How Do You Determine the Permeability of Steel Screws Used in Electromagnets?

[Jdo300]

Hello All,

I'm working on a project involving the use of electromagnets and I am trying to do some calculations to predict the B-Field strength of the coils I make. For the core, I'm just using some common 1/4-20 steel machine screws (the common ones you can get from Home Depot and Lowes) but I'm not sure how to account for the permeability of the steel in my calculations.

Does anyone have any idea how one might determine this information? I know that the material will not have a fixed value (BH Curve) but if I could know what kind of steel is used, that would help a lot. Does anyone have any idea about this?

Thanks,
Jason O

 

[anorlunda]

The material is likely carbon steel. But there are many formulations of carbon steel with different permeabilities. You'll have to refer to the manufacturer.

 

[eq1]

Measure it. :)

 

[DaveE]

I would just measure it, but that would require some instrumentation. What sort of electrical instruments do you have available to make measurements?

 

[eq1]

The YouTube video I linked shows how to make a gaussmeter with a multimeter a compass.

Or one can do it this way pretty easily.
https://meettechniek.info/passive/magnetic-permeability.html