介绍了新版国际标准关于焊缝超声衍射时差技术（TOFD）的验收等级，为国内焊缝衍射时差技术验收标准的制定或修订提供参考。TOFD不但能精确测量缺陷深度，而且也适用于常规的焊缝检查，通过合理的设置，TOFD也能检测复杂的几何结构。

The latest edition of international standard about the acceptance levels of welds using time-of-flight diffraction technique is introduced which provides reference for the establishment and revision of the acceptance criteria of welds using time-of-flight diffraction technique of national standard. TOFD not only can accurately measure the depth of defects, but also can be applied to conventional weld inspection. Through reasonable settings, TOFD can also detect complex geometric structures.