ASTM A213 T91 Alloy Steel Boiler Tubes

ASTM A213 T91 alloy steel boiler tubes are high-performance tubes made from ferritic-martensitic alloy steel. These tubes are specifically designed to handle high temperatures and pressures in boilers, superheaters, and heat exchangers. The T91 grade is widely used in power plants, refineries, and other industries that demand superior performance under extreme conditions. With the combination of chromium and molybdenum, the T91 alloy offers excellent strength, durability, and corrosion resistance.

Key Features

• Material Composition: Made from a chromium-molybdenum alloy, which increases the tube’s strength, hardness, and high-temperature resistance.
• Seamless Construction: These tubes are manufactured without any welding seams, ensuring uniform strength and the ability to withstand high pressures.
• High-Temperature Resistance: The T91 alloy is optimized for use in extreme temperature environments, maintaining its integrity and performance even under intense heat.
• Corrosion and Oxidation Resistance: The addition of chromium provides excellent resistance to oxidation and corrosion, increasing the longevity of the tubes even in aggressive environments.

Applications

• Power Plants: Used extensively in superheaters and boilers to transport high-pressure steam at elevated temperatures.
• Petrochemical Industry: Ideal for equipment that must operate under high heat and corrosive conditions, such as heat exchangers.
• Oil and Gas: Suitable for pipelines and systems that are exposed to high-pressure, high-temperature conditions.
• Chemical Industry: Essential for heat exchangers and reactors, where reliability under thermal stress is critical.

Advantages

• Exceptional Durability: These tubes maintain their strength and performance even in extreme temperature and pressure environments, providing long service life.
• Superior Heat Resistance: The T91 grade has been optimized for high-temperature applications, preventing thermal expansion and material degradation under heat stress.
• Enhanced Corrosion Resistance: The chromium and molybdenum composition offers excellent protection against corrosion, oxidation, and erosion, even in aggressive environments.
• High Mechanical Strength: The alloy’s composition ensures that the tubes have a high tensile and yield strength, making them suitable for high-stress applications.

Specifications

ASTM A213 T91 alloy steel boiler tubes offer exceptional performance in industries requiring reliable and durable materials that can withstand high temperatures and pressures. Their corrosion resistance, thermal stability, and mechanical strength make them indispensable in applications such as power generation, oil refining, and chemical processing.

• Grade: T91
• Outer Diameter: Available in various sizes based on specific requirements
• Wall Thickness: Supplied in varying thicknesses to match different industrial needs
• Length: Available in random or fixed lengths
• Standards: ASTM A213 / ASME SA213 specifications
• Type: Seamless Ferritic Alloy Steel Tube

ASTM A213 T91 and ASTM A335 P91

Grade T91 specified in ASTM A213 which do Ferrite and Austenitic boiler superheater and heat exchanger seamless steel tube while grade P91 specified in ASTM A335 do Ferritic and alloy seamless steel tube intended for high-temperature service. Grade T91 and P91 steel pipes have a similar chemical composition and mechanical properties. As for their difference, we can say that they have been substituted for another one when the same purpose.

What is the material of T91 tube?

The SA 213 T91 Tube is composed with a chemical composition of chromium, carbon, manganese, nickel, silicon molybdenum, nitrogen, and a few other trace elements. These tubes possess excellent corrosion and oxidation resistance properties due to the SA213 T91 material used in their production.

What is the standard specification of ASTM A213 tubing?

ASTM A213 tubing sizes and thicknesses usually furnished to this specification are 1⁄8 in. [3.2 mm] in inside diameter to 5 in. [127 mm] in outside diameter and 0.015 to 0.500 in. [0.4 to 12.7 mm], inclusive, in minimum wall thickness or, if specified in the order, average wall thickness.

What is ASTM A213 material?

What Is ASTM A213 / ASME SA213 Tubing? ASTM A213 tubing is seamless ferritic steel and austennitic alloy SS (stainless steel) tubing used in boilers for super heaters, and heat exchangers. ASTM A213 is available in multiple grades.

What is the difference between P91 and T91 material?

P91 and T91 are both high-temperature ferritic-martensitic steels commonly used in power plant components like boilers, steam pipes, and pressure vessels. They have similar chemical compositions and mechanical properties, but there are some differences between the two materials.

