Magnetic tendencies in SS

[kamran]

It is often said about SS304 and SS316 that they tend to develop slight magnetic tendencies when cold-work but that this does not happen when they are annealed.

What is the reason behind this?

[mechcolor]

This is due to the formation of martensite and lattice starining after deformation during cold work. This phase is a ferromagnetic one. Different austenitic stainless steels behave differently. It depends on the work hardening ability of any austenitic stainless steel. Fully austenitic ones have the least which results in almost no change in magnetic behavior. Like type 316 is more austenitic than type 304 due to higher nickel content and is lesser sensitive to change in magnetic behavior upon cold work. Similar is the case with type 310.

Annealing process helps austenitic stainless steels in returning to their non-magnetic nature.

[kamran]

Thanks. This really helped.