【国外标准】 Standard Practice for Exposing and Evaluating Metals and Alloys in Surface Seawater

4.1 The procedures described herein are recommended for evaluating the corrosion or marine fouling behavior, or both, of materials exposed to quiescent or local tidal flow conditions, or both.4.1.1 This practice is not intended to cover the influence of high seawater velocity or the behavior of materials in seawater which has been transported from its source.4.1.2 Some aspects of this practice may be applicable to testing in tanks and troughs, which are continuously provided with surface seawater pumped directly from the source. Additionally, some aspects may also be applicable to deep ocean testing.NOTE 1: Guide G78 provides guidance for conducting crevice corrosion tests under controlled seawater test conditions.4.2 While the duration of testing may be dictated by the test objectives, exposures of more than six months or one year are commonly used to minimize the effects of environmental variables associated with seasonal changes or geographic location, or both. Refer also to 7.3 for test duration recommendations.4.3 The procedures described are applicable for the exposure of simple test panels, welded test panels, or those configured to assess the effects of crevices, or both, such as those described in Guide G78. In addition, they are useful for testing of actual components and fabricated assemblies.4.4 It is prudent to include control materials with known resistance to seawater corrosion or fouling, or both, as described in Test Method D3623.NOTE 2: Materials which have been included in ASTM Worldwide Seawater Corrosivity Studies include UNS K01501 (carbon steel), UNS C70600 (90/10 CuNi) and UNS A95086 (5086-H116 Al).2, 4NOTE 3: In the case of evaluations of aluminum alloys, care should be exercised in the location of specimens near copper or high copper-containing alloys. In some instances, it is not sufficient to simply electrically isolate specimens to prevent bi-metallic (galvanic) corrosion; copper ions from nearby corroding copper or copper-base alloys can deposit on aluminum and accelerate its corrosion.1.1 This practice covers conditions for the exposure of metals, alloys, and other materials in natural surface seawater such as those typically found in bays, harbors, channels, and so forth,2 as contrasted with deep ocean testing.3 This practice covers full immersion, tidal zone and related splash, and spray zone exposures.2, 41.2 This practice sets forth general procedures that should be followed in conducting seawater exposure tests so that meaningful comparisons may be made from one location to another.1.3 This practice identifies recommended procedures for evaluating the effects of natural surface seawater on the materials exposed.1.4 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.1.5 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.