What Does Caustic Cracking Mean?
Caustic cracking is a form of stress corrosion cracking most frequently encountered in carbon steels or iron-chromium-nickel alloys that are exposed to concentrated hydroxide solutions at temperatures of 482°F (250°C).
This phenomenon mostly occurs in boilers where caustic soda (NaOH) has been added in small amounts to boiler water to prevent scaling. However, caustics (alkalis) may become concentrated amounts in crevices around rivet heads and at hot spots. When combined with the considerable fabrication stresses around rivet holes, this can cracking of the steel boiler shells and tube plates.
Caustic cracking is also known as caustic embrittlement.