AN OVERVIEW - PREVENTION AND CONTROL OF STRESS-CORROSION CRACKING

Prevention and control procedures are divided into approaches based on metallurgical, electrochemical (or environmental), mechanical (stress), and operational aspects. Metallurgical approaches involve modifications in alloy composition, including impurity control, or structure, including grain size control. Electrochemical or environmental control may be through control of the potential, inhibition, or application of coatings - organic, metallic, etc. Control of residual stresses may sometimes appear to be a valuable approach to prevention (e. g. , full or partial thermal stress relief and the introduction of compressive stresses into the surfaces where cracks might initiate). Although operating conditions will frequently be dictated by other considerations, the minimization of stress changes or cyclic loading and the reduction of temperature will often offer benefits. Finally, some consideration is given to the implications of having to live with cracks where prevention cannot be achieved.