焊缝超声波检测时DAC曲线的制作与应用..doc

焊缝超声波检测时ＤＡＣ曲线的制作与应用 摘要在超声波检测时，为了避免漏检，超声检测人员通常用较高的灵敏度（二次波或三次波的灵敏度）作为扫查灵敏度。当在扫查过程中发现缺陷时，根据缺陷波距一次波、二次波（三次波）的水平位置远近选用水平差值最小的波次的灵敏度对缺陷进行定量。因此在超声波检测时应用DAC曲线，不仅可灵敏的监测出缺陷的位置所在，而且简单方便。 本文分析了超声波检测在检测时对检测结果的分析，应用DAC曲线和DAC曲线的多种制作方法，并对比分析了各种DAC曲线的制作方法TC4大直径钛合金棒材超声波探伤保证准确的灵敏度及建立曲线进行声程补偿可有效解决材料探伤杂波较高的问题保证大直径棒材的有效检测以保证探伤结果的准确性、可靠性。DAC曲线；缺陷定量；评定依据 Production and Application of DAC Curve in Ultrasonic Testing of WeldsAbstract In ultrasonic testing, in order to avoid detection, ultrasonic testing personnel usually with high sensitivity (sensitivity of two times wave or three times the wave ) as the scanning sensitivity. When the find defects during scanning process, according to the distance of defect wave from a wave, the two wave (the three wave) level location select the least level difference between wave sensitivity as the quantify defects. The application of DAC curve in ultrasonic testing, not only can sensitively detect the location of defects,but also be simple and convenient. This paper analyzed the ultrasonic testing in the detection of the analysis on the test results, making a wide variety of applications of DAC curve and DAC curve, and analyzed the advantages and disadvantages of various methods of DAC curve analysis such as: linear connection method; least squares fitting; Lagrange fitting curve method, and also introduces the gain wave detection of DAC curve and DAC curve of attenuation measurement. Application of DAC curve in engineering practice is very extensive. Which based on the TC4 large diameter titanium alloy bars-ultrasonic testing as an example to demonstrate that DAC curve can be used for acoustic sensitivity to ensure the accuracy of compensation and establishment of curve, which can effectively solve the problem of high material testing noise, ensure the effective detection of large diameter bars, in order to guarantee the accuracy, reliability of testing results. Keywords　 Ultrasonic testing; DAC curve; Defect quantitative; Assessment basis