304 stainless steel screws
304 stainless steel screws
(OP)
I have(2)304 stainless steel screws that are made by different mfr.
One mfr I know how they are formed, the other appears to be formed the same but I can't verify that.
Both are going into situations where they are being required to be non magnetic, or as little as possible.
Both screws are cold formed, have a 1/4-20 thread for 1" , 3/8" dia. x 1/8" thick shoulder and a 9/16" diameter x .100 thick head.
What will cause both to show a different magnetism from each other.
When I touch the end of one with a magnet it reacts as if it is "steel" and the other screw does not react as much.
The magnet i'm using is a neodymium magnet with 3.6 lbs pull.
The screw that acts as if "steel" has been passivated, demagnetized, the Gauss reading showed 0.0 and certified by the vendor that it is indeed 304 st stl.
Even after the demag process it still shows more magentism than the other screw.
I'm not holding the magnet on the part long enough to create a charge inthe screw, just touching the end and they pick up.
I have not yet had this material analyzed, that is the next step.
Any and all thoughts would be very much appreciated.
Regards,
Hinged
One mfr I know how they are formed, the other appears to be formed the same but I can't verify that.
Both are going into situations where they are being required to be non magnetic, or as little as possible.
Both screws are cold formed, have a 1/4-20 thread for 1" , 3/8" dia. x 1/8" thick shoulder and a 9/16" diameter x .100 thick head.
What will cause both to show a different magnetism from each other.
When I touch the end of one with a magnet it reacts as if it is "steel" and the other screw does not react as much.
The magnet i'm using is a neodymium magnet with 3.6 lbs pull.
The screw that acts as if "steel" has been passivated, demagnetized, the Gauss reading showed 0.0 and certified by the vendor that it is indeed 304 st stl.
Even after the demag process it still shows more magentism than the other screw.
I'm not holding the magnet on the part long enough to create a charge inthe screw, just touching the end and they pick up.
I have not yet had this material analyzed, that is the next step.
Any and all thoughts would be very much appreciated.
Regards,
Hinged





RE: 304 stainless steel screws
RE: 304 stainless steel screws
Thank you for the reply, I did forget to indicate we did have the "steel" reacting sample solution annealed and it didn't appear to do anything.
Any other thoughts?
Regards,
Phil
RE: 304 stainless steel screws
It is either so loaded with martensite that it won't clean up in a simple anneal, or
it is not 304, and it is loaded with ferrite, or carbides, or other trash.
My guess is that it isn't really 304.
Gauss readings mean nothing. that would only tell you if it was magnetized. You need to know if it is ferromagnetic.
You don't really want to use fasteners like this. Have some made in S21904 (21-6-9, Nitronic 40) and don't anneal them.
They will be non-magnetic even as cold formed.
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Plymouth Tube
RE: 304 stainless steel screws
RE: 304 stainless steel screws
As stated above if it came from across the ponds there is no telling what it's made of. The majority of small SS fasteners are now from overseas.
To get a 304 SS fastener that is not ferromagnetic normally requires a special order.