Building bridges with niobium-bearing steel
25 July 2021
Steel producers respond to demand for high performance bridge steels with niobium
Paper written by Steven G. Jansto Ph.D., Principal Partner at Research and Development Resources and a CBMM Technical Consultant working on behalf of CBMM North America, Inc. Copyright © CBMM.
This article was first published on www.niobium.tech as "Steel producers respond to demand for high performance bridge steels with niobium" and later the July 2021 edition of the T.I.C. Bulletin, our quarterly journal, with the kind permission of CBMM.
- The civil engineering community is looking toward steel producers to provide the next generation of bridge materials that meet robust performance standards, offer design-flexibility, provide durability and resiliency, and allow for faster, lower cost bridge construction. Steel producers are responding with alloyed, high performance steels containing Niobium (Nb).
- Nb-containing bridge steels have demonstrated a consistency in the base mechanical properties, as well as exhibiting outstanding toughness, weldability and corrosion resistance.
- Lower carbon Nb-alloy steel designs are cost-effective in mill production, enabling the entire supply chain, from designer through to the end user, to realize the benefits of Nb as an additive.
Nb-containing weathering steels for bridge construction are proving to be economical and extremely valuable as a carbon footprint environmental asset. Eliminating the need for steel painting generates an initial 10% cost saving. Without painting, exposure to contaminated blast debris or volatile organic compounds (VOC) is eliminated. Life cycle cost savings can exceed 30% due to extended corrosion resistance and less overall maintenance.
Nb-containing bridge steels are being produced by steelmakers to respond to the demand for better performing, value-added bridge materials. These steels possess a combination of exceptional properties – high strength, excellent weldability, impressive toughness at low temperature, desired ductility, superb corrosion resistance and high formability. High performance steels (HPS) that include weathering steels for bridge structures, possess an optimized balance of these primary properties, providing a cost-effective product for bridge structures at strength levels from 355MPa to 700MPa, and demonstrating excellent corrosion resistance. The combination of a desirable strength-toughness balance, favourable weathering properties and reduced pre-heat temperatures for welding in these low carbon Nb-bridge steels generates significant cost savings. When selected for new bridge construction or the rehabilitation of existing bridges, Nb-containing low carbon bridge steels are made in the form of net shape cast beams and/or welded plate sections that ensure lighter, more corrosion-resistant superstructures. The enhancements give designers and structural engineers the opportunity to specify HPS to further improve bridge structure design and performance.
Read the full article at Bulletin No.186