ASTM A213 T9 is a chromium-molybdenum alloy steel tube grade used for seamless boiler, superheater, and heat-exchanger service. In this product form, the T9 base tube is fitted with high-frequency welded fins to increase external surface area and improve gas-side heat transfer, making it a strong fit for economizer duty in high-temperature heat-recovery systems. ASTM A213 also defines typical tube supply sizes, chemical limits, mechanical requirements, and test expectations for this material family.

Common Applications

This product is commonly selected for boiler economizers, industrial boiler rear-end heat-recovery sections, waste heat recovery equipment, HRSG-related heat-transfer modules, and other high-temperature exchanger service where durable heat transfer and reliable tube strength are required. Because T9 is a Cr-Mo alloy grade with elevated high-temperature capability, it is especially suitable where flue-gas-side heat recovery and long service life are both priorities.

Key Benefits

High-temperature alloy base tube for demanding thermal service.
High-frequency welded fins for efficient and stable fin attachment.
Increased heat-transfer surface area for improved economizer performance.
Suitable for continuous service in boiler and heat-recovery environments.
Custom fin height, fin pitch, fin thickness, and bare-length design can be made to project requirements.

Inspection Methods

ASTM A213 requires each tube to be subjected to either a hydrostatic test or a nondestructive electric test, unless otherwise specified in the purchase order. The specification also includes tension testing, hardness testing, flattening tests, and flaring tests as part of tube qualification.

Size Range

Item	Typical ASTM A213 Supply Range
Base tube outside diameter	1/8 in to 5 in (3.2 mm to 127 mm)
Minimum wall thickness	0.015 in to 0.500 in (0.4 mm to 12.7 mm)
Length	Specific or random, by order
Other diameters	Can be furnished if they meet the other requirements of the specification

Note: The size range above refers to the ASTM A213 base tube supply range; the finned-tube geometry is typically customized for each project.

Chemical Composition of ASTM A213 T9

Element	Composition (%)
Carbon (C)	≤ 0.15
Manganese (Mn)	0.30–0.60
Phosphorus (P)	≤ 0.025
Sulfur (S)	≤ 0.025
Silicon (Si)	0.25–1.00
Chromium (Cr)	8.00–10.00
Molybdenum (Mo)	0.90–1.10

UNS designation: K90941.

Mechanical Properties of ASTM A213 T9

Property	Requirement
Tensile strength, min.	415 MPa (60 ksi)
Yield strength, min.	205 MPa (30 ksi)
Elongation, min.	30%

Tags:

Studded Tube

Solid Fin Tube

Serrated Finned tube

Embedded G Fin Tube

Extruded Fin Tube

Wound Fin Tube

Low Fin Tube

Square Fin Tube

Longitudinal Finned Tube

Enhanced Heat Transfer Tube

Fin Tube Support

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Heat Exchanger Tube

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Boiler Tube

Nickel Alloy Steel Boiler Tube

Stainless Steel Boiler Tube

Duplex Stainless Steel Boiler Tube

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Carbon Steel Boiler Tube

Fired Heater Parts

Baffle Plate

Tubesheet

Studded Tube

Solid Fin Tube

Serrated Finned tube

Embedded G Fin Tube

Extruded Fin Tube

Wound Fin Tube

Low Fin Tube

Square Fin Tube

Longitudinal Finned Tube

Enhanced Heat Transfer Tube

Fin Tube Support

Return Bend

Heat Exchanger Tube

Stainless Steel Heat Exchanger Tube

Duplex Stainless Steel Heat Exchanger Tube

Super Duplex Stainless Steel Heat Exchanger Tube

Nickel Alloy Steel Heat Exchanger Tube

Copper Alloy Steel Heat Exchanger Tube

Titanium Alloy Steel Heat Exchanger Tube

Alloy Steel Heat Exchanger Tube

U Bend Heat Exchanger Tube

Carbon Steel Heat Exchanger Tubes

Boiler Tube

Nickel Alloy Steel Boiler Tube

Stainless Steel Boiler Tube

Duplex Stainless Steel Boiler Tube

Alloy Steel Boiler Tube

Carbon Steel Boiler Tube

Fired Heater Parts

Baffle Plate

Tubesheet

products details

Studded Tube

Solid Fin Tube

Serrated Finned tube

Embedded G Fin Tube

Extruded Fin Tube

Wound Fin Tube

Low Fin Tube

Square Fin Tube

Longitudinal Finned Tube

Enhanced Heat Transfer Tube

Fin Tube Support

Return Bend

Heat Exchanger Tube

Stainless Steel Heat Exchanger Tube

Duplex Stainless Steel Heat Exchanger Tube

Super Duplex Stainless Steel Heat Exchanger Tube

Nickel Alloy Steel Heat Exchanger Tube