Steel Rebars Meet Strength and Durability Demands

Abstract

A thermomechanical treatment widely used to enhance the mechanical properties of steel rebar creates a microstructural gradient — a tempered martensitic outer shell for strength and a ferritic-pearlitic core for ductility — that enables rebars to meet required tensile properties even in steels with high inclusion content. This article examines the trade-off inherent in that approach: while the treatment reliably meets mechanical performance targets, the tempered martensitic outer layer is more susceptible to corrosion than the ferritic-pearlitic core, exhibiting intergranular corrosion and pitting at MnS inclusions under early chloride exposure. Because rebar quality and treatment completeness can vary by producer and country, on-site inspection remains necessary, and the corrosion vulnerability of the outer shell raises concerns for infrastructure designed to meet 100-year service life requirements.