Investigation of the effect of niobium on mechanical properties of hot rolled steel

The increasing competitive environment and product diversity in today's conditions in which the steel industry is rapidly developing have led manufacturers to reduce costs. Especially in the last years, the use of micro-alloy elements has been one of the cost-reducing measure in the production of high-strength steels which are highly demanded. Steels with higher strength values which are produced by adding micro-alloy elements to plain-carbon steels are called micro-alloyed steels. In this study, the influence of the addition of Nb (by micro-alloying) on the microstructure, and thus mechanical properties of a hot rolled steel was investigated. It has been observed that the addition of Nb led to grain refinement by segregating within the grains as well as increasing the hardness due to its carbide forming capability. By adding small amount of Nb to the steel, the yield and tensile strengths were increased significantly. In addition, the ductility and toughness values of the steel were also improved.