Premium SA213 T22 Seamless Alloy Tube for Superheaters, Reheaters, High-Pressure Boilers, Heat Exchangers, and High-Temperature Industrial Piping
Womic Steel produces high-quality SA213 T22 Seamless Alloy Steel Tube, manufacturing chromium-molybdenum (2.25Cr-1Mo) ferritic alloy tubes in accordance with ASTM A213 / ASME SA213 specifications. Our SA213 T22 tubes meet the demanding requirements of the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code, with a minimum tensile strength of 415 MPa and excellent creep resistance at elevated temperatures up to 565°C (1050°F). These seamless alloy tubes are the ideal choice for superheaters, reheaters, high-pressure boilers, heat exchangers, and high-temperature industrial piping systems requiring superior creep strength and oxidation resistance over extended service life.
Manufacturer: Womic Steel
1. Product Definition and Scope
SA213 T22 (UNS K21590) is a seamless ferritic alloy steel tube specified under ASTM A213 / ASME SA213 for use in boilers, superheaters, heat exchangers, and other high-temperature pressure-containing equipment. The “T22″ designation indicates a nominal composition of 2.25% chromium and 1% molybdenum, which provides excellent high-temperature strength, creep resistance, and oxidation resistance superior to T11. T22 is widely used in power generation, petrochemical processing, and refinery applications where operating temperatures reach up to 565°C.
Manufacturing Process: T22 tubes shall be manufactured by the seamless process and shall be either hot-finished or cold-finished, as specified. T22 is typically supplied in the annealed, normalized and tempered, or stress relieved condition. The higher chromium and molybdenum content compared to T11 provides enhanced creep rupture strength for more demanding service conditions.
Grade Designation:
| Designation | Meaning |
| SA213 | ASME specification for seamless ferritic and austenitic alloy-steel tubes for boilers, superheaters, and heat exchangers |
| T22 | Grade designation: 2.25% Chromium – 1% Molybdenum ferritic alloy |
| UNS K21590 | Unified numbering system designation for T22 |
Equivalent Standards and Grades:
| Standard | Equivalent Grade |
| ASTM A213 / ASME SA213 | T22 |
| ASTM A335 | P22 (pipe form) |
| EN 10216-2 | 10CrMo9-10 (1.7380) |
| DIN 17175 | 10CrMo910 |
| JIS G3462 | STBA 24 |
| BS 3059 | 622-490 |
| ISO 2604 II | S35 |
Manufacturer: Womic Steel
2. Chemical Composition Requirements
The chemical composition of SA213 T22 is precisely controlled to achieve the desired high-temperature strength, creep resistance, and oxidation resistance. The 2.25% chromium content provides enhanced oxidation resistance, while the 1% molybdenum content significantly enhances creep strength at elevated temperatures.
SA213 T22 Chemical Composition (Heat Analysis – Seamless Tube):
| Element | Composition (%) – Minimum | Composition (%) – Maximum |
| Carbon (C) | 0.05 | 0.15 |
| Manganese (Mn) | 0.30 | 0.60 |
| Phosphorus (P) | — | 0.025 |
| Sulfur (S) | — | 0.025 |
| Silicon (Si) | 0.50 | 1.00 |
| Chromium (Cr) | 2.00 | 2.50 |
| Molybdenum (Mo) | 0.87 | 1.13 |
| Vanadium (V) | — | 0.12 (optional) |
Composition Notes:
| Element | Engineering Note |
| Chromium (2.00-2.50%) | Provides good oxidation and corrosion resistance at elevated temperatures |
| Molybdenum (0.87-1.13%) | Significantly enhances creep strength and high-temperature stability |
| Silicon (0.50-1.00%) | Deoxidation; improves oxidation resistance |
| Carbon (0.05-0.15%) | Balanced for strength and weldability |
T22 offers a substantial increase in creep-rupture strength over T11, making it suitable for the hottest superheater and reheater sections where metal temperatures reach 565°C. The higher Cr content also provides a more protective oxide scale, reducing scaling and prolonging tube life.
3. Mechanical Properties
The mechanical properties of SA213 T22 seamless tubes are specified to ensure reliable performance under high-temperature and high-pressure operating conditions.
Tensile Requirements (Room Temperature):
| Property | Minimum | Typical | Unit |
| Tensile Strength | 415 MPa (60 ksi) | 450-550 MPa | — |
| Yield Strength (0.2% offset) | 205 MPa (30 ksi) | 280-350 MPa | — |
| Elongation in 2 in. or 50 mm | 30% | 35-40% | — |
For thin walls, elongation adjustment follows the same formula as T9/T11.
