Investigating the Influence of Trace Tantalum on the Microstructure and Mechanical Properties of Niobium Microalloyed Steels

The global production of niobium-microalloyed steels is now a well-established industrial practice. Initially driven by experimental insights into niobium's ability to refine steel microstructures during thermomechanical processing, this technology has become especially prevalent in low-alloy steels. An important aspect of niobium's production is its natural association with tantalum, which often leads to the co-extraction of both elements. This paper investigates the impact of tantalum traces, present as a contaminant in FeNb, on the microstructure and mechanical properties of niobium-microalloyed steels. The study reveals that tantalum's presence leads to further refinement of austenitic grains without negatively affecting the alloys' yield strength. Additionally, this tantalum contamination enhances the steel samples' toughness. By exploring these subtle effects, this study provides new insights into tantalum's influence on microalloyed steels, particularly regarding microstructural refinement and mechanical performance in two specific Nb-microalloyed steel compositions.