高温再热器管蠕变剩余寿命和材质状态评估

Estimation of Creep Residual Life and Material State of High-temperature Reheater Tubes

通过宏观检查、外径测量、金属壁厚和内壁氧化皮厚度测量及割管分析,对高温再热器管进行了蠕变剩余寿命和材质状态评估。结果表明,在正常工况下,高温再热器管管子抽查位置处的蠕变剩余寿命均大于4万h,满足一个大修期正常运行;部分管样的抗拉强度R m已低于标准要求的下限值,3、4号管样显微组织为均为铁素体+碳化物,球化均为4~5级,且内壁氧化皮厚度均已处于较厚水平。建议对高温再热器管进行全面的蠕变剩余寿命评估,及时更换蠕变剩余寿命短于4万h的管段。

The residual creep life and material state of high-temperature reheater tubes were estimated by means of macroscopic 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 position of the high-temperature reheater tube was more than 40000 hours,which could satisfy the normal operation of a major repair period.The tensile strength R m 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 inner wall oxide thickness was at a relatively thick level.It is recommended that a comprehensive creep residual life assessment be carried out for high-temperature reheater cube and timely replacement of sections with creep residual life less than 40000 hours.