某发射筒端盖在周转过程中出现密封失效，通过理化检验和失效模拟试验等方法，对该端盖密封失效的原因进行了分析。结果表明：端盖外表面在周转过程中受到机械外力作用产生了裂纹，裂纹不断扩展导致泄漏失效；将包装箱内缓冲材料厚度适当增加，使发射筒与缓冲材料的间隙小于1 mm，可有效避免此类失效的发生。

The sealability of a canister cover was failed in turnover period. The causes of sealability failure of the canister cover were analyzed by means of physical and chenical examination, failure simulation experiment and so on. The results show that the cracks on the outer surface of canister cover caused by the mechanical force in turnover period extended and led to leakage failure. Increasing the thickness of the buffer material in the packing box and making the gap between the canister and the buffer material within 1 mm could effectively avoid this kind of failure.