【国外标准】 Standard Practice for Conducting and Evaluating Laboratory Corrosion Tests in Soils

4.1 This practice provides a controlled corrosive environment that has been utilized to produce relative corrosion information.4.2 The primary application of the data from this practice is to evaluate the performance of metallic materials for use in soil environments.4.3 This practice may not duplicate all field conditions and variables such as stray currents, microbiologically influenced corrosion, non-homogeneous conditions, pollutants in the soil, and long cell corrosion. The reproducibility of results in the practice is highly dependent on the type of specimen tested and the evaluation criteria selected as well as the control of the operating variables. In any testing program, sufficient replicates should be included to establish the variability of the results.4.4 Structures and components may be made of several different metals; therefore, the practice may be used to evaluate galvanic corrosion effects in soils (see Guide G71).4.5 Structures and components may be coated with sacrificial or noble metal coatings, which may be scratched or otherwise rendered discontinuous (for example, no coating on the edges of metal strips cut from a wide sheet). This test is useful to evaluate the effect of defective metallic coatings.4.6 Structures and components may be coated or jacketed with organic materials (for example, paints and plastics), and these coatings and jackets may be rendered discontinuous. The test is useful to evaluate the effect of defective or incompletely covering coatings and jackets.NOTE 1: The corrosivity of soils strongly depends on soluble salt content (related parameters are chemistry and soil resistivity, see Test Methods G57 and G187), acidity or alkalinity (measured by soil pH, see Test Method G51), Temperature, and oxygen content (loose, for example, sand, or compact, for example, clay, soils are extreme examples, see Test Method G200 – oxidation-reduction potential). The manufacturer, supplier, or user, or combination thereof, should establish the nature of the expected soil environment(s) and select the test environment(s) accordingly. Multiple types of soil can be used to determine the effect of this variable.1.1 This practice covers procedures for conducting laboratory corrosion tests in soils to evaluate the potential for corrosion attack on engineering materials in soils. The test is conducted under laboratory ambient temperature unless the effect of temperature is being evaluated. This practice does not include provisions for microbiological influenced corrosion (MIC) testing, nor its influence on results.1.2 This practice covers specimen selection and preparation, test environments, evaluation, and reporting of test results.1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.1.4 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.1.5 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.