"Equivalence between ASTM B-117 vs. ISO 9227 NSS"

A. Hi Sergio, ASTM B117 [affil link] does not address corrosion behavior of test specimens, but describes the parameters for conducting a salt spray test. So if you want to know how to set up a salt spray cabinet or how to make the salt solution, then B-117 is a reference. But benchmarking performance is something altogether different. I suggest that you send some parts out for testing according to the ISO standard to see if they meet the spec. That's the only way to know for sure.

A. ASTM B117 [affil link] and ISO 9227 are essentially the same-- standard specifications for conducting corrosion testing. ASTM B117 [affil link] is specific to neutral salt spray, whereas ISO 9227 also covers acetic acid (AASS) and copper acetic acid (CASS) tests. Conventional electroplated zinc (9 micrometer thickness) that is subsequently coated with a yellow chromate conversion coating typically produces less than 5% red rust after 96 hour salt spray testing. In order to meet the same % red rust for 300 hours of testing, you will need to do something different. Options include the following:

1. Thicker zinc plating (12+ micrometers) with a thicker chromate (olive green instead of yellow)
2. A sealer over the existing zinc plating + yellow chromate
3. Something totally different like zinc-alloy plating, organic coatings, etc.

A. Hi, Sagar.

As Toby mentions, ISO 9227 includes CASS testing, which is more aggressive than neutral salt spray. But which, is any, accelerated test is appropriate depends on what the finish is, and what you hope to test against. Remember that accelerated testing is not a proper indication of real world performance. Good luck.

Regards,

A. Hi Neeraj. Brian Terry has directly answered your question, but please post your situation rather than an abstract question so that readers can best help you. Thanks.

What do you want to test? ... because the specs you mention have to do with how to design and operate a salt spray cabinet; generally the plating, painting, or other metal finishing spec for your components tells you how to test them and how to interpret the results of the tests. A requirement that a component 'pass' an accelerated corrosion test isn't often meaningful until the finishing spec tells you what that means :-)

Good luck.

Regards,

A. Hi Ollie. Do you have both specs in your possession? If you do, you should be able to check what Toby has told us: that ASTM B117 [affil link] covers only one type of test, Neutral Salt Spray; different ASTM standards are used to call out other salt spray tests like AASS ( ASTM G85 [affil link]) and CASS (ASTM B368 [affil link]) ... whereas ISO 9227 covers all three.

ASTM apples are fairly close to ISO apples, but not to ISO oranges. Are you certain that the 1500 hour ISO rating is for Neutral Salt Spray? If so, which is probably the case, you're pretty close to comparing apples to apples, so the finishes don't sound equivalent if one lasts 6000+ hours in NSS and the other fails at only 1500 hours. Good luck.

Regards,

A. Hi Sergio,

ISO 9227 [affil link] is used to check corrosion resistant performance for metal parts or metallic plating parts by using salt solution 5% (NSS method - neutral salt spray). This standard also has option for acetic acid salt spray (AASS), copper-accelerated acetic acid salt spray(CASS)

ASTM B117 [affil link] is used to test salt pray for metal parts or metallic plating parts by using salt solution 1%.

The step by step how to test set-up is almost the same between ASTM B117 [affil link] & ISO 9227.

Time range to test is usually: 24h, 48h, 72h, 96h, 120h, 144h,.....

300h ISO 9227 & 96h ASTM B117 [affil link] is not equivalent in 02 factors: salt solution & time duration, since the quality also not the same.

Hope it useful for you.