Abstract
Time dependent damage of structural materials attracts a great deal of attention, because environmental and loading conditions became more severe with the appearance of high efficient and big scale machine and structures. The period of employment is also longer under the present economic situations, which closes up the time dependent fracture of stress corrosion cracking (SCC) and corrosion fatigue (CF). In the present paper, life estimation method of SCC and CF in structural materials will be discussed based upon the experimental results that cracks are mostly initiated from corrosion pits in corrosive environment followed by the growth of cracks to final fracture. The threshold value of crack initiation KISCC and ΔKCF from corrosion pit is almost constant considering the pit being sharp surface crack, and thereafter the growth period can be calculated based upon fracture mechanics approach considering environmental growth characteristics such as short crack growth problems, crack closure due to corrosion products, and so forth. Flow chart to estimate SCC and CF life of structural materials is presented.
