Subzero Material Properties of Advanced High-Strength Cold-Formed Steel Alloys

The overall temperature in high latitude regions has been rapidly increasing in recent years, creating a demand for infrastructure to support increasing human activities. Recent advances in material science have resulted in the development of advanced high-strength steels (AHSS), which are new grades of cold-formed steel (CFS) with unprecedented strength. To design safe infrastructure, the material properties of AHSS under subzero temperatures must be quantified. An experimental investigation following the steady-state test protocol was carried out to quantify the subzero temperature effects on the material properties of AHSS and conventional CFS sheets with yield strengths ranging from 395 MPa to 1200 MPa. Two types of AHSS (dual phase and martensitic) and two types of conventional CFS (mild and high-strength low-alloy) were investigated at temperatures down to −60 ∘C. The stress–strain relationship, elastic modulus, and key stresses and strains were reported from the experiments. The results show that AHSS’s material properties do not degrade but are mildly strengthened at subzero temperatures than at ambient, which indicates that AHSS is a suitable construction material for structural members in high-latitude regions. Furthermore, modeling on stress–strain relationships of AHSS and conventional CFS at subzero temperatures was developed, demonstrating excellent fits with the experiment data.

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