1. Manufacturing process: P91 is a modified version of T91 steel. The manufacturing process of P91 involves more strict heat treatment techniques and stricter quality control measures compared to T91.
2. Strength: P91 steel has a higher yield strength and tensile strength compared to T91 steel. This makes P91 more suitable for high-pressure applications where strength is crucial.
3. Creep resistance: Both P91 and T91 exhibit excellent creep resistance at elevated temperatures. However, due to the modified manufacturing process, P91 has slightly better creep resistance than T91.
4. Fabricability: T91 steel has better fabricability compared to P91 steel. It is easier to weld and form T91 components compared to P91 components.
5. Cost: P91 steel is generally more expensive compared to T91 steel due to the additional manufacturing processes and quality control measures involved.

In summary, P91 and T91 are very similar materials with slight differences in terms of strength, creep resistance, fabricability, and cost. The choice between the two materials depends on the specific application requirements and cost considerations.

ASTM A213 T91 Alloy Steel Boiler Tubes PMI testing

ASTM A213 T91 Alloy Steel Boiler Tubes Equivalent Material

Chemical Composition of ASTM A213 T91 Alloy Steel Boiler Tubes

Mechanical properties of ASTM A213 T91 Alloy Steel Boiler Tubes

Heat Treatment of ASTM A213 T91 Alloy Steel Boiler Tubes

Note:

1. Heat treatment shall be carried out separately and in addition to heating for hot forming.
2. ASTM Grain Size No. listed, or coarser, unless otherwise indicated.

Application of ASTM A213 T91 Alloy Steel Boiler Tubes:

Allowable service temperature: ASTM A213 T91 alloy steel pipe is mainly used for manufacturing high temperature superheater, reheater and other pressure parts of subcritical and supercritical power plant boilers with metal wall temperature not exceeding 625 ° C, and also for pressure vessels and nuclear power high temperature pressure parts.

Application of T / P91 boiler pipe in petrochemical industry: T / P91 can be used to replace T / P22 and T / P5 tubes in distillation, cracking units and refineries because of its good high temperature mechanical properties and high temperature hydrogen resistance. Moreover, t / P91 is more suitable for boilers in sulfur rich environment than t / P22 and T / P5. Generally speaking, P91 pipe with pipe diameter greater than 168mm and T91 pipe with pipe diameter less than or equal to 168mm belong to the same steel type, and the requirements for chemical composition and mechanical properties are the same.

Related ASTM A213 T91 Alloy Steel Boiler Tubes

Scope

(A) Maximum, unless range or minimum is indicated. Where ellipses (...) appear in this table, there is no requirement, and analysis for the element need not be determined or reported.
(B) It is permissible to order T2 and T12 with a sulfur content of 0.045 max. See 16.3.
(C) Alternatively, in lieu of this ratio minimum, the material shall have a minimum hardness of 275 HV in the hardened condition, defined as after austenitizing and cooling to room temperature but prior to tempering. Hardness testing shall be performed at mid-thickness of the product. Hardness test frequency shall be two samples of product per heat treatment lot and the hardness testing results shall be reported on the material test report.
(D) The terms Niobium (Nb) and Columbium (Cb) are alternate names for the same element.
(A) Maximum, unless a range or minimum is indicated. Where ellipses (...) appear in this table, there is no minimum and analysis for the element need not be determined or reported.
(B) The method of analysis for Nitrogen shall be a matter of agreement between the purchaser and the producer.
(C) For these alloys, there is no common grade designation. The UNS number uniquely identifies these alloys.
(D) For small diameter or thin walls, or both, where many drawing passes are required, a carbon maximum of 0.040% is necessary in Grades TP304L, TP304LN, TP316L, and TP316LN.
(E) Grade S30434 shall have (Ti + 1/2 Nb) of not less than 2 times and not more than 4 times the carbon content.
(F) Grade TP347LN shall have an Nb content of not less than 15 times the carbon content.
(G) Grade TP348 shall have an Nb + Ta content of not less than 10 times the carbon content and not more than 1.10%.
(H) Grade TP348H shall have an Nb + Ta content of not less than 8 times the carbon content and not more than 1.10%.
(I) Iron shall be determined arithmetically by difference of 100 minus the sum of the other specified elements.
(J) Al + Ti shall be 0.85 % min; 1.20 % max.
(K) Grade TP444 shall have Ni + Cu = 1.00 max.
(L) Grade TP444 shall have Ti + Nb content not less than 0.20 + 4(C+N) and not more than 0.80 %.
(M) N08020 shall have an Nb + Ta content of not less than 8 times the carbon content and not more than 1.00%.
(N) The terms Niobium (Nb) and Columbium (Cb) are alternate names for the same element.

