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# cold worked austenitic SS B/H curves

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## cold worked austenitic SS B/H curves

(OP)
I'm trying to do a 2D FEA analysis of some devices that have deep drawn austenitic stainless steel components.  If these parts were annealed I would use a constant permeability of about 1.005 or just leave them out of the analysis completely.  However, since they have a lot of cold work they are more permeable.

The problem I'm running into is the data I've got gives single values of permeability as a function of percent cold work, ie 304 is 1.16 at 30% cold work & 2.30 at 50% cold work.  304L can go even higher, 8.5 at 50% cold work.  Using constant permeability like that is creating obvious computational errors at high induction levels.  With a constant permeability of 1.005 I'm getting 0.5 T in the SS while a constant permeability of 3 yields 1.2 T and 8 gives over 2 T in the same spot.  Those values are obviously not right.

So I need to use a non-linear B/H curve for these austenitic stainless steels like I do for the ferritic materials.  The problem is, I don't have such curves.  Does anybody have a reasonable B/H curve for cold worked austenitic SS or know where to get such data?

The Help for this program was created in Windows Help format, which depends on a feature that isn't included in this version of Windows.

### RE: cold worked austenitic SS B/H curves

(OP)
I'm sure it will but I need some place to start.  Surely this stuff has to saturate at relatively low flux density levels which isn't happening with a constant permeability model.

The Help for this program was created in Windows Help format, which depends on a feature that isn't included in this version of Windows.

### RE: cold worked austenitic SS B/H curves

The cold drawing is converting some of the austenite to martensite, producing a magnetic response.  Since most of the martensitic grades saturate out in the 1.7T range, I'd suggest making a hybrid magnetization curve with an arbritrary permeability and a saturation level near 1.7T (maybe lower).  It certainly would not be perfect, but it is a start.

### RE: cold worked austenitic SS B/H curves

(OP)
MagMike - I'm planning on taking an approach along those lines.  However, since only a (small?) portion of the the austenite is converting to martensite, I would think 1.7 T is too high.  I'd love to have some actual data.  I've contacted KJS Magnetics but I doubt they can measure my actual parts (too small).  Hopefully they can provide some data on bar samples.

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The Help for this program was created in Windows Help format, which depends on a feature that isn't included in this version of Windows.

### RE: cold worked austenitic SS B/H curves

I have samples of cold drawn tube, but alas no way to measure them.

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Plymouth Tube

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