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本文讨论了用超声测定表面开口裂纹深度的方法。用超声横波和表面波对线切割人工裂纹进行了测量。文章认为,当表面开口裂纹深度大于5毫米时,可用横波端部最大反射波法测量。当裂纹深度在2.5～10毫米之间时,可用表面波绕裂纹传布双探头法(频率1.25兆赫)测量,在人工裂纹试块上测量误差近于1毫米。当表面裂纹深度小于2.5毫米时〔h(深度)<λ(波长)〕有可能使用较低频率(1.25兆赫)超声表面波(单探头或双探头)绘制波幅——深度曲线,并以此来确定表面浅裂纹的深度。
This article discusses the use of ultrasonic method to determine the depth of surface cracks. Ultrasonic shear waves and surface waves were used to measure the artificial cracks in wire cutting. The article holds that when the depth of the crack in the surface opening is more than 5 mm, the maximum reflection wave method at the end of the transverse wave can be used for the measurement. When the crack depth is between 2.5 and 10 mm, it can be measured by applying a double-probe method (frequency 1.25 MHz) to the crack around the crack. The measurement error on the artificial crack test block is about 1 mm. [H (depth) <λ (wavelength)] It is possible to plot the amplitude-depth curve with a lower frequency (1.25 MHz) surface acoustic wave (single probe or dual probe) when the surface crack depth is less than 2.5 mm Determine the depth of shallow surface cracks.