针对管道内壁开口裂纹缺陷的检测与定量问题，根据超声检测端角反射和端点衍射理论，使用相控阵超声技术对其进行检测。试验结果表明，管道内壁微小裂纹的高度与反射回波的高度成线性关系，端角反射法能有效测定20 mm厚管道内壁深度不大于4 mm裂纹的高度；端点衍射法能有效测定20 mm厚管道内壁深度不大于2 mm裂纹的高度，对于不同壁厚的管道，端点衍射法和端角反射法所能测定的最小裂纹高度不同，两方法结合可实现管道内壁裂纹缺陷的有效检测。

Aiming at the detection and quantification of crack defects in pipeline inner wall opening, in this paper, studies have been made of the theoretical calculation and experimental results by using the ultrasonic testing end angle reflection theory, endpoint diffraction theory and phased array detection technology. The experimental results show that the height of micro crack on the inner wall of pipeline is linearly proportional with the height of reflected echo, and the end angle reflection method can effectively measure the height of cracks of being less than or equal to 4 mm in the inner wall of 20 mm thick pipeline. The endpoint diffraction method can effectively measure the height of crack which depth is not more than 2 mm in the inner wall of 20 mm thick pipeline. For pipes with different wall thickness, the minimum crack height measured by diffraction method is different. The above-mentioned findings are helpful for realizing the effective detection of pipeline inner wall crack.