ASTM A249 TP321H Welded Austenitic Steel Boiler Superheater Heat Exchanger Tube

Shaanxi Shangyou Stainless Steel Co., Ltd. supplies ASTM A249 TP321H welded austenitic steel tubes for global boiler manufacturers, power generation equipment fabricators, heat exchanger producers, and EPC contractors requiring titanium-stabilized, high-carbon tubing with enhanced creep resistance at sustained elevated temperatures. Produced to ASTM A249/A249M, this specification covers nominal-wall-thickness welded tubes and heavily cold worked welded tubes made from austenitic steels for boiler, superheater, heat exchanger, or condenser applications.

ASTM A249 is the standard specification for welded austenitic steel tubes intended for heat transfer service. TP321H (UNS S32109) is a high-carbon modification of TP321, with carbon content controlled to 0.04-0.10% and titanium stabilization (Ti ≥4×(C+N)% up to max 0.70%), specifically intended for high-temperature service such as for superheaters and reheaters. The higher carbon content provides enhanced creep and stress-rupture performance at sustained elevated temperatures, while titanium stabilization prevents chromium carbide precipitation in the heat-affected zone during welding, preserving intergranular corrosion resistance without post-weld heat treatment. The tubing is manufactured from flat-rolled stock by an automatic welding process and is furnished in the heat-treated condition. The specification covers sizes from 1/8 in. [3.2 mm] inside diameter to 12 in. [304.8 mm] outside diameter and wall thicknesses from 0.015 to 0.320 in. [0.4 to 8.1 mm].

ASTM A249 TP321H welded tubes are specified for sustained high-temperature heat-transfer service where creep resistance and intergranular corrosion stability are critical.

Typical applications include:

• Boiler tubes and waterwall panels in power generation
• Superheater and reheater tubes in steam systems
• Heat exchanger tubes in refinery and petrochemical plants
• Condenser tubes in high-temperature service
• Furnace internals and tube hangers
• Waste heat recovery units
• Chemical processing equipment at elevated temperatures

Key selection considerations: Choose TP321H over standard TP321 when the service temperature exceeds ~800°F (427°C) and creep/rupture properties are important—the H-grade's controlled higher carbon content (0.04-0.10%) provides deliberate carbide strengthening that improves high-temperature load-bearing capacity. Titanium stabilization (≥4× carbon content) prevents chromium carbide precipitation in the heat-affected zone, preserving intergranular corrosion resistance in the 425-815°C service range without requiring post-weld heat treatment. The heat-treated condition is mandatory for all tubes under A249. The grain size of TP321H shall be determined in accordance with test methods.

Shangyou Stainless Steel provides value-added processing including custom cutting, beveling, and end protection.

All tubes are packed with export-standard protection including protective end caps, steel strapping, waterproof wrapping, and wooden pallets or steel frames.

Quality documents include MTC 3.1, inspection reports, packing list, and heat number traceability. Third-party inspection (SGS, TUV, BV) can be arranged upon request.

ASTM A249 is the standard specification for welded austenitic steel tubes for boiler, superheater, heat exchanger, or condenser service.

UNS S32109.

Cr 17.0-19.0%, Ni 9.0-12.0%, C 0.04-0.10%, Ti ≥4×(C+N)% (max 0.70%), Fe Balance.

Tensile ≥515 MPa, Yield ≥205 MPa, Elongation ≥35%.

TP321 has max 0.08% carbon; TP321H has 0.04-0.10% carbon. TP321H is specifically intended for high-temperature service where creep and stress rupture properties are important.

1/8 in. [3.2 mm] inside diameter to 12 in. [304.8 mm] outside diameter, with wall thickness 0.015 to 0.320 in. [0.4 to 8.1 mm].

Yes, all material must be furnished in the heat-treated condition.

1100°C (cold-finished), followed by rapid quench.

Titanium stabilizes the alloy by binding carbon, preventing chromium carbide precipitation (sensitization) in the heat-affected zone during welding.

Boilers, superheaters, reheaters, heat exchangers, condensers, power generation, and refinery heaters.

Need ASTM A249 TP321H welded tubes for boiler, superheater, or heat exchanger applications at elevated temperatures? Send requirements including grade, OD/wall thickness/length, quantity, and intended service temperature.

Shangyou Stainless Steel provides custom sizes, processing, and export solutions for global B2B customers.