1.1 本规程涵盖了脉冲回波超声波检验的要求，并包括当制造商规定进行超声波检验时，或当买方在收到时进行超声波检验时，用于定义铝合金锻造产品适用质量水平的标准。 1.2 如果交付后材料发生塑性变形，则本规程不适用。 1.3 本规程中描述的超声波检测用于检测平行于或几乎平行于产品表面的方向上的内部不连续性。该测试通过浸入法或接触法进行，使用脉冲纵波，由包含单晶或电互连多晶体组合的搜索单元发射和接收。 不包括采用穿透透射或角束技术的超声波检测。 注1: 采用角束技术的超声波测试需要特殊的参考试块、搜索装置和扫描程序，当合同或采购订单要求进行此类测试时，买方和卖方应进行协商。 1.4 以英寸-磅为单位的数值应视为标准值。括号中给出的值是到国际单位制的数学转换，仅供参考，不被视为标准值。 1.5 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。 1.6 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====== 5.1 许多因素，例如受检零件的入口和背面的状况、超声波束相对于入口表面的倾角以及测试系统性能特征的变化，可能会导致不连续指示和背面反射的幅度出现显著差异。 这些因素会严重影响本规程中概述的超声波检测的可靠性和定量值。 5.2 不连续尺寸的准确评估也受到搜索单元特征变化和可能影响反射率的不连续表面不规则性的显著影响。由于这些原因，鉴于测量的定量值有限，本规程中概述的超声波比较可能暗示的不连续尺寸必须视为“明显”或“估计”。 5.3 由于测试系统中的众多交互变量可能会对超声波检测的结果产生不利影响，因此难以确定检测到的不连续性对受检产品机械性能的实际定量影响。 虽然本规程提供了制造过程中产品质量的可靠控制，但它不适用于作为本规程所涵盖的受检产品制造的部件的最终质量和性能的唯一指标。

1.1 This practice covers the requirements for pulse-echo ultrasonic inspection and includes criteria used to define applicable quality levels of aluminum-alloy wrought products when performance of the ultrasonic test by the producer is specified, or when ultrasonic inspection is performed by the purchaser upon receipt. 1.2 This practice is not applicable if plastic deformation is introduced into the material after delivery. 1.3 The ultrasonic test described in this practice is employed to detect internal discontinuities oriented in a direction parallel to, or nearly parallel to, the surface of the product. The test is performed either by the immersion method or the contact method using pulsed longitudinal waves which are transmitted and received by a search unit containing either a single crystal or a combination of electrically interconnected multiple crystals. Ultrasonic tests employing either the through-transmission or the angle-beam techniques are not included. Note 1: Ultrasonic tests employing angle-beam techniques require special reference blocks, search units, and scanning procedures and are subject to negotiation between the purchaser and the seller when such tests are required by the contract or purchase order. 1.4 The values stated in inch-pound units are to be regarded as the standard. The values given in parentheses are mathematical conversions to SI units which are provided for information only and are not considered standard. 1.5 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. 1.6 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 ====== 5.1 A number of factors such as the condition of the entry and back surfaces of the inspected part, the inclination of the ultrasonic beam with respect to the entry surface, and variations in the performance characteristics of the test system may cause significant differences in amplitudes of discontinuity indications and back reflections. These factors can seriously impair the reliability and the quantitative value of the ultrasonic test outlined in this practice. 5.2 Accurate evaluations of discontinuity size are also significantly affected by variations in search unit characteristics and by irregularities in discontinuity surfaces which can influence reflectivity. For these reasons, the discontinuity sizes that may be implied by the ultrasonic comparisons outlined in this practice must be regarded as “apparent” or “estimated” in recognition of the limited quantitative value of the measurement. 5.3 Because numerous interacting variables in a test system can adversely influence the results of an ultrasonic inspection, the actual quantitative effects of detected discontinuities upon the mechanical properties of the inspected product are difficult to establish. Although this practice provides a reliable control of product quality during manufacture, it is not applicable as an exclusive indicator of the ultimate quality and performance of components fabricated from the inspected products covered by this practice.