High Cycle Fatigue Failure of Burner Feeder Line in a Heavy-duty Gas Turbine Engine

摘要

A number of fuel gas supply pipes or feeder lines of heavy-duty gas turbine engines for power generation were found cracked in two sister engines of a power plant, this after approximately 100000 operating hours. Cracks originated from the outer diameter (OD) of the feeder pipes, at the fusion fine of the fillet weld that joined the subject pipes to the main burner bodies. The incident components failed by high cycle fatigue (HCF) fracture. The failure mechanism is purely mechanic. No evidence of corrosion or any other contributing mechanism was found. Design, manufacture, such as welding coating, burner assembly, and burner installation are all unrelated to the failure, The root cause of the failure is excessive dynamic service loading.