Distribution Patterns of Material Properties for Crosssection of Coldformed Thickwalled Steel Rectangular Tubes

Abstract:

Five hundred and sixty eight test coupons taken from thirty coldformed thickwalled steel square and rectangular tubes with different sizes of sections, thickness of plates, grades of steel and different manufacturers were tested to investigate the effects of coldforming process on the material properties of different parts of sections. The test results indicate that the coldforming effects have obvious influence on the strength and ductility of coldformed thickwalled sections. The difference of material properties between two adjacent plates connected to the plate containing weld can be ignored. The yield and tensile strength of weld portion and corner parts are enhanced compared with the adjacent plates. The yield strength enhancement factors of corner parts increase with the increase of the ratio of the length of centerline to the inside diameter of corners, but the enhancement factors for tensile strength are independent on the respective parameters. Based on the investigation, distribution patterns of yield strength, tensile strength, tensile to yield ratio and percentage elongation of coldformed thickwalled steel rectangular hollow sections were proposed, which can be used for strength and stability analysis of corresponding beams and columns, while the coldforming effects are to be taken into account.