Nitronic 40 vs 21-6-9
Nitronic 40 vs 21-6-9
(OP)
My customer wants to minimize magnetic permeability for a small diameter shaft. He has chosen Nitronic 40 and is getting good results. Apparently, Nitronic 40 is a trademarked material of AK Steel. The "generic" equivlaent of Nitronic 40 is 21-6-9. I would gain some supply flexibility if I could also use 21-6-9. Is there a difference in these materials?





RE: Nitronic 40 vs 21-6-9
This is fairly available (we make a lot of tubing in this alloy).
= = = = = = = = = = = = = = = = = = = =
Plymouth Tube
RE: Nitronic 40 vs 21-6-9
bar--> UNS S21900 (Type XM-10) according to ASTM A276 or UNS S21904 (Type XM-11) according to ASTM A276 for 0.04% max Carbon
wire--> UNS S21900 (Type XM-10) according to ASTM A580 or UNS S21904 (Type XM-11) according to ASTM A580
Nitronic 40 is a tradename from Armco, but they don't even produce bar and wire anymore, so you are not gaining anything by specifying this on a drawing.
RE: Nitronic 40 vs 21-6-9
Make it optional
Mfgenggear
if it can be built it can be calculated.
if it can be calculated it can be built.
RE: Nitronic 40 vs 21-6-9
Thanks for your response. With some additional reserarch we found that Armco was bought by AK Steel and that AK Steel licenses Electralloy to produce their Nitronic materials here in the US. I am unclear if Electralloy's Nitronic 40 is in anyway superior (or even different) from steel made to UNS S21904 (Type XM-11) according to ASTM A276 for 0.04% max Carbon. Electralloy does specify that carbon is .04 max.
I have found other mills that produce materials that are similar that do not use the Nitronic 40 trademark. For example, we purchased a small amount from one mill that designates their material as N40 (21-6-9). They do produce to ASTM A276-10 (XM-11 Condition A). The chemistry and phyical properties all match up nicely. Unfortunately, the property that my customer is most interested in (low magnetic permeability) is not addressed in the mill certs from these other mills. And, I don't know what factors influence magnetic permeability. My customer is reluctant to move away from something that works. Testing is an option, but for right now, the burden of proof is on us to make a change.
Thanks again for your help. If you have any other insight, I would appreciate it.
RE: Nitronic 40 vs 21-6-9
RE: Nitronic 40 vs 21-6-9
If they haven't shaved the Ni and Mn too low then it will stay nonmagnetic even when heavily cold worked.
We buy sheep from Allegheny (ATI Ludlum).
= = = = = = = = = = = = = = = = = = = =
Plymouth Tube
RE: Nitronic 40 vs 21-6-9
Ed has expert level knowledge about this, so I concur with his assessment. I also think that jwhit provided some useful information relative to phase stability and the Schaeffler diagram. You can make some comparisons among the various heats that you have received to see if any of them have theoretically produced ferrite. Botttom line, I doubt that specifying the material according to the ASTM designation is going to change the final performance-- specifying Nitronic 40 on your drawing isn't guaranteeing anything relative to magnetic properties.
RE: Nitronic 40 vs 21-6-9
I wish that I could blame spell check
= = = = = = = = = = = = = = = = = = = =
Plymouth Tube
RE: Nitronic 40 vs 21-6-9
----------------------------------------
The Help for this program was created in Windows Help format, which depends on a feature that isn't included in this version of Windows.