Investigations on cold-forming effect of cold-drawn duplex stainless steel tubular sections

Abstract

The cold-drawing process is currently a significant way of manufacturing cold-formed structural tubular sections at room temperature. Furthermore, cold-drawing is more suitable for forming thick-walled sections with large dimensions than cold-rolling. Plastic deformation experienced during section forming causes increases in the mechanical properties and it also induces residual stresses in the cold-formed cross sections. This paper experimentally examined residual and material stress distributions in two types of cold-drawn tubular sections - three Circular Hollow Sections (CHS) and three Square Hollow Sections (SHS), and material-duplex (S22053) stainless steel. Based on the experimental findings, strength enhancement in CHS was not obvious owing to annealing treatment, removing cold work and increasing ductility. In this case, transverse bending residual stresses in CHS were only considered due to cold-forming effect. The residual stress distribution patterns including longitudinal and transverse stresses and predictive models for enhanced strength of the flat face of cold-drawn duplex stainless steel square hollow sections were developed. Comparisons of the predictions and the test data show that the proposed models were in good accuracy.