Hardness Requirements:
| Property | Maximum |
| Brinell Hardness (HBW) | 163 |
| Rockwell Hardness (HRB) | 85 |
High-Temperature Tensile Properties (Reference Values):
| Temperature (°C) | Tensile Strength (MPa) | Yield Strength (MPa) |
| 20 | 450-550 | 280-350 |
| 300 | 420-500 | 230-290 |
| 400 | 400-480 | 210-270 |
| 500 | 350-430 | 180-240 |
| 565 | 280-360 | 140-200 |
Creep Rupture Strength (Typical Values):
| Temperature (°C) | 100,000 Hour Stress (MPa) |
| 500 | 80-100 |
| 540 | 50-65 |
| 565 | 40-50 |
| 590 | 25-35 |
T22′s higher Mo content (0.87-1.13%) provides a marked increase in creep-rupture strength over T11, making it the preferred material for the hottest sections of subcritical and supercritical boilers.
4. Heat Treatment Requirements
T22 steel tubes shall be reheated for heat treatment according to the following methods.
Heat Treatment Requirements:
| Grade | Heat Treat Type | Subcritical Annealing or Tempering Temperature (min) |
| T22 (K21590) | Full or isothermal anneal; normalize and temper | 1200°F (650°C) min |
Heat Treatment Process Details:
| Condition | Process | Temperature Range | Application |
| Normalizing | Heating followed by air cooling | 900-960°C (1650-1760°F) | Refine grain structure |
| Tempering | Reheating after normalizing | 650-730°C (1200-1350°F) | Develop final mechanical properties |
| Full Annealing | Slow cooling from austenitizing temperature | 870-900°C (1600-1650°F) | Softest condition for forming |
Proper heat treatment is essential to develop the tempered bainitic or martensitic microstructure that provides optimum creep resistance.
Manufacturer: Womic Steel performs heat treatment in accordance with ASTM A213 / ASME SA213 requirements. Heat treatment certificates are provided upon request.
5. Dimensional Tolerances
Outside Diameter Tolerances – Hot Finished:
| OD Range (mm) | Tolerance (mm) |
| OD ≤ 101.6 | +0.4 / -0.8 |
| 101.6 < OD ≤ 190.5 | +0.4 / -1.2 |
| 190.5 < OD ≤ 228.6 | +0.4 / -1.6 |
Outside Diameter Tolerances – Cold Drawn:
| OD Range (mm) | Tolerance (mm) |
| OD < 25.4 | ±0.10 |
| 25.4 ≤ OD ≤ 38.1 | ±0.15 |
| 38.1 < OD < 50.8 | ±0.20 |
| 50.8 ≤ OD < 63.5 | ±0.25 |
| 63.5 ≤ OD < 76.2 | ±0.30 |
| 76.2 ≤ OD ≤ 101.6 | ±0.38 |
Wall Thickness Tolerances:
| Condition | Tolerance |
| Hot Finished (OD ≤ 101.6, WT ≤ 2.4) | +40% / -0 |
| Hot Finished (OD ≤ 101.6, WT > 4.6) | +28% / -0 |
| Cold Drawn | ±10% of nominal thickness |
Ovality and Length Tolerances follow the same general requirements as T9/T11.
6. Available Sizes and Specifications
T22 Seamless Tube Size Range:
| Parameter | Hot Finished | Cold Finished |
| OD Range (mm) | 12.7 – 219.1 | 6.35 – 101.60 |
| WT Range (mm) | 1.6 – 15.0 | 0.5 – 12.7 |
| Standard Length (m) | 6 – 12 | 6 – 12 |
Common T22 Tube Sizes (OD x WT in mm):
| OD (mm) | WT 2.5 | WT 3.0 | WT 3.5 | WT 4.0 | WT 5.0 | WT 6.0 | WT 8.0 |
| 25.4 | ✓ | ✓ | ✓ | ✓ | ✓ | — | — |
| 31.8 | — | ✓ | ✓ | ✓ | ✓ | ✓ | — |
| 38.1 | — | ✓ | ✓ | ✓ | ✓ | ✓ | — |
| 44.5 | — | — | ✓ | ✓ | ✓ | ✓ | — |
| 50.8 | — | — | — | ✓ | ✓ | ✓ | — |
| 60.3 | — | — | — | — | ✓ | ✓ | — |
| 63.5 | — | — | — | — | ✓ | ✓ | — |
| 76.2 | — | — | — | — | — | ✓ | ✓ |
| 88.9 | — | — | — | — | — | ✓ | ✓ |
| 101.6 | — | — | — | — | — | ✓ | ✓ |
U-Bend Tubes: Available upon request with post-bending stress relief heat treatment.
