Application of TP347HFG Seamless Steel tube
Overview
TP347HFG stainless steel tube is widely used in petroleum, chemical, power and other industries. Its performance and quality control are of great importance. This article provides a detailed introduction to its performance characteristics, quality control and welding process, offering a comprehensive understanding of this advanced material.
As a high-alloy austenitic stainless steel, it exhibits excellent corrosion resistance, high-temperature performance and mechanical properties, along with good strength and toughness at room temperature, as well as favorable formability and weldability.
Standards & Dimensions
Product Standards: Seamless Ferritic and Austenitic Alloy Steel Tubes for Boilers, Superheaters and Heat Exchangers.
Specifications:
- Outer diameter 10 mm ~ 762 mm · flexible range
- Wall thickness 1 mm ~ 100 mm · customized
Chemical Composition (TP347H)
| Element | Mass fraction (%) |
|---|---|
| C | 0.06 ~ 0.10 |
| Si | ≤ 1.0 |
| Mn | ≤ 2.00 |
| P | ≤ 0.045 |
| S | ≤ 0.030 |
| Ni | 9.00 ~ 13.00 |
| Cr | 17.00 ~ 19.00 |
| Nb+Ta | 8×C ~ 1.0 |
🔬 Fine-tuned composition for high-temperature stability.
Mechanical Properties (Seamless)
| Property | Value |
|---|---|
| Tensile strength (MPa) | ≥550 |
| Yield strength (MPa) | ≥205 |
| Elongation (%) | ≥35 |
💪 Excellent ductility and strength at both room and elevated temperatures.
Performance Characteristics
TP347HFG stainless steel tube is a high-alloy austenitic stainless steel with excellent corrosion resistance, high-temperature performance and mechanical properties. It exhibits good strength and toughness at room temperature, as well as favorable formability and weldability. At elevated temperatures, TP347HFG stainless steel tube features outstanding thermal stability and creep resistance, and can maintain its mechanical properties and dimensional stability under long-term high-temperature service.
Heat Treatment (TP347HFG)
TP347HFG steel tubes are supplied in the solution-annealed condition. The production involves three processes:
Fine-grained structure significantly boosts performance.
Oxidation & Corrosion Resistance
🧪 steam oxidation Tests on fine-grained TP347HFG steel tubes at 650°C and 700°C in steam show that its steam oxidation resistance is significantly superior to conventional TP347H steel tube. The finer the grain size, the better the oxidation resistance. Under the same conditions, the oxidation corrosion depth is approximately half that of conventional TP347H.
⚱️ coal ash corrosion High-temperature corrosion resistance tests in coal ash environment using synthetic ash demonstrate that TP347HFG has high-temperature corrosion resistance equal to or better than conventional TP347H steel tube. Similarly, a finer grain size results in better high-temperature corrosion resistance.
Quality Control
Strict quality control is implemented during production to ensure the quality and reliability of TP347HFG stainless steel tube.
- Raw material quality – qualified raw materials with stable composition are selected and rigorously inspected.
- Advanced processing – advanced equipment and technology ensure dimensional accuracy and surface quality.
- Non-destructive testing – strict NDT guarantees internal soundness and defect-free quality.
- Final inspection & acceptance – finished tubes comply with relevant standards.
Welding Process
Welding is a critical process in the application of TP347HFG stainless steel tube, and its quality directly affects the overall performance and service life of the pipeline. Appropriate welding procedures and consumables shall be adopted to ensure that the mechanical properties and corrosion resistance of welded joints match those of the base metal.
Key welding controls:
- Welding parameters, travel speed and heat input shall be controlled to prevent overheating and welding defects.
- Strict post-weld inspection and testing to ensure welding quality and operational safety.
📊 TP347HFG vs. Conventional TP347H
| Property / Test | TP347HFG (fine grain) | Conventional TP347H |
|---|---|---|
| Steam oxidation depth (650°C) | ~0.12 mm (approx. half) | ~0.24 mm |
| High-temp corrosion (coal ash) | Equal or better | Baseline |
| Grain size | Fine (ASTM ≥ 7) | Coarser (ASTM 4~6) |
| Creep rupture strength | Superior | Standard |
📌 Finer grain size directly improves both oxidation and corrosion resistance. Under the same conditions, the oxidation corrosion depth is approximately half that of conventional TP347H.