QC of Magnetic Permeability of StainLess Steel
QC of Magnetic Permeability of StainLess Steel
(OP)
I have a requirement for a Deep Drawn Stainless Steel Component to have a Relative Permeability of less than 1.05. The austenitic annealed material meets this spec. but a high percentage of cold work could raise the value.
Finding a metal fabricator to tool and manufacture the part who also is familiar with the magnetic requirements and has a QC system in place for it has been a problem.
How should the requirement for low permeability be controlled and measured by our component vendor?
Finding a metal fabricator to tool and manufacture the part who also is familiar with the magnetic requirements and has a QC system in place for it has been a problem.
How should the requirement for low permeability be controlled and measured by our component vendor?
RE: QC of Magnetic Permeability of StainLess Steel
Is there a correlation to be had between surface (work) hardening and magnetic permability?
RE: QC of Magnetic Permeability of StainLess Steel
Yes, depending on type of austenitic SS, the perm can increase significantly with cold work.
Typical numbers are published by the mills. This is one example- see page 4 :
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RE: QC of Magnetic Permeability of StainLess Steel
That is very interesting, thank you!
RE: QC of Magnetic Permeability of StainLess Steel
RE: QC of Magnetic Permeability of StainLess Steel
Ron
RE: QC of Magnetic Permeability of StainLess Steel
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There are other 3xx series that have alloy additions that are intended to suppress strain hardening, but my mind is blank right now. If I think of which ones, I'll repost later.
Monel or Aluminum may also be an option
RE: QC of Magnetic Permeability of StainLess Steel
RE: QC of Magnetic Permeability of StainLess Steel
Are you familiar with it and how does it compare to the Severn Gage?
Ron
RE: QC of Magnetic Permeability of StainLess Steel
Operating Instructions
Magnetoscop 1.069 Measuring Device
Permeability Probe, X1
Calibration Standard MU 1.2
Batteries (5) AA
Carrying Case
The Magnetoscop provides a "value" (as opposed to the "less than / more than" standard comparsion provided by the Severn Gage). Please let us know how your evaluation goes.
RE: QC of Magnetic Permeability of StainLess Steel
The unit is a microprocessor driven digital readout meter that comes with a probe and calibration standard. The standard we received is 1.223 u. On power up, you place the probe on the standard, enter the perm value (1.223) and the processor self calibrates. When done, the unit reads 1.000 when the probe is in air. When the probe is placed on the test piece (in our case austenitic Stainless Steel)the permeability value is displayed directly.
Next week we will verify correlation in the readings of the two units. Our plan is to consign one unit to our vendor and the other to our incoming inspection. We need to be able to reproduce each others reading.
RE: QC of Magnetic Permeability of StainLess Steel
Ron