Neutral Salt Spray Test

Purpose of salt spray test

The Neutral Salt Spray test (NSS) is an artificially accelerated simulated salt spray environment test. The salt spray test chamber is used to artificially create a salt spray environment, which will contain (5±0.5%) sodium chloride and salty water (pH 6.5~7.2) is sprayed through the spray device. Let the saline water settle on the test piece to be tested, and observe the surface corrosion state after a certain period of time to evaluate the quality of the product's salt spray corrosion resistance.Compared with the natural environment, the concentration of chloride in the saline water spray environment can be several times or dozens of times than that of the general natural environment saline water spray content. Thus, it greatly increases the corrosion rate. The NSS test is carried out on the product and the results are obtained. The time is also greatly shortened. For example, if a product sample is tested in a natural exposure environment, it may take 1 year for it to corrode, while in an artificially simulated saline water environment, it only takes 24 hours to obtain similar results.

NSS test time

We follows the CNS8886 salt spray test method to conduct the salt spray corrosion resistance test of the product. The test time is 96 hours, which is equivalent to about 4 years in the natural environment. (The specific time conversion is: neutral salt spray test 24h ⇌ natural environment 1 year)

Conversion of salt spray test and actual days. (Note: The data is for reference only, surface treatment, coating type, and base metal will all affect the corrosion curve, and the number of days is not static).

  • One-hour NSS test is approximately equal to 5 days of coastal days and 15 days of natural exposure to the environment.
  • The 24-hour salt spray test (NSS) is approximately equal to 120 coastal days, and the number of natural exposure days in a year.