Failure Analysis of Aviation Torsional Springs

作     者：HOU Weiguo ZHANG Weifang LIU Xiao WANG Zongren DING Meili 

作者机构：School of Reliability and System Engineering Beihang University Beijing 100191 China 

出 版 物：《Chinese Journal of Aeronautics》 (中国航空学报（英文版）)

年 卷 期：2011年第24卷第4期

页      面：527-532页

核心收录：

学科分类：08[工学] 080203[工学-机械设计及理论] 080502[工学-材料学] 0805[工学-材料科学与工程（可授工学、理学学位）] 0802[工学-机械工程] 0825[工学-航空宇航科学与技术] 0801[工学-力学（可授工学、理学学位）] 080201[工学-机械制造及其自动化] 

基　　金：The authors gratefully appreciate the support by Hongdu Aviation Industry Group Ltd. of China  and also the language help from ZHENG Fei and YAO Jing 

主　　题：springs failure residual stress hydrogen-induced delayed cracking 

摘      要：Cracks and fractures occur during the assembly process to a type of torsional springs used in the aviation mechanism. Besides visual examination, other experimental techniques used for the investigation are： 1） fracture characteristics, damage morphology and fractography by scanning electron microscopy （SEM）, 2） spectrum analysis of covering, 3） metallographic observation of cracks and 4） hydrogen content testing. The results are obtained through the analysis of manufacture process and experimental data. Since no changes of microstructure are found, failures are irrelevant to the material. The cracks and fractures initiate on the inner surface, cracks initiate before the cadmium plating and after the winding. No obvious stress corrosion cracks are found near the crack source region. The opening direction of cracks is consistent with the residual tensile stress of the spring inner surface, and the springs are easy to contact hydrogen media between the spring winding and the cadmium plating. The cracks are caused by hydrogen-induced delayed cracking under the action of the residual tensile stress and hydrogen.