347 stainless steel is a columbium/tantalum stabilized austenitic chromium-nickel stainless steel. This material is stabilized against chromium carbide formation by the addition of columbium and tantalum. Since these elements have a stronger affinity for carbon than chromium, columbium-tantalum carbides precipitate within the grains instead of forming at the grain boundaries. 347 should be considered for applications requiring intermittent heating between 800ºF (427ºC) and 1650ºF (899ºC) or for welding under conditions which prevent a post-weld anneal. 347 is non-magnetic.
| Element | Percent by Weight | |
|---|---|---|
| C | Carbon | 0.080% |
| Mn | Manganese | 200.00% |
| P | Phosphorus | 4.50% |
| S | Sulfur | 0.03 |
| Si | Silicon | 75.00% |
| Cr | Chromium | 17.00-19.00 |
| Ni | Nickel | 9.00-12.00 |
| Nb | Columbium and | 10xC min to 1.00 max |
| Ta | Tantalum | |
| N | Nitrogen | 10.00% |
| Fe | Iron | Balance |