Characterization of tensile deformation process in mild steel by infrared imaging

Abstract

It is well known that during tensile testing, a part of the mechanical work done on the specimen is transformed into heat energy. The rate of rise in temperature and the maximum temperature attained depends on the nature of the material, its deformation behaviour and conditions of the test. The recent advances in infrared sensors and image / data processing techniques enable observation and quantitative analysis of the heat energy dissipated during such tensile tests. In this study, infrared imaging technique has been successfully used to characterise the tensile deformation in AISI type 1025 grade steel. Apart from identifying the different stages during tensile deformation, the technique provided an accurate full-field temperature image by which it was possible to visualise the formation of Luders Band in real tiem which otherwise cannot be observed during conventional mechanical testing practices. The technique is a pootential NDE tool that can be used for on-line detection of thermal gradients during mechanical testing and fabrication processes.