Seamless Stainless Steel TP347 Tube
Distinguished by the strategic addition of Niobium (Columbium), our TP347 tubing prevents chromium carbide precipitation during prolonged exposure to temperatures in the 427°C - 816°C (800°F - 1500°F) range. This makes them indispensable for mission-critical applications in chemical reactors, high-pressure steam systems, and aerospace components. Through advanced cold-drawing and precise solution annealing, GZH ensures every tube maintains a uniform microstructure and optimized mechanical strength for demanding industrial media.
"While TP347 provides excellent corrosion resistance, we also offer TP347H (UNS S34709) with higher carbon content for superior creep strength in temperatures above 1000°F."
What Is a Seamless Stainless Steel TP347 Tube?
Stainless Steel TP347 Seamlesstube is a high-performance, precision-engineered tube crafted from a single, solid billet of a niobium-stabilized austenitic stainless steel alloy. Unlike welded tubes, it has no weld joint, ensuring superior structural integrity and reliability, especially under high-stress and high-temperature conditions. The"347"designation refers to a specific grade stabilized with niobium (also known as columbium). This stabilization prevents the formation of chromium carbide precipitates in the heat-affected zone of welded areas, which would otherwise lead to intergranular corrosion. This makes it an ideal choice for applications where the component will be exposed to temperatures in the carbide precipitation range of 800-1500°F (425-816°C).
Key Features and Advantages
Seamless TP347 Tube offer a unique combination of benefits that make them invaluable in demanding high-temperature environments:
Excellent High-Temperature Stability: The niobium stabilization prevents carbide precipitation, ensuring the material maintains its corrosion resistance and structural integrity even after being exposed to high temperatures.
Good Corrosion Resistance: It provides good resistance to a wide range of corrosive media, similar to standard 304 stainless steel.
High Pressure and Temperature Tolerance: The seamless construction and robust material allow the tube to safely handle high internal pressures and extreme temperatures.
High-Temperature Strength: It maintains good tensile and yield strength at elevated temperatures, providing reliable performance in a wide range of thermal applications.
Superior Weldability: The stabilized composition allows for excellent weldability without the need for post-weld annealing, simplifying fabrication.
Product Specifications and Data
To provide a comprehensive overview of this high-performance material, here are the detailed technical specifications and performance data for Stainless Steel 347.
Table 1: Chemical Composition of Stainless Steel 347
The composition of Stainless Steel 347 is carefully balanced to achieve its superior high-temperature stability and corrosion resistance.
Grade | C | Cr | Ni | Mn | P | S | Si | Other |
| 347 | ≤0.08 | 17.00-19.00 | 9.00-13.00 | ≤2.00 | ≤0.035 | ≤0.030 | ≤1.00 | Nb≥10*C% |
| 347H | 0.04-0.10 | 17.00-19.00 | 9.00-13.00 | ≤2.00 | ≤0.035 | ≤0.030 | ≤1.00 | Nb≥8*C% |
Note: The niobium content must be at least ten times the carbon content to ensure stabilization.
Table 2: Typical Mechanical Properties of Stainless Steel 347
Stainless Steel 347 is specifically designed to maintain its strength and shape in high-temperature, high-stress environments.
Grade | Yield strength ksi(MPa) | Tensile Strength ksi(MPa) | Elongation % | Hardness Brinell/Vickers | Hardness Rockwell |
| 347 | ≥30(205) | ≥75(515) | ≥35 | ≤192 HBW/200HV | ≤90HRB |
| 347H | ≥30(205) | ≥75(515) | ≥35 | ≤192 HBW/200HV | ≤90HRB |
Table 3: Typical Physical Properties of Stainless Steel 347
These physical properties highlight the material's ability to perform reliably under a wide range of conditions.
