| Author |
Message |
George A. Everding, AIA, CSI, CCS, CCCA
Senior Member
Username: geverding
Post Number: 421
Registered: 11-2004
| | Posted on Friday, April 18, 2008 - 11:52 am: |    |
In the past few months, I have run into three seemingly unrelated issues with stainless steel corrosion. While I still believe them to be unrelated, I am wondering if anyone else has had similar issues recently:
Case 1: Stainless steel toilet accessories rusted shortly after installation. We had specified 304. When our CA used the magnet test, the magnet stuck, and we were able to determine that the contractor furnished 400 series accessories.
Case 2: Stainless steel exterior handrail showed rusting and pitting after one winter of use. Again, the magnet test failed, and we are now working under the assumption that, again, the specified 304 stainless was not supplied.
Case 3: Stainless steel rods supporting a canopy were scratched and showed rust. We are still working on resolving the causes to this one, but in this case 304 was specified and used.
I don't think I have had three other instances of stainless steel corrosion in new products in thirty years of practice, and find it odd that now there have been three in six months, on three completely unrelated projects. Coincidence? Probably. But have any of you noticed more problems with corrosion in stainless steel recently than in the past, either through contractors providing the wrong alloy, or through improper handling and installation? |
Bob Woodburn, RA CSI CCS CCCA LEED AP
Senior Member
Username: bwoodburn
Post Number: 239
Registered: 01-2005
| | Posted on Friday, April 18, 2008 - 12:47 pm: | |
In a really severe environment (salty sea air, etc.), type 316 is even better at resisting rust than 302 or 304, but even then, it may discolor enough to need cosmetic cleaning once or twice a year. Another alloy is even better than 316, but I forget the number.
However, you mentioned "scratches" in one case. Even the most rust-resistant stainless alloy will appear to be rusting if it is wire-brushed with a tool previously used on ordinary steel -- it picks up standard steel particles and embeds them in the surface scratches in the stainless, where they rust. So, always require that any tool used on stainless has never ever been used before on non-stainless steel, lest it contaminate the surface. |
Steven Bruneel, AIA, CSI-CDT, LEED-AP
Senior Member
Username: redseca2
Post Number: 98
Registered: 12-2006
| | Posted on Friday, April 18, 2008 - 01:04 pm: | |
Here in San Francisco we have to deal constantly with a moist marine environment where I try to specify 316 or 316L, and would like to try 2205 if it was more widely available.
But is the problem, you quickly find availability limited for many items beyond 304 grade, and 300 for hardware.
If you come to San Francisco and visit the Cliff House (not one of mine) at Point Lobos, you can see their (less than 5 year old) exterior guardrails with the stainless steel sheet/shape material holding up very well, but plenty of rust on the hardware and other items, suggesting a mix of grades.
There is no test outside of a laboratory I know of to tell the difference between 304 and 316.
Please let us know if you find out that something that isn't stainless steel was substituted. I would hate to start having to include a metalurgist when we do our punch lists. |
Richard L Matteo, AIA, CSI, CCS
Senior Member
Username: rlmat
Post Number: 270
Registered: 10-2003
| | Posted on Friday, April 18, 2008 - 08:45 pm: | |
Type 316/316L is definately the way to go for exterior stainless steel. |
Richard Howard, AIA CSI CCS LEED-AP
Senior Member
Username: rick_howard
Post Number: 172
Registered: 07-2003
| | Posted on Friday, April 18, 2008 - 09:46 pm: | |
George's original post is about not getting what you have specified. Possibly some products are now made overseas with the same lack of oversight that allowed high lead levels in darn near everything to make it to the US; toys, jewelry, dental implants, dishes, etc.
Chinese production of stainless metals is way up this past year, while most of the rest of the world saw production declines. Make some steel with a little extra chromium (400 series) and you get something that closely resembles nickel stainless (300 series) at a lower cost, but without any of the benefits of the nickel. |
J. Peter Jordan
Senior Member
Username: jpjordan
Post Number: 265
Registered: 05-2004
| | Posted on Friday, May 23, 2008 - 05:06 pm: | |
I had a similar problem many years ago in Hawaii. In punching out the building, I noticed a number of rust spots on stainless steel locksets and hinges. All of us were freaking out until we realized that all of this stuff was mounted on doors on exterior corridors across from welded steel pipe railing. The grinding operation had generated a lot of steel "dust", some of which settled on stainless steel surfaces and shortly began to corrode (similar to Rob's report above). The hardware consultant told us that this could be easily solved by cleaning, which we did. Had we not taken care of this, the corroding steel would have pitted the stainless. I was reminded of what a Florida architect once told me, stainless steel is just "stain less" steel.
Sorry, I don't remember what the cleaner was, just that the contractor said it worked great. |
Anne Whitacre, FCSI CCS
Senior Member
Username: awhitacre
Post Number: 770
Registered: 07-2002
| | Posted on Friday, May 23, 2008 - 07:13 pm: | |
I also have this vague feeling that 304 is being made slightly differently than it was before -- I also have had more instances of corrosion on 304 than I ever remember before, and have turned to specifying 316 -- which I never used to do, even near the coast. in one case, the owner's cleaning products were corrosive enough to pit 304 (this was in Iowa); in another, the snow-melting compound corroded the stainless (in upstate New York; in another, the typical 304 handrails in a swimming pool enclosure needed to be replaced with 316. My sense is that there has been a change in how the stainless is made, because I'm seeing the same issues that George remarked upon. |
Anonymous
| | Posted on Saturday, May 24, 2008 - 12:44 pm: | |
304 should have never been used in/near swimming pools anyhow...always 316 due to chlorinating & other chemicals. |
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