Estimation of Creep Residual Life and Material State of High-temperature Reheater Tubes
The residual creep life and material state of high-temperature reheater tubes were estimated by means of mac-roscopic inspection,outer diameter measurement,metal wall thickness and inner wall oxide thickness measurement,and tube cutting analysis.The results showed that under normal working conditions,the creep residual life at measured posi-tion of the high-temperature reheater tube was more than 40000 hours,which could satisfy the normal operation of a ma-jor repair period.The tensile strength Rm of some tube samples was lower than the lower limit required by the standard. The microstructure of No.3 and No.4 tube samples was ferrite+carbide,the spheroidization was grade 4~5,and the in-ner wall oxide thickness was at a relatively thick level.It is recommended that a comprehensive creep residual life assess-ment be carried out for high-temperature reheater cube and timely replacement of sections with creep residual life less than 40000 hours.