ASTM A213 T11 Tubing Specification - BLOG

Product description

ASTM A213 Grade T11 is a seamless ferritic chromium-molybdenum (Cr-Mo) tube used in hot steam and flue-gas environments. The grade is formulated for pressure-bearing components in power boilers, HRSGs, petrochemical heaters and high-temperature heat exchangers where carbon steel can't hold oxidation resistance or creep strength.
Octal Pipe supplies T11 in normalized-and-tempered condition, with dimensional control, full testing to ASTM A213/A1016 and mill certificates, so it can go straight into boiler and process fabrication.

astm a213 t11 tubing bundles for boiler and superheater service - octal pipe

Chemical composition

Element	Content (%)	Function
C	0.05 – 0.15	Provides strength and creep resistance, stays weldable
Mn	0.30 – 0.60	Ductility, hot workability
Si	0.50 – 1.00	Supports oxidation resistance
P	≤ 0.025	Limits embrittlement
S	≤ 0.025	Controlled for toughness
Cr	1.00 – 1.50	Scaling resistance in steam / flue gas
Mo	0.44 – 0.65	Creep and rupture strength

This chromium–molybdenum balance is lower than T22 or other higher-Cr grades, which is why T11 bends and welds more easily, but still survives 500–600 °C service.

Mechanical properties

Property	Requirement	Purpose
Tensile strength	≥ 415 MPa (60 ksi)	Overall load capacity
Yield strength (0.2%)	≥ 205 MPa (30 ksi)	Prevents permanent deformation
Elongation	≥ 30%	Needed for bending, coiling, welding
Hardness	≤ 163 HBW	Keeps toughness for thermal cycling

These values match the normalized-and-tempered delivery condition that power and refinery projects usually specify.

Manufacturing and heat treatment

For boiler tube service the route matters as much as the chemistry. Octal Pipe uses a seamless route under ASTM A213/A1016:

alloy billet is hot-pierced or extruded to form a sound hollow
the tube is hot-rolled or cold-drawn to the ordered OD, wall and surface finish (important for heat-exchanger tubes)
the tube is normalized at about 940–980 °C to refine the ferritic matrix, remove banding and equalize mechanical properties along the length
the tube is tempered at about 675–755 °C to restore ductility and lock a fine dispersion of carbides in place

This N+T cycle is what gives T11 its stable microstructure: chromium can build a tight oxide film, molybdenum can do its job in creep strengthening, and the tube doesn't become too hard to weld. After heat treatment, tubes are straightened, hydrostatically tested, and examined by the NDE method ordered (eddy-current or ultrasonic) before marking and packing. Every step is recorded so the tube is traceable back to the heat.

Dimensional range

Parameter	Range / details
Outside diameter	12.7 – 127 mm (0.5 – 5 in)
Wall thickness	1.2 – 12 mm
Length	Up to 12 m; SRL / DRL / cut-to-length
End finish	Plain, beveled, or prepared for U-bending / finning
OD tolerance	typically ± 1% (per ASTM A1016)
Wall tolerance	typically ± 10%
Straightness	typically ≤ 0.8 mm/m

This covers common boiler panel tubes, superheater/reheater coils, and refinery heater coils.

Service performance

In operation T11 forms a uniform chromium-rich oxide, so tube metal loss and scale build-up are slower than with carbon steel. Molybdenum slows creep and rupture, which is important for tubes that sit under temperature and pressure for thousands of hours. Because the structure is tempered ferrite, the tube tolerates start–stop cycles in HRSGs and cogeneration plants without losing straightness too quickly. Welds retain integrity after PWHT when qualified low-alloy filler metals are used.

Applications

boiler waterwall, superheater, reheater and economizer tubes in thermal power plants
HRSG / combined-cycle steam generators
petrochemical and refinery process heaters
high-temperature shell-and-tube heat exchangers
hot utility and process lines inside power and chemical units

Inspection and documentation

Testing is performed in accordance with ASTM A213 and the general A1016 requirements. That includes hydrostatic or eddy-current examination for wall soundness, tensile and hardness tests per heat-treatment lot, flattening/flaring to prove ductility, plus visual and dimensional inspection. For projects with higher QA/QC, Octal Pipe can add ultrasonic or radiographic checks. All tubes are supplied with EN 10204 3.1 or 3.2 MTCs so the owner can file chemical, mechanical and NDE results by heat number.

Why source ASTM A213 T11 from Octal Pipe

real seamless Cr-Mo tubing in normalized-and-tempered condition, not just generic carbon-steel tube
dimensions, tests and marking aligned with power, boiler, HRSG and refinery specifications
export-ready bundles with end protection for long-distance shipment
engineering support to match T11 with related Cr-Mo grades (T22, A335 P11/P22) when the same unit uses several alloys
page structure written product-first and technically specific, to help your new site get indexed as a supplier page, not template content

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