Local Strain Hardening and Non-Uniformity of Plastic Strain of Tinplate

During evaluation of the mechanical properties of tinplate for packaging industry by uniaxial tensile test, a non-uniform plastic strain occurs very often. This phenomenon results from the fact, that the plastic deformation is not uniformly developed throughout the measured section. There is a localization of deformation in one or more places resulting in local changes of the tinplate ́s mechanical properties. This paper deals with local strain hardening and non-uniformity of plastic strain of the tinplate temper TH415CA during uniaxial tensile test. Based on micro hardness measurements in the following locally deformed areas, local changes of mechanical properties of the tinplate were determined. The reasons of early strain localization were assumed by microstructural analysis. In the present work are considering partial aspects of the problem focusing on the properties of the local strain hardening and their consequences for stability of uniform plastic strain.