Development of Nb-bearing microalloyed steels: JSPL experience

Niobium bearing microalloyed steel has become the standard material in plate and strip for line pipe, automotive and construction grades of steel. Jindal Steel and Power Limited (JSPL) has developed various Nb-based microalloys steel grade with in-house technology to cater to the needs of such applications. The development of these grades requires significant research work both in steel-making and processing technology. The development of Nb-microalloyed steel has been found to satisfy higher strength and impact requirements of steel while saving in production costs. This paper presents and discusses various studies conducted on the use of Nb microalloying to achieve the desired mechanical and microstructural properties both in structural and wide plates. The need for high quality, low inclusion, steels for making Nb-bearing structural beams and optimization of the API X70 plate process route are also discussed together with the benefits of applying a low carbon (<0.06%) plus Nb concept for enhanced properties and also cost advantages. (AU)