Corrosion-assisted cracking in life optimisation of power plant components

Corrosion assisted cracking becomes important for ageing plant components which are subjected to loading while in contact with an aggressive environment. Fracture mechanics test techniques and data reduction methods have been shown to be useful to predict component behaviour; nevertheless, it is necessary to further investigate the validity of such methods when environmental effects are present. In this case, in particular for low-allow steels used in power generation plants, time-dependent effects are important and strain rate is a key parameter. This paper, making reference to the results of a cooperation between CISE and ENEL to study the behaviour of materials for power generation plants, presents a procedure recommended for preventing and controlling environmentally assisted cracking in ageing components. Results of research programmes will be shown, where a contribution to the solution of actual problems is given.