Stainless steel on Lawrence?

[David Schwab]

Well I can tell you a good part of why this stuff is so expensive is that Carpenter ships a 1 oz, trifold, 4 color brochure on heavy cardstock via UPS 2 day Express Hard Pack.

The info presented is;

5 soft magnetic alloys in order of cost from lowest to highest:
Iron, Silicon Iron, Ferritic Stainless, Nickel Iron, Iron Cobalt.

In order of Permeability (sensitivity) -low to high:
Ferritic Stainless, Iron Cobalt, Iron, Silicon Iron, Nickel Iron.

In order of strength (Flux Density) -low to high:
Nickel Iron, Ferritic Stainless, Silicon Iron, Iron, Iron Cobalt.

Nickel-Iron alloys seem like they would be the most promising for pickups and they are recommending HyMu "800" for tape head laminations.

Is that making any sense to anyone?

Seems like Silicon Iron has a good average here.

[salvarsan]

Re-hijacking the thread

Carpenter Tech blah blah.

5 soft magnetic alloys in order of cost from lowest to highest:
Iron, Silicon Iron, Ferritic Stainless, Nickel Iron, Iron Cobalt.

In order of Permeability (sensitivity) - Yada yada

In order of strength (Flux Density) -low to high: mumble blah

Is that making any sense to anyone?

Yeh. Its the same chart they put on the tech info page for registered users.

Permeability and saturation point are the big ones.
Saturation is the limiting magnetic flux that you can pump through something.

The nickel/iron alloys are highly! permeable but reach saturation early.
Iron-Cobalt alloy properties are reversed respectively.

For real numbers, magnetic stainless like T430 saturates ~15kGauss while ordinary steel (1018 & similar) saturates at 150kGauss. T430 permeability is also about 1/10 that of steel -- it may not conduct magnetism well enough for use in pickups.

HyMu-80 conducts magnetism excellently, permeability ranges 500kG to 1MG, but saturates at low field strengths.

For practical purposes, 1018 steel with a nickel plate on the exposed parts is cheapest and best. Joe Barden blades are made exactly that way.

Pickup Slugs and blades made of HyMu-80 or similar are a pricey solution for use with weak magnets.

With all that, I've ordered a few feet of T416 stainless for fun and games. It's too cheap to reject out of hand.

-drh