The main difference between 347 and 347H is that 347H has more carbon content. While 347 is better at resisting sensitisation, 347H has improved creep strength.
ASTM A312 Stainless Steel 347 Seamless Pipe Manufacturer
We, Xintongda Special Steel, are a renowned manufacturer and global supplier of stainless steel 347 seamless (SMLS) pipes in China and other major countries. SS 347 is a weld-free austenitic SS pipe made of iron-chromium-nickel alloy and stabilised with Columbium (Niobium). It contains 17-19% chromium, 9-13% nickel, around 0.08% carbon, and trace amounts of manganese, silicon, phosphorus, and sulfur. This chemical composition makes SS 347 pipe highly resistant to corrosion in oxidising environments. Our SS 347 seamless pipes strictly comply with the ASTM A312 standard. The added columbium (niobium) stabilises the alloy and resists carbide precipitation against intergranular corrosion. The pipe can resist chromium carbide precipitation at high temperatures ranging from 800 to 1500°F (427-816°C) for intermittent service and up to 1650oF for continuous service. These characteristics make the 347 pipe more preferable over 304 or 316 in high-temperature applications like aerospace, chemical processing, and boilers.
Our 4 decades of experience and multiple international certifications enable us to have great control over quality. As we have many manufacturing facilities, we can produce up to 25,000 tons of stainless steel 347 pipes annually.
Here are some product specifications of SS 347 pipes:
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Standard
ASTM A312
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OD Range
6-1016 mm
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Thickness
1-65 mm
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Length
≤ 18 m
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Technical Data
Technical Data
SS 347 Seamless Pipe Manufacturing Process
To manufacture 347 Seamless Stainless Steel Pipe, we first heat and pierce a billet of this alloy to make it hollow. Then, we refine and elongate this hollow shell using hot-working and cold-finishing techniques for the desired dimensions and improved surface quality. The next step is solution-annealing to restore corrosion resistance and stabilise the microstructure. The final step includes pickling and straightening before it is sent for dimensional checks and non-destructive testing. View production process
What are the Key Features of 347 Stainless Steel Pipe
There are 3 main characteristics that make the 347 pipe stand out from others. These include corrosion resistance, high-temperature performance, and weldability & formability.
- Corrosion Resistance: The chromium present in this alloy forms a layer of oxide when exposed to oxygen at high temperatures to resist oxidation. Also, the addition of columbium stabilises the steel by preventing chromium carbide precipitation.
- High-Temperature Performance: The 347seamless pipe’s stabilised austenitic structure with added niobium (Cb) prevents sensitisation at high temperatures. This maintains strength and prevents intergranular corrosion.
- Weldability & Formability: 347 pipe’s austenitic structure makes it easily weldable and formable.
ASTM A312 TP347 Seamless Pipe Equivalent Material
The SS 347 seamless pipe is also known by its UNS standard as UNS S34700, European/ German standard as W.Nr. 1.4550, and many other equivalents.
| GRADE | UNS | GB | JIS | ISO | DIN/EN | GOST | |
| ISC | NEW | ||||||
| 347 | S34700 | S34778 | 06Cr18Ni11Nb | SUS347 | X6CrNiNb18-10 | 1.4550 | 08X18H12Б |
100% Certified Testing & Documentation
- EN 10204 3.1 and EN 10204 3.2 Material Test Certificates (MTC)
- Raw Materials Certificate
- 100% PMI
- Heat Treatment Charts
- Third-Party Inspection Report
- Surface roughness and size measurement
- Manufacturer Test Certificate (Impact Testing, Flattening, Flare, Bend, Hardness, Intergranular, Pitting Corrosion, Grain size, ET, UT, HT)
- Laboratory Test Certificate from the Government-Approved Lab
Industrial Applications of SS 347 Seamless Pipe
Stainless steel 347 seamless pipe has 5 main industrial applications. Let us study them in detail below:
Power Generation
Because of its good high-temperature strength and creep resistance, 347 pipe is used in high-pressure systems like boiler tubes, steam lines, turbine components, and heat recovery systems.
Aerospace
The pipe’s outstanding heat and oxidation resistance make it suitable for aircraft exhaust manifolds, jet engine components, fuel, and hydraulic lines.
Oil & Gas
ASTM A312 TP347 pipe is extensively used in refineries, pressure vessels, pipelines, boilers, and heat exchangers due to its excellent high-temperature strength.
Chemical & Petrochemical
For chemical & petrochemical industries, this pipe is used in fluid transport, steam lines, heat-transfer equipment, and refineries.
Food Processing
Used in high-temperature steam lines, hot oil and heat-transfer fluid pipelines, exhaust, vent, and hot condensate lines in food plants.
Frequently Asked Questions
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What is the difference between 347 and 347H?
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What are the typical mechanical properties of 347 pipes?The mechanical properties of 347 include tensile strength of around 515 MPa, minimum yield strength (0.2% offset) of 205 MPa, and elongation of at least 40%.
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Under what standards is SS 347 Seamless pipe manufactured?Our SS 347 seamless pipe is manufactured under ASTM A312 standards.
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What kinds of applications are these 347 pipes suitable for?347 pipes are suitable for aerospace, petrochemical, oil & gas, and power generation.