火力发电厂机组在运行检修时，需对气缸轴瓦表面进行无损检测，以及时发现微小运行缺陷，并进行修复处理。根据现场实际情况，合理优化了渗透检测工艺，有效地发现了微小缺陷。该工艺的优化既满足了检测质量的要求，也提高了发现缺陷的能力。

Following the thermal generator units being put into work, surface defect detection is needed for the axle bush of an air cylinder after it is examined and repaired in order to discover the tiny defects in running process and try to deal with them timely. This paper tends to optimize the penetrant testing technique reasonably according to the actual running state, through which the tiny defects will be detected effectively. The improved technique both satisfies the requirement of testing quality and enhances the flaw detecting ability as well.