These types of stainless steel are austenitic chromium steels containing colubium. They are recommended for parts fabricated by welding which cannot be subsequently annealed. These types also are used for parts which are intermittently heated and cooled to temperatures between 800°F and 1600°F. The addition of columbium produces a stabilied type of stainless that eliminates carbide precipitation and, consequently, intergranular corrosion.
Availability - Stainless Steel 347/347H
Seamless Stainless Steel Pipes 1/2" - 8"
Stainless Steel Tubes 1/2" - 8"
Weld Stainless Steel Pipes 1/2" - 12"
Stainless Steel Pipe Fittings 1/2" - 12"
Stainless Steel Flanges 1/2" - 12"
Stainless Steel Tubes 1/2" - 8"
Weld Stainless Steel Pipes 1/2" - 12"
Stainless Steel Pipe Fittings 1/2" - 12"
Stainless Steel Flanges 1/2" - 12"
Specifications - Stainless Steel 347/347H
| ASTM |
A312, A403
|
| ASME |
SA312, SA403
|
Chemical Composition - 347/347H
| C | Co | Cr | Mn | Ni | P | S | Si | Ta |
| Max | Max | Max | Max | Max | ||||
| 0.08% | Trace* | 17% - 20% | 2.0% | 9% - 13% | 0.04% | 0.03% | 0.75% | Trace* |
*The columbium plus tantalum content shall not be less than 10 times the carbon content and not more than 1.0%. 347H Stainless Steel requires the columbium plus tantalum content to be not less than 8 times the carbon content and not more than 1.0%.
Design Features - Stainless Steel 347/347H
- Superior general corrosion resistance over Type 321 Stainless Steel due to stabilization with columbium.
- Reduced tendencies to form continuous networks of chromium carbides at the grain boundaries.
- Better high temperature properties than 304 Stainless Steel or 304L Stainless Steel. Generally used for parts which are intermittently heated up to 1500°F. For continuous service the maximum temperature is 1650°F.
- Type 347 has high carbon (.04 to .10) for better high temperature creep properties.
- Improved intergranular corrosion resistance.
Typical Applications - 347/347H
Airplane exhaust manifolds
Pump Shafts
Mechanical Seals
Heat Exchangers
Stainless Steel Pipe Fittings
Ball Valves
Stainless Steel Pipes
Boiler shells
Process equipment
Expansion joints
Stainless Steel Flanges (i.e. flanges, slip-ons, blinds, weld-necks, lapjoints, long welding necks, socket welds, elbows, tees, stub-ends, returns, caps, crosses, reducers, and pipe nipples)
Cabin heaters
Fire walls
Flexible couplings
Pressure vessels
Pump Shafts
Mechanical Seals
Heat Exchangers
Stainless Steel Pipe Fittings
Ball Valves
Stainless Steel Pipes
Boiler shells
Process equipment
Expansion joints
Stainless Steel Flanges (i.e. flanges, slip-ons, blinds, weld-necks, lapjoints, long welding necks, socket welds, elbows, tees, stub-ends, returns, caps, crosses, reducers, and pipe nipples)
Cabin heaters
Fire walls
Flexible couplings
Pressure vessels
Tensile Requirements - 347/347H
Tensile Strength (KSI): 75
Yield Strength (KSI): 30
KSI can be converted to MPA (Megapascals) by multiplying by 6.895.
Source: Zhejiang Yaang Pipe Industry Co., Limited (www.yaang.com)
