None of those steels are manufactured for their magnetic properties, therefore there will be considerable variation heat to heat. The producers of those steels could possibly provide data if they also produce magnetic alloys & therefore have the capability to make the measurements and you are buying lots & lots of steel from them. Otherwise you will have to send samples to independent laboratories for testing.
ndtkansas,
just to have an idea about 15.5PH and 17.4PH magnetic performance in different condition and other properties, in annex ,you can see a technical paper ( 5th Europeen Congress Stainless Steel Science and Market, Seville -Spain- September 2005 ). Please take into consideration that magnetic permeabilty is strongly influence by chemical composition ( balance between Cr/Ni equivalent)at same heat treatment condition.Lower Cr/Ni ratio could be a 15.5PH , higher one a 17.4PH. The presence of Austenite at different aging temperature affects (decreases )magnetic permeability. The values of Magnetic Permeabilty shown in the technical paper, are the result of a lot of data coming from different lot and heat of these grades. Magnetic properties of these PH grades and soft Martensitic were required by Euoropean Automotive Industries ( high pressure security system and injection ) . I hope this paper could give you a little help. However,if you wanted to know magnetic propertis of other alloy grades,you firstly decide in wich condition you need to evaluate( annealed or hardened and tempered, ground, cold drawn )and then prepare the specimens avoiding any kind of tension or strain hardening. Test must be done by a Permeameter ( CC )that allows to know Hc, Jsat , Bsat , Br, ( from Bsat or from 1 Tesla )and magnetic permeability. A Coercimeter only gives Coercive force (Hc ) from Bsat.
Finally, dgallup is right but, perhaps, some Steel Producer could "open " his "heart" and files as well and give you more data free of charge.
