Abstract: The new generation of value-added low carbon-low manganese microalloyed structural steel for both low and high yield strength and energy absorption applications is under development. These materials engineering considerations are shifting designers to consider new lower cost and more robust construction materials even for low yield strength applications. The civil engineering and end user community demand structural reinforcing bars, shapes, beams and plates with improved energy absorption and fatigue properties. With more severe climatic conditions, demands for improved fire and seismic resistance, yield-to-tensile ratio consistency, improved bendability and weldability are in the forefront. These attributes are difficult to obtain from steel producers today with their current higher carbon microalloyed steel approaches and hot rolling practices. 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, further property improvements result for 0.015 to 0.030%Nb in low carbon steel with appropriate hot rolling metallurgy for S355 and S420 beams and for S500 and S600 low carbon reinforcing bars.
Author: Steven G. Jansto
Keywords: Energy Absorption, Grain Refinement, Manganese, Niobium