Sub-zero temperature mechanical properties of cold-rolled steel sheets

Cold-formed steels are replacing conventional building materials in many building applications due to the many benefits including lightweight and low cost of construction. Recent research has focused on the fire resistance of cold-formed steel (CFS) construction at material and member levels and advanced the knowledge of their fire performance significantly. However, the performance of CFS members at sub-zero temperatures has not been investigated. Although several studies have been conducted on the mechanical properties of other types of steel at sub-zero temperatures, no studies have been conducted on sub-zero temperature mechanical properties of thin cold-formed steels. In this research, low and high strength cold-rolled steel sheets were tested in the temperature range of 20 to -70 degrees C to determine their sub-zero temperature mechanical properties. Predictive equations are proposed for yield strength, Young's modulus, upper yield strength, ultimate strength and stress at 2% total strain using the experimental results. Finally, suitable stress-strain models are recommended for the prediction of sub-zero temperature stress-strain curves and their use in numerical studies.