Alloy Steel T11 Tubes – ASTM A213 / ASME SA213 T11 (1¼Cr-½Mo, UNS K11597) Seamless Boiler Tubes
ASC LLP, Mumbai, supplies alloy steel T11 tubes. These are ASTM A213 / ASME SA213 Grade T11 seamless 1¼Cr-½Mo tubes for boilers, superheaters, reheaters and heat exchangers, hot-finished or cold-drawn, with EN 10204 3.1 certificates. See all our boiler tubes.
What is T11 Material?
T11 (UNS K11597) is a chrome-moly low-alloy steel with about 1¼% chromium, ½% molybdenum and 0.5 – 1.0% silicon. Molybdenum gives creep strength at high temperature. Chromium and silicon improve resistance to oxidation and scaling in steam. T11 keeps its strength well above the range of carbon-steel boiler tubes such as SA210, and it is widely used for superheater and reheater sections up to about 550 °C.
ASTM A213 covers seamless ferritic and austenitic alloy steel boiler, superheater and heat-exchanger tubes, from about 3.2 mm ID up to 5″ (127 mm) OD and 0.4 – 12.7 mm wall. ASME SA213 is the identical Boiler & Pressure Vessel Code version. The same material as pipe is A335 P11.
Properties of SA213 T11 Tubes
- Creep strength: much higher than carbon steel above about 450 °C.
- Oxidation resistance: chromium and silicon slow steam-side scaling at superheater temperatures.
- Formable and weldable: 163 HB maximum hardness allows bending and swaging; welds need preheat and PWHT (P-No. 4).
- Limits: T11 is not a corrosion-resistant alloy, and for the hottest superheater sections T22 or T91 is used.
Read more: the role of chromium in T11 tubes.
ASTM A213 / ASME SA213 T11 Tube Specifications
| Item | Details |
| Specification | ASTM A213 / ASME SA213, Grade T11 (general requirements A1016) |
| UNS | K11597 |
| Type | Seamless – hot finished or cold drawn; round tube |
| Size | About 3.2 mm ID to 127 mm (5″) OD; wall 0.4 – 12.7 mm (average or minimum) |
| Heat treatment | Full or isothermal anneal, or normalise + temper at 650 °C (1200 °F) min. |
| Length | Fixed lengths to drawing; U-bends and coils on request |
| Ends | Plain, square cut; bevelled on request |
| Testing | Tension, flattening, flaring, hardness; hydrostatic or NDE (eddy current / UT); PMI |
| Certificate | EN 10204 3.1; IBR / third-party inspection on request |
SA213 T11 Tube Size & Weight Chart (Typical Boiler Sizes)
| OD (mm) | Wall (mm) | ID (mm) | Weight (kg/m) |
| 25.4 | 2.6 | 20.2 | 1.46 |
| 31.8 | 3.2 | 25.4 | 2.26 |
| 38.1 | 3.6 | 30.9 | 3.06 |
| 38.1 | 4.5 | 29.1 | 3.73 |
| 44.5 | 4.0 | 36.5 | 3.99 |
| 50.8 | 5.0 | 40.8 | 5.65 |
| 57.0 | 5.6 | 45.8 | 7.10 |
| 63.5 | 6.3 | 50.9 | 8.89 |
A213 tubes are ordered by OD × average or minimum wall, not by pipe schedule. Any size within the A213 range can be supplied. Weights calculated at 7.85 g/cm³. For NPS pipe sizes, see A335 P11.
T11 Material Chemical Composition (UNS K11597)
| Element | ASTM A213 T11 (%) |
| Carbon (C) | 0.05 – 0.15 |
| Manganese (Mn) | 0.30 – 0.60 |
| Phosphorus (P) | 0.025 max. |
| Sulphur (S) | 0.025 max. |
| Silicon (Si) | 0.50 – 1.00 |
| Chromium (Cr) | 1.00 – 1.50 |
| Molybdenum (Mo) | 0.44 – 0.65 |
Mechanical Properties of SA213 T11 Tubes
| Property | ASTM A213 T11 |
| Tensile strength, min. | 415 MPa (60 ksi) |
| Yield strength, min. | 205 MPa (30 ksi) |
| Elongation in 50 mm, min. | 30% |
| Hardness, max. | 163 HBW / 170 HV / 85 HRB |
Physical Properties of T11
| Property | Value (approx., at 20 °C) |
| Density | 7.85 g/cm³ |
| Modulus of elasticity | ≈ 205 GPa |
| Thermal conductivity | ≈ 42 W/m·K |
| Magnetic | Yes (ferritic) |
T11 Equivalent Grades
| Standard | Equivalent / related grade |
| ASTM / ASME | A213 / SA213 T11 (K11597) |
| EN 10216-2 | 10CrMo5-5 (1.7338) |
| JIS G3462 | STBA23 |
| Pipe | ASTM A335 P11 |
| Fittings / forgings / plate | A234 WP11, A182 F11, A387 Grade 11 |
Applications of Alloy Steel T11 Tubes
| Industry | Typical T11 tube applications |
| Power plants | Superheater, reheater and economiser tubes; headers and links |
| HRSGs | Superheater and evaporator sections |
| Refineries & petrochemicals | Heater tubes and high-temperature heat exchangers |
| Industrial boilers | Superheated steam coils, including finned and studded tubes |
T11 vs T12, T22 & T91
| Grade | Nominal composition | Tensile / yield min. (MPa) | Typical use |
| T11 | 1¼Cr-½Mo-Si | 415 / 205 | Superheaters and reheaters to about 550 °C |
| T12 | 1Cr-½Mo | 415 / 220 | Similar service, lower silicon |
| T22 | 2¼Cr-1Mo | 415 / 205 | Higher creep strength |
| T91 | 9Cr-1Mo-V-Nb | 585 / 415 | Hottest superheater / reheater sections |
Detailed comparison: T11 vs T12 tubes. Finned T11 tubes (similar to EN 10216-2 10CrMo5-5) are available for economisers and waste-heat boilers.
