Samspillet mellem korrosion og udmattelse

Reactions between metal and environment can influence crack initiation as well as crack growth under fatigue by several mechanisms. Active corrosion allways accel-lerate the crack initiation while the creation of stable passi-ve film under same circumstances can delay fatigue crack initiation. Crack growth can be accellerated by anodic dissolution, but very often the accellerated effect is connected to hydrogen embrittlement due to hydrogen uptake from a cathodic proces.Compared to crack growth rate in air it is assumed that the increased rate seen for steel in sea water under cathodic protection is due to hydrogen embrittlement, while the increased rate found for steel in district heating water can be explained by the combined action from anodic dissolution and hydrogen uptake in the steel.