DEVELOPMENT OF AN EARING MODEL WITH CONSIDERATION FOR THE CRYSTALLOGRAPHIC TEXTURE OF SHEET METAL DURING AXISYMMETRIC DRAWING

A calculation model is developed for earing during cylindrical drawing of metallic materials, which is based on the phenomenological criterion of plasticity and takes into account the crystallographic texture of the material. The model was verified by comparing the calculated earing defects with those observed in drawing tests on an aluminum preform. Further simulation shows that deformation orientations ({112}<111>, {110}<112>, {123}<634>, and {100}<011>) lead to earing at an angle of 45° to the rolling direction, while recrystallization orientations ({100}<001> and {110}<001>) lead to earing in the rolling and transverse directions. Crystallographic orientation {110}<001> gives maximum earing, while orientation {123}<634> leads to minimum one. In all the cases, the contribution of plastic anisotropy and yield stress anisotropy to earing is almost the same, with a slight predominance of the influence of the yield strength anisotropy. The earing pattern changes in materials with a two-component ({112}<111> + {100}<001) texture: as the proportion of the {112}<111> orientation grows, earing defects in the rolling and transverse directions are reduced, while they form at an angle of 45° to the rolling direction. Considering such influence, the minimum earing coefficient is achieved at 55-60% of the {112}<111> component.