Hydrogen Embrittlement of a Boiler Water Wall Tube in a District Heating System

A district heating system is an eco-friendly power generation facility with high energy efficiency. The boiler water wall tube used in the exposed to extremely harsh conditions, and unexpected fractures often occur during operation. In this study, a corrosion failure analysis of was performed elucidate mechanisms. study revealed that overheating by flames cause tube. With increase temperature localized region microstructure not only changed from ferrite/pearlite martensite/bainite, which made it more susceptible brittleness, but also developed tensile residual stresses water-facing side generating cavities or microcracks along grain boundaries inside High-temperature hydrogen embrittlement combined stress cracking initiated many created intergranular fracture.