Standard Guide for Crevice Corrosion Testing of Iron-Base and Nickel-Base Stainless Alloys in Seawater and Other Chloride-Containing Aqueous Environments

Abstract

4.1 This guide covers procedures for crevice-corrosion testing of iron-base and nickel-base stainless alloys in seawater. The guidance provided may also be applicable to crevice corrosion testing in other chloride containing natural waters and various laboratory prepared aqueous chloride environments. 4.1.1 While this guide focuses on testing of iron-base and nickel-base stainless alloys, the procedures and evaluations methods described herein have been successfully applied to characterize the crevice corrosion performance of other alloy systems (see, for example, Aylor et al.4). Note 1: In the case of copper alloys, the occurrence of crevice-related corrosion associated with different corrosion mechanisms takes place immediately adjacent to the crevice former rather than within the occlusion. 4.2 This guide describes the use of a variety of crevice formers including the nonmetallic, segmented washer design referred to as the multiple crevice assembly (MCA) as described in 9.2.2. 4.3 In-service performance data provide the most reliable determination of whether a material would be satisfactory for a particular end use. Translation of laboratory data from a single test program to predict service performance under a variety of conditions should be avoided. Terms, such as immunity, superior resistance, etc., provide only a general and relatively qualitative description of an alloy's corrosion performance. The limitations of such terms in describing resistance to crevice corrosion should be recognized. 4.4 While the guidance provided is generally for the purpose of evaluating sheet and plate materials, it is also applicable for crevice-corrosion testing of other product forms, such as tubing and bars. 4.5 The presence or absence of crevice corrosion under one set of conditions is no guarantee that it will or will not occur under other conditions. Because of the many interrelated metallurgical, environmental, and geometric factors known to affect crevice corrosion, results from any given test may or may not be indicative of actual performance in service applications where the conditions may be different from those of the test.