GB/T 20853-2026 Corrosion of metals and alloys—Corrosion in artificial atmosphere—Accelerated corrosion test involving exposure under controlled conditions of humidity cycling and intermitted spraying of a salt solution

Scope

This document describes two closely related atmospheric accelerated testing procedures that combine intermittent salt spray exposure and dynamic humidity variation patterns. Procedure A is conducted under constant dew point conditions, while Procedure B is conducted under constant temperature conditions. These methods are used to evaluate the corrosion resistance of metals in environments significantly influenced by chloride ions (primarily from sodium chloride, such as that found in winter road de-icing salts). However, the test results cannot comprehensively predict the corrosion resistance of the tested metal materials in all possible service environments, but only provide information on the relative corrosion resistance of the materials in salt-contaminated environments and under humidity variation conditions. These two laboratory accelerated corrosion testing procedures are suitable for: - Metals and their alloys (ferrous and non-ferrous); - Metal coatings; - Chemical conversion coatings; - Organic coatings on metal substrates; - Material and coating combinations involving galvanic corrosion and/or crevice corrosion effects. Note 1: If low-alloy stainless steels, particularly austenitic stainless steels, are tested according to this document, excessive pitting corrosion may occur, which does not represent their corrosion behavior in most actual service environments. Note 2: Due to the continuous heating during the test, this document is not applicable to the testing of wax-based and oil-based rust inhibitors. This document also specifies the requirements for testing equipment and includes detailed quality control procedures, including recommended instruments. This document does not specify the size of the samples, the exposure time for specific products, or the interpretation of the results. These details will be specified in the corresponding product specifications.

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