ASTM A213 TP321H Stainless Steel Seamless Tube
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GNEE is a professional manufacturer of high-performance stainless steel tubing, widely used in various critical heat transfer applications. With 18 years of experience in stainless steel tubing manufacturing, our ASTM A213 TP321H seamless stainless steel tubing features a bright annealed finish. Mechanical property requirements do not apply to ASTM A213 seamless tubing with an inner diameter less than 1/8 inch [3.2 mm] or a wall thickness less than 0.015 inch [0.4 mm]. Other sizes are available upon request.
ASTM A213 TP321H is a seamless stainless steel tubing designed for high-temperature applications such as boilers, superheaters, and heat exchangers. Due to its seamless construction (no welds), it is stronger and more reliable than welded tubing, making it particularly suitable for critical infrastructure projects. TP321H seamless tubing exhibits excellent mechanical properties at high temperatures, with a minimum tensile strength of 515 MPa and a yield strength of 205 MPa. These requirements include a minimum creep rupture strength of 100 MPa for 10,000 hours at 815°C (1500°F), and thermal expansion stability against deformation under constant thermal load.
Chemical Composition of TP321H (UNS S32109)
| Element | Requirement (%) | Notes |
| Carbon (C) | 0.04–0.10 | Controlled carbon range for high-temperature stability |
| Manganese (Mn) | 2.00 max | |
| Phosphorus (P) | 0.045 max | |
| Sulfur (S) | 0.030 max | |
| Silicon (Si) | 1.00 max | |
| Chromium (Cr) | 17.0–19.0 | Provides oxidation resistance |
| Nickel (Ni) | 9.0–12.0 | Austenite stabilizer |
| Titanium (Ti) | 4(C+N)–0.70 min | Stabilization against sensitization |
Heat Treatment Specifications for TP321H (UNS S32109)
| Parameter | Requirement | Notes |
| Grade | TP321H | Titanium-stabilized austenitic stainless steel |
| UNS Number | S32109 | |
| Heat Treat Type | Solution treatment | |
| Solution Treating Temperature | 2000°F [1090°C] | Higher than standard TP321 (1900°F/1040°C) |
| Cooling Media | Water or other rapid cooling | Prevents carbide precipitation |
Mechanical Properties of TP321H (UNS S32109)
| Property | Requirement | Notes |
| Grade | TP321H | Titanium-stabilized austenitic stainless steel |
| UNS Designation | S32109 | |
| Tensile Strength, min | 75 ksi [515 MPa] | Matches standard TP321 requirements |
| Yield Strength, min | 30 ksi [205 MPa] | 0.2% offset method |
| Elongation in 2 in. or 50 mm, min | 35% | Standard elongation for austenitic grades |
| Hardness, max | 192 HBW/200 HV | Brinell/Vickers hardness |
| Hardness, max | 90 HRB | Rockwell B scale |
ASTM A213 Stainless Steel Tubes Outside Diameter and Wall Thickness Tolerance
| OD, mm | OD Tolerance |
|---|---|
| < 25.4 | +/- 0.10 |
| 25.4 – <= 38.1 | +/- 0.15 |
| > 38.1 -< 50.8 | +/- 0.20 |
| 50.8 -< 63.5 | +/- 0.25 |
| 63.5 -< 76.2 | +/- 0.30 |
| 76.2 – <= 101.6 | +/- 0.38 |
| > 101.6 – <= 190.5 | +0.38/-0.64 |
| > 190.5 – <= 228.6 | +0.38/-1.14 |
Applications
ASTM A213 TP321H steel pipes are widely used in boiler superheaters, reheaters, and high-temperature process piping systems in power plants and industrial furnaces. They maintain structural integrity, oxidation resistance (up to 1000°C), and thermal fatigue durability even under cyclic heating and cooling conditions.
TP321H steel pipes undergo rigorous quality control, including hydrostatic testing (typically 20-25 MPa), non-destructive testing (ultrasonic or eddy current testing), and surface treatment (pickling or bright annealing to improve corrosion resistance), to ensure compliance with ASTM A213 specifications and provide reliable performance in critical high-temperature applications.
Packaging and Marking:
Packaging shall be in bundles or laminated wooden crates, wrapped in plastic, and appropriate protective measures shall be taken to ensure seaworthiness for transport or as required.
Marking shall comply with the provisions of A1016/A1016M specifications and shall include whether the pipes are hot-worked or cold-worked, including but not limited to: standard, grade, size, furnace number, and batch number.
