In sequential of multistep forming operations, the material which has already undergone permanent deformation is expected to behave differently in each stage of deformation than the as-received material. The effect of such changes on (i) the materials ability to distribute strain uniformly, (ii) the strain limits, and (iii) the residual ductility have been studied for a mild steel and for a dual-phase steel. Steels of both materials were balanced biaxially prestrained for different levels of strains and then uniaxial properties and forming limits were determined. Both materials were found to suffer a rapid loss of uniform strain and residual ductility. Forming limits of both steels were found to decrease with prestrain except for stretch-type deformation in the sheet plane. The prestrain produces strain softening1 in mild steel; whereas, this is observed only in 90 deg to the rolling direction in dual-phase steel. In balanced biaxially prestrained (5 percent major and minor strain) dual-phase steel, during hemispherical punch stretching, necking mostly occurs in the rolling direction as opposed to the transverse direction in the as-received material. Such effect can be explained in terms of loss of stability which is observed in uniaxial property of this material.

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