New generation niobium bearing structural steels for future infrastructure demands

Abstract

The new generation of value-added low carbon niobium (Nb) microalloyed beam, plate and rebar construction steels for both low and high yield strength and energy absorption applications are shifting designers to these new high performance lower cost materials. The civil engineering and end user community demand structural reinforcing bars, shapes, beams and plates with improved energy absorption and fatigue properties. The future market demands better fire and seismic resistance, yield-to-tensile ratio consistency, improved bendability and weldability. These attributes are difficult to obtain from steel producers today with their current higher carbon microalloyed steel approach. However, there is a global shift in motion to low C–Nb bearing construction steels displacing traditional materials. For example, in the construction beam sector and rebar sector improved properties result for 0.02–0.04%Nb in low carbon steel for S355 and S420 beams and for S500 and S600 low carbon reinforcing bars.