Failure Analysis on Cracking of Furnace Tube of a Thermal Power Plant

By means of macroscopic examination, chemical compositions analysis, mechanical properties test and metallographic examination, cracking reasons of the furnace tube of a thermal plant were analyzed. The results show long-term operation at high temperature resulted in the occurrence of creep, decrease of mechanical properties and cracking of the furnace tube. It was suggested to strengthen monitoring work to the furnace tubes during their service and repairing process, set creep bulge control point at high temperature positions of the boiler, and control the enlistment of the furnace tubes with relative creep rate being less than 2% to insure the normal and safe operation of the boiler.