Q. Explain caustic Stress Corrosion Cracking?

Dilution of the caustic prior to injection into a relatively hot stream will minimize the potential of caustic Stress Corrosion Cracking (SCC) (historically referred to as caustic embrittlement). Optimum dispersion and injection, well upstream of elbows, is recommended to prevent pooling along the bottom or erosion of elbows.

Care should be taken to prevent process conditions that can create wet and dry conditions allowing the caustic to concentrate and lead to SCC. This has been known to occur in boiler tubes or under localized deposits in general equipment.

From a safety perspective, extreme care in handling caustic should be exercised to prevent skin contact. Eyes are particularly sensitive areas.