Type 347 Stainless Steel
347 stainless steel is variant of the basic austenitic 18/8 Grade 304 with added Columbium – the introduction of Columbium stabilizes the steel and eliminates carbide precipitation which subsequently causes intergranular corrosion.
The steel has excellent forming and welding qualities and excellent toughness even at cryogenic temperatures.
Benefits of 347 Stainless Steel
- Higher creep stress and rupture properties when compared with 304
- Ideal for high temperature service
- Overcomes sensitization and intergranular corrosion concerns
- Can be used in elevated temperature applications for ASME Boiler and Pressure Vessel Code applications
- Due to stabilisation the material offers better overall corrosion resistance when compared to 304/304L
- Excellent mechanical properties
- A high carbon version (347H) is also available
Typical Uses
- Heat exchangers
- High temperature steam service
- High temperature chemical process
Both 347/347H are used primarily in elevated temperature applications.
Mechanical Properties of Type 347
| Description | Type 347 |
|---|---|
| Proof Stress 0.2% (MPa) | 205 |
| Tensile strength (MPa) | 515 |
| Elongation A5 (%) | 40 |
| Hardness | HB: 201 HRB: 92 |
Chemical Composition of Type 347
| UNS No | S34700 |
| EN | 1.4550 |
| AISI | 347 |
| Carbon (C) | 0.08 |
| Silicon (Si) | 0.75 |
| Manganese (Mn) | 2.00 |
| Phosphorus (P) | 0.045 |
| Sulphur (S) | 0.030 |
| Chromium (Cr) | 17.00 – 19.00 |
| Molybdenum (Mo) | |
| Nickel (Ni) | 9.00 – 13.00 |
| Nitrogen (N) | |
| Other | Cb:10xC1.00 |