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347 Stainless Steel UNS S34700
347 stainless steel is a columbium/tantalum stabilized austenitic stainless steel. Similar to 321 stainless, it has good intergranular-corrosion resistance compared to typical 18-8 type alloys. With the addition of columbium and tantalum, which have a stronger affinity for carbon than chromium, the carbides will tend to randomly precipitate at the grain boundaries rather than form continuous patterns.
Applications: 347 stainless steel is widely used in aircraft exhaust, collector rings, expansion joints and in high temperature chemical processing
347 is resistant to atmospheric conditions and should be considered for applications requiring intermittent heating between the temperatures of 800f (427c) and 1650f (899c)
| Carbon | 0.08% | Manganese | 2.00% |
| Phosphorus | 0.045% | Sulfur | 0.030% |
| Silicon | 1.00% | Chromium | 17.00 - 19.00% |
| Nickel | 9.00 - 13.00% | Columbium/Tantalum | 0.40 - 0.90% |
| Iron | 63.95 - 70.44 |
Corrosion Resistance
The following table is for reference only, many factors can affect the corrosive resistance, a corrosion test for each application should be applied.
| Phosphoric Acid | Moderate | Acetic Acid | Moderate |
| Sodium Hydroxide | Moderate | Sea Water | Restricted |
| Salt Spray | Good | Nitric Acid | Good |
| Sulfuric Acid | Moderate | Humidity | Excellent |
| Sour Oil/Gas | Moderate |
Typical Room Temperature Mechanical Properties 347
| 0.2% Yield Strength | Ultimate Tensile Strength | % Elongation in 2” (50.8mm) | % Reduction of Area | Brinell Hardness | Izod Impact Strength | |||
|---|---|---|---|---|---|---|---|---|
| ksi | Mpa | ksi | Mpa | Ft-lb | J | |||
| 37 | 255 | 90 | 621 | 50 | 65 | 150 | 110 | 149 |
Heat Treatment
- Annealing:
- Heat to 1850/2000 F (1010/1093c) and quench in water. Brinell hardness approximately 150.
- Hardening:
- Cannot be hardened by heat treatment, it can only be hardened through cold working.
- Stabilizing:
- If temperature during use is expected up to 1600 degrees, stabilizing between 1550/1650f (843/899c) can be used for optimum intergranular corrosion.
- Machinability:
- When machining 347 its chip is tough and stringy, use rigid tooling with heavy cuts to prevent work hardening.
- Specifications:
- AMS 5646 ASTM A182 ASTM A276 ASTM A314 ASTM A473 QQS 763 ASME SA182 EN10204 DIN3.1B
- Shapes Manufactured:
- Flat Bars, Square Bars, Round Bars, Rings, Hollows, Discs, Blocks and special Shapes. Send us a drawing to see how we can save you material and Machining time!
The information in this data sheet is for information only and should not be used for engineering.
Materials
