A stainless is defined as 12% minimum Chromium, which can encompass many stainless grades. There are sub categories of this Austenitic type stainless though. Depending on the composition, some materials are more Austenitic than others; primarily due to their Nickel (Ni), Manganese (Mn), Carbon (C) and Nitrogen (N) contents. To consider this further, you need to understand the corollary to Austenite; Ferrite and Martensite are what many people are looking for when they require magnetism, or magnetic permeability. When you mix Austenite and Ferrite it is a Duplex (contains both, nearly equal amounts). A low Ferrite number generally indicates a lower magnetic permeability. Stainless that is high in Ni, Mn, C, or N or a combination thereof can be an indicator that it will have a lower Ferrite content. Some stainless steels with generous amount of these attain a negative ferrite calculation, using Schaefflers diagram you can predict these on a graph or us a Ferrite Number (FN) formula to arrive at the estimate.