Corrosion resistance plays a major role in material testing by influencing how long a product will last and how durable it is. The ASTM B117 allows samples of coated metals exposed in a test chamber in a controlled corrosive environment. Only after conducting appropriate long-term air exposure tests to confirm and extend the corrosion performance should it be considered. The ASTM B117 standard, often applied in salt spray (fog) testing, is one of the most well-known techniques for evaluating corrosion resistance. This blog post will explore the contents of ASTM B117-11, its significance, and the steps need to do a salt spray test under this standard.
Understanding ASTM B117-11
ASTM International, a global leader in setting standards, developed the ASTM B117-11 test procedure. This standard outlines how to set up and keep a salt spray (fog) testing environment. The main goal of this test is to evaluate how well a material or coating resists corrosion, especially in a controlled, accelerated corrosive setting. To compare the corrosive resistance of different metals, the ASTM B117 test technique is taken into consideration for the salt spray chamber. The test procedure examines the adherence of the coating with corrosion creep and ascertains the metal’s propensity to corrode when scratched. The testing process assesses the maritime environment’s resistance to corrosion. Paints, coatings, and metals are tested to see if they can withstand corrosion or exposure to maritime settings (salt fog, temperature, and moisture). But the actual environmental circumstances are unpredictable and outside the purview of the usual test protocol.A Salt Spray Chamber’s Components
Typical components of a salt spray test chamber used for ASTM B117-11 testing consist of:- Cabinet: Constructed from materials that are resistant to corrosion to endure the demanding testing conditions.
- Spray Nozzle: Ensures that the salt solution is evenly distributed throughout the chamber.
- Solution Reservoir: Holds the salt solution, which is typically 5% sodium chloride.
- Heating System: Keeps the test temperature at the necessary level, usually about 35°C.
- Control System: Provides correct control over test variables including humidity, temperature, and spray time.
Conducting the Salt Spray Test
The next steps define the ASTM B117-11 technique for conducting a salt spray test:- Sample Placement: Make sure the test specimens are not in contact with the walls of the room or with one another. This arrangement guarantees uniform exposure to the saline mist.
- Configuring the limits: A fine, continuous mist of the salt solution can be produced by adjusting the spray settings and setting the temperature to 35°C.
- Conducting the Examination: Run the chamber for the allotted time; this will be several thousand hours or a few hours, depending on the needs of the test.
- Monitoring: Throughout the test, keep an eye on the chamber to make sure the limits for the spray, temperature, and humidity are constant.
Benefits of Applying ASTM B117-11
When testing for salt spray, ASTM B117-11 has the next advantages:- Standardisation: Offers a reliable, consistent way to assess corrosion resistance.
- Accelerated testing: Replicates extended exposure to corrosive conditions in a condensed amount of time.
- Comparability: This makes it possible to compare outcomes between various coatings and materials.