UNS S32100|1.4541|TP321 Seamless Stainless Steel Tube
Distinguished by the strategic addition of Titanium (Ti), our TP321 tubing prevents chromium carbide precipitation during prolonged exposure to temperatures in the 427°C - 816°C (800°F - 1500°F) range. This makes them indispensable for mission-critical applications in heat exchanger tubes, aircraft exhaust systems, and petrochemical refinery infrastructure. Through advanced cold-drawing and precise solution annealing, XinZhe ensures every tube maintains a uniform microstructure and optimized mechanical strength for demanding thermal cycling conditions.
“Our precision-controlled Titanium-to-Carbon ratio ensures that carbides are fully stabilized, preventing sensitization even after welding and high-temperature service.”
What Is a Seamless Stainless Steel TP321 Tube?
Seamless TP321 (UNS S32100 / W.Nr. 1.4541) tube is a titanium-stabilised austenitic stainless steel developed for elevated-temperature service. The titanium addition ties up carbon as stable titanium carbides, preventing chromium carbide precipitation and the intergranular corrosion that would otherwise occur in the sensitisation range of 425–815 °C.
ASTM A213 TP321 Seamless Stainless Steel Tube (UNS S32100 / EN 1.4541) is a titanium-stabilized austenitic stainless steel tube designed for high-temperature and corrosion-resistant applications.
Unlike welded tubes, TP321 seamless tubes are manufactured from a solid billet through extrusion or cold drawing, ensuring:
The addition of titanium (Ti) stabilizes the material by binding carbon, effectively preventing chromium carbide precipitation within the temperature range of 425°C–816°C (800°F–1500°F). This provides excellent resistance to intergranular corrosion, especially after welding or prolonged thermal exposure.
Compared to TP304 / TP304L stainless steel tubes, TP321 offers significantly better performance in high-temperature cyclic environments.
Key Features and Technical Advantages
1. Excellent Intergranular Corrosion Resistance
- Titanium stabilization (Ti ≥ 5×(C+N)) prevents sensitization
- Ideal for applications involving welding and high heat
2. Superior High-Temperature Performance
- Continuous service up to 870°C (1600°F)
- Strong oxidation resistance in thermal cycling conditions
3. Seamless Structural Integrity
- Homogeneous grain structure
- Tight dimensional tolerances
- Reliable under high-pressure conditions
4. Enhanced Fabrication & Weldability
- Suitable for complex fabrication processes
- Typically does not require post-weld heat treatment
5. Cost-Effective Alternative to Nickel Alloys
- Comparable high-temperature resistance
- Lower cost compared to Inconel and other Ni-based alloys
Product Specifications and Data
- ASTM A213 / ASME SA213 (Seamless Tubes)
- ASTM A312 (Optional for piping systems)
- EN 10216-5 (1.4541)
- JIS G3463 / G3459
- GB/T 14976
To provide a comprehensive overview of this high-performance material, here are the detailed technical specifications and performance data for Stainless Steel 321.
The composition of Stainless Steel 321 is carefully balanced to achieve its superior high-temperature stability and corrosion resistance.
Table 1: Chemical Composition of Stainless Steel 321
| Cr | Ni | P | S | Ti | Mn | Si | C |
| 17.00 - 19.00 | 9.00 - 12.00 | ≤ 0.045 | ≤ 0.030 | ≥ 5×(C+N), ≤0.70 | ≤ 2.00 | ≤ 1.00 | ≤ 0.08 |
Note: The titanium content must be at least five times the carbon content to ensure stabilization.
Stainless Steel 321 is specifically designed to maintain its strength and shape in high-temperature, high-stress environments.
Table 2: Typical Mechanical Properties of Stainless Steel 321
| Tensile Strength | Yield Strength | Elongation | Hardness |
|---|---|---|---|
| ≥ 515 MPa | ≥ 205 MPa | ≥ 35% | ≤ 192 HBW |
These physical properties highlight the material's ability to perform reliably under a wide range of conditions.
Table 3: Typical Physical Properties of Stainless Steel 321
| Density | Melting Point | Thermal Expansion | Thermal Conductivity | Modulus of Elasticity | Electrical Resistivity |
|---|---|---|---|---|---|
| 8.0 g/cm³ | 1398 - 1454 °C | 16.6 µm/m·°C (20-100°C) | 16.3 W/m·K (20°C) | 193 GPa | 0.72 x 10⁻⁶ Ω·m (20°C) |
Dimensional Standards and Tolerances
TP321 seamless tubes are manufactured to the dimensional tolerances of ASTM A213 / A213M and ASTM A269, with high-temperature service orders often referencing ASME SA213 as well.
