ASTM A213 T91 Alloy Steel Seamless Tubes Manufacturer & Exporter

USA Piping Solution is a leading manufacturer, stockist and exporter of ASTM A213 T91 Alloy Steel Seamless Tubes. Also designated as SA 213 T91 under ASME standards and identified by UNS K91560, these tubes are engineered for high-temperature, high-pressure service in boilers, superheaters and heat exchangers. Our ASTM A213 T91 Seamless Tube inventory is available in a wide range of sizes, schedules and end conditions with IBR certification, mill test certificates (MTC) and third-party inspection available on request. We supply to power plants, refineries and OEM fabricators across India, USA, UAE and 40+ countries. The T91 Tube Material is acidic and chloride resistant, making it suitable for the most demanding boiler and process environments. Contact us for a SA 213 T91 Tube price list and availability.

What is ASTM A213 T91 / SA 213 T91?

ASTM A213 T91 is a ferritic-martensitic alloy steel tube made from a 9% chromium – 1% molybdenum – vanadium steel, developed specifically for high-temperature service in power generation and petrochemical industries. It is part of ASTM A213 — the standard specification for seamless ferritic and austenitic alloy-steel boiler, superheater and heat-exchanger tubes.

SA 213 T91 is the ASME (American Society of Mechanical Engineers) equivalent of ASTM A213 T91. Both specifications cover the same modified 9Cr-1Mo-V steel and are interchangeable in most boiler and pressure vessel applications. This grade is commonly referred to as P91 when used in pipe formASTM A335 P91 Alloy Steel Pipe.

The ASTM A213 T91 Seamless Tube undergoes normalising at 1040°C followed by tempering at a minimum 760°C to achieve its exceptional combination of creep strength, toughness and weldability. Because of its higher alloy content, it can replace heavierASTM A213 T22 tubes with thinner walls, reducing overall system weight and cost.

Key Advantages of ASTM A213 T91 Tubes

• Superior creep strength at elevated temperatures up to 650°C
• Excellent oxidation and corrosion resistance due to high Cr-Mo content
• Thinner wall requirements compared to lower-alloy grades, reducing overall weight
• Weldable with standard TIG, MIG and SMAW processes (with proper PWHT)
• Compliant with ASTM, ASME, EN and GOST international standards
• IBR (Indian Boiler Regulation) approved for boiler applications
• T91 Buffer Tube — resistant to acidic media and chloride stress corrosion

ASTM A213 T91 Seamless Tube Specifications

Parameter	Details
Product Name	ASTM A213 T91 Seamless Tube
Size (Seamless)	6.35 mm OD to 101.60 mm OD
Standards	ASTM A213 / ASME SA213
Equivalent Standards	EN 10216-2, GOST 550-75, WN 1.4903, ASTM A335
Material / UNS	T91, UNS K91560
Equivalent Material	X10CrMoVNb9-1, 1.4903, P91, K91560
Type	Seamless
Outer Dimensions	6 – 2500 mm OD; WT: 1 – 200 mm
Wall Thickness	Schedule 3 mm to 15 mm (up to 200 mm on request)
Schedules	STD, SCH 20, 40, 80, 100, 120, 140, 160, XXH
Form	Round, Square, Rectangular, Hydraulic
Length	Max 1 – 12 m (single/double random or fixed)
End Condition	Plain, Bevelled, Threaded
Finish	Hot Finished (HF) / Cold Drawn (CD)

ASTM A213 T91 Chemical Composition (UNS K91560)

The ASTM A213 T91 chemical composition is tightly controlled to achieve the balance of creep strength, oxidation resistance and weldability required for supercritical boiler service. The UNS K91560 designation identifies this specific alloy chemistry:

Element	Composition (%)
Carbon (C)	0.07 – 0.14 %
Manganese (Mn)	0.30 – 0.60 %
Phosphorus (P)	0.020 % max
Sulfur (S)	0.010 % max
Silicon (Si)	0.20 – 0.50 %
Chromium (Cr)	8.00 – 9.50 %
Molybdenum (Mo)	0.85 – 1.05 %
Vanadium (V)	0.18 – 0.25 %
Niobium / Columbium (Nb)	0.06 – 0.10 %
Nitrogen (N)	0.030 – 0.070 %
Nickel (Ni)	0.40 % max
Aluminum (Al)	0.02 % max
Titanium (Ti)	0.01 % max
Zirconium (Zr)	0.01 % max

SA 213 T91 Mechanical Properties

The SA 213 T91 Tube must meet the following minimum mechanical properties as specified in ASTM A213 / ASME SA 213. The composition of the ASTM A213 T91 Tube provides a minimum yield strength of 415 MPa and minimum tensile strength of 585 MPa, with a maximum hardness of 250 HBW:

Property	Value
Tensile Strength (min)	585 MPa (85 ksi)
Yield Strength (min)	415 MPa (60 ksi)
Elongation (min)	20 %
Hardness (max)	250 HBW / 25 HRC
Heat Treatment	Normalise at 1040°C + Temper at min 760°C

ASTM A213 T91 Seamless Tube Sizes & Dimensions

We stock and supply ASTM A213 T91 Seamless Tubes in the following standard and custom dimensions. Both A213 T91 Hot Finished Tube and T91 Steel Cold Drawn Tube forms are available:

Parameter	Range / Details
Outer Diameter (OD)	6.35 mm to 101.60 mm (¼" to 4")
Wall Thickness	0.8 mm to 15 mm (Sch 20 to XXS); up to 200 mm on special order
Length	Single random (4–7 m), Double random (7–14 m), Fixed lengths
End Condition	Plain end, Bevelled end, Threaded
Finish	Hot Finished (HF), Cold Drawn (CD)
Standards	ASTM A213 / ASME SA 213
Equivalent	EN 10216-2, GOST 550-75, WN 1.4903, X10CrMoVNb9-1