Grades containing the letter, H, in their designation, have requirements different from those of similar grades not containing the letter, H. These different requirements provide higher creep-rupture strength than normally achievable in similar grades without these different requirements.

The tubing sizes and thicknesses usually furnished to this specification are 1/8 in. [3.2 mm] in inside diameter to 5 in. [127 mm] in outside diameter and 0.015 to 0.500 in. [0.4 to 12.7 mm], inclusive, in minimum wall thickness or, if specified in the order, average wall thickness. Tubing having other diameters may be furnished, provided such tubes comply with all other requirements of this specification.

The values stated in either SI units or inch-pound units are to be regarded separately as standard. Within the text, the SI units are shown in brackets. The values stated in each system may not be exact equivalents; therefore, each system shall be used independently of the other. Combining values from the two systems may result in non-conformance with the standard. The inch-pound units shall apply unless the “M” designation of this specification is specified in the order.

Referenced Documents (purchase separately)

ASTM Standards

• A262 Practices for Detecting Susceptibility to Intergranular Attack in Austenitic Stainless Steels
• A941 Terminology Relating to Steel, Stainless Steel, Related Alloys, and Ferroalloys
• A1016/A1016M Specification for General Requirements for Ferritic Alloy Steel, Austenitic Alloy Steel, and Stainless Steel Tubes
• E112 Test Methods for Determining Average Grain Size

AWS Specifications

• A5.23/A5.23M Specification for Low-Alloy Steel Electrodes and Fluxes for Submerged Arc Welding
• A5.5/A5.5M

Terminology

Definitionx—For definitions of terms used in this speci- fication, refer to Terminology A 941.

Ordering Information

It shall be the responsibility of the purchaser to specify all requirements that are necessary for products under this specification. Such requirements to be considered include, but are not limited to, the following:

1.1 Quantity (feet, metres, or number of lengths),

1.2 Name of material (seamless tubes),

1.3 Grade (Tables 1 and 2),

1.4 Condition (hot finished or cold finished),

1.5 Controlled structural characteristics (see 6.3),

1.6 Size (outside diameter and minimum wall thickness, unless average wall thickness is specified),

1.7 Length (specific or random),

1.8 Hydrostatic Test or Nondestructive Electric Test (see 10.1),

1.9 Specification designation and year of issue,

1.10 Increased sulfur (for machinability, see Note B, Table 1, and 15.3), and

1.11 Special requirements and any supplementary require- ments selected.

General Requirements

Product furnished to this specification shall conform to the requirements of Specification A 1016/A 1016M, including any supplementary requirements that are indicated in the purchase order. Failure to comply with the general require- ments of Specification A 1016/A 1016M constitutes noncon- formance with this specification. In case of conflict between the requirements of this specification and Specification A 1016/ A 1016M, this specification shall prevail.

Materials and Manufacture

1 Manufacture and Condition—Tubes shall be made by the seamless process and shall be either hot finished or cold finished, as specified. Grade TP347HFG shall be cold finished.

Heat Treatment

1 Ferritic Alloy and Ferritic Stainlexx Steelx—The fer- ritic alloy and ferritic stainless steels shall be reheated for heat treatment in accordance with the requirements of Table 3. Heat treatment shall be carried out separately and in addition to heating for hot forming.

2 Auxtenitic Stainlexx Steelx—All austenitic tubes shall be furnished in the heat-treated condition, and shall be heat treated in accordance with the requirements of Table 3. Alter- natively, immediately after hot forming, while the temperature of the tubes is not less than the minimum solution treatment temperature specified in Table 3, tubes may be individually quenched in water or rapidly cooled by other means (direct quenched).

3 If any controlled structural characteristics are required, these shall be so specified in the order as to be a guide as to the most suitable heat treatment.

Heat Treatment and Grain Size Requirements^A

ASTM A213M-09 Material Comparison Tables

ASTM A213M-09 Mechanical properties

Note

A Maximum, unless range or minimum is indicated. Where ellipses (...) appear in this table, there is no requirement, and analysis for the element need not be determined or reported.

B It is permissible to order T2 and T12 with a sulfur content of 0.045 max. See 16.3.

C Alternatively, in lieu of this ratio minimum, the material shall have a minimum hardness of 275 HV in the hardened condition, defined as after austenitizing and cooling to room temperature but prior to tempering.

Hardness test frequency shall be two samples of product per heat treatment lot and the hardness testing results shall be reported on the material test report.

