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Are SS304 and SS314 magnetic or non-magnetic?

Is SS304 or SS314 magnetic or non-magnetic? Our parts are some nuts and screws. Could you please tell me about the difference between SS304 or SS314 and SS316? Our vendors provide these part as magnetic but we need non-magnetic.

Ronnie Hou
- Suzhou, Jiangsu, China
2004

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First of two simultaneous responses --

Non magnetic

Chris Snyder
plater - Charlotte, North Carolina
2004

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Second of two simultaneous responses -- 2004

It depends. When work hardened, say by being pulled through a die to get a smaller, more uniform size, the 300 series stainless stainless steels become ferromagnetic. To get non-magnetic screws from magnetic ones, you can anneal the parts- say, 1000 °C for an hour followed by a fairly fast (at least blowing cold air) cooling.

Good luck!

Lee Gearhart
metallurgist - E. Aurora, New York

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Ronnie,

It is my understanding that those stainless grades (300 series)are not ferromagnetic unless they have had some fairly serious machining done to them (cutting threads might apply). Put "stainless magnetic" into this sites search engine and you see some good discussions on this subject such as:

www.finishing.com/71/36.shtml and www.finishing.com/112/70.shtml

Trent Kaufman
electroplater - Galva, Illinois
2004

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304 stainless steel has a composition C<0.8; Cr 17.5-20; Ni 8-11; Mn<2; Si<1; S<0.03%. 314 has C 0.25; Cr 23-26; Ni 19-22; Mn 2; Si 1.5-3; P<0.045 and S <0.03%. Finally 316 is C 0.03; Cr 16-18.5; Ni 10-14; Mn 2-3; Si<2; P<0.045, S <0.03%. These are all austenitic stainless steels, so they should not be magnetic. They cannot be heat treated, but it is possible to work harden them. I ma not a metallurgist, but since working them will increase their hardness, I would expect the austenitic phase to locally change to ferritic and martensitic. If it does could induce a small degree of magnetic property, but it would be very small. If I am wrong, no doubt someone will say so! Either way, I would not expect the nuts to be very magnetic, so I would be suspicious of the alloy being used.

Trevor Crichton
R&D practical scientist
Chesham, Bucks, UK
2004