347 Stainless Steel
UNS S34700
Description
Type 347 stainless steel is a specific type of austenitic stainless steel, which imparts excellent corrosion resistance properties. 347 stainless steel is stabilized with niobium, which allows it to avoid intergranular corrosion when heated to its sensitization temperature range. 347 stainless steel has excellent resistance to oxidation, even surpassing that of 321 in strong oxidizing conditions. The alloy also possesses good creep strength compared to other 300 series stainless steels. It also possesses good low temperature toughness, non-magnetic in the annealed condition, and can only be strengthened by cold working.
Chemical Component
| Ni | Cr | Nb + Ta | Si | C | Mn | S | P | Fe |
|---|---|---|---|---|---|---|---|---|
| 9.0-13.0% | 17.0-19.0% | Nb 10*C (Cb 8*C)-1.0% | 0.75% max | 0.04-0.08% | 2.0% max | 0.03% max | 0.045% max | Balance |
Basic Information
| Items | 347 Stainless Steel |
|---|---|
| Catalog | ACMA-Fe-A017 |
| Density | 0.282 lb/in3 |
| Melting Range | 2550-2635 °F |
| Coefficient of Thermal Expansion, in/in°F x 10-6 | 70-212 °F: 9.2 |
| Thermal Conductivity, Btu·ft/ft2·hr·°F | At 212 °F: 112.5; At 932°F: 147.7 |
| Electrical Conductivity, 68°F (20°C), %IACS | At 70 °F: 28 |
Material Forms
Alfa Chemistry offers 347 stainless steel in a variety of forms, including Plate, Round Bar, Sheet, Wire, Coil.
Mechanical Properties
- Minimum specified properties, ASTM A 240
| Ultimate Tensile Strength, ksi | 0.2% Yield Strength, ksi | Elongation, % | Hardness Max, Brinell |
|---|---|---|---|
| 75 | 30 | 40 | 201 |
- Typical tensile and impact properties
| Temperature, °F | 68 | 400 | 800 | 1000 | 1200 | 1350 | 1500 |
| Ultimate Tensile Strength, ksi | 93.3 | 73.6 | 69.5 | 63.5 | 52.3 | 39.3 | 26.4 |
| 0.2% Yield Strength, ksi | 36.5 | 36.6 | 29.7 | 27.4 | 24.5 | 22.8 | 18.6 |
Specifications
Features
- Good creep strength up to 1500 °F.
- Maintains good corrosion resistance in applications where the temperature is between 800 °F and 1500 °F.
- Good resistance to intergranular corrosion in the as welded condition.
Applications
- Oil Refineries
- Fluid catalytic cracking units (FCC)
- Hanger rods
- Recuperator tube sheets shell, supports
- Especially where temperatures exceed 550°F and resistance to sulfidation is needed
- Fired heater tubes
- Distributor trays and thermowells
- Equipment in and around reactors (good resistance to polythionic acid)
* Technical data included herein should be used as a guideline only, and should not be construed as maximum or minimum values for specification or for final design, or for a particular use or application. The data may be revised anytime without notice.
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Alfa Chemistry is a manufacturer of standard & custom specialty metals & alloys. We stock a wide variety of alloys in different shapes and specifications. If you can't find the product or specification you need, please contact us directly.
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