Austenitic SS 347 Pipes and Tubes
347 stainless steel pipe and 347 stainless steel tube or Grade 347/34H Stainless Steel Pipes and tubes is a higher carbon variant alloy austenitic stainless steel grade with tantalum and columbium added which contribute to giving them outstanding intergranular corrosion resistance.
Chemical Properties
|
GRADE |
Cr |
Ni |
C |
Mn |
P |
Si |
Fe |
S |
Cb) |
|
|---|---|---|---|---|---|---|---|---|---|---|
|
SS 347H |
MIN |
17 |
9 |
0.04 |
– |
– |
– |
– |
10 x (C) |
|
|
MAX |
19 |
13 |
0.1 |
2 |
0.045 |
1 |
BALANCE |
0.03 |
1 |
|
|
SS 347 |
MIN |
17 |
9 |
– |
– |
– |
– |
– |
8 x (C) |
|
|
MAX |
19 |
13 |
0.08 |
2 |
0.045 |
1 |
BALANCE |
0.03 |
1 |
Grade 347 stainless steel pipes and tubes is a columbium/tantalum stabilized austenitic chromium-nickel stainless steel. Stainless Steel 347 has slightly improved corrosion resistance over type 321 stainless steel in strongly oxidizing environments.
Specification
Stainless steel 347/347H Seamless Pipe : ASTM/ASME SA 312/ A 312
Stainless steel 347/347H Seamless tube : ASTM/ASME SA 213/A 213
Stainless steel 347/347H ERW Pipe : ASTM/ASME SA 312/ A 312
Stainless steel 347/347H ERW Tube :ASTM/ASME SA 249/ A 249
Production Process
Grade SS 347/H or UNS S34700/S37409 are manufactured such as ERW ( Electric Resistance Welded), Seamless and EFW ( Electric Fusion Welding) Pipes and Tubes having different form such as round,square, rectangle etc having specific end as Plain End, Bevel End and Threaded End with nominal thickness of different schedule ranging from SCH 5 to SCH XXS.
The process through which 347 stainless steel pipe and tubes can be manufactured include cold pilgering process, Extrusion process, tube mill Process also Piercing process followed by heat treatment and mechanical testing.
Fabrication and Heat treatment
Stainless steel 347 is recommended in the working temperature range of 2100° – 2250° F (1149° – 1232° C) and ideal in applications like forging, upsetting and other hot work processes. This alloy is not recommended under temperatures below 1700° F (927° C). To re-attain the maximum corrosion resistance, the material needs to be water quenched or completely annealed after working.
Alloy 347 Pipes and 347 stainless steel tube develop high strength and hardness through a variety of heat treatment processes. Due to Precipitation hardening Stainless Steel 347 Pipes, or hardenable chromium – nickel alloys, are classified as martensitic or semi – austenitic steel.
Properties
Grade 347 stainless steel or UNS S34700 stainless steel grade is slightly better in corrosion resistance when compared to type 321 in strongly oxidizing environments. SS 347 has columbium to stabilize it which is preferred in aqueous and low-temperature environments as it has good resistance capabilities to intergranular attacks.
Mechanical Properties
|
Grade |
Tensile Strength |
Yield Strength |
Elongation |
Hardness, MAX |
|
|---|---|---|---|---|---|
|
[MPA] |
[MPA] |
(% in 50mm) min |
HRB |
HRC |
|
|
SS 347 |
515 |
205 |
35 |
92 |
201 |
|
SS 347H |
515 |
205 |
35 |
92 |
201 |
347 stainless steel tube and pipe have superior welding and forming capability and they are frequently utilized in heat exchangers, petroleum refineries, welded fabrication, pressure vessels, parts of aircraft engines and in power generation.
SS 347 ERW Pipes are austenitic in the annealed state, but martensitic in the hardened condition and these pipes achieve high tensile properties in heat treated conditions.347 stainless steel properties are superior when compared to SS 304. SS 347 needs higher initial forces. Stainless steel 347 is a bit tougher and ductile can be easily stamped, blanked, spun, and drawn.
PHYSICAL PROPERTIES
|
Grade |
Density (Kg/m3) |
Melting range |
Elastic Modulus (GPa) |
Mean Co-eff of Thermal Expansion (μm/m/°C) at 0-100°C |
Thermal Conductivity (W/m.K) at 100°C |
Specific Heat ( J/Kg.K) at 20°C |
Electric Resistivity at 20°C Ω mm2 /m |
|---|---|---|---|---|---|---|---|
|
SS 347/347H |
7.96 |
1398-1446 °C |
190-210 |
17.3 |
16.3 |
500 |
0.73 |
Application
347 Stainless steel is commonly used for equipment fabrications, which is good in services under extreme corrosive conditions and it is frequently used in petroleum refining industries.
- Petrochemical Industry
- Oil and Gas Industry
- Chemical Industry
- Power Plant Industry
- Energy Industry
- Pharmaceuticals Industry
- Pulp & Paper Industry
- Food Processing Industry
- Aerospace Industry
- Refining Industry
