If iron cobalt and nickel are magnetic (which I think is the right term, but it feels wrong since magnets stick but it doesn’t magnet to other steel) then why does using nickel to make stainless steel render steel non-magnetic?
Or is my metallurgical understanding just completely off?
In: Physics
Ok so simple explanation.
Steel is magnetic because of its crystal structure.
Think of a marshmallow and toothpick model from grade school. Let’s pretend that the normal Cube shape is magnetic and other shapes like pyramids aren’t.
Stainless steel replaces some of the marshmallows with apples. The apples make the cube shape all weird with pyramids and other shapes so it’s not magnetic. There are still some Cubes, but not enough to make a magnet stick.
But you can sometimes make it magnetic by bending it or hitting it. Bending the steel squashes the model back into enough cubes to make the magnet work again.
Same thing with heating normal steel. The marshmallows get hot and the cubes sag, so it stops being magnetic. When it cools back down the cubes form up again.
Cause the two magnetic fields cancel each other out.
Also because the manufacturing process and the heat changes the metal enough to make it not magnetic.
I don’t know the answer to your question but metals attracted to magnets are referred to as ferrous
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For the purposes of ELI5, magnetism occurs when the atoms inside your material are all aligned in the same direction (imagine a bunch of tiny magnets all aligned N-S in perfect unison).
When we melt the iron and nickel down to make steel (along with anything else getting mixed in), we run into 2 issues for magnetism:
1. Adding that much heat will cause all the atoms to jiggle around a lot more which throws them out of alignment. If you make the atoms hot enough, they permanently fall out of alignment. We call that point the Curie Temperature – the temp at which natural magnets lose their magnetism.
2. Even if the iron stays in alignment, you now have a bunch of atoms all mixed throughout the iron which means that whatever was all previously aligned is now spaced way out by other atoms so it’s “less dense” in a sense. This drop in “magnetic density” makes the magnet effects vanish.
it’s not magnetic? ive never seen it to not be. huh.
Austenitic grades of stainless steel like 304 (also known as 18-8) are non magnetic due to austenite’s crystalline structure being non magnetic. You can cold work stainless to force the austenite to change into martensite, which is magnetic.
There are other grades like ferritic and martensitic stainless as well as ferritic-austenitic which are called duplex stainless that are also magnetic.
Source: I made pipe fittings from all kinds of grades of carbon and stainless steels and nickel alloys.
This is also an effect of steel beingan alloy, where the new metal is not a simple combination of the ingredients and cannot be seperated
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