how to remove magnetic properties in 360 Brass screws

[Lyndazz]

Hello,

we have produced parts made from 360 Brass and after machining the parts have testing with Severn Low Mu tester with no insert per customer requirement and failed. What has to be done to the screws to remove all magnetic properties from the parts. Has anyone had this problem?

 

[TugboatEng]

360 brass has iron in it. Iron can be demagnetized by heating to it's Curie temperature which is just over 1400°F. 360 brass melts at over 1600°F. Will your parts tolerate this bake? I don't know.

Edit:
I see now that your parts are failing on magnetic permeability and not due to magnetism. You are likely going to have to reproduce the parts with a material that has lower permeability. Look for alloys without iron.

 

[EdStainless]

Like many Cu alloys with Fe the magnetic condition has a lot to do with how the Fe is dispersed in the structure.
This has to do with all of the prior thermomechanical history of the material.
There is nothing that you can do now.
This requirement (and testing) should have been on the RM purchase order.
How low of a perm are you after?
You may need a different alloy.

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P.E. Metallurgy, consulting work welcomed

 

[TugboatEng]

Brass metals are challenging. They aren't exactly alloys and combine in unusual ways. You can blend nickel and iron (both magnetic) to make an austintic alloy that is non-magnetic. Meanwhile, you can blend copper and zinc to make brass but the zinc will still act independently in the compound can result in dezincifation in some environments. I am assuming the up to 0.35 iron content is behaving as iron in the brass compound (not alloy).

 

[MagBen]

WE have a standard process to de-mag the austenitic stainless, PH alloys etc. bar by passing products through an AC solenoid coil. fine magnetism can be built up at drawing/handling/grinding/machining whatever cold working.

but first make sure the testing is correct. often at a time, retest passes by wiping off any metal dust which are magnetic that can increase permeability.

also, i am curious, how can you test without an insert as a standard for a specific Mu? i donot think you can test an a muneral Mu number, but rather, it is a range of two Mus, as a go or no go relative testing.

 

[EdStainless]

For those who don't know the Severn gauge uses a permanent magnet and interchangeable inserts with different perm values.
What it tells you is if the perm exceeds the value on the insert.
The drawback is that you are testing at one specific field level and there is no control over this.
I have a Severn gauge and I used to make magnets for them as well.

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P.E. Metallurgy, consulting work welcomed

 

[hacksaw]

You are dealing with a difficult issue, and requires a better understanding of what your customers design actually involves.