Guidelines for the preparation of salt spray grade standards

With the acceleration of industrialization, particularly in marine environments, coastal regions, and specific industrial sectors such as chemicals, automobile manufacturing, and electronic equipment production, products are facing severe challenges from salt fog corrosion. To ensure product reliability and durability, it is crucial to establish and implement scientific standards for salt fog resistance levels. This standard aims to clearly define key elements such as the definition of salt fog resistance levels, test environments and methods, evaluation of corrosion resistance, material selection and treatment, design and protective measures, the scope of standard application, as well as test reporting and judgments, providing unified technical specifications and evaluation criteria for relevant industries.

I. Level Definition and Classification

‌Definition of Salt Fog Resistance Levels‌: Salt fog resistance levels are quantitative indicators used to measure a product's ability to resist salt fog corrosion, typically classified based on the degree of surface or internal performance degradation after exposure to salt fog under specific conditions.

‌Level Classification‌:

Level 1: The basic level, suitable for general products not directly exposed to salt fog environments.

Levels 2-5: Medium protection levels, gradually increasing resistance to salt fog environments, suitable for products used in some outdoor or near-shore areas.

Levels 6-8: High protection levels, specifically designed for harsh marine environments, ensuring products maintain good performance in long-term salt fog environments.

Levels 9-10:Extreme protection levels, requiring products to operate stably in extremely harsh marine environments, such as deep-sea equipment and naval ship equipment.

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II. Test Environments and Methods

Test Environments‌: Should simulate real salt fog conditions, typically using sodium chloride (NaCl) solution atomized through compressed air to form a salt fog environment with a specified concentration. Temperature, humidity, and salt fog concentration need to be adjusted according to specific level requirements.

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Test Methods‌: Including but not limited to Neutral Salt Fog Test (NSS), Acetic Acid Salt Fog Test (ASS), Copper-Accelerated Acetic Acid Salt Fog Test (CASS), etc., selecting appropriate test methods based on product characteristics and the type of corrosion to be evaluated.

IV. Evaluation of Corrosion Resistance

Evaluation Standards‌: Based on a comprehensive assessment of changes in product appearance after testing (such as rust, coating peeling), loss of mechanical performance (such as reduced strength), and changes in electrical performance (such as increased resistance).

Rating Basis‌:According to the evaluation results, combined with the thresholds set in the specific level standards, the corrosion resistance of the product is rated.

V. Material Selection and Surface Treatment

Material Selection‌: Priority is given to materials with excellent corrosion resistance, such as stainless steel, specially treated aluminum alloys, weathering steel, etc.

Surface Treatment‌: Enhance the corrosion resistance of materials through surface treatment techniques such as electroplating, thermal spraying, chemical plating, and anodizing.

VII. Scope of Standard Application

This standard applies to all products that require assessment of salt fog corrosion resistance, including but not limited to metal products, electronic products, automotive parts, ship equipment, marine engineering facilities, etc.

VIII. Test Reporting and Judgments

Test Reporting‌:Detailed records of test conditions, methods, processes, results, and evaluation conclusions serve as important documents for product quality certification and technical exchanges.

Judgments‌:Based on the test report, comparisons with the level requirements in the standard are made to determine whether the product is qualified, and corresponding certificates of conformity or notices of non-conformity are issued.

In summary, the formulation and implementation of salt fog resistance level standards are of great significance for improving product corrosion resistance, extending service life, and ensuring user safety. Various industries should actively adopt and continuously improve relevant standard systems based on their actual situations.