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Product Overview
Stainless Steel 347 is a columbium (niobium) stabilized austenitic stainless steel. It offers excellent resistance to intergranular corrosion following exposure to temperatures in the chromium carbide precipitation range from 800 to 1500°F (427 to 816°C). Grade 347H is the higher carbon version, which provides enhanced creep strength at temperatures above 1000°F (537°C). Like Grade 321, 347 is utilized for its superior mechanical properties in high-temperature service. Steel Emporium stocks 347/347H pipes primarily for oil refineries, power plants, and chemical processing where high-heat stability is mandatory.
Key Advantages & Features
High-Temp Stability
Stabilized with Niobium to handle prolonged exposure up to 1500°F.
Intergranular Protection
Excellent resistance to sensitization during welding and high-heat service.
Superior Creep Strength
347H variant offers higher stress-to-rupture properties than 304 or 321.
| Grade | C | Mn | Si | Cr | Ni | Nb + Ta | P | S |
|---|---|---|---|---|---|---|---|---|
| SS 347 | 0.08 max | 2.0 | 0.75 | 17-19 | 9-13 | 10 x C min | 0.045 | 0.030 |
| SS 347H | 0.04-0.10 | 2.0 | 0.75 | 17-19 | 9-13 | 8 x C min | 0.045 | 0.030 |
| Property | Value (Minimum) |
|---|---|
| Tensile Strength (MPa) | 515 MPa (75 ksi) |
| Yield Strength 0.2% Offset (MPa) | 205 MPa (30 ksi) |
| Elongation (% in 50mm) | 40% |
| Hardness (Brinell) max | 201 HBW |
| Density (kg/m³) | 7960 kg/m³ |
| UNS | Werkstoff No. | JIS | EN Name | AFNOR |
|---|---|---|---|---|
| S34700 / S34709 | 1.4550 / 1.4912 | SUS 347 / 347H | X6CrNiNb18-10 | Z6CNNb18-10 |
Industrial Applications
Oil Refineries
Fluid catalytic cracking units (FCCU).
Power Generation
Steam superheaters & boiler tubes.
Chemical Process
Welded pressure vessels & reactors.
Frequently Asked Questions
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