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Stainless Steel 347 is an austenitic chromium-nickel stainless steel, AISI 347 has excellent intergranular corrosion resistance and oxidation resistance at high temperatures. 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.
AISI 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. SS347 is non-magnetic.
It features excellent corrosion resistance comparable to 304 stainless steel.
It restrains chromium carbide formation, resists sensitization, and has good intergranular corrosion resistance between 427°C and 816°C.
It exhibits certain strength of creep resistance even in strong oxidizing environment at high temperature of 816°C.
It is easy to form and weld.
It has good low temperature toughness.
Overall, Stainless Steel 347 has similar performance like 321 (304 plus Ti) but is superior to 321.
Grade | C≤ | Mn | P≤ | S≤ | Si≤ | Cr | Ni | Nb |
347 | 0.08 | 2.0 | 0.045 | 0.03 | 0.75 | 17.0-19.0 | 9.0-13.0 | 10*C-1.0 |
Tensile, min, ksi[MPa] | Yield, min, ksi[MPa] | Elongation, %(min) | Hardness, HB（max） |
75【515】 | 30【205】 | 40 | 201 |
| Parameter | Value |
|---|---|
| Density | 7.98 g/cm³ (0.288 lb/in³) |
| Melting Range | 1398–1453°C (2550–2650°F) |
| Thermal Expansion (20–100°C) | 16.6 µm/m·°C |
| Mean CTE (20–600°C) | 18.5 µm/m·°C |
| Thermal Conductivity | 16.2–19.5 W/m·K (11–13.5 btu·in/ft²·h·°F) |
| Specific Heat Capacity | 500 J/kg·K (0.12 Btu/lb·°F) |
| Max Continuous Service Temp | 925°C (1700°F) |
| Temp (°C) | Thermal Conductivity* (W/m·K) | Yield Strength Retention |
|---|---|---|
| 316 | 16.3 | 135 MPa |
| 347 | 17.8 (>316) | 152 MPa (>316) |
| 304 | 16.2 | 130 MPa |
STANDARD | WERKSTOFF NR. | UNS | JIS | GOST | EN |
347 | 1.4550 | S34700 | SUS347 | 08Ch18N12B | X6CrNiNb18-10 |
Corrosion Resistance
347 stainless steel exhibits excellent corrosion resistance over a wide range of temperatures and concentrations. It can withstand many organic and sufficiently diluted mineral acids, depending on the temperature of the solution. 1.4550 withstands uniform corrosion in strong mineral acids such as hot concentrated nitric acid and hot strong alkaline solutions. Due to its niobium content, the risk of susceptibility to intergranular corrosion is significantly reduced compared to other austenitic grades.
Cold Working
347 steel can be easily formed and fabricated by all cold working processes. The material can be drawn and bent. Any cold working process increases its strength and hardness and may make it slightly magnetic. Work hardening is intensified by the partial transformation of the austenite to hard martensite.
Weldability
1.4550/347 has excellent weldability and is suitable for all conventional welding methods (such as MMA, MIG, MAG, TIG, SAW, LBW, or RSW), except for autogenous welding. Compared to carbon steel, 1.4550 has a thermal expansion rate approximately 50% higher and a lower thermal conductivity.
| Products | Standard | Show |
| 347 stainless steel pipe | ASTM A312, ASTM A213 |  |
| 347 stainless steel tube | ASTM A269 |  |
| 347 stainless steel sheet/plate | ASTM A240 |  |
| 347 stainless steel bars | ASTM A276, ASTM A479 |  |
| 347 stainless steel forging/flange | ASTM A182 |  |
| 347 stainless steel BW fittings | ASTM A403 |  |
Petrochemical, food, paper, etc
Exhaust manifold and branch pipe of aero engine
Turbine compressor hot gas pipeline
Aircraft collector rings
Aircraft exhaust stacks
Boiler casings
