I'm not experienced at making suppressors, but I do know that if you want something that needs to be corrosion resistant and will operate at high temps, you usually look at stainless or other alloy steels. It really depends on exactly what someone means when they say "strength". Some steels are better at wear resistance, some have higher tensile strength (like the bolts that hold engines together), some are meant to bend without fatiguing (springs), etc. It seems to me like the best materials for a suppressor would be stainless steels, or the exotic super alloys like inconel (jet engine parts are made from inconel). But again, I'm not a suppressor maker, so I'd really have to defer to Jayson on that. It may be some issue like there are manufacturing limitations that don't let you take advantage of the properties of stainless steel.
Also, you might be asking for two opposing things - it might be that the most rust proof would be stainless, but that the most "blow proof" as you put it would be a standard non-stainless steel, in which case you'll have to pick the one that is MOST important.