Analysis of Tube Burst in Boiler Platen Reheater of 600 MW Subcritical Coal Turbine Generator Set

In order to analyze the cause of tube bursting in the boiler plate reheater of a 600 MW subcritical coal turbine generator unit, various methods including macroscopic observation, chemical composition analysis, metallographic structure inspection, hardness detection and mechanical property testing were employed for experimental analysis. It could be found that prolonged operation at high temperatures exceeding 100,000 h leaded to structural changes in the pipe section and accelerated aging processes. Consequently, the thermal strength of the steel pipe decreases while the creep rate increased in this section. Additionally, it was observed that the thickness of the pipe wall at the outer arc position was lower than its design value which made it more susceptible to failure. The findings indicated that the primary cause of tube explosion in plate reheaters was long-term overheating failure.