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Girgaon, Mumbai - 400004
Stainless Steel 347H Seamless Tubes Manufacturer in India
What Are Stainless Steel 347H Seamless Tubes?
Stainless Steel 347H Seamless Tubes are high-carbon, niobium-stabilized austenitic stainless steel tubes manufactured without a longitudinal weld for applications involving elevated temperatures and demanding service conditions. Grade 347H is designated as UNS S34709 and is based on the 18 chromium–10 nickel austenitic stainless steel family, with niobium added to improve stability during high-temperature exposure.
The higher carbon content of 347H provides greater strength at elevated temperatures, while niobium helps limit chromium carbide precipitation during prolonged heating. This makes the grade particularly suitable where creep resistance, stress-rupture strength and resistance to intergranular corrosion are important. Its seamless construction is also well suited to pressure and fluid-handling systems where a continuous tube structure is preferred.
Depending on the intended application, Stainless Steel 347H Seamless Tubes are manufactured and supplied to relevant ASTM and ASME specifications, including ASTM A213 and applicable ASTM A269 requirements. Available dimensions can include different outside diameters, wall thicknesses, schedules, surface finishes and lengths to suit equipment and project specifications.
Because of its high-temperature performance and stabilized chemistry, 347H seamless tubing is used in heat exchangers, boilers, refinery equipment, power generation systems, chemical processing units, petrochemical plants, high-temperature piping and aerospace-related applications. The grade is especially useful for components exposed to repeated or prolonged elevated-temperature service.
Kamal Steels is a Manufacturer and Stockist of Stainless Steel 347H Seamless Tubes, supplying standard and customized tubing for domestic and international projects. Material can be provided with MTC, inspection documentation, testing reports and export-standard packaging according to customer requirements.
Table of Contents
- Stainless Steel 347H Seamless Tube Specifications
- Stainless Steel 347H Seamless Tube Size Chart
- Stainless Steel 347H Seamless Tube Standards
- Stainless Steel 347H Seamless Tube Features
- Stainless Steel 347H Chemical Composition
- Stainless Steel 347H Mechanical Properties
- Stainless Steel 347H Seamless Tube Applications
- Industries Using Stainless Steel 347H Seamless Tubes
- Frequently Asked Questions
Stainless Steel 347H Seamless Tube Specifications
Stainless Steel 347H Seamless Tubes are available in different dimensions and material conditions to meet applicable standards and specific service requirements.
| Specification | Stainless Steel 347H Seamless Tubes |
|---|---|
| Material | Stainless Steel |
| Grade | 347H |
| UNS | S34709 |
| Tube Type | Seamless |
| ASTM Standards | ASTM A213, ASTM A269 |
| ASME Standards | ASME SA213, Applicable ASME SA Specifications |
| Outside Diameter | As per requirement |
| Wall Thickness | As per requirement |
| Schedule | As required |
| Length | Random, Fixed or Customized |
| Finish | Annealed, Pickled, Bright Annealed, Polished or As required |
| Form | Round Tube |
Stainless Steel 347H Seamless Tube Size Chart
Stainless Steel 347H Seamless Tubes are supplied in a range of outside diameters and wall thicknesses. Dimensions can be selected according to pressure, temperature, equipment design and project requirements.
| Tube Size | Outside Diameter (mm) | Wall Thickness | Length |
|---|---|---|---|
| 1/2" | 12.70 | As required | As required |
| 3/4" | 19.05 | As required | As required |
| 1" | 25.40 | As required | As required |
| 1-1/2" | 38.10 | As required | As required |
| 2" | 50.80 | As required | As required |
| 3" | 76.20 | As required | As required |
| 4" | 101.60 | As required | As required |
| 6" | 152.40 | As required | As required |
| 8" | 203.20 | As required | As required |
Stainless Steel 347H Seamless Tube Standards
The appropriate standard is selected according to the tube application, dimensions, manufacturing requirements and service conditions. Common specifications include:
| Standard | Application / Product Requirement |
|---|---|
| ASTM A213 | Seamless ferritic and austenitic alloy-steel boiler, superheater and heat-exchanger tubes |
| ASTM A269 | Seamless and welded austenitic stainless steel tubing for general corrosion-resisting service |
| ASME SA213 | Applicable seamless ferritic and austenitic alloy-steel tubing requirements |
| ASME SA269 | Applicable austenitic stainless steel tubing requirements for general service |
Stainless Steel 347H Seamless Tube Features
Stainless Steel 347H is particularly valued for maintaining mechanical strength and structural stability during prolonged exposure to elevated temperatures.
