Summary for salt spray test chambers Discussion
salt spray test chambers are discussed as a way to judge corrosion resistance, but the key point from the answer is that accelerated corrosion tests are not truly equivalent to real-world exposure. The reply to Ceren Bayram explains that you cannot reliably convert 96 hours in a salt spray chamber into a fixed number of hours outdoors or guarantee a part will not corrode for a specific time in service. Instead, these tests are meant to be a consistent, repeatable manufacturing benchmark for comparing processes, shops, or batches. The answer also notes that the acceptance duration chosen for salt spray or similar accelerated tests is often somewhat arbitrary or based on experience, much like other accelerated methods such as vibration testing. The practical takeaway is to use these tests for comparison and quality control, not as a direct life predictor.
Q. Hello everyone,
We are looking for a procedure for corrosion test of our Assembly parts which is the combination of 2024 Aluminum, titanium and some steel fasteners. There are some specs in automotive industry to apply some cycles, but in Aerospace industry generally MIL-STD-810
[⇦ this spec on DLA] is used. We wonder about the evaluation criteria of these tests.
For example,
Some test centers apply 96 hour cycles. What is the equivalent of this time in real conditions?
How can we guarantee that it will not corrode for how many hours under real conditions?
Thank you for your considerations.
Ceren Bayram
– Turkey Ankara
December 11, 2023
A. Ceren,
Accelerated corrosion test methods are generally regarded as not being equivalent to real-world conditions. You cannot say that a salt spray chamber for X hours equals X * Y hours out in the field.
Perhaps a rough equivalence could be found for some things, but this would not be consistent enough for wide application.
Rather, the purpose of accelerated corrosion test methods is to provide a manufacturing benchmark that is consistent and repeatable, and can be used to compare the output of one manufacturing process to another, or the same process done by different shops, or at the same shop across different batches.
I believe that in general the time span chosen for acceptance with the accelerated corrosion test methods (salt spray, et al.) is somewhat arbitrary, or perhaps guided by experience.
No doubt the same could be said for all accelerated testing methods, such as vibration testing.
Ray Kremer
Stellar Solutions, Inc.
McHenry, Illinois
January 4, 2024