压缩天然气加气站瓶式压力容器能否正常运行直接关系到城市的安全。采用无损检测方法对在役瓶式压力容器进行检测是保障加气站安全运行的一项措施，其中超声波探伤是最佳的选择。对于超声检测灵敏度的确定，可利用自制的对比试块，以线切割槽模拟缺陷，考虑衰减补偿；而对外圆横波周向探伤时，可采用外圆双孔法校准仪器，解决折射角校准，前沿的确定和扫描速度调节等问题。

It′s directly related to the city safety to have the bottle pressure vessel of the compressive natural gas station well-operated. Applying the non-destructive testing for the in-service inspection of the bottle pressure vessel is one way to secure the safety operation of the gas station,and the ultrasonic testing is the best choice. Regarding the confirmation on the sensitivity of the UT,it could be tested by the contrast block made by the operator themselves,simulating the disfigurement via the cut line flute,and further considering about the attenuation. For the circumferential transverse wave testing on the outside surface,the outer-circumferential dual-hole calibration instruments could be used to solve those problems on the calibration of the refraction angle,the fixation of the front distance,and the adjustment of scanning speed etc.