Hot Rolled Dimensional Tolerances

OD Range	Wall Thickness (WT)	OD Tolerance (mm)	WT Tolerance (%)
≤101.6 mm	≤2.4 mm	+0.4 / −0.8	+40 / −0
≤101.6 mm	2.4 < WT ≤ 3.8 mm	+0.4 / −0.8	+35 / −0
≤101.6 mm	3.8 < WT ≤ 4.6 mm	+0.4 / −0.8	+33 / −0
≤101.6 mm	>4.6 mm	+0.4 / −0.8	+28 / −0
>101.6 mm	2.4 < WT ≤ 3.8 mm	+0.4 / −1.2	+35 / −0
>101.6 mm	3.8 < WT ≤ 4.6 mm	+0.4 / −1.2	+33 / −0
>101.6 mm	>4.6 mm	+0.4 / −1.2	+28 / −0

Cold Drawn Dimensional Tolerances

Outside Diameter (OD)	OD Tolerance (mm)
< 25.4 mm	±0.10
25.4 ≤ OD ≤ 38.1 mm	±0.15
38.1 < OD < 50.8 mm	±0.20
50.8 ≤ OD < 63.5 mm	±0.25
63.5 ≤ OD < 76.2 mm	±0.30
76.2 ≤ OD ≤ 101.6 mm	±0.38
101.6 < OD ≤ 190.5 mm	+0.38 / −0.64
190.5 < OD ≤ 228.6 mm	+0.38 / −1.14

UNS K91560 T91 Boiler Tube Weight Chart (NPS / ANSI B36.10M)

NPS (in)	OD (in)	Schedule	WT (in)	ID (in)	Weight (lb/ft)
1/2	0.84	STD / 40	0.109	0.622	0.85
1/2	0.84	XH / 80	0.147	0.546	1.09
3/4	1.05	STD / 40	0.113	0.824	1.13
3/4	1.05	XH / 80	0.154	0.742	1.48
1	1.315	STD / 40	0.133	1.049	1.68
1	1.315	XH / 80	0.179	0.957	2.17
1½	1.900	STD / 40	0.145	1.610	2.72
2	2.375	STD / 40	0.154	2.067	3.65
3	3.500	STD / 40	0.216	3.068	7.58
4	4.500	STD / 40	0.237	4.026	10.79

Manufacturing Process of ASTM A213 T91 Tubes

Each ASTM A213 T91 Alloy Steel Seamless Tube is manufactured through a fully controlled process:

1. Melting & Casting: Raw materials are melted in an electric arc furnace and refined through vacuum degassing to remove impurities and ensure chemical homogeneity.
2. Hot Rolling: Steel is hot-rolled into tube form using mandrel mill, rotary piercing or extrusion processes.
3. Heat Treatment: T91 tubes undergo normalisation at 1040°C (1904°F) followed by air cooling, then tempering at a minimum of 760°C (1400°F) to optimise toughness and mechanical properties.
4. Cold Drawing (if required): Tubes are cold-drawn to achieve precise dimensions and improved surface finish. The T91 Steel Cold Drawn Tube is drawn after the cold rolling procedure for excellent finish and enhanced properties.
5. Testing & Inspection: Each tube undergoes rigorous non-destructive testing (ultrasonic, eddy current) and destructive testing (tensile, impact, hardness), plus hydrostatic testing and visual inspection.
6. Surface Finishing: Tubes are pickled, passivated or coated as per customer requirements. IBR Approved SA213 T91 High Pressure Tube is manufactured following all standards set by the Indian Boiler Regulation.

Applications of SA 213 T91 Boiler Tubes

The SA213 T91 Boiler Tube is widely specified in industries requiring sustained high-temperature, high-pressure performance:

• Power Generation: Superheaters, reheaters and steam headers in subcritical, supercritical and ultra-supercritical boilers. SA 213 T91 Tubes are the industry standard for modern power plant design.
• Oil & Gas Refining: High-temperature process piping, crude oil heater coils and reformer furnace tubes.
• Petrochemical Industry: Hydrocracker and hydrotreater reactor internals and heat recovery steam generators (HRSG).
• Nuclear Energy: Heat exchangers and pressure boundary components operating at elevated temperatures. SA 213 T91 Heat Exchanger Tube is available in single random, double random and custom lengths.
• Aerospace & Defence: High-pressure, high-temperature fluid handling systems.
• Marine & Shipbuilding: Boiler tubes and heat exchanger applications in marine vessels.
• Chemical Processing: High-pressure reactors, autoclaves and thermal processing equipment. ASTM A213 Gr T91 Furnace Tubes are available in thickness between 3 mm – 12 mm.
• Fertiliser Production: High-temperature and high-pressure process vessels and reformer tubing.

ASTM A213 T91 Seamless Tubes offer the best balance of cost and high-temperature performance for most modern supercritical power plant designs. At higher temperatures, consider upgrading to T92.

Benefits of ASTM A213 T91 Alloy Steel Seamless Tubes

• T91 tubes exhibit exceptional creep strength and thermal fatigue resistance for prolonged high-temperature service.
• The 9% chromium content provides excellent resistance to oxidation and scaling in aggressive environments.
• Higher strength allows thinner walls compared to T22 and T11, reducing system weight and material cost.
• Can be welded using TIG, MIG and SMAW processes with appropriate preheat and PWHT.
• Minimal maintenance requirements translate to lower total cost of ownership.
• Meets ASTM, ASME, EN 10216-2 and GOST standards ensuring global acceptance.
• Certified to Indian Boiler Regulations for pressure vessel and boiler applications in India.

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