焊接的无损检验.焊接接头的超声波检验

[中文适用范围]： 本文件规定了对厚度≥8 mm 的金属材料熔焊接头进行手动超声波检测的技术，这些金属材料在 0 °C 至 60 °C 的物体温度下表现出低超声波衰减（特别是由于散射）。 它主要用于焊接材料和母材均为铁素体的全熔透焊接接头。 本文件中规定的与材料相关的超声波值是基于超声波声速为（5920±50）m/s（纵波）和（3255±30）m/s（横波）的钢。 本文件规定了四个测试级别，每个级别对应于不同的缺陷检测概率。 附件 A 给出了测试级别 A、B 和 C 选择的指南。 本文件规定，针对特殊应用的测试级别 D 的要求应符合通用要求。 测试级别 D 只能在规范定义时使用。 这包括铁素体钢以外的金属测试、部分熔透焊缝测试、自动化设备测试以及物体温度在 0 °C 至 60 °C 范围之外的测试。 本文件可用于评估不连续性，以达到验收目的，通过以下任一技术： a) 主要基于不连续性的长度和回波幅度进行评估； b) 通过探头移动技术根据不连续性的特征和尺寸进行评估。 [外文原描述]： This document specifies techniques for the manual ultrasonic testing of fusion-welded joints in metallic materials of thickness ≥8 mm which exhibit low ultrasonic attenuation (especially that due to scatter) at object temperatures from 0 °C to 60 °C. It is primarily intended for use on full penetration welded joints where both the welded and parent material are ferritic. Where material-dependent ultrasonic values are specified in this document, they are based on steels having an ultrasonic sound velocity of (5 920 ± 50) m/s for longitudinal waves and (3 255 ± 30) m/s for transverse waves. This document specifies four testing levels, each corresponding to a different probability of detection of imperfections. Guidance on the selection of testing levels A, B, and C is given in Annex A. This document specifies that the requirements of testing level D, which is intended for special applications, be in accordance with general requirements. Testing level D can only be used when defined by specification. This includes tests of metals other than ferritic steel, tests on partial penetration welds, tests with automated equipment, and tests at object temperatures outside the range 0 °C to 60 °C. This document can be used for the assessment of discontinuities, for acceptance purposes, by either of the following techniques: a) evaluation based primarily on length and echo amplitude of the discontinuity; b) evaluation based on characterization and sizing of the discontinuity by probe movement techniques.