Table 4: The Standard of Stainless Steel Seamless Tube Size Tolerance Size Chart :
| Standard | OD(D) | Tolerance（MM) | Thickness(S) | Tolerance(MM) | Length | Tolerance | |
| MM | Common | High | MM | MM | |||
| EN 10216-5 HFD | 30≤D≤219.1（D2) | ±1.0% or ±0.5mm, whicever is the greater(取较大者) | T1, T≤4 | ±15% or ±0.6mm, whicever is the greater(取较大者) | L≤6M | +5/0 | |
| T2 | ±12.5% or ±0.4mm, whicever is the greater(取较大者) | ||||||
| 219.1≤D≤610 (D1) | ±1.5% or ±0.75mm, whicever is the greater (取较大者) | T≤0.05D | +22.5%/-15% | 6 | +10/0 | ||
| T1, 0.05D | ±15% or ±0.6mm, whicever is the greater(取较大者) | ||||||
| T2, T>0.09D | ±12.5% or ±0.4mm, whicever is the greater(取较大者) | L>12 | +by agreement/0 | ||||
| EN 10216-5 CFD | D3(D≤219.1) | ±0.75% or ±0.3mm, whicever is the greater(取较大者) | T3 | ±10% or ±0.2mm, whicever is the greater(取较大者) | |||
| D4(D≤219.1) | ±0.5% or ±0.mm, whicever is the greater(取较大者) | T4 | ±7.5% or ±0.15mm, whicever is the greater(取较大者) | ||||
| ASTM A213 HFD | D≤100 | +0.4/-0.8 | D<100,S≤2.4 | +40%/0 | HFD, all size | +5.0/0 | |
| +0.4/-1.2 | D<100,2.4 | +35%/0 | |||||
| +0.4/-1.6 | D<100,3.8 | +33%/0 | |||||
| D<100,S>4.6 | +28%/0 | ||||||
| 100 | +0.4/-1.2 | D>100, 2.4 | +35%/0 | ||||
| 200 | +0.4/-1.6 | D>100,3.8 | +33%/0 | ||||
| D>100,S>4.6 | +28%/0 | ||||||
| ASTM A213 CFD | D<25 | ±0.10 | D≤38.1 | +20%/0 | CFD, D<50.8 | +3.0/0 | |
| 25≤D≤40 | ±0.15 | ||||||
| 40 | ±0.20 | ||||||
| 50≤D<65 | ±0.25 | ||||||
| 65≤D<75 | ±0.30 | D>38.1 | +22%/0 | CFD, D≥50.8 | +5.0/0 | ||
| 75≤D≤100 | ±0.38 | ||||||
| 100 | +0.38/-0.64 | ||||||
| 200 | +0.38/-1.14 | ||||||
| ASTM A269 | D≤13 | ±0.13 | D≤13 | ±15% | D<38 | +3.2/0 | |
| 13 | ±0.13 | 13 | ±10% | ||||
| 38≤D<89 | ±0.25 | D>38 | +4.8/0 | ||||
| 89≤D<140 | ±0.38 | ||||||
| 140≤D<203 | ±0.76 | ||||||
| 203≤D<305 | ±1.01 | ||||||
| 305≤D<356 | ±1.26 | ||||||
| ASTM A270 | D<25 | ±0.13 | For weld pipe all size | ±12.5% | +3.0/0 | ||
| 25-50 | ±0.20 | ||||||
| 50-75 | ±0.25 | ||||||
| 75-100 | ±0.38 | For CD SMLS pipe D≤38.1 | +20%/0 | ||||
| 100-140 | ±0.38 | +5.0/0 | |||||
| 140-200 | ±0.75 | For CD SMLS pipe D>38.1 | +22%/0 | ||||
| 200-300 | ±1.25 | ||||||
Common Industrial Applications
Aerospace and Defence
- Hydraulic and fuel system tubing
- High-temperature bleed-air lines
- Engine and airframe component tubing
Power Generation
- Superheater and reheater tubing
- Steam and condensate circuits
- Boiler and heat recovery tube banks
Petrochemical and Refining
- Process and transfer line tubing
- Reformer and cracker furnace tubing
- Heat exchanger and condenser tubes
Food and Pharmaceutical
- Hygienic process and transfer tubing
- High-temperature sterilisation circuits
- Purified water and clean-steam lines
Quality Assurance and Manufacturing Process
Certification and Documentation
All TP321 tubes are supplied to ASTM A213 / A213M with EN 10204 3.1 mill test certificates. Stabilisation verification, PMI reports and full heat-number traceability are available on request.
