Introduction and objective
The aim of the project is to study and establish the relations between phase compositions and the localisation and fracture failure behaviour in a boron alloyed steel. The studied steel material is used for ultra-high strength components in the automotive industry. The increased demand for low-weight car structure solutions are based on very strong driving forces such as care for the environment and climate as well as safety considerations. Knowledge and presence of methods for failure predictions in e.g. crashworthiness analyses are necessary prerequisites for optimal use of ultra-high strength materials in car structures.
Car structures are usually spot welded. The spot weld process typically lead to varying micro-structures in the vicinity of the weld. The variation is caused by different temperature histories in the range of the spot weld during the welding process. Due to the temperature history are material properties expected to vary in the range of the spot weld.
Based on previous research and experimental results it is the aim to develop a fracture model of spot welds on boron-alloyed components that can predict fracture failure in heat affected zones. Furthermore it is the intention to develop a detailed submodel of a spot weld with the resulting microstructure from the welding process.
The research project “Modelling of failure criteria based on micro-structure evolution in boron-alloyed steel components” (Optus 2) is a cooperation between Gestamp Hardtech, Volvo Cars, Ford Forschungszentrum in Aachen and the division of solid mechanics at the Technical University of Luleå.