Sound technical content, curated with aloha by
Ted Mooney, P.E. RET
Pine Beach, NJ
The authoritative public forum
for Metal Finishing since 1989
-----
What grades of iron and steel make the best magnets
Q. I am looking for steel grade which could retain fairly good amount of ferromagnetism (residual magnetic field). I am looking to magnetize that steel with an electromagnet and want that steel to retain magnetism after the driving source is removed. Usually, screw drivers are made of such steel and we can pick-up small objects (pins e.g.) with them. But I don't know which grade of steel that is, or if there is some other grade with high magnetic properties? I will be thankful for any help.
Regards,
- Ringwood, Hampshire, United Kingdom
2003
A. Surely it is more difficult to find a steel that will not retain its magnetism. Virtually all steels, with the exception of some high alloy and stainless steels will retain their magnetism. To prevent them going rusty you may need to electroplate them, or perhaps coat them with electroless nickel.
Trevor Crichton
R&D practical scientist
Chesham, Bucks, UK
2003
A. Hi Arfan. Screwdrivers are probably hardened medium carbon tool steel, say 0.6 to 0.75% carbon, possibly grade S5 -- not as soft as structural steel or plate, but not as hard as a file. Generally, hard steels retain magnetism better than soft iron or soft steel. But I don't think the exact type of steel is critical for making a magnet.
Electrical current is one way to magnetize the item, but stroking it with a powerful magnet is another way which may be easier. Stroke it repeatedly from one end all the way to the other, but only in one direction because magnets have two poles and reversing the direction of the stroke will undo your efforts. Best of luck.
Most readers here, including myself, are more versed in metal finishing than in magnetism; so if any reader feels they know more about it and can straighten us all out, they're probably right :-)
Regards,
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
November 21, 2012
Q. Hello all. I'm working on a piece where I want sheets of magnetic material which will stick to itself. As I understand carbon steels and some types of stainless steel are magnetic but they don't stick to each other? Is there any way to get steel sheets to have a magnetic attraction? Alternatively is there another material I could use? Is there any sort of magnet that can be drawn out into a sheet or thin plate around a 1 mm thick? Rubber magnets aren't strong enough for my purpose either.
Siena ShepardArt student - Portland oregon usa
November 1, 2015
A. Hi Siena. All carbon steels and some stainless steels are ferromagnetic, which means they are attracted to a magnet. In addition they can be made magnetic, i.e., able to attract steel and other ferromagnetic materials. Although it's hard to say whether you can make the sheets sufficiently and permanently magnetic enough for your needs, and magnetic in the orientation you need (north pole where you want it, south pole where you want it, presumably at opposite ends of the 1mm sheet thickness), it certainly sounds theoretically do-able. Good luck.
Regards,
Ted Mooney, P.E. RET
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
November 2015
Electromagnet?
October 8, 2016
Q. What is it, how do you make one? I used to have a globe that would float when you turned it on. I would like to make one. I was told that it was electromagnetic and that's what made it float.
Susan PrattHobbyist - San Diego california
A. Susan,
We have one of those, but we lost the power cord so it doesn't work.
You will be able to find the basics of an electromagnet on wikipedia or a web search. For a "floating" object specifically, I imagine it requires one or more electromagnets designed and arranged in a very specific manner. If I wanted to make a unit like that myself, I think I would have to purchase some and take them apart to see how others have done it.
Ray Kremer
Stellar Solutions, Inc.
McHenry, Illinois
October 25, 2016
Q, A, or Comment on THIS thread -or- Start a NEW Thread