Do you know what salt spray testing is? What does this method entail, and is it really necessary? If you’d like to learn more about this, feel free to continue reading today’s blog article.
What Is Salt Spray Testing?
Salt spray testing, also known as salt fog testing, is a test that is designed to simulate a corrosive environment. In simple terms, this testing helps product designers and manufacturers check out the corrosion resistance of surface coatings.
Salt spray testing has existed for decades and is widely used in several industries to test against corrosion. For example, the durability of a fastener depends on how it performs in a corrosive environment. If a fastener gets rusted, it is much more prone to failure. This is where salt spray testing comes in.
In summary, salt spray testing is an important accelerated test that simulates a corrosive environment to a large extent though it is impossible to recreate real-world conditions in a laboratory setting. It is a standardised corrosion test method that does not cost much, is quick to perform, and can be repeated quickly.
What Is The Process Of Salt Spray Testing?
Salt spray testing is performed in a laboratory. Depending on the requirements, the manufacturer may engage the services of an accredited laboratory equipped with the right testing equipment for this test.
A special testing chamber is used to conduct this salt spray test. This chamber is capable of holding the sample piece at a certain angle. It works by spraying saline water at the sample while maintaining the required temperature.
Below is the procedure of salt spray or salt fog testing as per ISO 9227-2017. The process may be changed to conform to a particular standard depending on the product and testing requirements.
The testing sample is first prepared. Certain parts of the sample are typically protected with tape. One part of the surface is then scribbled with the help of a sharp tool for producing a scratch. This scratch cuts through the coating on the surface and exposes the metal substrate underneath.
The salt solution is then prepared with a 5% concentration. Inside the testing chamber, the temperature is typically kept at 37°C to simulate accelerated corrosion. The pH of the solution is maintained between 6.5 and 7.2.
The sample is exposed to the salt solution for a period of 24 hours, 72 hours, or more than 1000 hours as per the requirements of the test.
At the end of the set time period, the specimen is examined by experts for any signs of corrosion. If the sample is corrosion free, it is said to have passed the salt spray testing.
The Benefits Of Salt Spray Testing Method
One of the biggest benefits of this salt spray testing is that it is an efficient testing procedure and is relatively inexpensive. Additionally, it can be repeated as many times as one needs rather quickly.
With that said, this testing method also has certain downsides. One of the downsides of this testing method is that it does not exactly replicate real-world corrosive conditions. In most cases, this testing method is used for maintaining certain standards when it comes to coating processes.
Overall, salt spray testing is one of the most efficient methods to check the corrosion resistance of a particular coating. It does have a big limitation in that it does not completely replicate real-world conditions. This is why this testing method is used more as a way to maintain standards for coating processes.
Compliance Engineering is the leading provider of product testing services as per various standards. Our team of experts can help you with a wide range of tests for your products to make sure they conform to the required standards.