Metal finishing Q&As since 1989

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Corrosion issues re Stainless mesh alloy 304 & 316

2003

Stainless woven mesh is currently being used in the residential areas of Australia.
Today the 2 alloys used are 304 & 316 in an aluminium frame,in allowing clear vision this mesh is painted and in some cases it is also separated from the aluminium using a rubber wedge of some description for corrosion protection .

I require someone with technical information to advise me on the how I can prevent corrosion on alloy 304 (coastal areas of Australia).

Please advise me as I have been given distorted information relating to the benefits if any between these 2 alloys , also is 304 alloy subject to corrosion more than 316 based on same application methods.

Clive Sinclair-
Distributor of Aluminium & Stainless - Woodvale, Perth, Australia

Type 304 stainless steel is inferior to Type 316 with respect to corrosion resistance in chloride containing environments. Type 316 has ~ 2% Mo added, which improves pitting resistance, the predominant problem for austenitic (3xx series) stainless steels when exposed to salt water. Type 304 is not usually recommended for such exposure. You should discuss this problem with a metallurgist from a competent stainless steel supplier. Carpenter, AK Steel, Allegheny Ludlum, Avestapolarit, and Sandvik all provide technical assistance for their stainless products.

Toby Padfield
- Michigan
2003

While there is significant galvanic potential between these two materials, there does not seem to be a galvanic cell in this application. I would agree with Toby that the 304 is unsuitable for long term exposure in a coastal environment. This has been covered many times in previous "hot line" questions.

John Hetherington
- Canada
2003

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Toby is correct re material, but for existing installations, cleaning and washing will minimize corrosion of both 304 and 316. See ÎCoastal Corrosion“ from the Australian Stainless Steel Development Association (http://www.assda.asn.au/).

See also Î304 ˙ the Place to Start“ and Î316 ˙ the First Step Up“ for a comparison of the 2 alloys.

Ken Vlach [deceased]
- Goleta, California
Finishing.com honored Ken for his countless carefully researched responses. He passed away May 14, 2015.
Rest in peace, Ken. Thank you for your hard work which the finishing world, and we at finishing.com, continue to benefit from.
2003