Microstructure and Mechanical Properties of Burst Tube of Superheater of 12Cr1MoV Steel

Burst tube of high temperature superheater of 12Cr1MoV steel in station boiler was studied. The difference of microstructure and mechanical properties between back and fire side of burst tube of superheater were analyzed by macroscopic obsewation, metallographic examination, hardness test and chemical composition analysis. The results show that the high temperature superheater tubes have obvious deterioration, and there were obvious differences in microstructure and mechanical properties between back and fire side of burst tube of superheater. The deterioration phenomenon of the pipe at the fire side was more serious, and the pearlite is 4.5 grade spheroidizing. The tensile and hardness indexes at room temperature are significantly lower than back side, indicating that the long term high temperature flue gas scour in the furnace has a more significant effect on the deterioration of the fire side to the high temperature superheater tube.