30CrMnSiNi2A小直径钢棒外径较小,曲率较大,超声波声束入射情况复杂,影响钢棒超声波探伤的因素多。本文主要采用双晶探头,对直径24mm的钢棒对比试块和带有自然缺陷的钢棒进行试验,试验采取改变探头频率、晶片排列方向和声束交会区深度三个因素进行对比试验,寻找合适的探头检测频率、晶片排列方向和声束交会区深度与钢棒直径之间的关系,优化小直径钢棒的超声波探伤工艺,提高缺陷检出率。 30CrMnSiNi2A small diameter steel rod smaller diameter, larger curvature, the ultrasonic beam incident is complicated, affecting the many factors of ultrasonic testing. In this paper, a dual-crystal probe was used to test the steel bars with diameter of 24mm and the steel bars with natural defects. The test was conducted by changing the probe frequency, orientation of the wafer and the depth of the sound beam rendezvous zone. The appropriate probe detection frequency, wafer alignment direction and sound beam intersection depth and the relationship between the diameter of the steel rod to optimize the small diameter steel rod ultrasonic flaw detection technology to improve the detection rate of defects.