Towards industrial applicability of (medium C) nanostructured bainitic steels (TIANOBAIN)

Abstract

The project aimed at exploring the industrial feasibility of new super-high strength steels (SHSS) made using innovative processing methods and based on medium carbon nanostructured bainitic microstructures. It was envisaged that the steels could be applied in engineering applications in the transport industry and wear-resistant applications for example in the mining industry. The microstructural concept that was exploited, with the purpose of attaining UTS > 1600MPa, is the ausformed bainite in medium carbon steels (0.4-0.5 wt.%). In this process, austenite is deformed and during subsequent cooling and holding at lower temperatures (than that in regular practice) the unrecrystallized austenite transform to refined bainite with enhanced strength and toughness properties. The industrialization of this new steel design concept, involving innovative process development and novel design of relatively inexpensive compositions, is accompanied by new manufacturing risks and uncertainties in terms of achieving advanced mechanical and in-use properties (tensile, impact and fracture toughness, wear, bendability, etc.). Therefore, this project intended to gather information in terms of chemical composition design, alternative TMCP routes, microstructural evolution, mechanical properties and in-use performance to assess the potential of novel bainitic steel grades in order to develop recommendations for viable industrial processes.