magnetic permeability of 1010 CRS over temp

[sensorsguy]

I have a Hall sensor application that uses a Sm2Co17 rare earth magnet and a 1010 CRS pole piece. I am interested in performance over a temperature range from 25C to 150C. I can find properties of the Sm2Co17 over temp, but I can find virtualy nothing on the steel. Can anyone help me find data on the permeability of 1010 CRS over temp?

 

[MagMike]

I looked through my copy of Bozorth's Ferromagnetism. He doesn't have a curve for steel, but the one for iron should be sufficient (at least the trends will be the same). At 25degC, the maximum permeability is about 2750. At 150degC, the maximum permeability increases to 4000.

The initial permeability did not change significantly.

Prior heat-treatment can change this, so treat these numbers as approximate. The chart I saw mentioned that the iron was annealed at 800degC.

Hope this helps.

 

[sensorsguy]

The data seems kind of counterintuitive to me. Increasing magnetic permeabibility with temp seems analagous to increasing electrical conductance, which I thought decreased at higher temps. Perhaps my perception and/or my logic are/is flawed.

In any case, thanks for the info.

 

[MagMike]

I admit it does seem a counterintuitive. However, the coercivity (resistance against demagnetization) decreases with increasing temperature. As a result, it becomes easier to magnetize the material, thus the permeability increases.