1.1 本规程主要涵盖可用于各种试样和施加应力方法的试验介质。暴露时间、失效标准等都是可变的，没有具体规定。 1.2 本应力腐蚀试验规程适用于7XXX系列Al-Zn-Mg-Cu合金（含0.26 % 铜 1.3 以英寸-磅单位表示的值应视为标准值。括号中给出的值是对SI单位的数学转换，仅供参考，不被视为标准值。 1.4 本标准并不旨在解决与其使用相关的所有安全问题（如有）。本标准的使用者有责任在使用前建立适当的安全、健康和环境实践，并确定监管限制的适用性。 参见第节 8. 其他预防措施。 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《国际标准、指南和建议制定原则决定》中确立的国际公认标准化原则制定的。 =====意义和用途====== 4.1 本规程通常用于应力腐蚀筛选，以开发含0.26以下的Al-Zn-Mg-Cu合金 % 铜可比较成分、热机械加工、其他制造变量和施加应力大小等变量对应力腐蚀抗力的影响。 4.2 对于给定的机械应力方法，低铜Al-Zn-Mg-Cu合金在大气中的相对应力腐蚀耐受性与沸腾性能更好相关 % 氯化钠溶液比其他加速测试介质 ( 7- 9 ) 此外，这种做法相对快速。 4.3 本规程不适用于2XXX（Al-Cu）、5XXX（Al-Mg）、6XXX（Al-Mg-Si）和7XXX（Al-Zn-Mg-Cu）系列合金，这些合金的含量超过1.2 % 铜 4.3.1 对于含有0.26 % 和1.2 % 铜，对于这一惯例或惯例，没有达成一致意见 第44页 与使用中的抗应力腐蚀性更好相关 ( 5- 8. , 10 ) .

1.1 This practice primarily covers the test medium which may be used with a variety of test specimens and methods of applying stress. Exposure times, criteria of failure, and so on, are variable and not specified. 1.2 This stress-corrosion testing practice is intended for statically loaded smooth non-welded or welded specimens of 7XXX series Al-Zn-Mg-Cu alloys containing less than 0.26 % copper. 1.3 The values stated in inch-pound units are to be regarded as standard. The values given in parentheses are mathematical conversions to SI units that are provided for information only and are not considered standard. 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. See Section 8 for additional precautions. 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 normally used for stress-corrosion screening for the development of Al-Zn-Mg-Cu alloys containing less than 0.26 % copper. Effects on stress-corrosion resistance due to variables such as composition, thermo-mechanical processing, other fabrication variables, and magnitude of applied stress may be compared. 4.2 For a given mechanical method of stressing, the relative stress-corrosion resistance of the low copper Al-Zn-Mg-Cu alloys in atmospheric exposure correlates better with performance in boiling 6 % sodium chloride solution than with other accelerated testing media ( 7- 9 ) . In addition, this practice is relatively rapid. 4.3 This practice is not applicable to 2XXX (Al-Cu), 5XXX (Al-Mg), 6XXX (Al-Mg-Si), and the 7XXX (Al-Zn-Mg-Cu) series alloys containing more than 1.2 % copper. 4.3.1 For 7XXX series alloys containing between 0.26 % and 1.2 % copper, there is no general agreement as to whether this practice or Practice G44 correlates better with stress-corrosion resistance in service ( 5- 8 , 10 ) .