1.1 本试验方法涵盖了定量加速实验室评估从隔热材料中浸出的含有离子的提取溶液对碳钢水性腐蚀影响的程序。该实践的主要目的是与隔热材料和相关材料一起使用，这些材料有助于或可替代地抑制碳钢的水性腐蚀，因为可溶性离子被隔热材料内的水浸出。定量评估标准是质量损失腐蚀率（MLCR），以密耳/年为单位，根据清洁后暴露的金属试片腐蚀造成的重量损失确定。 1.2 该试验方法不能涵盖所有可能导致水腐蚀的现场条件。其目的是提供一种获得非主观数值的加速方法，用于判断可能来自隔热材料或其他实验溶液中所含离子的碳钢腐蚀的潜在贡献。计算的数值是质量损失腐蚀速率。该计算基于在试验持续时间内平均分布的一般腐蚀和为试验创建的实验电池的暴露面积。在现场情况下发现的腐蚀和这种加速试验还涉及点蚀、边缘效应和随时间变化的速率。 1.3 可以通过在溶液中添加腐蚀性离子来模拟外部污染，从而改变为测试中使用而制备的绝缘提取溶液。可以添加预期提供缓蚀作用的离子来研究其抑制作用。 1.4 制备的实验室离子溶液用作参考溶液和对照品，以提供校准和比较的方法。 2. 1.5 可以测试其他液体的潜在腐蚀性，包括冷却塔水、锅炉给水和化学原料。添加的化学抑制剂或应用于金属的保护涂层也可以使用实践的一般指南进行评估。 1.6 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。 1.7 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。 1.8 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 加速腐蚀试验的结果不应被视为金属设备使用寿命的指标。许多因素需要考虑是否适用于具体情况。请参阅指南 C1696 和实践 G31 以获取更多信息。 5.2 与绝缘相关的腐蚀是绝缘制造商、规范编写者、设计人员、承包商、用户和设备操作员关注的一个重要问题。一些材料规范包含测试方法（或其他材料规范中包含的参考测试方法），用于评估钢、铜和铝的腐蚀绝缘。 在某些情况下，这些测试不适用或无效，并且没有对精度和偏差进行评估。 5.3 正确选择、安装和维护隔热系统将减少未隔热结构上经常发生的腐蚀。然而，当绝缘系统的防风雨保护层失效时，通常会产生绝缘下腐蚀（CUI）所需的水环境条件。绝缘层可能含有、收集或浓缩腐蚀剂，或其组合，通常存在于工业和沿海环境中。如果不存在水，这些电解质就不能迁移到金属表面。 导致金属表面水性腐蚀的电化学反应不能在没有水和电解质的情况下发生。导致腐蚀速率增加的其他环境因素是氧气和升高的温度（接近沸点）。 5.4 氯化物和其他腐蚀性离子在许多环境中很常见。主要的防腐措施是保护绝缘层和金属免受污染和潮湿。通常使用各种绝缘盖、护套和金属涂层来防止水渗透和与金属接触。 5.5 该程序可用于评估所有类型的隔热和防火材料（工业、商业、住宅、低温、火灾- 电阻、绝缘水泥），其使用无机或有机材料制造，有表面或无表面，可获得过滤的提取溶液。 5.6 该程序也适用于绝缘附件，包括与绝缘和绝缘产品相关的护套、盖子、粘合剂、水泥和粘合剂。 5.7 绝缘的热处理（按照制造商的建议，最高可达最大潜在暴露温度）可用于模拟可能的使用条件。 5.8 粘合剂可以通过首先干燥，然后提取水来测试，或者通过将已知量的测试粘合剂施加到绝缘试件上，然后提取来测试。 5.9 绝缘水泥可以通过浇铸板、干燥和提取或使用未固化的绝缘水泥粉末进行提取来进行测试。 5.10 使用有助于被测碳钢腐蚀的各种浓度溶液制备的参考试验作为比较标准。使用含有氯化物的溶液以及仅使用去离子水的“空白”试验。 5.11 可以对经过特殊配方的绝缘材料进行研究，通过改变基本成分或加入某些化学添加剂，在腐蚀性离子存在的情况下抑制腐蚀。腐蚀性离子也可以添加到绝缘提取溶液中，以确定存在的任何抑制剂的有效性。 5.12 不同类型和厚度的保护性表面处理和涂层可以应用于碳钢，并使用各种腐蚀性液体进行比较。 5.13 由于影响腐蚀的因素很多，建议进行几组测试。测试的平均值和测试结果之间的标准偏差用于数据。大部分腐蚀文献建议每次试验至少使用三个试样。查阅指南 G16 用于应用于腐蚀数据的其他统计方法。

1.1 This test method covers procedures for a quantitative accelerated laboratory evaluation of the influence of extraction solutions containing ions leached from thermal insulation on the aqueous corrosion of carbon steel. The primary intent of the practice is for use with thermal insulation and associated materials that contribute to, or alternatively inhibit, the aqueous corrosion of carbon steel due to soluble ions that are leached by water from within the insulation. The quantitative evaluation criteria are Mass Loss Corrosion Rate (MLCR) expressed in mils per year determined from the weight loss due to corrosion of exposed metal coupons after they are cleaned. 1.2 This test method cannot cover all possible field conditions that contribute to aqueous corrosion. The intent is to provide an accelerated means to obtain a non-subjective numeric value for judging the potential contribution to the corrosion of carbon steel that can come from ions contained in thermal insulation materials or other experimental solutions. The calculated numeric value is the mass loss corrosion rate. This calculation is based on general corrosion spread equally over the test duration and the exposed area of the experimental cells created for the test. Corrosion found in field situations and this accelerated test also involves pitting, edge effects, and the rate changes over time. 1.3 The insulation extraction solutions prepared for use in the test can be altered by the addition of corrosive ions to the solutions to simulate contamination from an external source. Ions expected to provide corrosion inhibition can be added to investigate their inhibitory effect. 1.4 Prepared laboratory ionic solutions are used as reference solutions and controls, to provide a means of calibration and comparison. 2 1.5 Other liquids can be tested for their potential corrosiveness including cooling tower water, boiler feed, and chemical stocks. Added chemical inhibitors or protective coatings applied to the metal can also be evaluated using the general guidelines of the practice. 1.6 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. 1.7 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. 