A failure analysis was conducted on a 1½ inch diameter UNS N08800 hydrogen unit preheat tube that failed in service. Based on chemical and metallographic analyses the failure was attributed to liquid metal embrittlement by zinc. The zinc source is thought to be the Cu/Zn catalyst for the low temperature shift converter located downstream of the preheat tubes.

Subject
Coils, Materials, Tubes, Fracture surfaces, Transgranular stress corrosion cracking, Intergranular cracking, Zinc oxide, Mechanical failure, Metals, Zinc, Catalysts, Cracks, Hydrogen
Keywords:
Liquid metal corrosion, Liquid metal embrittlement, UNS N08800, zinc, hydrogen unit, furnace, heater
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2003
Association for Materials Protection and Performance (AMPP)
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