Material properties and residual stresses of cold-formed high strength steel hollow sections

•Cold-formed high strength steel hollow sections were examined.•Material characterizations were conducted through 66 tensile coupon tests.•Cold-forming effects were investigated on halves of the three hollow sections.•A new material model for high strength steel was proposed.•Residual stresses on three sections were measured and reported.

This paper presents the experimental investigation on the material properties and residual stress distributions of cold-formed high strength steel hollow sections. The nominal yield stresses (0.2% proof stresses) of the hollow sections were 700, 900 and 1100 MPa. The sections were composed of 9 square hollow sections, 2 rectangular hollow sections and 6 circular hollow sections. 66 tensile coupons were tested to determine the modulus of elasticity, 0.2% tensile proof stress, ultimate tensile strength and elongation at fracture of the material. The results were also compared with the American, Australian and European standards. Based on the Ramberg–Osgood expression, a new constitutive model for high strength steel material is proposed. On three of the hollow sections, strength variation and cold-forming effect were studied by testing coupons extracted from different locations of the cross-sections. Residual stresses were also investigated both in longitudinal and transverse directions on three hollow sections using wire-cutting method. A total number of 82 longitudinal strips and 3 transverse rings were cut from the original sections.