High Frequency Welded Finned Tubes TP347H Base Tube & CS Fins for Boilers & Heaters

ASTM A376 TP347H Stainless Steel Base Tube with Carbon Steel High-Frequency Welded Finned Tube for HRSG Economizers and High-Temperature Waste Heat Recovery

In Heat Recovery Steam Generators (HRSG), utility boiler economizers, and high-temperature flue-gas waste heat recovery systems operating above 500–650 °C, operators encounter limited heat-transfer surface area, progressive fin loosening under thermal cycling, elevated contact resistance, and base-tube degradation from oxidation and creep. Our ASTM A376 TP347H seamless austenitic stainless steel base tube fitted with continuous carbon steel fins by high-frequency resistance welding provides a robust metallurgical bond that maintains thermal performance under cyclic high-temperature service while substantially increasing external surface area on the flue-gas side.

Product Structure – ASTM A376 TP347H Base Tube + Carbon Steel Fins with High-Frequency Welding Process

The tube comprises a seamless ASTM A376 TP347H (UNS S34709) austenitic stainless steel base tube with continuous solid carbon steel fin strip helically wound and continuously welded to the outer surface by high-frequency resistance welding (HFW).

The HFW process generates localized melting at the fin root and tube surface under controlled pressure, forming a continuous metallurgical bond without filler metal. This produces a high-integrity weld with excellent thermal conductivity, resistance to thermal shock, and long-term stability under vibration and temperature cycling typical of HRSG and boiler economizer duty.

Chemical Composition – ASTM A376 TP347H Base Tube and Carbon Steel Fin Material

Dimensional Range and Tolerance – ASTM A376 TP347H + CS High-Frequency Welded Finned Tube

Performance Advantages in HRSG and High-Temperature Flue-Gas Service

• Continuous metallurgical weld ensures near-zero contact resistance and eliminates the progressive fin detachment common with tension-wound or embedded designs under thermal cycling.
• TP347H base tube delivers superior creep strength, oxidation resistance, and resistance to intergranular corrosion at elevated temperatures (continuous service capability up to approximately 815–850 °C oxidation limit; pressure-part design governed by ASME allowable stresses).
• Carbon steel fins provide cost-effective surface-area enhancement on the flue-gas side while the stainless base tube handles high-pressure steam or process fluid.
• High bond strength withstands vibration, soot-blowing, and thermal shock typical of HRSG economizers and waste-heat boilers.
• Heat-transfer efficiency increased substantially versus bare tubes, enabling higher heat recovery within existing plot space and reduced tube-row count.

Application Focus – HRSG Economizers, Utility Boiler Waste Heat Recovery & Petrochemical High-Temperature Service

These ASTM A376 TP347H + carbon steel HFW finned tubes are specified for:

• Heat Recovery Steam Generator (HRSG) economizers and evaporators recovering gas-turbine exhaust heat
• Utility boiler economizers and air preheaters operating on high-temperature flue gas
• Waste-heat recovery units in petrochemical and refining plants
• High-temperature process heaters and convection sections where enhanced external heat transfer is required on the gas side

The product increases recoverable heat from high-temperature flue gas streams, improves overall plant thermal efficiency, and reduces the risk of base-tube failure from oxidation or creep while maintaining reliable fin attachment under cyclic service.

Packaging, Logistics & Commercial Terms

Tubes are packed in robust plywood cases or steel-frame wooden crates with internal supports and end protection to prevent fin deformation during ocean or overland transport. Export packing meets ISPM 15 requirements where applicable.

• MOQ: 200–500 kg or equivalent length (negotiable for prototype or small trial lots)
• Price Basis: FOB Chinese main ports (Shanghai, Ningbo, Tianjin, etc.)
• Lead Time: 35–60 days after order confirmation and receipt of deposit or L/C, depending on quantity, diameter, and fin configuration
• Payment: T/T or irrevocable L/C at sight

Certificates & Quality Control – ASTM A376 TP347H Material Traceability

Each shipment is supplied with:

• EN 10204 3.1 Mill Test Certificate covering chemical composition, mechanical properties, and heat treatment of the ASTM A376 TP347H base tube
• Dimensional inspection reports and weld integrity records
• Hydrostatic testing and/or non-destructive examination (eddy current, ultrasonic, or liquid penetrant) as specified
• ISO 9001 quality management system certification
• Optional third-party inspection (SGS, BV, Lloyd’s, etc.)