As per ASTM G85 atandard 

Period of Test—Designate the period of test in accordance with the specifications covering the material or product being tested or as mutually agreed upon between the purchaser and the seller. Exposure periods of multiples of 24 h are suggested.

you can check in the standards too.

Good morning!

The main Question would be: What is the reason for your test? A connection between salt spray test performance and real life performance is not possible, this is a comparative test. Thus the only useful test would be a comparison between different samples. What should the test tell you?

It is accelerated test which creates high concentration environment as well as temperature.

It is a mandatory Quality check for the material Data Sheet in the most of the coating and painting companies.

yes, as you mention this is a comparative test. You can not connect this into actual environment. for that you need to wait for years to get the result from actual environment.

people who are in this field will understand how much life it can give for the normal atmosphere like seashore. for that you need some experience.

Make your job first: Literature survey, standards.

You probably will not find the exact solution for YOUR material and YOUR application. Then you can contact the community with a specific question!

Dera Mr Sheikh

Salt spary test is geneally done on Plated and Passivated steel components for assesing  its corrosion resistence.

@Wilhelm Erning

We use bare aluminum tube as evaporator tube in refrigerator. The alloy grade is A1060/ A1050. Recently we found some evaporator tube leak after 1 to 1.5 year service. We collected corrosion product and carried EDS and XRF analysis and also took FESEM analysis of the leak. We found all evidence of pitting corrosion. We found presence of chlorine by EDS analysis of the corrosion product. Water (water comes into contact with aluminum tube) may be responsible for the corrosion as it contains chlorine. Now we try to find out the sources of that corrosion by creating similar condition in Lab.

So to ensure whether it is pitting corrosion or not and to find out the probable sources of the corrosion we have taken decision to carry out salt spray test. Beside this we should also carry out pitting analysis by immersing tube into fresh water with the help of standard lab experiment.

I also inform you that I should also do salt spray analysis for bare tube, zinc coated tube and anodized tube to find out its comparative life span.

Dear Esakkiraja Neelamegan,

Please follow my previous comment.

Dear Heinz Palkowski,

would you please go through literature review (my comment) above ? :P 

Dear Günther Lange,

i have provided all the information above. would you need more information ?

Dear

before performing any salt spray test you should fix the interpretation of the results. why to perform such a test ? which information do you expect from this test ? in any case the duration of the test is strctly related to the ifnal application., Based on metl composition and working condition, standard give you duration of the tests in terms of hours. But, I stress againg, first of all it is mandatory to understand why the test has to be performed, and how to interpret the resutls.

Dear Marco Ormellese,

We use bare aluminum tube as evaporator tube in refrigerator. The alloy grade is A1060/ A1050. Recently we found some evaporator tube leak after 1 to 1.5 year service. We collected corrosion product and carried EDS and XRF analysis and also took FESEM analysis of the leak. We found all evidence of pitting corrosion. We found presence of chlorine by EDS analysis of the corrosion product. Water (water comes into contact with aluminum tube) may be responsible for the corrosion as it contains chlorine. Now we try to find out the sources of that corrosion by creating similar condition in Lab.

So to ensure whether it is pitting corrosion or not and to find out the probable sources of the corrosion we have taken decision to carry out salt spray test. Beside this we should also carry out pitting analysis by immersing tube into fresh water with the help of standard lab experiment.

I also inform you that I should also do salt spray analysis for bare tube, zinc coated tube and anodized tube to find out its comparative life span.

Could you please inform me that how long at least I should perform the SALT SPRAY TEST on Aluminum evaporator tube to get so ?

Dear

I stress that to demonstrate pitting corrosion is the cause of failure you have to perform pitting analysis by immersing tube into fresh water. Salt spray test do not give you any informationabout pitting, bu only comparison amon different metals. In any case if you need th duration o the test, I need to know th wetting time. If wetting time is 100%, the minimum duration is 168 h according to ASTM B 117, but test cabn last 1000, or 1400 h. tst end once you see spots of corrosion on the panels.

Thank you Marco Ormellese