Competition in the steel market continues to drive further improvements in product quality and performance. Three fundamental attributes frequently govern modern steel product developments: lowering cost, increasing strength levels in combination with enhancing ductility, formability and weldability. Cost can be decreased via reductions in conventional alloying elements and micro alloying additions. However, this decrease must be controlled so as to not compromise the solid solution and precipitation strengthening.

In this project, we investigate the effects of steel composition (in particular Cr, Mo, Nb and V additions) and processing history (deformation temperature, strain levels, coiling temperature and time) on the mechanical properties of novel ferritic-bainitic structural steels. This investigation is carried out using simulation of thermomechanical processing in a Gleeble testing facility and detailed microstructural characterisation using state-of-the art instruments and mechanical testing.

Dr Andrii Kostryzhev is part of a Research Team within the Steel Research Hub whose area of research aims to develop a new steel grade and processing technology which could deliver a significant improvement in steel strength from the currently produced levels (yield strength of 500 MPa). The objective is to understand the effects of micro-alloying element additions and processing parameters on the strengthening mechanisms operating in ferritic-bainitic structural steels.

The progress in this research so far has found that minor additions of 0.5 wt.% (Cr + Mo)  in combination with microalloying with Nb + V to the steel composition, together with a new processing technology, increases steel yield strength to 700 MPa.

If the project results are implemented in practice they will facilitate growth in Australian steel usage via new markets in high strength steels. With a future view of growing demand for steels with high strength to weight ratio, this will provide substantial economic benefit.