AISI 347 / UNS S34700 (Austenitic) Stainless Steel
Chemistry, mechanical properties, physical properties, and practical selection notes for rolled AISI 347 products.
Performance & Use Notes
- Nb-stabilized 304-type; improved resistance to intergranular corrosion after welding or high-temperature exposure.
- Often used in similar stabilized-temperature service ranges as 321.
Standards & Designations
ASTM A240 ♦ UNS S34700
Data Tables
- Nb-stabilized 304-type; improved resistance to intergranular corrosion after welding/high-temp exposure.
| Chemical composition (wt%) | Limits |
|---|---|
| C | 0.08 max |
| Cr | 17.0–19.0 |
| Ni | 9.0–13.0 |
| Nb+Ta | 10xC min to 1.00 max |
| Mn | 2.00 max |
| Si | 1.00 max |
| P | 0.045 max |
| S | 0.030 max |
| N | 0.10 max |
| Mechanical (annealed) | Requirements (min / max) |
|---|---|
| YS | 30 ksi min |
| UTS | 75 ksi min |
| Elongation | 40% min |
| Hardness | B95 max |
Values shown are typical/spec limits at room temperature unless noted; requirements vary by product form, size, and specification.
347 stainless steel from Source21 is a niobium stabilized austenitic stainless steel grade designed for sustained performance in high temperature and oxidizing environments. Similar to Type 321 but stabilized with niobium also known as columbium Type 347 stainless steel resists carbide precipitation during prolonged heat exposure preserving corrosion resistance and mechanical strength in welded and fabricated components. It is widely used in refineries heat exchangers boilers power generation equipment and exhaust systems where thermal stability and reliability are essential.
Source21 supplies 347 stainless steel in coil, strip, sheet, foil, and bar, all produced to meet ASTM A240, AMS 5512, and AMS 5646 standards.
Contact the Source21 team to place an order explore material availability or receive expert guidance for high temperature stainless steel applications supported by reliable supply and responsive service.