Influence of Strip Cooling Rate on Lüders Bands Appearance During Subsequent Cold Deformation

Abstract

This paper presents the results of study of Lüders bands appearance on hot rolled strip during cold deformation. The research was carried out on niobium microalloyed steel. After the thermomechanical treatment the strip was cooled at different rates. Samples taken from hot rolled strip were tested by stretching to fracture with simultaneous application of the methods thermography and digital image correlation. The analysis of measurement results was performed with the software packages IRBIS 3 professional and MatchID. Significant differences were found in the samples tested at different cooling rates. In the samples cooled at a lower cooling rate, the appearance of Lüders bands in the elastoplastic area was determined. The appearance of Lüders bands was not observed in the samples cooled at a higher rates.