Effect of manufacturing process on material properties at the corners of G450 cold-formed steel channel sections

Abstract

The use of cold-formed steel structures in the construction industry has become widely popular over the past decade. This has led to the necessary understanding of the effects of cold-working process on cold-formed steel members. The manufacturing process of cold-formed steels starts with cold-rolling the hot-rolled steel sheet under a series of rollers until a thickness is achieved. The process is followed by cold-bending to create cold-formed sections with desired shapes at ambient temperature. The plastic deformation associated with the rolling and bending processes results in strain hardening of the material and this in turn affects the properties. This paper presents both microstructural and micromechanical investigations on the blank and bent areas of 3.0 mm thick C-shaped cold-formed sections. Vickers hardness tests show a hardness increase at the bent areas. The observation of the bent region using scanning electron microscopy (SEM) reveals changes in the grain structures. Additionally, electron backscatter diffraction (EBSD) measurements have been conducted for an in-depth characterization. Understanding the changes in the microstructure of the material will provide insight on the mechanical behavior of these members.