Material Comparison Tables (ASTM ℃KS, JIS, DIN, BS, NBN, NF, UNI)

A 213 - Seamless Alloy Steel Boiler and Heat Exchanger Tubes

Seamless tube processing

With years of expertise, we provide a diverse array of steel tube processing options. From sawing and machining tube blanks to intricate bending and upsetting operations, we actively assist you throughout your projects.

Our capabilities extend to eccentricity reduction and concentricity enhancement through turning and grinding. We excel in creating complex geometries using processes like rotary swaging and axial forming. Additionally, we offer property modifications via partial heat treatment, ensuring tailored solutions for your specific needs.

Variable wall thicknesses

Drilling / stamping / lasering

Peeling / roller burnishing

Cold forming

Cutting

Beveling

Deburring

Thread rolling / threading

Partial hardening

Turning / milling / grinding

Reducing / expanding

Delivery

Steel pipe delivery status(condition)

Steel pipe delivery status(condition): cold / hard (BK), cold / soft (BKW), after cold stress relief annealing (BKS), annealing (GBK), normalized (NBK).

Condition on delivery of steel pipe

Term	Symbol	Explanation
Cold-finished/hard (cold-finished as-drawn)	BK	No heat treatment after the last cold-forming process. The tubes therefore have only low deformability.
Cold-finished/soft (lightly cold-worked)	BKW	After the last heat treatment there is a light finishing pass (cold drawing) With proper subsequent processing, the tube can be cold-formed (e.g. bent, expanded) within certain limits.
Annealed	GBK	After the final cold-forming process the tubes are annealed in a controlled atmosphere or under vacuum.
Normalized	NBK	The tubes are annealed above the upper transformation point in a controlled atmosphere or under vacuum.

The general cold strip mills, volume should go through continuous annealing (CAPL unit) to eliminate cold hardening and rolling stress, or batch annealing reach the mechanical properties of the corresponding standard specifies. Cold rolled steel surface quality, appearance, dimensional accuracy better than hot-rolled plate, and right-rolled thin product thickness is about 0.18mm, so the majority of users favor.

Cold rolled steel coil substrate products deep processing of high value-added products. Such as electro-galvanized, hot dip galvanized, electro-galvanized fingerprint resistant, painted steel roll damping composite steel, PVC laminating steel plates, etc., so that the excellent quality of these products has a beautiful, high resistance to corrosion, has been widely used.

Cold rolled steel coil finishing after annealing, cut the head, tail, trimming, flattening, smooth, heavy volume, or longitudinal clipboard. Cold-rolled products are widely used in automobile manufacturing, household electrical appliances, instruments, switches, buildings, office furniture and other industries. Steel plate strapping package weight of 3 to 5 tons. Flat sub-volume typically 3 to 10 tons / volume. Coil diameter 6m.

Packing

Bare packing/bundle packing/crate packing/wooden protection at the both sides of tubes and suitably protected for sea-worthly delivery or as requested.

Placing steel pipes into containers

There are probably hundreds of different methods for packing a pipe, and most of them have merit, but there are two principles that are vital for any method to work prevent rusting and Sea transportation security.

• Plastic caps plugged at the two sides of pipe ends
• Should be avoided by the steel strapping and transport damage
• Bundled signs should be uniform and consistent
• The same bundle(batch) of steel pipe should be came from the same furnace.
• The steel pipe has the same furnace number, the same steel grade, the same specifications.

Our packing can meet any needs of the customers.

Our team of experienced sales specialists proudly partners with gas and chemical processors, power generation plants, oil refineries, and related industries to offer piping components and value-added services.

The most important and desired changes in alloy steel are

Alloy steels are made by combining carbon steel with one or several alloying elements, such as manganese, silicon, nickel, titanium, copper, chromium and aluminum. These metals are added to produce specific properties that are not found in regular carbon steel. The elements are added in varying proportions (or combinations) making the material take on different aspects such as increased hardness, increased corrosion resistance, increased strength, improved formability (ductility); the weldability can also change.

• Increased hardenability.
• Increased corrosion resistance.
• Retention of hardness and strength.
• Nearly all alloy steels require heat treatment in order to bring out their best properties.

Alloying Elements & Their Effects

• Chromium – Adds hardness. Increased toughness and wear resistance.
• Cobalt – Used in making cutting tools; improved Hot Hardness (or Red Hardness).
• Manganese – Increases surface hardness. Improves resistance to strain, hammering & shocks.
• Molybdenum – Increases strength. Improves resistance to shock and heat.
• Nickel – Increases strength & toughness. Improves corrosion resistance.
• Tungsten – Adds hardness and improves grain structure. Provides improved heat resistance.
• Vanadium – Increases strength, toughness and shock resistance. Improved corrosion resistance.
• Chromium-Vanadium – Greatly improved tensile strength. It is hard but easy to bend and cut.

