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ASTM A312 TP321H Welded Stainless Steel Pipes for Elevated Temperature Service

TP321H welded stainless steel pipes are high carbon, titanium-stabilized austenitic pipes developed for improved strength and structural reliability in high-temperature pressure systems.

Product Overview – ASTM A312 TP321H Welded Pipes

ASTM A312 TP321H is the high carbon version of 321 stainless steel. The higher carbon content increases high-temperature strength while titanium stabilization prevents carbide precipitation.
TP321H welded pipes are produced using precision ERW welding methods and are solution annealed and tested according to ASTM A312 specifications.

This grade is commonly specified for boiler components, superheaters, refinery piping systems, and thermal power plants where elevated temperature strength is critical.
Compared to standard 321, TP321H provides better creep resistance and improved performance under sustained heat exposure.

Standard & International Identification - ASTM A312 TP321H Welded Pipes

Standard ASTM A312 / ASME SA312
Grade TP321H
UNS S32109
EN 1.4941

Technical Specifications – TP321H 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 TP321H Welded Pipes

(As per ASTM specification)
ElementMax (%)
Carbon (C)0.04 – 0.10%
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 – 12.0%
Titanium (Ti):5xC min to 0.70% max
Iron :Balance
Note: Higher carbon improves high-temperature strength.

Mechanical Properties – TP321H Welded Pipes

PropertyMinimum Value
Tensile Strength≥ 515 MPa
Yield Strength≥ 205 MPa
Elongation35%
TP321H offers improved creep resistance and strength retention at elevated temperatures.

Heat Resistance & Performance Advantages- ASTM A312 TP321H Welded Pipes

SS 321H welded pipes provide:

🔸 Enhanced high-temperature strength
🔸 Improved creep resistance
🔸 Titanium stabilization for structural integrity
🔸 Resistance to intergranular corrosion

For boiler and refinery systems operating under heat stress, TP321H is often preferred over 321.

Major Industrial Applications of TP321H Welded Pipes

  • 🔸Thermal power plants
  • 🔸Boiler and superheater systems
  • 🔸Oil & gas refineries
  • 🔸Petrochemical units
  • 🔸Pressure vessels
  • 🔸High temperature steam lines

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Key Advantages of TP321H Welded Pipes

Reliable creep resistance Suitable for high-pressure heat systems Industrial and export-grade material Long service life in thermal environments High carbon for improved elevated temperature strength

Contact Our Team for Boiler & Refinery Requirements

Download 321H Technical Data Sheet & MTC

Frequently Asked Questions

–ASTM A312 TP321H Welded Pipes

What is the difference between 321 and 321H?
321H has higher carbon content, which improves high-temperature strength and creep resistance.
Is TP321H suitable for boiler applications?
Yes. It is commonly used in boilers, superheaters, and high-pressure steam systems.
What is the UNS number of SS 321H?
The UNS designation is S32100.
What is the UNS number of SS 321H?
Yes. It performs reliably in sustained elevated temperature environments.
Do you supply ASTM A312 TP321H welded pipes in India?
Yes. We supply and export TP321H welded stainless steel pipes from Mumbai with full inspection certification.
What sizes are available in 321H welded pipes?
Sizes typically range from 1/8″ NB to 36″ NB in multiple schedules as per ASME standards.