1.8 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 Results from this accelerated corrosion test shall not be considered as an indicator of the useful life of the metal equipment. Many factors need consideration for applicability to specific circumstances. Refer to Guide C1696 and Practice G31 for additional information. 5.2 Corrosion associated with insulation is an important concern for insulation manufacturers, specification writers, designers, contractors, users and operators of the equipment. Some material specifications contain test methods (or reference test methods contained in other material specifications), for use in evaluating the insulation with regard to the corrosion of steel, copper, and aluminum. In some cases these tests are not applicable or effective and have not been evaluated for precision and bias. 5.3 A properly selected, installed, and maintained insulation system will reduce the corrosion that often occurs on an un-insulated structure. However, when the protective weather-resistant covering of an insulation system fails, the conditions for the aqueous environment necessary for corrosion under insulation (CUI) often develop. It is possible the insulation contains, collects, or concentrates corrosive agents, or a combination thereof, often found in industrial and coastal environments. If water is not present, these electrolytes cannot migrate to the metal surface. The electrochemical reaction resulting in the aqueous corrosion of metal surfaces cannot take place in the absence of water and electrolytes. Additional environmental factors contributing to increased corrosion rates are oxygen, and elevated-temperature (near boiling point). 5.4 Chlorides and other corrosive ions are common to many environments. The primary corrosion preventative is to protect insulation and metal from contamination and moisture. Insulation covers, jackets, and metal coating of various kinds are often used to prevent water infiltration and contact with the metal. 5.5 This procedure can be used to evaluate all types of thermal insulation and fireproofing materials (industrial, commercial, residential, cryogenic, fire-resistive, insulating cement) manufactured using inorganic or organic materials, faced or unfaced, for which a filtered extraction solution can be obtained. 5.6 This procedure can also be applicable to insulation accessories including jacketing, covers, adhesives, cements, and binders associated with insulation and insulation products. 5.7 Heat treatment of the insulation (as recommended by the manufacturer up to the maximum potential exposure temperature) can be used to simulate possible conditions of use. 5.8 Adhesives can be tested by first drying followed by water extraction or by applying a known quantity of the test adhesive to a test piece of insulation and then extracting. 5.9 Insulating cements can be tested by casting a slab, drying, and extracting or by using the uncured insulating cement powder for extraction. 5.10 Reference tests prepared with various concentrations of solutions that are conducive to the corrosion of the tested carbon steel serve as comparative criteria. Solutions containing chloride, as well as “blank” tests using only de-ionized water are used. 5.11 Research can be done on insulation that has been specially formulated to inhibit corrosion in the presence of corrosive ions through modifications in basic composition or incorporation of certain chemical additives. Corrosive ions can also be added to the insulation extraction solutions to determine the effectiveness of any inhibitors present. 5.12 Protective surface treatments and coatings of different types and thickness can be applied to the carbon steel and compared using various corrosive liquids. 5.13 Several sets of tests are recommended because of the number of factors that affect corrosion. An average of the tests and the standard deviation between the test results are used on the data. Much of the corrosion literature recommends a minimum of three specimens for every test. Consult Guide G16 for additional statistical methods to apply to the corrosion data.