Pipes, Tubes and Hollow Sections

Norms

• API 5L – Line Pipe
• ASTM A 53 – Black and Hot-Dipped, Zinc-Coated, Welded and Seamless, Steel Pipe
• ASTM A 106 – Seamless Carbon Steel Pipe for High-Temperature Service
• ASTM A 213 – Seamless Ferritic and Austenitic Alloy-Steel Boiler, Superheater, and Heat-Exchanger Tubes
• ASTM A 269 – Seamless and Welded Austenitic Stainless Steel Tubing for General Service
• ASTM A 312 – Seamless, Welded, and Heavily Cold Worked Austenitic Stainless Steel Pipes
• ASTM A 333 – Seamless and Welded Steel Pipe for Low-Temperature Service
• ASTM A 335 – Seamless Ferritic Alloy-Steel Pipe for High-Temperature Service
• ASTM A 358 – Electric-Fusion-Welded Austenitic Chromium-Nickel Stainless Steel Pipe for High-Temperature Service and General Applications
• ASTM A 671 – Electric-Fusion-Welded Steel Pipe for Atmospheric and Lower Temperatures
• ASTM A 672 – Electric-Fusion-Welded Steel Pipe for High-Pressure Service at Moderate Temperatures
• ASTM A 790 – Seamless and Welded Ferritic/Austenitic Stainless Steel Pipe
• ASTM A 928 – Ferritic/Austenitic (Duplex) Stainless Steel Pipe Electric Fusion Welded with Addition of Filler Metal
• EN 10208-2 – Steel pipes for pipelines for combustible fluids – Part 2: Pipes of requirement class B
• EN 10210-1/2 – Hot finished structural hollow sections of non-alloy and fine grain steels
• EN 10216-1 – Seamless steel tubes for pressure purposes – Part 1: Non-alloy steel tubes with specified room temperature properties
• EN 10216-2 – Seamless steel tubes for pressure purposes – Part 2: Non-alloy and alloy steel tubes with specified elevated temperature properties
• EN 10217-1 – Welded steel tubes for pressure purposes – Part 1: Non-alloy steel tubes with specified room temperature properties
• EN 10217-2 – Welded steel tubes for pressure purposes – Part 2: Electric welded non-alloy and alloy steel tubes with specified elevated temperature properties
• EN 10219-1/2 – Cold formed welded structural hollow sections of non-alloy and fine grain steels
• EN 10297-1 – Seamless circular steel tubes for mechanical and general engineering purposes – Part 1 Non-alloy and alloy steel tubes

Grade

• API 5L Gr. A, B, X42, X52, X60, X65, X70
• ASTM A 53 Gr. A, Gr. B
• ASTM A106 Gr. A, B, C
• ASTM A 213 TP 304, 304L, 304H, 316, 316L, 316H, 321, 321H, T5, T9, T11
• ASTM A 269 TP 304, 304L, 304H, 316, 316L, 316H, 321, 321H
• ASTM A 312 TP 304, 304L, 304H, 316, 316L, 316H, 321, 321H
• ASTM A 333 Gr. 3, Gr. 6 ASTM A 335 P1, P2, P5, P9, P11, P12, P22, P91, P92
• ASTM A 358 TP 304, 304L, 304H, 316, 316L, 316H, 321, 321H
• ASTM A 671 CC 60, CC 65, CC 70
• ASTM A 672 CC 60, CC 65, CC 70
• ASTM 790 UNS S31803, UNS S32205, UNS S32750, UNS S32760
• ASTM A928
• EN 10208-2 L245, L 290, L360
• EN 10210-1 S235 JRH, S275 JOH, S275 J2H, S355 JOH, S355 J2H
• EN 10216-1 P235 TR1/2
• EN 10216-2 P235 GH, P265 GH
• EN 10217-1 P235 TR1/2, P275 TR1/2
• EN 10217-2 P235 GH, P265 GH
• EN 10219-1 S235 JRH, S275 JOH, S275 J2H, S355 JOH, S355 J2H
• EN 10297-1 E235, E275, E315, E355, E470

Alloying Elements

Commonly used alloying elements and their effects are listed in the table given below.