It is commonly stated that “stainless steel is non-magnetic”. This is not strictly true and the real situation is rather more complicated. The degree of magnetic response or magnetic permeability is derived from the microstructure of the steel. A totally non-magnetic material has a relative magnetic permeability of 1. Austenitic structures are totally non-magnetic and so a 100% austenitic stainless steel would have a permeability of 1. In practice this is not achieved.

IntroductionAustenitic stainless steels are generally non-magnetic with magnetic permeabilities of around 1.0. Permeabilities above 1.0 are associated with the amount of either ferrite or martensite phases present in the 'austenitic' steel and so depend on:chemical composition cold work and heat tr

When selecting stainless steel hardware, it is important to understand the differences between the variety of grades and finishes available so you can choose the products that will work most safely and effectively for your purposes. It's difficult to distinguish between these two types of steel visually, but significant differences between the two steel types do exist and are important to understand. Below is a basic guide to the similarities and differences of 304 grade and 316 grade stainless steel.