动车组空心车轴外表面裂纹超声波探伤横波探头最佳折射角度研究及其试验验证

Study and Experimental Verification on Optimal Refraction Angle of Transverse Wave Probe Used for Ultrasonic Flaw Detection on the Outer Surface of EMU/DMU Hollow Axle

用于动车组空心车轴外表面裂纹超声波探伤横波探头的折射角类型较多,而具有不同折射角的横波探头探伤灵敏度存在较大差异。分析空心车轴外表面平直段和曲线段裂纹超声波检测原理,从提高超声波往返透射比、减小主声束盲区2个角度考虑,35°横波探头检测效果最佳。设计制作空心车轴外表面人工裂纹实物试块,开展试验验证。试验结果表明:横波探头角度越小,灵敏度越高;平直段灵敏度明显高于圆弧段;同一圆弧上的刻槽,距离水平切点位置越远,灵敏度越低;圆弧部位曲线半径越小,灵敏度越低。

There are many types of refraction angles of transverse wave probes for ultrasonic detection of cracks on the outer surface of hollow axle of EMU/DMU, while there are great differences in flaw detection sensitivity of transverse wave probes with different refraction angles. The principle of ultrasonic detection of cracks in straight and curved sections on the outer surface of hollow axle is analyzed. In consideration of improving the round-trip transmittance of ultrasonic and reducing the blind area of main sound beam, the detection effect of 35° transverse wave probe is the best. The physical test block of artificial crack on the outer surface of hollow axle is designed and manufactured,and the test verification is carried out. The test results show that the smaller the angle of transverse wave probe is, the higher the sensitivity is;the sensitivity of transverse wave probe in straight section is significantly higher than that in circular section;for notches on the same arc, the farther the notch from the horizontal tangent point, the lower the sensitivity of transverse wave probe is;the smaller the radius of the arc, the lower the sensitivity of transverse wave probe is.