- High-temperature strength
- Good creep and stress-rupture resistance
- Niobium-stabilized austenitic structure
- Good resistance to intergranular corrosion
- Excellent resistance to oxidation at elevated temperatures
- Good general corrosion resistance
- Higher carbon content than standard 347 grade
- Suitable for prolonged high-temperature service
- Good fabrication and welding characteristics
- Available in different sizes, wall thicknesses and finishes
Stainless Steel 347H Chemical Composition
The chemistry of 347H is designed around a chromium-nickel austenitic base with niobium stabilization. The controlled carbon and niobium levels support its performance during elevated-temperature exposure.
| Element | Composition (%) |
|---|---|
| Chromium | 17.0 - 19.0 |
| Nickel | 9.0 - 13.0 |
| Niobium + Tantalum | 8 × C min. to 1.00 max. |
| Carbon | 0.04 - 0.10 |
| Manganese | 2.00 max. |
| Silicon | 1.00 max. |
| Phosphorus | 0.045 max. |
| Sulfur | 0.030 max. |
| Iron | Balance |
Stainless Steel 347H Mechanical Properties
Stainless Steel 347H offers a useful balance of tensile strength, yield strength and ductility, with the grade specifically suited to elevated-temperature service. Typical minimum mechanical requirements include:
| Property | Minimum Requirement |
|---|---|
| Tensile Strength | 515 MPa min. |
| Yield Strength | 205 MPa min. |
| Elongation | 40% min. |
| Density | Approx. 8.0 g/cm³ |
Note: Final mechanical values should be verified against the applicable material specification, tube dimensions and material test certificate.
Stainless Steel 347H Seamless Tube Applications
The elevated-temperature strength and stabilized chemistry of 347H make its seamless tubes suitable for process equipment operating under prolonged thermal exposure.
Power Generation
Used in high-temperature equipment and systems exposed to elevated thermal conditions.
Heat Exchangers
Used for heat-transfer equipment requiring corrosion resistance and high-temperature stability.
Refinery Equipment
Used in process equipment operating under elevated temperatures and demanding service conditions.
Chemical Processing
Used in selected process systems requiring a stabilized stainless steel grade for thermal service.
High-Temperature Equipment
Used in tubular components exposed to prolonged heating and thermal cycling.
Petrochemical Systems
Used in selected process and fluid-handling systems requiring elevated-temperature performance.
Industries Using Stainless Steel 347H Seamless Tubes
347H seamless tubing is supplied to industries where equipment must withstand elevated temperatures while maintaining corrosion resistance and mechanical stability.
Power Industry
Used in high-temperature process and power-generation equipment.
Refinery Industry
Used in selected refinery systems exposed to elevated temperatures and corrosive process media.
Chemical Industry
Used in process equipment requiring stabilized stainless steel tubing for demanding thermal service.
Petrochemical Industry
Used in high-temperature process and fluid-handling applications.
Heat Processing Industry
Used in equipment exposed to prolonged heating and thermal cycling.
Engineering Industry
Used in fabricated equipment and tubular systems designed for elevated-temperature operation.
Frequently Asked Questions
Stainless Steel 347H Seamless Tubes are high-carbon, niobium (columbium)-stabilized austenitic stainless steel tubes manufactured from Stainless Steel 347H (UNS S34709 / WNR 1.4961). They provide excellent creep strength, oxidation resistance, and dependable performance during prolonged high-temperature service.
Our Stainless Steel 347H Seamless Tubes are manufactured according to ASTM A213, ASTM A269, ASME SA213, and ASME SA269 international standards.
SS 347H Seamless Tubes offer superior creep strength, excellent oxidation resistance, outstanding thermal stability, high-temperature mechanical strength, and excellent resistance to intergranular corrosion.
They are widely used in boilers, superheaters, reheaters, heat exchangers, petrochemical plants, refineries, thermal processing equipment, power generation facilities, and chemical processing industries.
SS 347H Seamless Tubes are available in various outside diameters, wall thicknesses, schedules, surface finishes, and custom cut lengths to meet diverse industrial requirements.
Each tube undergoes Hydrostatic Testing, Ultrasonic Testing (UT), Eddy Current Testing (ECT), Positive Material Identification (PMI), Chemical Analysis, Mechanical Testing, Flattening Test, Flaring Test, Intergranular Corrosion (IGC) Testing, and Dimensional Inspection.
SS 347H contains a higher carbon content than SS 347, providing improved creep resistance and superior mechanical strength during prolonged high-temperature service while retaining excellent oxidation resistance and niobium stabilization.
Yes. Every shipment includes EN 10204 3.1 Mill Test Certificates, inspection reports, complete material traceability, and third-party inspection certificates upon request.
Yes. Kamal Steels exports Stainless Steel 347H Seamless Tubes worldwide with export-standard packaging, complete documentation, and timely international delivery.
Kamal Steels offers ASTM-compliant Stainless Steel 347H Seamless Tubes with ready stock, certified quality, competitive pricing, stringent quality control, export-standard packaging, complete documentation, and dependable worldwide delivery for critical high-temperature industrial applications.