A213-TP347H TUBE ASTM Standard UNS S34709 Stainless Steel Seamless
Tube 347/347H
Alloy 347 is a stabilized, austenitic, chromium steel containing
columbium which allows for the elimination of carbide
precipitation, and, consequently, intergranualr corrosion. Alloy
347 is stabilized by the additions of chromium and tantalum and
offers higher creep and stress rupture properties than alloy 304
and 304L which may also be used for exposures where sensitization
and intergranualr corrosion are of concern. The addition of
columbium also allows Alloy 347 to have excellent corrosion
resistance, even superior to that of alloy 321. 347H is the higher
carbon composition form of Alloy 347 and demonstrates improved high
temperature and creep properties.
Specifications: UNS S34700 / S34709
APPLICATIONS:
Alloy 347 is frequently used for the fabrication of equipment,
which must be placed in service under severe corrosive conditions,
and is also common to the petroleum refining industries.
Applications that consistently used Alloy 347 include:
- High temperature chemical processes
- Heat exchanger tubes
- High temperature steam service
- High pressure steam pipes
- Radiant superheaters
- Boiler tubes
- Heavy duty exhaust systems
- General refinery piping
STANDARDS:
- ASTM/ASME: UNS S34700 / S34709
- EURONORM: FeMi35Cr20Cu4Mo2
- DIN: 2.4660
CORROSION RESISTANCE:
- Offers similar resistance to general, overall corrosion as Alloy
304
- Used for applications where alloys such as Alloy 304 are vulnerable
to intergranualr corrosion
- Generally used for heavy welded equipment which cannot be annealed
and for equipment which is operated between 800 to 150°F (427 TO
816°C)
- Alloy 347 is preferred over Alloy 321 for aqueous and other low
temperature environments
- Primarily used in high temperature environments where resistance to
sensitization is necessary, in turn preventing intergranualr
corrosion at lower levels
- Susceptible to stress corrosion cracking
- Exhibits oxidation resistance similar to all other 18-8 austenitic
stainless steels
hemical Properties:
| C | Cr | Mn | Ni | P | S | Si | Cb/Ta |
---|
347 | 0.08 max | min: 17.0 max: 20.0 | 2.0 max | min: 9.0 max: 13.0 | 0.04 max | 0.30 max | 0.75 max | min:10x C max: 1.0 |
347H | min: 0.04 max: 0.10 | min: 17.0 max: 20.0 | 2.0 max | min: 9.0 max: 13.0 | 0.03 max | 0.30 max | 0.75 max | min:10x C max: 1.0 |
Mechanical Properties:
Grade | Tensile Strength ksi (MPa) min | Yield Strength 0.2% ksi offset ksi (MPa) min | Elongation (% in 50mm) min | Hardness (Brinell) MAX | Hardness (Rockwell B) MAX |
---|
347/347H | 75 (515) | 30 (205) | 40 |
WELDABILITY
Austenitic stainless steels are considered to be the most weldable
out of all high alloy steels Can be welded by all fusion and
resistance welding processes
HEAT TREATMENT
Annealing temperature range is 1800 to 2000°F May be stress relief
annealed within the carbide precipitation range of 800 to 1500°F
without any danger of subsequent intergranualr corrosion Cannot be
hardened by heat treatment