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Re:copper clad on 416 steel

Re:copper clad on 416 steel

Re:copper clad on 416 steel

We have a torquer ring that goes in a vertical displacement gyro unit, the ring is made of 416 steel with a copper clad that is plasma sprayed on the front surface. the ring is a left/right directional type that is driven by the torque coil magnetic field. My first question is, What is the purpose of the copper cladding on the ring(this is the area that the torquer coil is aligned with) and the next question is that we now have some rings that do not have the magnetic properties (very weak) that previous rings had, some how the vendor has changed the process or material, can anyone that give me insite on what is going on?

RE: Re:copper clad on 416 steel

The copper may just be to prevent rusting of the 416.  If it is thin I can't imagine that it impacts any other properties.

You need to verify the thermomechanical history of the 416.  Is is annealed, notmalized, tempered??
You should check out the mechanical porperties and look at some microstructures.
I presume that you buy these to either specific magnetic properties or mechanical properties.
These may be 'harder', have higher H than previous batches, making them more difficult to magnetize.

= = = = = = = = = = = = = = = = = = = =
Corrosion never sleeps, but it can be managed.

RE: Re:copper clad on 416 steel

The material was spec only for annealling, the only varible with the process was suppose to be plasma spraying the copper on the steel. Could this process effect the magnetic properties?

RE: Re:copper clad on 416 steel

I wouldn't expect them to.  Variations in chemistry and annealing practice could result in vastly different properties though.  You need to measure the actual magnetic properties.

= = = = = = = = = = = = = = = = = = = =
Corrosion never sleeps, but it can be managed.

RE: Re:copper clad on 416 steel

Just a thought, but 416 is martensitic stainless steel which is magnetic.  All the 300 grades of stainless are austenitic i.e. non magnetic - could you have been supplied with the wrong material? (easy to check with a magnet)

Like EdS, I don't know what the copper layer is for, but there again I don't know how gyros work either.

RE: Re:copper clad on 416 steel

Not sure to understand your setup, as I don't know that kind of equipment.
Copper clad may be there to create eddy currents.
If the magnetic arrangement is such that a substantially constant magnetic induction traverses at right angles the copper surface (that should face the gap between the magnetic field and the ferromagnetic 416 steel ring), then the result would be that, by forcing one of the two parts to rotate, the other one is driven into rotation also. Now if the driven part is retained by a spring, its angle of rotation will be related to the rotational speed of the facing element. Or, if it is free to rotate but with some friction, it will rotate at a different speed, and the speed difference would also depend on the driving speed.
As someone noted above, copper thickness seems to be so small, that it is difficult to imagine it is there for conducting eddy currents: however copper conductivity is very high, so, if your equipment is just a small unit, then it might be as described above.
The characteristic of such a sensor would critically depend on copper quality and thickness, on the ferromagnetic properties of the 416 ring and of course on the strength of the magnetic field. The ring should be strongly attracted by a permanent magnet and have no residual magnetism when the magnet is removed.


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