Magnets and Stainless Steel Razor Blades


#1

On a recent show a caller said hubby had been scraping a sticker off the windshield & accidentally got a razor blade lost in the airbag area. The caller asked Ray for ideas how to retrieve it. Ray said to use a magnet, but since the razor blade was probably stainless steel, she’d have to stick the magnet to the back end of the razor blade, not the sharp, cutting front part. The back end of those single edge “scraper” razor blades, Ray said, is made of regular carbon steel, not stainless steel, so a magnet will stick to that part.

I got to thinking about this and decided to try an experiment, see if a magnet will stick to stainless steel or not. First I tried a stainless steel pot. Sure enough, the magnet wouldn’t stick to that. It just fell off. Next I tried a stainless steel steak knife. Ooops. The magnet stuck to that w/no problem.

So is that all to be expected? Is stainless steel made in different ways? The variety intended for cutting more magnet-attracting than stainless steel intended for cooking? If so, then wouldn’t the magnet stick to the stainless steel part of the razor blade too?


#2

There are many different types of stainless, some magnetic, some not.


#3

Maybe somebody here has a stainless steel razor blade and can tell us if a magnet sticks to it or not.


#4

And if you want some super strong magnets tear apart an old hard drive from the computer, those magnets are killer!


#5

The magnet I used I extracted from a small speaker. You know, it has a voice coil wrapped around a cylinder shaped magnet. I was thinking that magnet would be really strong, but in fact it is a pretty weak magnet. I have another magnet that is probably 1/1000 the volume of the speaker magnet, but 10 times as strong. I guess for some reason its better to use less powerful magnets in speakers. It was good to have a weak magnet though, b/c I could test Ray’s stainless steel theory better.


#6

Magnetism in stainless steel is determined by the amount of nickel it has. Many of the newer SS cookware has a layer of SS that is magnetic or an encapsulated steel disc in the bottom so it will work on an induction stove.


#7

I’m thinking that to make a stainless steel that will hold an edge you have to have more carbon and iron and less nickle. So the kind used for knives and razor blades will attract a magnet.


#8

Common 304 austenitic stainless has 19% chromium, 9% nickel, max 0.08% carbon, and is neither hardenable nor magnetic.

Typical 410 marstenitic stainless has 12.5% Cr, no Ni, max 0.15% C, and is both hardenable and magnetic.


#9

If you want a really strong magnet, you want neodymium. They’re so powerful that the government is trying to ban their use in toys because so many kids have swallowed them, and if a kid swallows more than 1 they will perforate the kid’s bowel trying to get to each other.


#10

A new data point. A magnet sticks to the (presumably) stainless steel blade in a Bic razor.


#11

No need to test. Only a hardenable, and therefore magnetic, stainless can hold an edge.


#12

That’s the ticket. Austenite is paramagnetic (300 series) and ferrite (400 series) is ferromagnetic.


#13

Being magnetic has nothing to do with heating on an induction stove. The ability to conduct the electric current generated by the high frequency magnetic field is what makes the pot hot.
Aluminum and copper pots heat just fine on an induction stove. Glass pots don’t.


#14

Not according to the induction stove top manufacturers.

http://theinductionsite.com/proandcon.php


#15

You’d think for heating a pot w/induction currents the main parameter would be the ohmic resistance of the material in the bottom of the pot. There’s probably a sort of Goldilocks resistance, not too little, not too much for optimum inductive heating. I suppose the magnetic permeability of the material would enter the equation too, since if I recall from 40 years ago physics classes, the amount of current induced is proportional to that constant.


#16

Per Wikipedia:

Iron and its alloys respond best to induction heating, due to their ferromagnetic nature. Eddy currents can, however, be generated in any conductor, and magnetic hysteresis can occur in any magnetic material.

It’s a function of the frequency used. I have experience melting uranium metal and zinc in induction furnaces. For the uranium, it was in a graphite crucible which is what coupled with the E-M waves. The zinc coupled directly.