Failure evaluation on a high-strength alloy SA213-T91 super heater tube of a power generation

• Main Authors: Ahmad J., Purbolaksono J., Beng L.C., Ahmad A.
• Other Authors: 57210531371
• Format: Article
• Published: SAGE Publications Ltd 2023
• Subjects: failure analysis; hardness measurements; high-strength alloy steel; micro-structure examinations; overheating; Alloy steel; Failure (mechanical); Failure analysis; Hardness; High strength steel; Microstructure; Outages; Pulverized fuel; Tubes (components); Failure investigation; Hardness measurement; Metal temperature; Micro and macro; Power station; Short-term overheating; Visual inspection; High strength alloys

This article presents failure investigation on a high-strength alloy SA213-T91 super-heater tube. This failure is the first occurrence involving the material in Kapar Power Station Malaysia. The investigation includes visual inspections, hardness measurements, and microscopic examinations. The failed super-heater tube shows a wide open rupture with thin and blunt edges. Hardness readings on all the as-received tubes are used for estimating the operating metal temperature of the super-heater tubes. Microstructures of the failed tube show numerous creep cavities consisting of individual pores and chain of pores which form micro- and macro-cracks. The findings confirmed that the super-heater tube is failed by short-term overheating. Higher temperatures of the flue gas due to the inconsistent feeding of pulverized fuels into the burner is identified to cause overheating of the failed tube.