There are three distinct test method in ISO the neutral salt spray (NSS), the acetic acid salt spray (AASS), and copper-accelerated acetic. ISO NSS. adv. auto technology banner. A discussion started in but continuing through Q. We have a customer, that we supply some zinc. The salt spray (or salt fog) test is a standardized and popular corrosion test method, used to Other important relevant standards are ISO, JIS Z and ASTM G The most common test for steel based materials is the Neutral Salt Spray test (often abbreviated to NSS) which reflects the fact that this type of test.
|Published (Last):||28 July 2010|
|PDF File Size:||16.29 Mb|
|ePub File Size:||3.97 Mb|
|Price:||Free* [*Free Regsitration Required]|
Retrieved from ” https: The second climate cycle comprises 0. Contact Ascott for Further Information.
You will then need to talk to your customer about the possibility of using one specification in lieu of the other. Test specimens are placed in an enclosed chamber, and exposed to a changing climate that comprises the following 3 part repeating cycle. Remember that accelerated testing is not a proper indication of real world performance.
Daily checking of testing parameters isl necessary to show compliance with the standards, so records shall be maintained accordingly. The salt spray tests are particularly useful for detecting discontinuities, such as pores and other defects, in certain metallic, organic, anodic oxide and conversion coatings. I suggest that you send some parts out for testing according to the ISO standard to see if they meet the spec.
It also describes the method employed to evaluate the corrosivity of the test cabinet environment. This test is also referred to as an ASS test. Failure to meet this requirement implies instability in the chemical process of the pre-treatment, or the paint quality, which must be addressed immediately, so that the upcoming batches are of the desired quality. However, these testing standards neither provide information of testing periods for the coatings to be evaluated, nor the appearance of corrosion products in form of salts.
Testing periods range from a few hours e. The salt spray test is one of the most widespread and long established corrosion tests. From Wikipedia, the free encyclopedia. Life cycle A standard is reviewed every 5 years 00 Preliminary. The most appropriate test cycle and spray solutions are to be agreed between parties. For this reason the salt spray test is most often deployed in a quality audit role, where, for example, it can be used to check the effectiveness of a production process, such as the surface coating of a metallic part.
The number of cycle repeats and therefore the test duration is variable. This is followed by 0. But we haven’t supported older browsers like IE8.
Electroplated zinc-nickel steel parts can last more than hours in NSS test without red rust or 48 hours in CASS test without red rust Requirements are established in test duration hours and coatings shall comply with minimum testing periods.
Salt spray test – Wikipedia
Check out our FAQs. The salt solution should be prepared according to the nature of the test in accordance with Paragraph 3 of ISO and the 3 options are summarised below.
The salt spray test has little application in predicting how materials or surface coatings will resist corrosion in the real-world, because it does 9227 create, replicate or accelerate real-world corrosive conditions.
This page was last edited on 29 Octoberat Chamber volumes vary from supplier to supplier. The salt fog fall-out rate is verified by using a minimum of two 80cm 2 funnels per salt spray atomiser, each inserted into a measuring cylinder graduated in ml.
Equivalence between ASTM B vs. ISO NSS
This is followed by nsz. Is there any equivalence between this two standards? In either case, the exposure to salt spray may be salt water spray or synthetic sea water prepared in accordance with the requirements of the test standard.
Final text received or FDIS registered for formal approval.
Hi David, There are several differences between the two specifications, including salt concentration range, salt analysis, water quality, angle of inclination of test panels, ns requirements, I think the temperature is about the only thing that has been standardised.
Is it possible to reduce test duration by some accelerated Testing? Painted surfaces with an underlying hot-dip galvanized coating can be tested according to this method.
Corrosion tests in artificial atmospheres – Salt spray tests
A requirement that a component ‘pass’ an accelerated corrosion test isn’t often meaningful until the finishing spec tells you what that means: May 21, A. This climate is maintained under constant steady state conditions.
Requirements are agreed between customer and manufacturer. ASTM B was the first internationally recognized salt spray standard, originally published in Test specimens are placed in an enclosed chamber and exposed to a continuous indirect spray of salt water solution, prepared in accordance with the requirements of the test standard and acidified to pH 3.
Sorry. You need to upgrade your browser
These acidified test solutions generally have a pH of 3. ISO standards by standard number. ASTM G85 is an example of a test standard which contains several modified salt spray tests which are variations to the basic salt spray test. Hot-dip galvanizing produces zinc carbonates when exposed to a natural environment, thus protecting the coating metal and reducing the corrosion rate.
This spray is io to fall-out on to the specimens at a rate of 1. Corrosion tests and standards: If there is a minimum volume required by a particular salt spray test standard, this will be clearly stated and should be complied with.