1.1 本规程涵盖了3.5中进行交替浸入应力腐蚀试验的程序 % 氯化钠（NaCl）( 注1 ). 主要用于铝合金试验（试验方法 G47 )和铁合金，但可用于其他对氯离子敏感的金属。它规定了试验的环境条件和控制方法。 注1: 有时在按照惯例制备的替代海水（不含重金属）中进行交替浸入应力腐蚀暴露 D1141 . 本规程的一般要求也适用于此类暴露，但所用试剂、溶液浓度和溶液pH值应符合规程的规定 D1141 . 1.2 这种做法可用于应力和非应力腐蚀试样。历史上，它曾用于应力腐蚀开裂测试，但通常用于其他形式的腐蚀，如均匀腐蚀、点蚀、晶间腐蚀和电偶腐蚀。 1.3 本规程适用于合金开发和交替浸渍试验作为连续批次相同材料质量控制试验的应用。因此，规定了严格的测试条件，以最大限度地保证结果的变化是由被测试材料的变化引起的。 1.4 以国际单位制表示的数值应视为标准值。 国际单位制后括号中给出的值仅供参考，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====== 4.1 3.5 % NaCl交替浸渍程序是一种通用的多用途程序，可对大多数金属进行有效比较，尤其是当试样暴露在高水平的外加应力或应力强度下时。 4.2 虽然交替浸泡试验是一种加速试验，被认为是某些自然条件的代表，但其目的不是预测在可能存在不同开裂模式的特殊化学环境中的性能。例如，它不能预测铝合金在高酸性环境中的性能，例如加热抑制红色发烟硝酸（IRFNA）。 在这种情况下，在替代浸入试验与预期服务环境之间建立关系之前，其结果的重要性值得怀疑。 4.3 虽然这一做法在某种程度上适用于所有金属，但它对所有合金的区别并不相同，即使在同一金属系统内。因此，应建立信息，以便在交替浸泡试验和自然环境中比较相关合金的性能。 注2: 交替浸入概念可用于腐蚀试样在其他溶液中的暴露，因为程序和设备提供了一组受控的条件。 这方面的细节超出了本惯例的范围。

1.1 This practice covers procedures for making alternate immersion stress corrosion tests in 3.5 % sodium chloride (NaCl) ( Note 1 ). It is primarily for tests of aluminum alloys (Test Method G47 ) and ferrous alloys, but may be used for other metals exhibiting susceptibility to chloride ions. It sets forth the environmental conditions of the test and the means for controlling them. Note 1: Alternate immersion stress corrosion exposures are sometimes made in substitute ocean water (without heavy metals) prepared in accordance with Practice D1141 . The general requirements of this present practice are also applicable to such exposures except that the reagents used, the solution concentration, and the solution pH should be as specified in Practice D1141 . 1.2 This practice can be used for both stressed and unstressed corrosion specimens. Historically, it has been used for stress-corrosion cracking testing, but is often used for other forms of corrosion, such as uniform, pitting, intergranular, and galvanic. 1.3 This practice is intended for alloy development and for applications where the alternate immersion test is to serve as a control test on the quality of successive lots of the same material. Therefore, strict test conditions are stipulated for maximum assurance that variations in results are attributable to variations in the material being tested. 1.4 The values stated in SI units are to be regarded as standard. The values given in parentheses after SI units 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 ====== 4.1 The 3.5 % NaCl alternate immersion procedure is a general, all-purpose procedure that produces valid comparisons for most metals, particularly when specimens are exposed at high levels of applied stress or stress intensity. 4.2 While the alternate immersion test is an accelerated test and is considered to be representative of certain natural conditions, it is not intended to predict performance in specialized chemical environments in which a different mode of cracking may be operative. For example, it does not predict the performance of aluminum alloys in highly acidic environments such as heated inhibited red fuming nitric acid (IRFNA). For such cases, the results of the alternate immersion test are of doubtful significance until a relationship has been established between it and anticipated service environments. 4.3 While this practice is applicable in some degree to all metals, it is not equally discriminative of all alloys, even within the same metal system. Consequently, information should be established to allow comparisons of performances of the alloy of interest in the alternate immersion test and in natural environments. Note 2: The alternate immersion concept can be useful for exposure of corrosion specimens in other solutions because the procedure and apparatus provide a controlled set of conditions. Details of this are beyond the scope of this practice.