Methods & requirements

ASTM B 117 Corrosion Test

Corrosion testing determines the resistance of materials to corrosion under specific environmental conditions, like temperature and humidity. Other accelerating factors can be presence of chemicals and the pH-level of the salt fog and pluviometry.

There are mainly two different types of corrosion test standards, field performance and accelerated corrosion tests. Cotec Labs is focused on different types of standardized corrosion tests.

What is important when choosing a test method is to make sure the controlled environment matches the natural outside environment in terms of behaviour of the protective coating when it degrades. Since the methods used in a laboratory environment are accelerated, studies must underpin the extrapolation of test duration.

Example Weiss, Salt-spray cabinets. Normally used for the Automotive industry, Engineering, building and furniture.

What is ASTM B117 test?

ASTM B 117 is a widely used standard that provides a test method for evaluating the corrosion resistance of metallic materials. The standard is maintained by ASTM International, an organization that develops and publishes voluntary consensus technical standards for a wide range of materials, products, systems, and services. It is an important standard for manufacturers, researchers, and other professionals involved in the production, use, and testing of metallic materials.

The purpose is to provide a uniform and reproducible test method for determining the corrosion resistance of metallic materials. The standard specifies the conditions for conducting a salt spray (fog) test, which exposes the material to a corrosive test environment by spraying it with a salt solution. The test is designed to simulate the corrosive effects of exposure to salt-laden atmospheres, such as those found in marine environments, and to provide a means of evaluating the suitability of materials for use in such highly corrosive test environments.

ASTM B117 Uses and Factors to Consider

ASTM B117 salt spray test standard is a test method for salt spray (fog) exposure that is widely used to evaluate the corrosion resistance of materials and surface coatings. Here are some of the uses and factors to consider:

Uses:

Qualifying protective coatings and materials for use in corrosive environments: The test method is used to test the resistance of coatings and materials to salt spray and other corrosive agents. This testing helps manufacturers ensure that their products will perform well in real-world conditions.
Quality control: ASTM B117 testing procedure is used to verify that coatings and materials meet specific performance requirements. It can also help identify problems with manufacturing processes or materials.
Research and development: The test method is often used in research and development to evaluate the effectiveness of new coatings and materials to resist corrosion.

Factors to consider:

Test duration: The test duration of ASTM B117 salt spray can range from a few hours to several hundred hours, depending on the material being tested and the desired level of corrosion resistance.
Sample preparation: The test sample(s) must be cleaned and prepared properly before testing to ensure accurate results. Any contaminants on the surface of the sample can affect the test results.
Test conditions: The test conditions, such as the concentration of salt spray solution, temperature, and humidity, must be carefully controlled to ensure a salt spray cabinet with accurate and repeatable results.
Interpretation of results: The results of ASTM B117 salt spray must be interpreted correctly to determine the level of corrosion resistance of the coating or material being tested. Factors such as the appearance of corrosion and the rate of corrosion must be considered when interpreting results.
Limitations: While ASTM B117 salt spray is a widely used test method, it has some limitations. For example, it does not simulate all types of corrosion environments, such as those with acidic or alkaline solutions, and it does not consider the effects of UV radiation or other environmental factors.

What results can you expect from a B117 Salt Fog Test?

The modified B117 salt spray test, also known as ASTM B117 salt fog test, is a standard test method used to evaluate the relative corrosion resistance of coated metals exposed and the coatings that are protecting the underlying metal. The salt spray tests involves subjecting a test specimen to a continuous salt fog or salt spray environment, typically for a specified duration of time, and then evaluating the corrosion effects and develops.

The results that can be expected from ASTM B117 salt spray depend on the material being tested and the test conditions. In general, the test is used to determine the degree of relative corrosion resistance of the material or coating adhesion being tested. The results can be expressed in terms of the appearance of the sample, the amount of corrosion, and the rate of corrosion.

A typical result of ASTM B117 salt spray is a rating based on the severity of corrosion. This rating is determined by visually inspecting the sample and assigning a rating based on the amount of corrosion observed. The ratings range from 0 (no corrosion) to 10 (severe corrosion). The specific rating that is considered acceptable will depend on the application and the requirements of the customer.

Overall, the ASTM B117 salt spray testing a useful tool for evaluating the relative corrosion resistance information of materials and coating adhesion, and the results can provide valuable information for product development, quality control, and product performance in real-world applications. All to make sure your product is corrosion resistant and that the coating adheres without corrosion crept.

Typical Experimental Parameters for the ASTM B117 Test

The standard is used for operating salt spray (fog) apparatus, used to determine the corrosion resistance of test samples. The typical experimental parameters for the ASTM B117 salt fog test are:

Test duration: The test duration for ASTM B117 salt spray is typically 24 to 72 hours, depending on the material being tested and the requirements of the application.
Test solution: The test solution used in ASTM B117 salt spray is a 5% salt solution, which is prepared by dissolving sodium chloride (NaCl) in distilled water. The pH of the solution is maintained between 6.5 and 7.2.
Test temperature: The test temperature for ASTM B117 is maintained at 35°C ± 2°C.
Humidity: The humidity of the test chamber is maintained at 95% ± 5%.
Spray rate: The spray rate in ASTM B117 is typically set at 1.0 to 2.0 ml per hour per square meter of surface area, with help of pressurized air.
Test specimens preparation: The specimens are prepared according to the requirements of the test method and are cleaned and dried before the test.
Evaluation of corrosion: The specimens are evaluated for corrosion after the test period. The evaluation is done by visual inspection or by measuring the mass loss of the specimen.

It is important to note that these parameters may vary depending on the specific requirements of the ASTM B117 salt spray test and the materials being tested.