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- Seamless stainless tubes 1.4301 / 1.4306 / 1.4307 / 304 / 304L
- Seamless stainless tubes 1.4401 / 1.4404 / 316 / 316L
- Seamless stainless tubes 1.4539
- Seamless stainless tubes 1.4541 / 1.4878 / 321 / 321H / 08Cr18Ni10Ti
- Seamless stainless tubes 1.4571 / 316Ti
- Seamless stainless tubes 1.4912/TP347H
- Seamless stainless tubes and hollow bars duplex steel
- Seamless stainless tubes and hollow bars in superduplex grade
- Seamless stainless steel tubes in heat resistant grade
- Seamless stainless steel tubes of martensitic steel 1H13 / 1.4006 / AISI410
- Seamless stainless steel tubes in superaustenitic steel
- Seamless stainless ferritic steel tubes 1.4510 / OH17T / X3CrTi17, 0H17T, AISI 430Ti
- Seamless stainless steel tubes in steel Alloy 800H
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Item length
Outside diameter (OD)
Wall thickness (WT)
Steel grade
Availability
Stainless steel seamless tube DN25 Ø 33,7 mm x 4 mm in grade 1.4912 / TP347H 100cm
- Length: 100cm
- Outside diameter (OD): 33.7 mm
- Wall thickness (WT): 4 mm
- Steel grade: 1.4912 / TP347H
Availability:
available
Dispatched within: 3 days
Stainless steel seamless tube DN25 Ø 33,7 mm x 4 mm in grade 1.4912 / TP347H 30cm
- Length: 30cm
- Outside diameter (OD): 33.7 mm
- Wall thickness (WT): 4 mm
- Steel grade: 1.4912 / TP347H
Availability:
available
Dispatched within: 3 days
Stainless steel seamless tube DN32 Ø 38 mm x 7,1 mm in grade 1.4912 100cm
- Length: 100 cm
- Outside diameter (OD): 38 mm
- Wall thickness (WT): 7.1 mm
- Steel grade: 1.4912
Availability:
available
Dispatched within: 3 days
Stainless steel seamless tube DN32 Ø 38 mm x 7,1 mm in grade 1.4912 10cm
- Length: 10 cm
- Outside diameter (OD): 38 mm
- Wall thickness (WT): 7.1 mm
- Steel grade: 1.4912
Availability:
available
Dispatched within: 3 days
Stainless steel seamless tube DN32 Ø 38 mm x 7,1 mm in grade 1.4912 20cm
- Length: 20 cm
- Outside diameter (OD): 38 mm
- Wall thickness (WT): 7.1 mm
- Steel grade: 1.4912
Availability:
available
Dispatched within: 3 days
Stainless steel seamless tube DN32 Ø 38 mm x 7,1 mm in grade 1.4912 30cm
- Length: 30 cm
- Outside diameter (OD): 38 mm
- Wall thickness (WT): 7.1 mm
- Steel grade: 1.4912
Availability:
available
Dispatched within: 3 days
Stainless steel seamless tube DN32 Ø 38 mm x 7,1 mm in grade 1.4912 40cm
- Length: 40 cm
- Outside diameter (OD): 38 mm
- Wall thickness (WT): 7.1 mm
- Steel grade: 1.4912
Availability:
available
Dispatched within: 3 days
Stainless steel seamless tube DN32 Ø 38 mm x 7,1 mm in grade 1.4912 50cm
- Length: 50 cm
- Outside diameter (OD): 38 mm
- Wall thickness (WT): 7.1 mm
- Steel grade: 1.4912
Availability:
available
Dispatched within: 3 days
Stainless steel seamless tube DN32 Ø 38 mm x 7,1 mm in grade 1.4912 60cm
- Length: 60 cm
- Outside diameter (OD): 38 mm
- Wall thickness (WT): 7.1 mm
- Steel grade: 1.4912
Availability:
available
Dispatched within: 3 days
Stainless steel seamless tube DN32 Ø 38 mm x 7,1 mm in grade 1.4912 70cm
- Length: 70 cm
- Outside diameter (OD): 38 mm
- Wall thickness (WT): 7.1 mm
- Steel grade: 1.4912
Availability:
available
Dispatched within: 3 days
Stainless steel seamless tube DN40 Ø 51 mm x 10 mm in grade TP347 120cm
- Length: 120 cm
- Outside diameter (OD): 51 mm
- Wall thickness (WT): 10 mm
- Steel grade: TP347
Availability:
available
Dispatched within: 5 days
Stainless steel seamless tube DN40 Ø 51 mm x 10 mm in grade TP347 130cm
- Length: 130 cm
- Outside diameter (OD): 51 mm
- Wall thickness (WT): 10 mm
- Steel grade: TP347
Availability:
available
Dispatched within: 5 days
Seamless stainless tubes 1.4912 / TP347H
Seamless stainless tubes 1.4912 / TP347H are high‑temperature, niobium‑stabilised austenitic stainless steel tubes supplied without a longitudinal weld. They are produced to meet applications where thermal stability, resistance to intergranular corrosion and good mechanical strength at elevated temperatures are required. In many standards you will see this material referenced as EN 1.4912 and in ASME/ASTM lists as TP347H (often shortened to 347H or grade 347H).
