1.1 本规程涵盖了在室温下制备和进行聚硫酸试验的程序，22 °C至25 摄氏度（72 °F至77 °F），以确定不锈钢或其他相关材料（镍铬铁合金）对晶间应力腐蚀开裂的相对敏感性。 1.2 本规程可用于评估处于“收到”状态或经过高温服务后的不锈钢或其他材料，482 °C至815 °C（900 °F至1500 °F），持续较长时间。 1.3 本规程适用于在含硫或硫化物环境中使用的不锈钢或其他相关材料的锻造产品、铸件和焊接金属。其他能够敏化的材料也可以根据该测试进行测试。 1.4 本规程可用于各种应力腐蚀试样、表面光洁度和施加应力的方法。 1.5 以国际单位制表示的数值应视为标准。 国际单位制后括号中给出的值仅供参考，不被视为标准值。 1.6 本标准并非旨在解决与其使用相关的所有安全问题（如有）。本标准的使用者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。 有关更具体的预防说明，请参阅第节 7. 。 1.7 本国际标准是根据世界贸易组织技术性贸易壁垒委员会发布的《关于制定国际标准、指南和建议的原则的决定》中确立的国际公认的标准化原则制定的。 ====意义和用途====== 4.1 多硫代酸在化学上被描述为H 2. S x 奥 6. ，其中x通常为3、4或5 ( 1. ) 3. 尽管可以超过50 ( 2. ) 这些酸性环境提供了一种评估不锈钢和相关合金对晶间应力腐蚀开裂的耐受性的方法。晶间沉淀物数量的增加会加速失效。聚硫酸试验的结果与晶间腐蚀试验的结果没有确切的相关性（试验方法 第28页 )。此外，该试验可能与氯化物或腐蚀性环境中的应力腐蚀开裂无关。 4.2 除了更局部和更深的开裂模式外，聚硫酸环境还可能产生浅晶间侵蚀区域。有必要对失效试样进行检查，以确认失效是由收缩截面的开裂而非机械失效引起的。

1.1 This practice covers procedures for preparing and conducting the polythionic acid test at room temperature, 22 °C to 25 °C (72 °F to 77 °F), to determine the relative susceptibility of stainless steels or other related materials (nickel-chromium-iron alloys) to intergranular stress corrosion cracking. 1.2 This practice can be used to evaluate stainless steels or other materials in the “as received” condition or after being subjected to high-temperature service, 482 °C to 815 °C (900 °F to 1500 °F), for prolonged periods of time. 1.3 This practice can be applied to wrought products, castings, and weld metal of stainless steels or other related materials to be used in environments containing sulfur or sulfides. Other materials capable of being sensitized can also be tested in accordance with this test. 1.4 This practice may be used with a variety of stress corrosion test specimens, surface finishes, and methods of applying stress. 1.5 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. 1.6 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 precautionary statements, see Section 7 . 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 Polythionic acids are chemically described as H 2 S x O 6 , where x is usually 3, 4, or 5 ( 1 ) 3 though can be more than 50 ( 2 ) . These acid environments provide a way of evaluating the resistance of stainless steels and related alloys to intergranular stress corrosion cracking. Failure is accelerated by the presence of increasing amounts of intergranular precipitate. Results for the polythionic acid test have not been correlated exactly with those of intergranular corrosion tests (Test Methods G28 ). Also, this test may not be relevant to stress corrosion cracking in chlorides or caustic environments. 4.2 The polythionic acid environment may produce areas of shallow intergranular attack in addition to the more localized and deeper cracking mode of attack. Examination of failed specimens is necessary to confirm that failure occurred by cracking rather than mechanical failure of reduced sections.