The research was focused on obtaining medium to high strength steel strips for strapping heavy products by applying continuous flux thermal treatments on common grades, cheap carbon steels. For steel strapping the behavior at alternate bending is an important issue, thus an objective of the research was to make sure that the treated products withstand a critical number of alternate bending cycles and further more an improvement of the resistance at alternate bending by applying thermal treatments in continuous flux was pursued.
The paper presents the results of the alternate bending test, SEM fractographs, optical analysis of the fracture surface and surface of the strip in the vicinity of the fracture surface after breaking by alternate bending using a stereo-microscope and optical analysis on etched and un-etched samples in transversal section along the rolling direction in the vicinity of the fracture surface using a metallographic optical microscope; for the following samples: the raw material in strain-ardened state, samples subjected to continuous flux quenching from 900 °C and tempering by passing through the furnace maintained at 600 °C, and samples subjected to quenching from 900 °C and tempering by passing through the furnace maintained at 700 °C