Why Buy T11 Tubes from ASC LLP?
- Certified material: SA213 T11 with EN 10204 3.1 certificates showing heat treatment, chemistry, hardness and test results; IBR on request.
- PMI checked before dispatch to avoid mix-ups with carbon steel or T12.
- Complete 1¼Cr-½Mo system: P11 pipes, WP11 fittings, F11 fittings, F11 flanges and SA387 Gr 11 plates.
- Exact lengths and U-bends to drawing.
Quality guide: manufacturing standards and QC for T11 tubes. Send OD, wall, length and quantity to sales@amardeepsteel.com, call 022-67439130 or contact us.
Frequently Asked Questions – Alloy Steel T11 Tubes
What is T11 material?
T11 is a 1¼% chromium, ½% molybdenum low-alloy steel (UNS K11597) supplied as seamless tube to ASTM A213 / ASME SA213. It is used for boiler superheater, reheater and heat-exchanger tubes at temperatures up to about 550 °C.
What is the chemical composition of SA213 T11?
SA213 T11 contains C 0.05–0.15%, Mn 0.30–0.60%, P 0.025% max., S 0.025% max., Si 0.50–1.00%, Cr 1.00–1.50% and Mo 0.44–0.65%.
What are the mechanical properties of T11 tubes?
Minimum tensile strength is 415 MPa (60 ksi), minimum yield strength 205 MPa (30 ksi), minimum elongation 30%, and maximum hardness 163 HBW (85 HRB).
What is the difference between T11 and P11?
T11 and P11 are the same 1¼Cr-½Mo material. T11 is seamless tube to ASTM A213 (up to 5″ OD, ordered by OD × wall), while P11 is seamless pipe to ASTM A335 (NPS sizes and schedules).
What is the difference between T11 and T22?
T22 contains about 2¼% Cr and 1% Mo, compared with 1¼% Cr and ½% Mo in T11, giving higher creep strength. Both have the same minimum room-temperature tensile and yield strength.
What is the equivalent of T11?
The European equivalent is EN 10216-2 10CrMo5-5 (1.7338) and the Japanese equivalent is JIS STBA23. Related product forms are A335 P11 pipe, A234 WP11 fittings, A182 F11 forgings and A387 Grade 11 plate.
Global Reach
ASC LLP supplies alloy steel boiler tubes, pipes and fittings to boiler makers, power plants and EPC contractors in the USA, Europe, the Middle East and Asia, with secure packing and full documentation. Buyers worldwide rely on our alloy steel T11 tubes for certified material and traceability.
Countries We Export To
UNITED STATES, EUROPE, UK, UAE, SAUDI ARABIA, OMAN, KUWAIT, JORDAN, QATAR, INDONESIA, MALAYSIA, BRAZIL, SPAIN, ITALY, FRANCE, GERMANY, BAHRAIN, SRI LANKA, AZERBAIJAN, AUSTRALIA, AUSTRIA, PHILIPPINES, TURKEY, RUSSIA, IRAN, IRAQ, CANADA, KOREA, JAPAN, YEMEN, FINLAND, ZIMBABWE, HUNGARY, PORTUGAL, VIETNAM, MOROCCO, THAILAND, SOUTH AFRICA, MEXICO, SINGAPORE, GREECE, KUWAIT, POLAND, NEW ZEALAND, SWEDEN, SWITZERLAND, BELGIUM, BHUTAN, BANGLADESH, TAIWAN, ROMANIA, CAMBODIA, KAZAKHSTAN, AFGHANISTAN.
