ASTM B The ASTM B Copper-Accelerated Acetic Acid Salt Spray, ( CASS) Test This test is performed in accordance with the specifications found in the. ASTM B Copper Accelerated Acetic Acid Salt Spray (Fog) Testing. Can be used to test the relative resistance to corrosion of anodized aluminium and. Testing Specifications of Cyclic Cycles we have met – ASTM, ASTM B, ASTM B, CASS, ASTM G85, GMW, GMW, SAE J, Ford CETP.
|Published (Last):||23 May 2017|
|PDF File Size:||6.23 Mb|
|ePub File Size:||14.27 Mb|
|Price:||Free* [*Free Regsitration Required]|
We are plating Asym with 20 microns of copper, 10 microns semi-bright nickel, 10 microns of bright nickel, 2 microns of micro porous nickel and finally 0,15 microns of conventional chromium coating. Should we consider that a failure? Should we consider the parts having failed the CASS TEST when pits appear in chromium layer or when the pits have crossed the nickel layer and copper appears?
Accelerated corrosion testing is a QA measure often undertaken to get an early indication if something goes out of whack in the processing, such that the aztm are unlikely to survive the previously expected period in the real world. Such tests are also often erroneously used as predictors of real life, despite the fact that the corrosion mechanisms are fundamentally different, and the approach will lead to erroneous expectations.
In either application, certain variations in the test procedures for different substrates and coatings may improve their predictive value. ASTM B [link by ed. Some automotive fuel components have this type of plating and CASS testing. The interpretation of CASS and any other corrosion test data is always subjective and open for debate.
This sort of thing is usually agreed upon between a customer and supplier based on technical experience and judgement.
I have not seen an industrial requirement that uses a microscopic analysis of pores or corrosion sites.
It could be done, but would you want a manufacturing process that requires constant microscopic analysis of test parts? This type of analysis may be asstm suited to research or an initial validation.
To minimize your searching efforts and to asrm multiple viewpoints, we’ve combined some threads into the b36 you’re viewing. Please forgive any resultant b3688 or failures of chronological order. If component resists hours B test, how many hours should it resist for B test?
What is organic coating? Chrome plating is organic or inorganic? The only way to accurately and reliably develop xstm correlation is to build one yourself. That is, put some parts in neutral salt spray and some in CASS and see what you get. Keep in mind that both tests have significant variability, so it’d actually take numerous tests, control panels or parts in both tests, multiple cabinets, etc.
There is no simple formula or factor to convert one test to another. They all induce different corrosion mechanisms on different substrates.
I talked to a guy who worked on the test, and he told me that they eventually determined that hours in CASS meant 1 year in Detroit’s environment in the 50s or 60s. If you’re not doing Ni-Cr plated parts, technically you’re not even using the right test. I’m sure many can relate.
CASS Test — Copper-Accelerated Acetic Acid Salt Spray (Fog) Test — (ASTM B368, B117)
Organic coatings are coatings that are based on organic chemicals basically chemicals that contain carbon. Most paints and powder coatings would be organic coatings. Inorganic coatings are coatings that don’t contain significant amounts of organic chemicals. Metallic coatings like galvanizing and nickel and chrome plating are inorganic.
There are probably some blurry areas, as there always are. We manufacture parts for mostly military end use. Our parts generally are aluminum with Cad Plating over electroless nickel plating. We are developing an alternative to Cadmium plating, and if there is a comparison that someone has done, it would be great to find the results of the comparison, i.
One of the reasons predictive correlation of accelerated corrosion testing to real life is problematic is that the corrosion mechanisms are fundamentally different.
For example, hot dip galvanizing is no doubt the most durable of any finish, often surviving on electrical transmission towers for 75 years or more with no maintenance. This is because it is a relatively thick zinc coating which under favorable conditions reacts with the small amount of carbon dioxide in the air over the months and years to form tight, glassy, complex zinc carbonate reaction products which greatly slow the corrosion of the zinc.
In a salt spray chamber these carbonate reaction products never form, and the zinc corrodes away rather quickly. If someone can suggest which of the two tests is better for your situation, or can propose another test, that would be great.
But we appended your inquiry to an earlier thread which touches on the difficulties of correlation. Unfortunately, I think the answer is that you will not know the real world life of your cadmium substitute, or how it compares to cadmium in the real world, except by real world testing. And only after that can you build a correlation to accelerated testing. While developing correlation is important, trying to develop a predictive correlation that doesn’t require real world testing probably won’t work.
Is there any other accelerated tests available to correlate NSS test to avoid the longer time? First a side note about CASS. According to him, CASS was used for chrome plated bumpers.
He didn’t say how they defined failure in the test or the field. You could probably say that about a lot of these tests.
That said, you generally cannot correlate accelerated tests to tests such as NSS for numerous reasons. Salt cabinets assuming they’re run properly, which is generally not true also have a great deal of variation that makes any correlation, in my opinion, greatly suspect. Note, however, that you must develop the test yourself. You must take the time to develop this asttm yourself because it depends on the paint, substrate, chamber, and test equipment.
I’m satm to use CASS test. It will give you a different corrosion mechanism. If you want to use CASS as a proxy for NSS, you will have to very carefully develop your own correlation which will depend on the substrate, paint, even the cabinet s themselves. You’ll also have to run periodic tests to verify that your correlation is still correct. This assumes, of course, that you’re running the 3b68 purely as a quality assurance test to make sure your process is running the same sample to sample.
If you’re trying to mimic some field failure, you’re talking completely different corrosion v368 We have a standard salt spray test equipment, but we want to do CASS test on this equipment.
If it is, what should we do? The supplier of your salt spray cabinet can advise you on this, but if not, it would be best to get access to ASTM B because it specifies the equipment and procedure required.
How to compare ASTM B117 Salt Spray and ASTM B368 CASS Test?
It’s only pages, and then xstm won’t be guessing whether your procedure complies based on internet rumors: So my question is whether there is any specific requirement of CASS test for threaded, knurled area? Pankaj, I doubt the standard gets that specific, it is probably more a matter to discuss with your customer.
If they only require that the non-knurled areas pass CASS, then you should be fine. Are these parts stainless steel, or a non-ferrous alloy perhaps? If the knurling process is causing iron contamination, passivating the parts should help.
Can we take astk as a thumb rule? You appear to be acknowledging that there is no correlation, but then asking whether the correlation would be Other than that, any correlation there may be would only be for a given plating on a given substrate The origin of your Good luck, but please accept the general thrust of this whole thread that any atsm between CASS, NSS, and real life are at best no better than astj backup data for your parts that you have accumulated to demonstrate them: I understand that would be a estimate especially considering there would be astk difference between what part of the country the vehicle would be “in the field” I am just looking to see if anyone has an opinion on this question.
Any opinions or thoughts would be appreciated.
How to compare ASTM B Salt Spray and ASTM B CASS Test?
Other materials and coatings corrode in fundamentally different ways such that CASS test results have essentially no bearing on their anticipated life. Thanks for your response Ted, aastm your time!
At the time, it was perhaps the biggest plating-on-plastics line in the country. It was a blast from the past hearing from you: It’s not possible to diagnose a finishing problem or the hazards of an operation via these pages.
All information presented is for general reference and does not represent a professional opinion nor the policy of an author’s employer.
From beautiful Pine Beach New Jersey: An ongoing discussion from through We thank you for help. Ray Kremer Stellar Solutions, Inc.