ASTM A312 TP347H HFW Serrated Finned Tube and SS Fins For Waste Heat Recovery Units
ASTM A312 TP347H HFW Serrated Finned Tube and SS Fins For Waste Heat Recovery Units
The ASTM A312 TP347H HFW Serrated Finned Tube represents the pinnacle of heat exchanger technology, combining high-strength stabilized
stainless steel with an advanced fin design to maximize thermal efficiency. This product is specifically engineered for demanding high-temperature applications where corrosion resistance, durability, and superior heat transfer are non-negotiable.
Utilizing High-Frequency Welding (HFW) technology, this tube integrates a stainless steel serrated fin onto a TP347H base tube. The result is a robust, high-performance component ideal for critical environments such as petrochemical furnaces, power generation boilers, and waste heat recovery units.
Here are some detailed breakdowns:
1. Base Tube: ASTM A312 TP347H
Chemical Composition (wt%, ASTM A312 Standard)
| Element | Min | Max | Notes |
| C | 0.04 | 0.10 | High carbon for elevated temperature strength |
| Cr | 17.0 | 19.0 | Corrosion & oxidation resistance |
| Ni | 9.0 | 13.0 | Stabilizes austenitic structure |
| Nb | ≥8×C% | 1.10 | Stabilizing element, prevents intergranular corrosion |
| Mn | — | 2.0 | — |
| Si | — | 1.0 | — |
| P | — | 0.045 | — |
| S | — | 0.030 | — |
| UNS No. | — | — | S34709 |
Mechanical Properties (Solution Annealed Condition)
| Property | Min Value | Unit |
| Tensile Strength | 515 | MPa |
| Yield Strength (0.2% Offset) | 205 | MPa |
| Elongation | 35 | % |
| Hardness (Typical) | ≤ 201 | HB |
2. Finned Type: HFW Serrated
Unlike solid continuous fins, serrated fins feature notches or segments cut into the fin strip before welding. This creates a "toothed" edge along the fin's surface
Function: This design serves two main purposes:
- Enhanced Heat Transfer: The serrations disrupt the boundary layer of air or gas flowing across the tube. By breaking up laminar flow and inducing turbulence, they significantly increase the convective heat transfer coefficient.
- Reduced Fouling: The segmented design allows for "self-cleaning" properties, preventing the buildup of dust, soot, or particulates that typically accumulate on solid fins
3. Fin’s Material: SS stainless steel
Benefit: Stainless steel fins maintain their structural integrity and oxidation resistance even when exposed to high exhaust gas temperatures or corrosive atmospheres.
4. Key Features & Benefits
| Feature | Technical Benefit | Commercial Benefit |
| High-Frequency Welded Bond | Zero contact resistance; metallurgical bond between fin and tube | Reliable performance under thermal cycling; no loosening of fins over time. |
| Serrated Fin Profile | Increased turbulence; higher heat transfer coefficient (up to 10-15% improvement over solid fins in some cases) | Smaller heat exchanger footprint required to achieve the same duty; material savings. |
| TP347H Stabilized Grade | High creep strength; resistance to intergranular corrosion at high temperatures | Extended service life in high-temperature furnaces and heaters; reduced downtime. |
| All-Stainless Construction | Uniform thermal expansion; superior oxidation resistance | Suitable for corrosive flue gases; eliminates galvanic corrosion risks. |
5. Applications
Due to its robust construction and high-temperature material properties, this product is best suited for:
- Fired Heaters & Furnaces: Specifically in the convection section where heat is recovered from flue gases.
- Steam Superheaters & Reheaters: In power plants and combined cycle facilities.
- Hydrocarbon Processing: Crude oil heaters, reformer furnaces, and hydrotreater units in refineries.
- Waste Heat Recovery Units (WHRU): Capturing energy from gas turbine exhaust or industrial process off-gases
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