药筒底座缺陷分析及失效可能性评估

Analysis of defects and the failure possibility evaluation of cartridge case base

利用直读光谱仪、光学显微镜和拉伸试验机对产生缺陷的钢制药筒进行了化学成分分析、力学性能试验、加工低倍流线和高倍金相观察,结合药筒的制造加工工艺过程和工作环境对其底座缺陷产生的原因进行了分析,结果表明,药筒底座缺陷是在冷挤压压底过程中由于金属相反方向变形而形成的表面裂纹,该缺陷的形成与原材料无关。根据药筒材质、缺陷类型以及强装药发射试验情况,利用断裂力学理论对药筒在放置和使用时缺陷扩展并导致失效的可能性进行了评估,根据理论计算得知,药筒在正常装药情况下缺陷扩展并导致断裂的可能性甚微。

By using the optical emission spectrometer(OES),the optical microscope(OM)and the tensile test machine(CM),chemical composition analysis,mechanical property testing,processing the low times streamline and high times metallographic observation of defects of cartridge are carried out. Combined with the manufacturing process and working environment of cartridge,the causes of the case base defects are analyzed. The results show that the cartridge base defect is surface crack formed by the metal deformation in the opposite direction in cold extrusion press process,which is irrelevant to the raw materials. According to the case materials,defect type and strong charge emission test conditions,the theory of fracture mechanics is used to evaluate the failure probability caused by the defect extension of cartridge in place and use. According to the theoretical calculation,for the cartridge in the normal charge case,there is little possibility of extended defects induced fracture.