1.1 本规程涵盖了pH值为7.2的Mattsson溶液的制备和使用，作为黄铜（铜锌基合金）的加速应力腐蚀开裂试验环境。描述了需要控制的变量（在目前已知的范围内）以及控制和标准化这些变量的可能方法。 1.2 本规程仅适用于黄铜（铜锌基合金）。不建议对其他铜合金使用此测试环境，因为结果可能是错误的，提供了完全误导性的排名。这尤其适用于含有铝或镍作为有意合金添加剂的合金。 1.3 本规程主要用于测试目的是确定不同黄铜在相同或不同应力条件下的相对应力腐蚀开裂敏感性，或确定 完全的 在一个或多个特定应力条件下，特定黄铜或黄铜部件的应力腐蚀开裂敏感性程度（如有）。当然，也存在使用此测试解决方案的其他合法测试目标。存在的拉伸应力可能是已知的或未知的、施加的或残余的。该规程可适用于锻造黄铜产品或部件、黄铜铸件、黄铜焊接件等，以及所有黄铜。 规定了严格的环境试验条件，以最大限度地保证应力腐蚀敏感性的明显变化可归因于被测材料或拉伸应力水平的实际变化，而不是环境变化。 1.4 本规程仅涉及测试环境的准备和控制。不建议进行表面处理或精加工，或两者兼有，因为这可能随测试目标而异。同样，也没有尝试推荐特定的应力腐蚀试样配置或施加应力的方法。实践中参考了可能使用的试样配置 G30 和STP 425 2. 1.5 以国际单位制表示的数值应视为标准值。本标准不包括其他计量单位。 1.6 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。 （有关更具体的安全危险声明，请参阅第节。） 8. .) 1.7 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 该测试环境被认为可以加速相对或 完全的 不同黄铜的应力腐蚀开裂敏感性程度。已发现其与导致应力腐蚀开裂的环境中的相应服务等级密切相关，应力腐蚀开裂被认为是由于微量水分和氨蒸汽的共同存在。目前尚不清楚加速排序在多大程度上与长期暴露于含有氨以外腐蚀剂的环境后获得的排序相关。这种环境的例子可能是恶劣的海洋大气（Cl − )、恶劣的工业环境（主要是SO 2. )，以及过热的无氨蒸汽。 4.2 目前不可能在pH 7.2 Mattsson溶液中规定任何特定的失效时间（根据任何特定的失效标准定义），该溶液对应于黄铜合金中可接受和不可接受的应力腐蚀行为之间的区别。这种特殊的相关性必须单独确定。 4.3 pH值为7.2的Mattsson溶液也可能在一定程度上导致黄铜的非应力一般腐蚀和晶间腐蚀。这导致可能将应力腐蚀故障与腐蚀引起的机械故障混淆- 减少净截面。这种危险在小截面试样、高施加应力水平、长暴露时间和抗应力腐蚀合金中尤其严重。建议仔细进行金相检查，以正确诊断故障原因。或者，可以暴露无应力对照试样，以评估应力独立腐蚀降低机械性能的程度。

1.1 This practice covers the preparation and use of Mattsson’s solution of pH 7.2 as an accelerated stress-corrosion cracking test environment for brasses (copper-zinc base alloys). The variables (to the extent that these are known at present) that require control are described together with possible means for controlling and standardizing these variables. 1.2 This practice is recommended only for brasses (copper-zinc base alloys). The use of this test environment is not recommended for other copper alloys since the results may be erroneous, providing completely misleading rankings. This is particularly true of alloys containing aluminum or nickel as deliberate alloying additions. 1.3 This practice is intended primarily where the test objective is to determine the relative stress-corrosion cracking susceptibility of different brasses under the same or different stress conditions or to determine the absolute degree of stress corrosion cracking susceptibility, if any, of a particular brass or brass component under one or more specific stress conditions. Other legitimate test objectives for which this test solution may be used do, of course, exist. The tensile stresses present may be known or unknown, applied or residual. The practice may be applied to wrought brass products or components, brass castings, brass weldments, and so forth, and to all brasses. Strict environmental test conditions are stipulated for maximum assurance that apparent variations in stress-corrosion susceptibility are attributable to real variations in the material being tested or in the tensile stress level and not to environmental variations. 1.4 This practice relates solely to the preparation and control of the test environment. No attempt is made to recommend surface preparation or finish, or both, as this may vary with the test objectives. Similarly, no attempt is made to recommend particular stress-corrosion test specimen configurations or methods of applying the stress. Test specimen configurations that may be used are referenced in Practice G30 and STP 425. 2 1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.6 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. (For more specific safety hazard statements see Section 8 .) 1.7 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 test environment is believed to give an accelerated ranking of the relative or absolute degree of stress-corrosion cracking susceptibility for different brasses. It has been found to correlate well with the corresponding service ranking in environments that cause stress-corrosion cracking which is thought to be due to the combined presence of traces of moisture and ammonia vapor. The extent to which the accelerated ranking correlates with the ranking obtained after long-term exposure to environments containing corrodents other than ammonia is not at present known. Examples of such environments may be severe marine atmospheres (Cl − ), severe industrial atmospheres (predominantly SO 2 ), and super-heated ammonia-free steam. 4.2 It is not possible at present to specify any particular time to failure (defined on the basis of any particular failure criteria) in pH 7.2 Mattsson’s solution that corresponds to a distinction between acceptable and unacceptable stress-corrosion behavior in brass alloys. Such particular correlations must be determined individually. 4.3 Mattsson's solution of pH 7.2 may also cause stress independent general and intergranular corrosion of brasses to some extent. This leads to the possibility of confusing stress-corrosion failures with mechanical failures induced by corrosion-reduced net cross sections. This danger is particularly great with small cross section specimens, high applied stress levels, long exposure periods and stress-corrosion resistant alloys. Careful metallographic examination is recommended for correct diagnosis of the cause of failure. Alternatively, unstressed control specimens may be exposed to evaluate the extent to which stress independent corrosion degrades mechanical properties.