1.1 本试验方法包括一种加速试验方法，用于评估气体泄漏检测液（LDF）在压缩气体服务中导致黄铜部件应力腐蚀开裂（SCC）的趋势。 1.2 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。 1.3 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。 1.4 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 黄铜部件通常用于阀门、压力调节器、连接器和许多其他部件的压缩气体服务中。虽然软黄铜不易受到氨应力腐蚀开裂的影响，但如果加工硬化黄铜的硬度超过约54 HR 30T（55HRB）（洛氏硬度）。黄铜部件的正常装配不应导致足够的加工硬化，从而导致对氨应力腐蚀开裂的敏感性。然而，已经观察到，部件的过度拧紧将使其容易发生应力腐蚀开裂，并且在已多次拧紧的旧部件中，该问题变得更加严重。在本试验中，在硬化条件下获得试样，并将其应变超过弹性极限，以加速应力腐蚀开裂的趋势。 5.2 通常情况下，使用LDF检查加压系统，以确保不会发生泄漏。LDF通常是含有表面活性剂的水溶液，这些表面活性剂会在泄漏部位形成气泡。如果LDF含有氨或其他可能导致黄铜SCC的药剂，则系统可能会发生严重损坏，危及其安全性和完整性。 5.3 测试LDF以确保其不会导致黄铜SCC，并确保这些产品的使用不会损害承压系统的完整性，这一点很重要。 5.4 已经发现，在发生应力腐蚀开裂之前，必须对黄铜进行腐蚀。原因是腐蚀过程导致铜和亚铜离子在电解液中累积。因此，添加金属铜和氧化亚铜（Cu 2. O） 如果存在导致SCC的试剂，则水溶液加速SCC过程。然而，将这些成分添加到不会引起应力腐蚀开裂的溶液中不会使应力黄铜开裂。 5.5 将溶液反复应用于试样，然后进行干燥，会导致溶液中的成分浓缩，从而进一步增加开裂速率。这还模拟了系统在其寿命期间可能会多次测试的服务。测试方法的这些特点加速了测试，并允许更快地获得答案。 5.6 本试验方法仅适用于黄铜。成功通过本试验并不能保证LDF可用于其他合金系统，如不锈钢或铝合金。

1.1 This test method covers an accelerated test method for evaluating the tendency of gas leak detection fluids (LDFs) to cause stress corrosion cracking (SCC) of brass components in compressed gas service. 1.2 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. 1.3 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. 1.4 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 Brass components are routinely used in compressed gas service for valves, pressure regulators, connectors and many other components. Although soft brass is not susceptible to ammonia SCC, work-hardened brass is susceptible if its hardness exceeds about 54 HR 30T (55HRB) (Rockwell scale). Normal assembly of brass components should not induce sufficient work hardening to cause susceptibility to ammonia SCC. However, it is has been observed that over-tightening of the components will render them susceptible to SCC, and the problem becomes more severe in older components that have been tightened many times. In this test, the specimens are obtained in the hardened condition and are strained beyond the elastic limit to accelerate the tendency towards SCC. 5.2 It is normal practice to use LDFs to check pressurized systems to assure that leaking is not occurring. LDFs are usually aqueous solutions containing surfactants that will form bubbles at the site of a leak. If the LDF contains ammonia or other agent that can cause SCC in brass, serious damage can occur to the system that will compromise its safety and integrity. 5.3 It is important to test LDFs to assure that they do not cause SCC of brass and to assure that the use of these products does not compromise the integrity of the pressure containing system. 5.4 It has been found that corrosion of brass is necessary before SCC can occur. The reason for this is that the corrosion process results in cupric and cuprous ions accumulating in the electrolyte. Therefore, adding copper metal and cuprous oxide (Cu 2 O) to the aqueous solution accelerates the SCC process if agents that cause SCC are present. However, adding these components to a solution that does not cause SCC will not make stressed brass crack. 5.5 Repeated application of the solution to the specimen followed by a drying period causes the components in the solution to concentrate thereby further increasing the rate of cracking. This also simulates service where a system may be tested many times during its life. These features of the test method accelerate the test and allow an answer to be obtained more rapidly. 5.6 This test method applies only to brasses. Successful passage of this test does not assure that the LDF will be acceptable for use on other alloy systems such as stainless steels or aluminum alloys.