1.1 本试验方法包括两个绝热材料实验室评估程序，以确定绝热材料是否因绝热材料中的可溶性氯化物而导致奥氏体不锈钢的外部应力腐蚀开裂（ESCC）。本实验室程序并非旨在涵盖所有可能导致ESCC的现场条件。 1.2 虽然1977年版的本试验方法（Dana试验）仅适用于芯吸型绝缘，但本版本中的程序适用于所有绝缘材料，包括水泥，其中一些材料在根据1977年版进行试验时会分解。吸湿绝缘材料是指在部分（50 % 至75 %) 在水中浸泡短时间（10分钟或更短时间）。 1.3 这些程序主要用于对特定制造商产品的基本化学成分进行鉴定的生产前测试，而不是用于持续质量保证或生产批次合规性的常规测试。试验方法 C871 另一方面，用于确认先前通过该测试方法发现可接受的后续批次绝缘的可接受化学性质。 1.4 以英寸磅为单位的数值应视为标准。括号中给出的值是国际单位制的数学转换，仅供参考，不被视为标准。 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。 1.6 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====== 5.1 一些奥氏体不锈钢合金的固有特征是，当暴露在某些腐蚀性环境中时，它们在应力点处容易开裂。ESCC的机制很复杂，还不完全清楚，但显然与某些冶金性质有关。 在没有抑制离子的情况下，氯离子和氟离子有可能诱发应力腐蚀开裂。 3. 5.2 氯化物在许多环境中很常见，因此应特别注意保护奥氏体不锈钢免受氯化物污染。 5.3 大多数隔热材料本身不会引起应力腐蚀开裂。生产前鉴定试验用于评估在实验室试验条件下，特定隔热材料不会导致敏化奥氏体不锈钢开裂。绝缘系统有可能通过腐蚀性离子在加热的不锈钢表面上的迁移和集中而起到收集介质的作用。暴露在高温下会导致水蒸发和化学反应速率增加。 含有腐蚀性离子、湿气和氧气的环境会增加应力腐蚀开裂的机会。 5.4 可提供特殊配方的绝缘材料，通过改变基本成分或加入某些化学添加剂，在氯化物存在的情况下抑制应力腐蚀开裂。 5.5 Karnes记录了28天测试测量绝缘材料腐蚀电位的能力， 4. 其数据似乎已用于规范中使用的可接受性曲线的构建 C795 以及其他规范。 5.6 本试验方法中使用的所有试样的金属( C692 )应合格（见第节 14 )以确定在试验条件下，氯离子会导致金属破裂，而去离子水单独不会导致破裂。

1.1 This test method covers two procedures for the laboratory evaluation of thermal insulation materials to determine whether they contribute to external stress corrosion cracking (ESCC) of austenitic stainless steel due to soluble chlorides within the insulation. This laboratory procedure is not intended to cover all of the possible field conditions that contribute to ESCC. 1.2 While the 1977 edition of this test method (Dana test) is applicable only to wicking-type insulations, the procedures in this edition are intended to be applicable to all insulating materials, including cements, some of which disintegrate when tested in accordance with the 1977 edition. Wicking insulations are materials that wet through and through when partially (50 % to 75 %) immersed in water for a short period of time (10 min or less). 1.3 These procedures are intended primarily as a preproduction test for qualification of the basic chemical composition of a particular manufacturer's product and are not intended to be routine tests for ongoing quality assurance or production lot compliance. Test Methods C871 , on the other hand, is used for confirmation of acceptable chemical properties of subsequent lots of insulation previously found acceptable by this test method. 1.4 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. 1.5 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 ====== 5.1 An inherent characteristic of some alloys of austenitic stainless steel is their tendency to crack at stress points when exposed to certain corrosive environments. The mechanisms of ESCC are complex and not completely understood but are apparently related to certain metallurgical properties. Chloride and fluoride ions have the potential to induce stress corrosion cracking in the absence of inhibiting ions. 3 5.2 Chlorides are common to many environments, so great care shall be taken to protect austenitic stainless steel from chloride contamination. 5.3 Most thermal insulations will not, of themselves, cause stress corrosion cracking. Preproduction qualification tests are used to evaluate that under the conditions of the laboratory test that specific thermal insulation materials do not cause cracking of sensitized austenitic stainless steel. Insulation systems have the potential to act as collecting media by means of transmigration and concentration of corrosive ions on heated stainless steel surfaces. Exposure to elevated temperature results in evaporation of water and increased chemical reaction rates. Environments containing corrosive ions, moisture, and oxygen will increase the chance for stress corrosion cracking. 5.4 Insulation materials are available that are specially formulated to inhibit stress corrosion cracking in the presence of chlorides through modifications in basic composition or incorporation of certain chemical additives. 5.5 The ability of the 28-day test to measure the corrosion potential of insulation materials is documented by Karnes, 4 whose data appear to have been used for construction of the acceptability curve used in Specification C795 and other specifications. 5.6 The metal for all of the coupons used in this test method ( C692 ) shall be qualified (see Section 14 ) to ascertain that under conditions of the test, chloride ions will cause the metal to crack, and deionized water alone will not cause cracks.