347 is a columbium/tantalum stabilized austenitic stainless steel that resists carbide precipitation during welding and intermittent heating to 800/1650°F (427/899°C). It has good high temperature scale resistance and, like 321 stainless, has superior intergranular-corrosion resistance compared to typical 18-8 type alloys. Since columbium and tantalum have stronger affinity for carbon than chromium, carbides of those elements tend to precipitate randomly within the grains instead of forming continuous patterns at the grain boundaries.
