某火箭发动机壳体在进行静力试验时发生开裂，通过化学成分分析、力学性能测试、金相检验、断口分析等方法，对壳体的开裂原因进行了分析。结果表明，成分偏析导致壳体在旋压过程中产生微观缺陷；在水压试验过程中，水中的活性离子会加速裂纹的扩展，导致壳体在静力试验时发生氢脆和应力腐蚀开裂。

The rocket engine shell cracked during the static test. The causes of cracking on shell were analyzed by means of chemical composition analysis, mechanical property test, metallographic examination and fracture analysis. The results show that the composition segregation caused the micro defects in the spinning process. In the process of hydrostatic test, the active ions in water accelerated the crack propagation, which resulted in hydrogen embrittlement and stress corrosion cracking of shell in static test.