Product Overview – ASTM A312 TP321H Seamless Pipes
ASTM A312 TP321H is the high carbon version of TP321 stainless steel. The increased carbon content improves high-temperature strength and creep resistance, making it suitable for long-term service above 500°C.
Like TP321, it contains titanium for stabilization, but the “H” grade is specifically intended for pressure vessels, boilers, and superheaters where elevated temperature strength is critical.
Seamless manufacturing ensures structural integrity under internal pressure and thermal stress.
Standard & International Identification -ASTM A312 TP321H Seamless Pipes
Technical Specifications – ASTM A312 TP321H Seamless Pipe
| Manufacturing Type : | Seamless |
| Available Sizes: | 1/8″ NB to 24″ NB |
| Schedules: | 5S, 10S, 40S, 80S, 160, XS, XXS |
| Length: | 6m, 12m, Custom Length |
| End Type : | Plain End (PE), Beveled End (BE) |
| Testing : | Hydrostatic Test, PMI,NDT |
| 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 ASTM A312 TP321H Seamless Pipe
(As per ASTM specification)
| Element | Max (%) |
|---|---|
| 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): | Minimum 5 × Carbon content |
| Iron (Fe) | Balance |
Note: The higher carbon range distinguishes 321H from standard 321.
Mechanical Properties of TP321H Seamless Pipes
| Property | Minimum Value |
|---|---|
| Tensile Strength | ≥ 515 MPa |
| Yield Strength | ≥ 205 MPa |
| Elongation | ≥ 35% |
321H provides better creep strength at elevated temperatures compared to 321.
High Temperature Performance & Advantages of TP321H Seamless Pipes
SS 321H seamless pipes offer:
When operating temperatures exceed 500°C for prolonged durations, 321H is preferred over 321.
Applications of ASTM A312 TP321H Seamless Pipes
- 🔸Heat recovery steam generators (HRSG)
- 🔸Superheaters
- 🔸Petrochemical pipelines
- 🔸Pressure vessels
- 🔸Oil & gas refineries
- 🔸Thermal processing equipment
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