Corrosion fatigue factors controlling

Mitigation or elimination of corrosion-fatigue cracks involves gaining control of the critical factors that govern the mechanism. 

It is often difficult to conduct laboratory tests in which both the environmental and stressing conditions approximate to those encountered in service. This applies particularly to the corrosive conditions, since it is necessary to find a means of applying cyclic stresses that will also permit maintenance around the stressed areas of a corrosive environment in which the factors that influence the initiation and growth of corrosion fatigue cracks may be controlled. Among these factors are electrolyte species and concentration, temperature, pressure, pH, flow rate, dissolved oxygen content and potential (free corrosion potential or applied). 

Corrosion, erosion, mechanical fatigue, operation at design limit and/or beyond it, calibration failure, design fault (such as wrong material selection), obsolescence, etc. are major contributing factors for degradation of equipment/system, and/or electrical control and instmmentation (EC I) items. 

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