Analysis and Expansion on the Sensitivity Classes of SEP1927-2010 Standards

The paper analyzes and expands sensitivity classes of SEP1927-2010 with calculation and experiment, and establishes the sensitivity classes and testing method for detecting smaller level inclusions, and develops smaller inclusions detection sensitivity level and detection methods. Not only improve the precision of water immersion ultrasonic testing equipment, but also reduced the differences of the water immersion ultrasonic testing and microscope detection method in determining the gap size of inclusions.