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
Stainless steel, such as AISI type 316 in the austenitic phase, has a magnetic permeability of 1.008 or so (i.e. almost negligible). Where this can change is when the metal is cold-worked during forming, hammering or drawing operations. The act of working the steel causes a phase transition from austenite to martensite within the microstructure of the steel in the strained regions, and this causes the steel to become ferromagmetic in those regions. The magnetic response can be subsequently eliminated with heat treatment. A full solution anneal will drive a phase change back to the fully austenitic condition.
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