As I mentioned in the previous article, I found it difficult to find saturation curves for common soft magnetic materials by searching the Internet. To help, I decided to share the data I have accumulated over a 20 year period. Here is a link to the data:

http://www.fieldp.com/magneticproperties.html/

Values are listed in text format so you can copy them and paste them into applications. The data are from a variety of sources, and I made some effort to ensure consistency. Nonetheless, Field Precision makes no claims about the accuracy of the values and accepts no responsibility for applications of the data. You are welcome to use them as is. If you have better values or find an error, please contact us a techinfo@fieldp.com.

The following materials are included

- Armco
- Cast iron
- Cast steel
- Cobalt
- Iron 1018
- Magnet steel
- Magnetite
- Nickel
- Pure iron
- Sheet steel
- Silicon steel
- Soft iron
- Steel 50H470
- Steel1008
- Steel1010
- Steel1018
- Steel1020
- Steel1030
- Tungsten steel

For the soft materials, the value of relative magnetic permeability (μr) is defined as

μr = *B*/*B0* = *B*/(μ0**H*) [1]

where the total magnetic flux density *B* is in tesla and the magnetic field *H* is in A/m. The quantity *B0* is the applied magnetic flux density and has units of tesla. Magnetic materials saturate at high values of *B*. The maximum contribution that a material can make to the total flux density occurs when all domains are completely aligned. The contribution is called the saturation flux density *Bs*. At higher fields, the total flux density is the sum of the peak material contribution and the applied flux density:

*B* = *B0* + *Bs*. [2]

In this limit, the relative permeability is

μr = *B*/(*B*–*Bs*). [3]

At high field, Eq. 3 implies that the saturation flux density is given by

*Bs* = *B* – *B*/μr. [4]

Some of the tables contained high enough values of *B* that is was possible to identify a consistent value of *Bs* from Eq. [4]. For these cases, I used Eq. 3 to extend the table to a standard value of *B* = 10.0 tesla to aid in the convergence of nonlinear numerical solutions.

For more information on **PerMag** and **Magnum**, please see http://www.fieldp.com/permag.html and http://www.fieldp.com/magnum.html.