The finishing.com Hotline: Serious Education ... plus the most fun you can have in metal finishing. Ted Mooney, Webmaster
Salt spray test for austenitic stainless steel.--
Q. Anyone know how long 303 stainless steel (free-machining, with sulfur) is supposed to hold up in standard neutral salt spray?
This is assuming it will pass the test at all, and that the material has been properly passivated (nitric/dichromate or citric acid per ASTM).
Thanks in advance. A quick response will be greatly appreciated.
microwave & cable assemblies
Mesa (what a place-a), Arizona
A. QQ-P-35C [link is to free spec at Defense Logistics Agency, dla.mil] says that the parts (they mention 303 containing sulfur) should pass 2 hours salt spray. They say to use Type II passivating solution.
Falls Township, Pennsylvania
Q. Anyone know how long the austenite stainless steel (grade SUS 304, 305, 316 and 316L) can withstand the salt spray mist testing before the first red rust spot appear.
The information is urgently needed.
Thank in advance. The prompt reply is much appreciated.
steel company - Malacca, Malaysia.
A. I have salt fog tested 304, 304L and 316 for 2500 hours and did not see red rust.
I do not have a report on this since I am not employed by that firm any longer.
The test was per ASTM ASTM B117 [link by ed. to spec at TechStreet] , surface was scribed. the test was to assure the paint adhered to the stainless after 2000 hours, not to find red rust. In the same test 409 stainless was tested.
I have routinely tested 304L and 409 stainless at 1500 hours per ANSI C57.12.28, Draft 5.
Hope this helped you.
TyTyrone L. Caley
- Jefferson City, Missouri
Q. Please give the details for the following subject
1. Method of salt spray test - corrosion resistance - life period - for all coatings like Zinc, hardchrome, anodising and painting on base materials iron, aluminium alloys, aluminium and brass materials.Palkannan
- Coimbatore - Tamilnadu-India
A. Hi Palkannan,
You could start getting the answers to those questions with the purchase of the following seven AESF illustrated lectures: Corrosion, Testing, Metallurgy, Zinc Plating, Chromium Plating, Anodizing, and Phosphate Conversion Coatings. Good luck -- but it's a broad question so there are no really quick answers. You might want to sign up for an AESF intensive training course, or a course by Kushner Plating School. Good luck.
Ted Mooney, P.E. RET
Pine Beach, New Jersey
Q. We have fabricated a stainless steel (SS 304) tank for oil (2%) emulsion in water for Roll Coolant System in Cold (steel) Rolling Mill. On filling of the oil-water emulsion, rust formation has been reported by the User. Is rust formation possible in SS 304 stainless steel, especially where the sheets have been welded?
Shall appreciate receiving any view & how this can be countered.Sandip Sen
Bangalore, Karnataka, India
June 22, 2011
A. If you have used SS 304 for a coolant tank then there should be no rusting and if you find some red rust like formation most likely they are some acid cleaning in that area which might have caused this, you can simply use a buffing wheel and your problem should be solved.
We had a similar problem and with just buffing we were able to get back our SS304 back in action, all the best.
End User - Bangalore, India