Periodic undercut

Cyclic testing consisting of short salt exposure, short drying period, and long period of high humidity. Undercutting from scribe is measured. 

If plant personnel do not succeed to improve the water quality within 36 hours so that the specified value 2 is undercut, the plant has to be shut down normally and carefully. If it is foreseeable that the specified value 2 will be undercut within the period necessary for achieving <100°C in the pressure vessel, the plant can be further operated. 

Some tests are continued imtil failure, as in SCC testing. However, in tests of protective coatings, as well as in others, periodic measurements of typical properties such as degree of undercutting are more adequate (Fig. 9.43). 

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