某離心壓縮機葉輪斷裂失效原因分析
發(fā)布時間：2017.02.17
上虞風機針對某型號離心壓縮機葉輪的斷裂失效問題，采用金相檢測手段檢測了失效葉輪的焊接接頭，并利用商用軟件ANSYS從焊接的角度對葉輪結(jié)構(gòu)受力進行了模擬計算與分析。結(jié)果發(fā)現(xiàn)，葉片和輪盤焊接角接頭存在應力集中，進一步計算表明，在存在焊接缺陷的情況下，較小的作用力就能促使應力達到很大峰值，應力集中加速了裂紋的擴展及失穩(wěn)，從而造成產(chǎn)品的結(jié)構(gòu)失效。
關(guān)鍵詞：離心壓縮機；葉輪；斷裂；應力集中
中圖分類號：TH452 文獻標志碼：A
Fracture Failure Analysis of a Certain Centrifugal Compressor Impeller
Abstract: To analyze the fracture failure of a centrifugal compressor impeller, the metallography oberservation was adopted to characterize the defects in the welded joint, while the comerical software ANSYS was used to simulated and analyze the force of the compressor impeller. The result indicates the exist of stress concentration around the welded root between the blade and the wheel. The stress simulation results exhibit that even the relative low force could induce the pretty high stress valuewhen there is defect, which would result in crack and fracutre. As the result, the stress concentration could accelerate crack progagation and finally result in failure of the whole structure.
Key words: centrifugal compressor；impeller；failure；stress concentration
1 概述
隨著離心壓縮機葉輪制造工藝技術(shù)的發(fā)展，出現(xiàn)了焊接結(jié)構(gòu)葉輪[1] ，這是風機葉輪制造工藝的一次變革，它使生產(chǎn)三元流、高速、高壓、高強度、特殊性能、窄流道、高質(zhì)量、長壽命及安全可靠的葉輪成為現(xiàn)實。近年來，高速離心葉輪已基本上全為焊接結(jié)構(gòu)[2-4] 。
某型號焊接結(jié)構(gòu)的離心葉輪采用低碳調(diào)質(zhì)鋼15MnNiCrMoV，運行一段時間后第3級葉輪發(fā)生失效，故障葉輪帶有明顯解體疲勞破壞特征。葉輪的宏觀裂紋位置在葉片進口輪蓋側(cè)，具體如圖1所示，可以清楚地觀察到疲勞源位于葉片與輪盤焊接引弧區(qū)。
