-rolled wire and to determine the optimal working conditions with materials. The deformation behaviors of wires with various n values were systematically compared using finite element method. The shape of the deformed wire was found to depend on the n value of the material. Both the contact width and lateral spreading of the wire decrease with increasing n, resulting in a large reduction in area with the n value. The strain homogeneity of the wire increases with the n value of the wire. The improvement in the strain homogeneity with the n value is attributable to two factors: a lower strain concentration in the central region and a higher overall elongation as n increases. In addition, the average effective strain of the wire cross section decreases with the n value of a material during wire flat rolling. The contact pressure distribution on the surface of the wire differs significantly depending on the n value. In materials with a low n value, the contact pressure exhibits a higher value at the entry and edge zones of the contact surface. By contrast, materials with high n values exhibit a higher contact pressure at the exit zone. This behavior can be explained by the strain hardening behavior of the material during wire flat rolling.
Abstract：The effect of the strain hardening exponent (n) of a material on the changes in shape, strain inhomogeneity, and contact pressure was investigated during wire flat rolling to understand its effect on the deformation behavior of a flat-rolled wire and to determine the optimal working conditions with materials. The deformation behaviors of wires with various n values were systematically compared using finite element method. The shape of the deformed wire was found to depend on the n value of the material. Both the contact width and lateral spreading of the wire decrease with increasing n, resulting in a large reduction in area with the n value. The strain homogeneity of the wire increases with the n value of the wire. The improvement in the strain homogeneity with the n value is attributable to two factors: a lower strain concentration in the central region and a higher overall elongation as n increases. In addition, the average effective strain of the wire cross section decreases with the n value of a material during wire flat rolling. The contact pressure distribution on the surface of the wire differs significantly depending on the n value. In materials with a low n value, the contact pressure exhibits a higher value at the entry and edge zones of the contact surface. By contrast, materials with high n values exhibit a higher contact pressure at the exit zone. This behavior can be explained by the strain hardening behavior of the material during wire flat rolling.
Joong-Ki Hwang. Strain hardening rate dependency of deformation shape, strain distribution, and contact pressure during wire flat rolling[J]. Journal of Iron and Steel Research International, 2023, 30(03): 475-486.
2023, Vol. 30 
