Wall Gauging & NDT for Drawn Shells
深冲壳体的壁厚与探伤检测
标签：检测标准, 壁厚公差, 超声, 水压试验, 质量控制
深冲壳体的常规检测组合：①壁厚——接触式超声测厚（ASTM E797 方法），高频探头沿壳体轴向分 8 环、每环 4 点测，壁厚公差通常按 ±8% 验收；②内部缺陷——X 射线查底部与侧壁夹渣、气孔；③承密性——水压试验取 1.5 倍工作压力保压 5 min 无渗。首件检验（FAI）记录全部数据并封样，量产每 500 件抽 1 件复测壁厚。铜壳无磁性，不能用磁粉探伤，荧光渗透或涡流是表面裂纹的替代方案。
The routine inspection set for drawn shells: (1) wall thickness by contact ultrasonics (ASTM E797), a high-frequency probe reading 8 axial rings × 4 points; ±8% of nominal is a typical tolerance. (2) Internal soundness — X-ray the base and wall for inclusions and porosity. (3) Pressure-tightness — hydro test at 1.5× working pressure for 5 min. Full first-article data is archived with a retained sample; re-check one shell per 500 in production. Copper is non-magnetic, so no MPI — use fluorescent penetrant or eddy current for surface cracks.