Non-Destructive Testing (NDT)
Hydrostatic or eddy-current testing is performed on 100% of tubes. Ultrasonic testing and dye-penetrant inspection are available for high-temperature and pressure-critical service.
Mechanical and Metallurgical Testing
Tensile, yield, elongation and hardness tests are carried out per heat. Short-time elevated-temperature tensile testing and intergranular corrosion testing per ASTM A262 Practice C are available where specified.
Third-Party Inspection
Inspection by SGS, BV, TUV or Lloyd’s can be arranged for project orders, with documented witness of mechanical testing, dimensional checks and final visual examination before packing.
TP321 vs TP304 / TP316 – Technical Comparison
TP321 is a titanium-stabilised austenitic grade designed for elevated-temperature service. Against TP304 it trades a little ambient strength for far better intergranular corrosion resistance after sensitisation; against TP316 it trades chloride pitting resistance for high-temperature stability.
Chemical Composition
- Titanium: TP321 ≥ 5 × C, stabilising the grade against sensitisation
- Carbon: TP321 ≤ 0.080 %, TP304 ≤ 0.080 %, TP316 ≤ 0.080 %
- Molybdenum: TP316 2.00–3.00 %; none in TP321 or TP304
- Nickel: TP321 9.0–12.0 %
High-Temperature Performance
- TP321 resists intergranular corrosion in the 425–815 °C sensitisation range where unstabilised grades are vulnerable
- TP321 maintains useful strength and oxidation resistance up to about 900 °C in continuous service
- TP304 and TP316 both suffer chromium carbide precipitation in that temperature band unless post-weld annealed
Corrosion and Mechanical Properties
- Tensile strength: all three ≥ 515 MPa
- Yield strength (0.2 %): TP321 ≥ 205 MPa, TP304 ≥ 205 MPa, TP316 ≥ 205 MPa
- TP316 has the highest PREN and the best chloride pitting resistance
- TP321 offers no advantage over TP316 in chloride-bearing ambient service
Selection Guidance
- Choose TP321 for welded high-temperature service, boiler and superheater tubing, and expansion bellows
- Choose TP304 for general-purpose ambient corrosion service
- Choose TP316 for chloride-bearing and reducing-acid service at moderate temperature
- Above roughly 540 °C under sustained load, step up to TP321H
Frequently Asked Questions
What is TP321 stainless steel tube?
TP321 (UNS S32100 / W.Nr. 1.4541) is a titanium-stabilised austenitic stainless steel developed for elevated-temperature service. Titanium ties up carbon as stable titanium carbides, preventing chromium carbide precipitation and the intergranular corrosion that would otherwise occur between 425 and 815 °C.
Why is TP321 used at high temperature?
Because titanium stabilisation suppresses sensitisation, TP321 can be used in the carbide precipitation range without loss of intergranular corrosion resistance. It also retains useful strength and oxidation resistance up to approximately 900 °C in continuous service, making it suitable for boiler, superheater and furnace tubing.
What is the difference between TP321 and TP321H?
TP321H (UNS S32109) is the high-carbon variant, with 0.04–0.10 % carbon against a 0.080 % maximum for TP321. The higher carbon content delivers improved creep and stress rupture strength above roughly 540 °C, and TP321H carries an additional elevated-temperature tensile test requirement under ASTM A213 T2.
Which standards cover TP321 seamless tubes?
TP321 seamless tubing is normally supplied to ASTM A213 / A213M and ASTM A269, with ASME SA213 frequently referenced for power and pressure service. Equivalent European specifications include EN 10216-5 grade 1.4541.
Ready to Request a Quotation?
Send your TP321 tube enquiry with application, service temperature, size (OD and wall thickness or schedule), quantity, length and inspection requirements.
UNS S31703|1.4438|TP317L Seamless Stainless Steel Tube
UNS S31700|1.4449|TP317 Seamless Stainless Steel Tube
UNS S34700|1.4550|TP347 Seamless Stainless Steel Tube
UNS S32109|1.4878|TP321H Seamless Stainless Steel Tube
UNS S32100|1.4541|TP321 Seamless Stainless Steel Tube
UNS N08904|1.4539|TP904L Seamless Stainless Steel Tube
UNS N08031|1.4562|Alloy 31 Seamless Tube
UNS S30815|1.4835|253MA Seamless Stainless Steel Tube
UNS S31254|1.4547|254SMO Seamless Stainless Steel Tube
UNS S34709|1.4912|TP347H Seamless Stainless Steel Tube