1.1 本规程涵盖了对环形焊缝进行机械化超声波检查的要求。评估基于机械化超声波检查的结果。验收标准基于工程关键评估（ECA）定义的缺陷极限或承包机构定义的其他验收/拒收标准。 1.2 本规程应适用于本规程用户之间商定的检查程序的制定。 1.3 以国际单位制表示的数值应视为标准。括号中的英寸-磅单位仅供参考。 1.4 本标准并非旨在解决与其使用相关的所有安全问题（如有）。本标准的用户有责任在使用前制定适当的安全、健康和环境实践，并确定监管限制的适用性。 1.5 本国际标准是根据世界贸易组织技术性贸易壁垒（TBT）委员会发布的《关于制定国际标准、指南和建议的原则的决定》中确立的国际公认标准化原则制定的。 ====意义和用途====== 4.1 本规程主要用于天然气和石油管道施工中使用的管道环形焊缝的机械化超声波检测。由于焊缝轮廓的变化，本规程经过适当修改后，也可用于检查修复焊缝。实践中描述的手动技术 E164 也可用于检查生产焊缝或修复焊缝。经适当修改后，本规程也可用于检查其他形式的对接焊缝，包括长焊缝。 4.2 所使用的技术基于分区判别，将焊缝分为大致相等的垂直检查段（区），每个垂直检查段（区）由一对超声波搜索装置进行评估。 看见 图1 对于典型区域。 图1 焊接区和不连续性的示意图 4.3 被检查材料的厚度通常为7至25毫米（0.28至1.00英寸）管道直径15厘米（6.0英寸）和更大，但如果可以证明该技术能够提供所需的分区区分，则该标准可能适用于其他厚度和直径。 4.4 检查区域通常为2至3毫米（0.08至0.12英寸）在高度上。对于大多数应用，这将需要使用接触聚焦搜索单元，以避免来自离轴几何反射器的干扰信号，并避免与相邻区域过度重叠。

1.1 This practice covers the requirements for mechanized ultrasonic examination of girth welds. Evaluation is based upon the results of mechanized ultrasonic examination. Acceptance criteria are based upon flaw limits defined by an Engineering Critical Assessment (ECA) or other accept/reject criteria defined by the Contracting Agency. 1.2 This practice shall be applicable to the development of an examination procedure agreed upon between the users of this practice. 1.3 The values stated in SI units are to be regarded as the standard. The inch-pound units given in parentheses are for information only. 1.4 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety, health, and environmental practices and determine the applicability of regulatory limitations prior to use. 1.5 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee. ====== Significance And Use ====== 4.1 This practice is intended primarily for the mechanized ultrasonic examination of pipe girth welds used in the construction of gas and oil pipelines. This practice, with appropriate modifications due to changes in weld profile, may also be used to examine repaired welds. Manual techniques such as described in Practice E164 may also be used to examine production or repaired welds. This practice, with appropriate modifications, may also be used to examine other forms of butt welds including long seams. 4.2 Techniques used are to be based on zonal discrimination whereby the weld is divided into approximately equal vertical examination sections (zones) each being assessed by a pair of ultrasonic search units. See Fig. 1 for typical zones. FIG. 1 Schematic Representation of Weld Zones and Discontinuities 4.3 Thicknesses of material examined are normally 7 to 25 mm (0.28 to 1.00 in.) and pipe diameters 15 cm (6.0 in.) and greater but this standard may apply to other thicknesses and diameters if the techniques can be proven to provide the required zonal discrimination. 4.4 Examination zones are typically 2 to 3 mm (0.08 to 0.12 in.) in height. For most applications this will require the use of contact focused search units to avoid interfering signals originating from off-axis geometric reflectors and to avoid excessive overlap with adjacent zones.