Product Overview – ASTM A312 TP347 Welded Pipes
ASTM A312 TP347 is a niobium (columbium) stabilized stainless steel grade developed to prevent chromium carbide precipitation during welding and high-temperature exposure.
TP347 welded pipes are manufactured using ERW welding processes and are solution annealed and tested in accordance with ASTM A312 standards.
This grade is widely used in oil refineries, thermal power plants, superheaters, and high-pressure steam systems where resistance to intergranular corrosion and structural reliability are essential.
Compared to 321 stainless steel, TP347 often offers improved performance in high-pressure and cyclic temperature environments.
Standard & International Identification - ASTM A312 TP347 Welded Pipes
Technical Specifications – TP347 Welded Pipes
| Manufacturing Method: | Welded / ERW |
| Available Sizes: | 1/8″ NB to 36″ NB |
| Wall Thickness: | SCH 5S to SCH 160 |
| Standard Length: | 6m, 12m, Custom Length |
| Surface Finish: | Pickled, Annealed, Industrial Finish |
| Pipe Ends: | Plain End (PE), Beveled End (BE) |
| Inspection: | Hydrostatic, Weld Seam Testing, PMI |
| Certification : | EN 10204 3.1 / 3.2 MTC |
| Dimensional compliance: | ASME B36.19M. |
All specifications are in accordance of ASTM A312 / ASME SA312 standards. Mechanical and chemical values are as per standard limits. Mill Test Certificates (MTC) available upon request.
Chemical Composition of TP347 Welded Pipes
(As per ASTM specification)
| Element | Max (%) |
|---|---|
| Carbon (C) | 0.08% |
| Manganese (Mn) | 2.00 % |
| Silicon (Si) | 1.00% |
| Phosphorus (P) | 0.045 % |
| Sulfur (S) | 0.030 % |
| Chromium (Cr) | 17.0 – 19.0% |
| Nickel (Ni) | 9.0 – 13.0% |
| Niobium (Nb + Ta): | 10xC min to 1.00% max |
| Iron : | Balance |
Note: Niobium stabilizes the structure and improves resistance to carbide precipitation.
Mechanical Properties – TP347 Welded Pipes
| Property | Minimum Value |
|---|---|
| Tensile Strength | ≥ 515 MPa |
| Yield Strength | ≥ 205 MPa |
| Elongation | 35% |
TP347 maintains mechanical strength and stability under elevated temperatures.
Heat Resistance & Corrosion Advantages- ASTM A312 TP347 Welded Pipes
SS 347 welded stainless steel pipes offer:
For refinery and power plant applications, TP347 is frequently specified.
Major Industrial Applications of TP347 Welded Pipes
- 🔸Thermal power plants
- 🔸Boiler and superheater systems
- 🔸Oil & gas refineries
- 🔸Petrochemical units
- 🔸Pressure vessels
- 🔸High temperature steam lines
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