低负荷工况下锅炉短管焊接失效检测研究

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Abstract：Theelements of phosphorus （P）andsulfur（S）inthe boiler water mayleadtopittingcorrosion，which can formcorrosion pits in the localarea of the welded joint metaland graduallyerodeand thin the wall thickness of the welded joint metal.Oncethewelded jointmetal ispenetrated，itwilleadtotheleakageofthemediumandcause the failure of the boiler system.Therefore，a detection method for the welding failure of boiler short tubes under low-load conditions is proposed.The laser-induced breakdown spectroscopy（LIBS） technology is used to conduct high-quality spectral measurements on the welded joints of boiler short tubes.By optimizing the measurement architecture，the influenceofthe oxide layerand thedeposition layeron the detection efect isavoided.In viewof thefluctuationofspectralcharacteristicscausedbytheinhomogeneityof the internal metallographicstructureof the boilershort tube，spectral correction techniquesare adopted，including Savitzky-Golay convolution diferentiation and least squares fiting，to improve the accuracy of spectral data.The K-SVM-RFE algorithm is used to select the featuresof spectral data，and thedecision functionof the linear kernelsupport vectormachine （SVM） iscombined to realize the detectionof welding failure of boiler short tubes underlow-load conditions.Theresults show that under low-loadconditions，the failure detection of the designed method has only3 detection errors，and thesensitivity is aboveO.95，which canrealizethedetectionofweldingfailureofboilershort tubesunderlow-loadconditions.

Keywords：low load operatingconditions;boiler short tube;welding failure detection;laser induced breakdown spectrometer; K-SVM-RFE algorithm

1序言

在工业锅炉的运行过程中，锅炉短管的焊接质量直接关系到整个系统的稳定性和安全性[1，21。（剩余6613字）