Manufacturer: Womic Steel maintains extensive inventory of SA213 T22 seamless tubes in common sizes for immediate dispatch.
7. Inspection and Testing Requirements
| Test / Inspection | Requirement | Acceptance Criteria | Frequency |
| Chemical Analysis | Required | Per ASTM A213 | Per heat |
| Tensile Test | Required | ≥415 MPa / ≥205 MPa | Per heat |
| Hardness Test | Required | ≤163 HBW / ≤85 HRB | Per heat |
| Flattening Test | Required | No cracks | Per lot |
| Flaring Test | Required | No cracks | Per lot |
| Hydrostatic Test or NDT | Required (100%) | No leakage or no flaws | Each tube |
Non-Destructive Testing (NDT) Options:
● Eddy Current Test (ECT) – 100% surface inspection
● Ultrasonic Test (UT) – 100% internal inspection
● Hydrostatic Test – Pressure integrity verification
● Hydrostatic Test Pressure Formula: P = 2St/D, hold time 5 seconds minimum.
8. Applications
SA213 T22 seamless tubes are specifically designed for the most demanding high-temperature applications.
| Industry | Application |
| Power Generation | Superheater tubes, reheater tubes, high-temperature boiler headers for subcritical and supercritical plants |
| Combined Cycle Power Plants | HRSG high-temperature superheater and reheater sections |
| Petrochemical | Hydrocracker and hydrotreater heat exchangers, high-temperature furnace tubes |
| Refining | Catalytic reformer piping, high-temperature heat exchanger tubes |
| Industrial Heating | High-temperature process heaters, radiant tube coils |
T22 is widely specified for the hottest superheater and reheater sections in fossil fuel power plants due to its proven creep strength and oxidation resistance at 565°C.
9. Comparison with Other Alloy Grades
| Grade | Nominal Composition | Max Service Temp | Typical Application |
| T11 | 1.25Cr-0.5Mo | 540°C | Superheater/reheater (moderate) |
| T22 | 2.25Cr-1Mo | 565°C | Hottest superheater sections |
| T9 | 9Cr-1Mo | 593°C | Higher temperature |
| T91 | 9Cr-1Mo-V-Nb | 650°C | Ultra-supercritical |
T22 provides a significant creep strength advantage over T11, making it the standard material for the hottest sections of subcritical boilers before transitioning to higher alloys like T91.
10. Welding Procedure for SA213 T22
T22 has higher hardenability than T11 and requires careful control of preheat and PWHT.
Recommended Welding Processes: GTAW (TIG) for root pass, SMAW with low-hydrogen electrodes for fill and cap.
Recommended Filler Metals:
| Filler Metal | AWS Classification |
| ER90S-B3 | AWS A5.28 (GTAW) |
| E9018-B3 | AWS A5.5 (SMAW) |
Critical Welding Requirements:
| Parameter | Requirement |
| Preheating Temperature | 150-250°C (300-480°F) – mandatory |
| Maximum Interpass Temperature | 300°C (572°F) |
| Post-Weld Heat Treatment (PWHT) | 650-730°C (1200-1350°F) – mandatory |
| PWHT Hold Time | Minimum 1 hour per 25mm thickness |
| Welding Consumables | Low hydrogen type |
Preheat is mandatory for all thicknesses. PWHT must be performed to temper the martensitic structure and relieve residual stresses. Hydrogen control is critical.
11. Traceability and Marking
Each tube is stencil marked with: Manufacturer name, ASTM A213/ASME SA213, T22, UNS K21590, size (OD x WT), heat number, length, and hydrostatic test / NDT method.
Marking Example:
| Line | Content |
| Line 1 | Womic Steel ASTM A213/ASME SA213 T22 |
| Line 2 | 50.8mm x 5.0mm x 6.0m |
| Line 3 | Heat No: H12345 / UNS K21590 |
| Line 4 | Hydro / ECT |
12. Quality Documents
● Mill Test Report (EN 10204 Type 3.1) – included
● Heat Treatment Certificate – included
● Hydrostatic Test Report – included
● NDT Report (upon request)
● Dimensional Inspection Report – included
● Certificate of Origin – included
● Third-Party Inspection – optional (SGS, BV, DNV, TUV, LR, ABS)
13. Contact Information
Website: www.womicsteel.com
E-mail: sales@womicsteel.com
Tel / WhatsApp / WeChat:
Victor: +86 15575100681
Jack: +86 18390957568
Womic Steel – Your reliable partner for SA213 T22 seamless alloy tubes, stainless steel products, and custom solutions for boiler, superheater, heat exchanger, and power generation applications.
Post time: Oct-20-2026