Sound technical content, curated with aloha by
Ted Mooney, P.E. RET
Pine Beach, NJ
The authoritative public forum
for Metal Finishing since 1989
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Help making non-magnetic stainless steel magnetic
2004
Dear Gentlemen:
I have found your site to be very interesting. I have a problem: my company has really cool bottle openers but they are made out of stainless steel and have no magnetic properties. Our competition who has beat us up consistently took those same openers and made them magnetic and now they stick to a magnetic disc and that attaches on ones belt. Does anyone have an idea or know how to make these stainless steel openers magnetic again? They said they had some wild alchemist help them figure it out!
Please help us get the upper hand.
Sincerely,
Craig L [last name deleted for privacy by Editor]ceo Tampa, Florida, USA
2004 Copper iridium would be about the only way, I think. Bill Reynolds [deceased] consultant metallurgist - Ballarat, Victoria, Australia We sadly relate the news that Bill passed away on Jan. 29, 2010. |
Make them out of a stainless that can be magnetized, IE: a 400 series. Cheapest is probably 410. Magnetize it after all other work is done. Common 18-8 or 300 series can not be magnetized to any great extent.
James Watts- Navarre, Florida
2004
Use ferritic or martensitic stainless steels. It is only the austenitic ones that are not very magnetic.
Trevor Crichton
R&D practical scientist
Chesham, Bucks, UK
2004
There are magnetic stainless steels. the 400 series which are typically used in cutlery are magnetic. Type 430 may be useful for your application. The only way I have made stainless materials act like a magnet is to expose them to intense magnetic fields. I was not sure if you want the material to act like a magnet or just be magnetic. The latter is simply choosing the right stainless steels. Type 409 really polishes up nice so you might try that.
T.J. Tarabulski- Brewster, New York
2004
2004
Craig, there's a couple of ways to get magnetic stainless steel. First, if you are using a 300 series like 304, 316, etc (sometimes called an 18-8 grade) then work hardened material is magnetic. In other words, the mill that you buy it from has to have rolled it down some after they annealed it. The level of magnetism is related to the level of working, so heavily worked material is most magnetic. The downside of work hardened material is that it is harder to form and bend and cut.
Second, you can use a ferritic or martensitic grade, also called '400 series'. For example, 440C is a cutlery grade, and after heat treating holds an edge well enough to be used for fine knives. 430 is a softer grade, about as strong as your current non-magnetic stainless.
The Nickel Development Institute has a superb guide, called "Design Guidelines for the Selection and Use of Stainless Steel", their publication number 9014. If you look hard enough, you can find it and download it from their site at www.nidi.org. Otherwise, just call them and ask for one, and they'll send it. Free. They just enjoy telling the world about their favorite element.
Lee Gearhart
metallurgist - E. Aurora, New York
Easy -- just use 400 series stainless steel.
Jim Treglio - scwineryreview.com
PVD Consultant & Wine Lover - San Diego,
California
2004
You all missed the point of the original letter, which was that the SAME nonmagnetic openers were rendered magnetic! Not that different openers with the same appearance were magnetic (which obviously would be done using 410 or similar stainless instead of 300 series), but that originally nonmagnetic openers were rendered magnetic. The magic of copper iridium has made a reappearance. It's still holiday time here in Australia - time for a bit of light-hearted fun. Condensing information from many sources in previous copper-iridium threads on this site, it seems that all that need be done is: Wrap the openers, with a copper-iridium coin and a few grains of rice, in black carbon paper. Have Froggy plunk his magic twanger, and Hey Presto! the rice pulling power of the coin is transmutated into the nonmagnetic openers so that they will then be pulled by a magnet. The metallurgical implications of this are profound to say the least, but need not concern us at this time. Bill Reynolds [deceased] consultant metallurgist - Ballarat, Victoria, Australia We sadly relate the news that Bill passed away on Jan. 29, 2010. 2004 Craig, please excuse our frivolity with the copper-iridium rice-pulling stuff. Some very funny letters were posted to the site a couple of years ago about the 'magical powers' of this stuff (see letter 12341 for starters) and it's hard to resist the opportunity to revisit the fun we had. Ted Mooney, P.E. Striving to live Aloha finishing.com - Pine Beach, New Jersey 2004 Hello everybody - Delhi, India 2005 |
I am interested in the exact grade number of stainless steel required to have a strong, relatively scratch-resistant shiny (able to be polished) steel surface that can be stamped that would hold a magnet reasonably strongly. I believe that the 400 series would work best, yet have non-oxidizable (rust-free) finish for a long time. The use for this is in a kitchen with magnets attached. HELP!
Steve Sholem- Phoenix, Arizona, USA
April 3, 2008
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