【摘要】 描述了超声波衍射时差法的基本原理,讨论了平行扫查(B扫描)和非平行扫查(D扫描)两种扫查方式,研究了波形图和灰度图两种缺陷图谱的相位特征,推导了缺陷精确定位定量的计算公式,并通过标准试块试验对三种典型缺陷进行了图谱分析。研究结果表明,TOFD技术能识别向表面延伸的缺陷,能对缺陷精确定量和定位并且检出率高,检测速度快。该方法在国内无损检测领域将得到广泛应用。更多还原

【Abstract】 Basic principle of time of flight diffraction(TOFD) method was described.Two scan modes D scan and B scan were discussed and the phase characteristic of oscillogram and grey-scale map was also studied.Formula to calculate the location and size of defects was given.The image analysis was carried on three typical defects on standard blocks.The results show that TOFD with the advantages of the high detectable rate and high test speed can tell the defects which are extending to the surface and can fix the location and size of the defects accurately.The TOFD method would be widely used in the NDT field in the future.更多还原