What this product is and why it matters
These are seamless (no welded seam) tubes manufactured from a stabilised austenitic stainless steel that contains niobium (columbium) to tie up carbon and prevent chromium carbide precipitation. The "H" in TP347H indicates a higher carbon content compared with standard 347, which improves creep and tensile strength at elevated temperatures. Because of these properties, 1.4912 / TP347H is widely used where components see long exposure to high temperatures or cyclic thermal loading.
Key technical characteristics
- High‑temperature strength: Enhanced creep resistance and tensile strength at elevated temperatures due to the higher carbon level.
- Stabilisation against sensitisation: Niobium addition prevents intergranular corrosion that can occur after exposure to temperatures in the sensitisation range.
- Good corrosion resistance: Typical austenitic stainless behaviour in many oxidising and mildly reducing environments at ambient and elevated temperatures.
- Excellent weldability and formability: Can be welded and formed using standard procedures for austenitic stainless steels; stabilisation reduces the need for post‑weld annealing to avoid sensitisation.
- Non‑magnetic in solution annealed state: As with most austenitic grades, the material is essentially non‑magnetic unless heavily cold worked.
Common applications and industries
Seamless 1.4912 / TP347H tubes are chosen where reliability under heat and pressure is essential. Typical uses include:
- Power generation: superheater and reheater tubes, boiler tubes and piping in steam plants.
- Petrochemical and chemical processing: heat exchangers, process piping and fittings exposed to high temperatures.
- Oil & gas and offshore: tubing for high‑temperature service and components exposed to cyclic thermal loading.
- Furnace and kiln construction: tubes and elements operating at sustained high temperatures.
- Automotive and transport: exhaust and turbocharger components in specialist high‑temperature or performance applications.
- General engineering and fabrication: pressure‑containing tubing, heat recovery systems and any application requiring a combination of high temperature strength and corrosion resistance.
Advantages of the seamless form
Choosing seamless tubes gives several practical benefits:
- Higher pressure capability: No longitudinal weld means more uniform mechanical properties and better burst/pressure resistance.
- Improved dimensional consistency: Seamless manufacture typically results in more concentric walls and consistent thickness.
- Better performance under cyclic or thermal stress: Absence of a seam reduces sites for crack initiation under fatigue or high‑temperature creep.
Standards, labelling and equivalents
The product is commonly designated as EN 1.4912 in European/British contexts and as TP347H in ASME/ASTM lists. You will also see it referred to simply as 347H or grade 347H. When specifying, use the full designation (e.g. seamless tube EN 1.4912 / TP347H) and include required dimensions, tolerances and any additional processing (annealing, pickling, polishing) to ensure correct supply.
Handling, fabrication and selection tips
- Welding: TP347H welds readily by common fusion and resistance methods. Stabilisation reduces the need for post‑weld solution anneal to avoid sensitisation; however, follow project or code requirements for heat treatment and filler metals.
- Forming: Good cold and hot forming capabilities, though heavy cold work can introduce some magnetism and reduce ductility.
- Corrosion considerations: While 347H resists intergranular corrosion, selection must still consider the specific environment (chlorides, sulphur compounds, etc.). For highly corrosive chemical environments, other austenitic or nickel alloys may be more suitable.
- Selecting 347 vs 347H: Choose 347H when higher creep strength at elevated temperatures is required; standard 347 may suffice for lower temperature applications.
Who buys seamless stainless tubes 1.4912 / TP347H?
Typical buyers include maintenance and procurement engineers, fabricators, pipeline and boiler contractors, OEMs in power and petrochemical industries, offshore and marine engineers, and specialist component manufacturers. The product suits both one‑off bespoke projects (for example garage or small workshop high‑temperature systems) and large industrial programmes (power stations, refineries, offshore platforms).
Available supply options and services
Seamless 1.4912 / TP347H tubes are usually available in a range of outer diameters, wall thicknesses and standard lengths. Common supply options include cold‑drawn or hot‑finished condition, solution annealed and pickled finishes, cut‑to‑length, and additional machining or testing on request (such as hardness checks, dimensional inspection or PMI/chemical verification). Confirm the exact mechanical and dimensional requirements when ordering.
If you need help selecting the correct size, finish or standard for your application, contact our technical sales team with your operating temperature, pressure and environment — we can advise which seamless stainless tube variant best meets the requirement.