Standard Practice for Exposing and Evaluating Metals and Alloys in Surface Seawater

Importancia y uso:

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, 4

Note 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.

Subcomité:

G01.04

Referida por:

G0078-20

Volúmen:

03.02

Número ICS:

77.060 (Corrosion of metals)

Palabras clave:

evaluation and reporting; exposure conditions; fouling tests; specimen preparation; surface seawater corrosion tests; test racks;