Characteristics
Alloy 347 (UNS S34700) is columbium stabilized austenitic stainless steel plate with good general corrosion resistance and somewhat better resistance in strong oxidizing conditions than 321 (UNS S32100). It has excellent resistance to intergranular corrosion after exposure to temperatures in the chromium carbide precipitation range of 800 – 1500°F (427 – 816°C). The alloy has good oxidation resistance and creep strength to 1500°F (816°C). It also possesses good low temperature toughness.
Chemical Analysis Weight %
(all values are maximum unless a range is otherwise indicated)
| Element | 347 | 347H |
| Chromium | 17.00 min.-19.00 max. | 17.00 min.-19.00 max. |
| Nickel | 9.00 min.-13.00 max. | 9.00 min.-13.00 max. |
| Carbon | 0.08 | 0.04 min.-0.10 max. |
| Manganese | 2.00 | 2.00 |
| Phosphorus | 0.045 | 0.045 |
| Sulfur | 0.03 | 0.03 |
| Silicon | 0.75 | 0.75 |
| Columbium & Tantalum | 10 x (C + N) min.-1.00 max. | 8 x (C + N) min.-1.00 max. |
| Iron | Balance | Balance |
Fabrication Data
Alloy 347 stainless steel coil can be easily welded and processed by standard shop fabrication practices.
The alloy is quite ductile and forms easily.
The high sulfur content of Alloy 303 also has a detrimental impact on hot workability. If hot forming is required, once again, 304 should be considered as an alternate selection.
The cold work hardening rate of 347 stainless steel coil makes it less machinable than 410 stainless steel, but similar to 304. The table below provides relevant machining data.
| Operation | Tool | Lubrication | Conditions | |||||
| Depth-mm | Depth-in | Feed-mm/t | Feed-in/t | Speed-m/min | Speed-ft/min | |||
| Turning | High Speed Steel | Cutting Oil | 6 | .23 | 0.5 | .019 | 12-16 | 39-52 |
| Turning | High Speed Steel | Cutting Oil | 3 | .11 | 0.4 | .016 | 18-23 | 59-75 |
| Turning | High Speed Steel | Cutting Oil | 1 | .04 | 0.2 | .008 | 23-28 | 75-92 |
| Turning | Carbide | Dry or Cutting Oil | 6 | .23 | 0.5 | .019 | 67-76 | 220-249 |
| Turning | Carbide | Dry or Cutting Oil | 3 | .11 | 0.4 | .016 | 81-90 | 266-295 |
| Turning | Carbide | Dry or Cutting Oil | 1 | .04 | 0.2 | .008 | 99-108 | 325-354 |
| Depth of cut-mm | Depth of cut-in | Feed-mm/t | Feed-in/t | Speed-m/min | Speed-ft/min | |||
| Cutting | High Speed Steel | Cutting Oil | 1.5 | .06 | 0.03-0.05 | .0012-.0020 | 16-21 | 52-69 |
| Cutting | High Speed Steel | Cutting Oil | 3 | .11 | 0.04-0.06 | .0016-.0024 | 17-22 | 56-72 |
| Cutting | High Speed Steel | Cutting Oil | 6 | .23 | 0.05-0.07 | .0020-.0027 | 18-23 | 59-75 |
| Drill ø mm | Drill ø in | Feed-mm/t | Feed-in/t | Speed-m/min | Speed-ft/min | |||
| Drilling | High Speed Steel | Cutting Oil | 1.5 | .06 | 0.02-0.03 | .0007-.0012 | 9-13 | 29-42 |
| Drilling | High Speed Steel | Cutting Oil | 3 | .11 | 0.05-0.06 | .0020-.0024 | 11-15 | 36-49 |
| Drilling | High Speed Steel | Cutting Oil | 6 | .23 | 0.08-0.09 | .0031-.0035 | 11-15 | 36-49 |
| Drilling | High Speed Steel | Cutting Oil | 12 | .48 | 0.09-0.10 | .0035-.0039 | 11-15 | 36-49 |
| Feed-mm/t | Feed-in/t | Speed-m/min | Speed-ft/min | |||||
| Milling Profiling | High Speed Steel | Cutting Oil | 0.05-0.10 | .002-.004 | 11-21 | 36-69 | ||
The cold work hardening rate of 347 stainless steel coil makes it less machinable than 410 stainless steel, but similar to 304. The table below provides relevant machining data.
