Non magnetic Stainless Steel

[mechy20]

All,
I am trying to locate a non magnetic stainless from the austenitic series. I tried a sample of 304 but even that was slightly magnetic. For my application unfortunately I cannot use Al or Brass.

From what I looked online, I read that even austenitic series get back a little magnetism after cold working. That the higher grades were better in not getting back their magnetic properties (like 316, 310 etc) compared to the lower grades like 303, 304 etc.

But the catch is I am looking for something that has a yield strength in the order of 50ksi. The higher grades are down to 26-30ksi.

Could someone give me a pointer or two on some other materials that are relatively common and fit the above characteristics in their non magnetism? My application wouldnt allow me to purchase any exotic materials.

Thanks in advance

 

[metengr]

If you want to stay with stainless steel, go to the web site below;

http://www.cartech.com/

Register, it is free. You can look up one of the standard grades of austenitic stainless steel, and others that Carpenter provides. One that I quickly spotted is Carpenter #10.

You can look at one of the Titanium alloys, as well. I don't consider it exotic, but it costs more than ss.

 

[EdStainless]

There are a number of options.
First, what are you calling ferromagnetic? Do you need 1.01, or do you need 1.0001?
Your best bet would be some of the high Mn, high N alloys like 21-6-9 (XM-11). This material is highly non-magnetic, even after some cold work.
Some of the other "Nitronic" grades are also good for this.

If you cold work much, and require very low magnetism you will need to anneal after forming.

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Rust never sleeps
Neither should your protection

http://www.trent-tube.com/contact/Tech_Assist.cfm

 

[mechy20]

Thanks all for your feedback.
EdStainless: So if I were to buy 316SS that is fully annealed, then I expect to have significantly low magnetism right? I dont care particularly for a permeability of 1.0001, I could definetely live with 1.01.
Thanks

 

[EdStainless]

Just remember, fully annealed 316L will have a yield strength of about 30ksi. It is soft.

What product for are you working with? sheet?

= = = = = = = = = = = = = = = = = = = =
Rust never sleeps
Neither should your protection

http://www.trent-tube.com/contact/Tech_Assist.cfm

 

[pdybeck]

mechy20,

You may buy fully annealed material that is not very magnetic, but some of your machining/forming operations will most likely cold work some of the material. Even turing a round bar in a lathe and removing material will cold work the material enough that it would cause it to slightly increase in magnetism (by how much I do not know). You could anneal it after machining/forming in order to eliminate some of the magnetic properties that were induced when cold working. This is what I think Ed was referring to. I would suggest setting up a test to check the properties upon arrival of the material, after manufacturing into useable parts, and then check the propeties of some parts after annelaing after manufacture. This would give you an idea of whether the material is suitable to what you are trying to do with it.

 

[mechy20]

pdybeck,
Thanks ! Infact the SS I brought from McMaster had some magnetism in it. Like expected coldworking definetely affected the properties. Also like EdStainless mentioned, low yield is bad for me, as I need these parts to be working for a long time. So for now I have decided to go with Al.
Once again thanks all for your feedback.

 

[EdStainless]

If you need some higher strength stainless there are some alloys such as 219 and Nitronic grades that are stronger and very non-magnetic. They will be much stronger than Al.

= = = = = = = = = = = = = = = = = = = =
Rust never sleeps
Neither should your protection

http://www.trent-tube.com/contact/Tech_Assist.cfm

 

[pdybeck]

mech20,

I just had some material quoted from Carpenter that is right up your alley. The material is 18Cr-2Ni-12Mn. It is essentially XM-28 or UNS S24100 under ASTM A276. This is an austenitic stainless steel that is nitrogen strengthened. It has minimum yield values of 55,000 psi in the annealed condition. It has very low magnetic permeability values even after cold working (not the case for most 300 series stainless steels). The low nickel content is wallet friendly. The quote came back with material prices just higher than 303.

http://www.matweb.com/search/SpecificMaterial.asp?bassnum=MQM241A

Pete

 

[RPstress]

Nitronic 40, aka 21-6-9: magnetic permeability 1.005 max. irrespective of condition. Fty ann. 50 ksi min; 15% cold reduction 118 ksi min.

Nitronic 50: magnetic permeability 1.004 irrespective of condition. Fty ann. 60 ksi; 15% cold reduction 135 ksi.

http://www.hpalloy.com

.

Nitronic 60: magnetic permeability 1.003 annealed, rising to 1.01 75% cold drawn. Fty ann. 55 ksi; 20% CD 105 ksi.

http://www.hpalloy.com

.

Could also try AK Steel as well as the usual suspects (

http://www.cartech.com

, etc.).

 

[pdybeck]

Quoted with Carpenter...

Nitronic 50 and 60 are expensive. Nitronic 40 is not a whole lot better. Quoted EnduraMet 32 or 18-2-12. Prices on 18-2-12 were decent, but it is not a stocked item and can't locate it in bar form anywhere. At a standstill right now.

Pete

 

[RPstress]

PS: watch out for things like corrosion and carburization during service making nominally non-magnetic materials into magnetic ones.