Aspectos do encruamento de metais previamente deformados a frio

Abstract

The effects of strain path changes on the mechanical behavior of predrawn bars were analyzed. Four metals were used in the experiments: AISI 304 stainless steel, AISI 420 stainless steel,copper and one aluminum alloy. Four or nine operation conditions were considered in the work, depending on the approach adopted. The deformation in the drawing process was studied through the visioplasticity and the stress-strain curves superposition techniques, allowing the evaluation of the strain distribution on the cross section of the samples and the investigation of the relationship between the redundant deformation factor and the parameter. The tensile behaviorof the drawn bars was also studied, and the influence of the drawing parameters and the structural features of the metals was analyzed. The drawn sample was also considered as composed by four concentric layers, and the specimens of each layer were subjected to tension tests. Therefore, the work hardening profile of the materials was evaluated, through the examination of the flow curves and the mechanical properties distribution along the radius of the sample. The comparative analysis of strength and ductility results of the full section and the drawn bars layerswith the purely tensioned metals data was performed, allowing the analysis of the prediction of the work hardening of the predrawn specimens through the annealed sample response. The substructural aspects of the central and the superficial layers of the metals were analyzed. In general, the results showed the effects of the strain path on the drawn bars tensile behavior, and also the influence of the strain path change magnitude, bringing forth some similarities between the materials used in the work.