ABSTRACT

The structural integrity analysis of an engineering component is based on information belonging to loading condition of the structure, to properties of engineering materials and their changes due to loading and environment, furthermore to material discontinuities resulting from production and/or operation. Beside this one of the driving intentions in the industry is weight reduction, which can be achieved by applying high strength materials. High strength steels produced by innovative processes, like thermomechanical rolling are increasingly applied in different engineering structures. The application of these metal grades enables longer life time, improved performance and thinner wall thickness, which require less welding activity. Besides these advantageous properties, these steel grades can contain material discontinuities, for example cracks, in their microstructure. Aiming to get information about their response to mechanical cyclic loads and static loads, low cycle fatigue and crack tip opening displacement investigations were carried out.