| Property | Value |
| Density | 8.0 g/cm³ |
| Melting Point | 1398 - 1454 °C |
| Thermal Expansion | 16.6 µm/m·°C (20-100°C) |
| Thermal Conductivity | 16.3 W/m·K (20°C) |
| Modulus of Elasticity | 193 GPa |
| Electrical Resistivity | 0.72 x 10⁻⁶ Ω·m (20°C) |
Table 4: The Standard of Stainless Steel Seamless Tube Size Tolerance Size Chart :
| Standard | OD(D) | Tolerance（MM) | Thickness(S) | Tolerance(MM) | Length | Tolerance | |
| MM | Common | High | MM | MM | |||
| EN 10216-5 HFD | 30≤D≤219.1（D2) | ±1.0% or ±0.5mm, whicever is the greater(取较大者) | T1, T≤4 | ±15% or ±0.6mm, whicever is the greater(取较大者) | L≤6M | +5/0 | |
| T2 | ±12.5% or ±0.4mm, whicever is the greater(取较大者) | ||||||
| 219.1≤D≤610 (D1) | ±1.5% or ±0.75mm, whicever is the greater (取较大者) | T≤0.05D | +22.5%/-15% | 6 | +10/0 | ||
| T1, 0.05D | ±15% or ±0.6mm, whicever is the greater(取较大者) | ||||||
| T2, T>0.09D | ±12.5% or ±0.4mm, whicever is the greater(取较大者) | L>12 | +by agreement/0 | ||||
| EN 10216-5 CFD | D3(D≤219.1) | ±0.75% or ±0.3mm, whicever is the greater(取较大者) | T3 | ±10% or ±0.2mm, whicever is the greater(取较大者) | |||
| D4(D≤219.1) | ±0.5% or ±0.mm, whicever is the greater(取较大者) | T4 | ±7.5% or ±0.15mm, whicever is the greater(取较大者) | ||||
| ASTM A213 HFD | D≤100 | +0.4/-0.8 | D<100,S≤2.4 | +40%/0 | HFD, all size | +5.0/0 | |
| +0.4/-1.2 | D<100,2.4 | +35%/0 | |||||
| +0.4/-1.6 | D<100,3.8 | +33%/0 | |||||
| D<100,S>4.6 | +28%/0 | ||||||
| 100 | +0.4/-1.2 | D>100, 2.4 | +35%/0 | ||||
| 200 | +0.4/-1.6 | D>100,3.8 | +33%/0 | ||||
| D>100,S>4.6 | +28%/0 | ||||||
| ASTM A213 CFD | D<25 | ±0.10 | D≤38.1 | +20%/0 | CFD, D<50.8 | +3.0/0 | |
| 25≤D≤40 | ±0.15 | ||||||
| 40 | ±0.20 | ||||||
| 50≤D<65 | ±0.25 | ||||||
| 65≤D<75 | ±0.30 | D>38.1 | +22%/0 | CFD, D≥50.8 | +5.0/0 | ||
| 75≤D≤100 | ±0.38 | ||||||
| 100 | +0.38/-0.64 | ||||||
| 200 | +0.38/-1.14 | ||||||
| ASTM A269 | D≤13 | ±0.13 | D≤13 | ±15% | D<38 | +3.2/0 | |
| 13 | ±0.13 | 13 | ±10% | ||||
| 38≤D<89 | ±0.25 | D>38 | +4.8/0 | ||||
| 89≤D<140 | ±0.38 | ||||||
| 140≤D<203 | ±0.76 | ||||||
| 203≤D<305 | ±1.01 | ||||||
| 305≤D<356 | ±1.26 | ||||||
| ASTM A270 | D<25 | ±0.13 | For weld pipe all size | ±12.5% | +3.0/0 | ||
| 25-50 | ±0.20 | ||||||
| 50-75 | ±0.25 | ||||||
| 75-100 | ±0.38 | For CD SMLS pipe D≤38.1 | +20%/0 | ||||
| 100-140 | ±0.38 | +5.0/0 | |||||
| 140-200 | ±0.75 | For CD SMLS pipe D>38.1 | +22%/0 | ||||
| 200-300 | ±1.25 | ||||||
Common Applications
The combination of high-temperature stability and excellent corrosion resistance of TP347 Stainless Steel Tube makes them a preferred choice for:
Power Generation: Used in superheater and reheater tubes for boilers.
Aerospace: In jet engine components, exhaust manifold tubing, and high-temperature fasteners.
Chemical and Petrochemical Processing: For furnace parts, heat exchangers, and expansion joints where temperatures are in the carbide precipitation range.
Waste Incineration: For components in waste incinerators and combustion chambers.
Manufacturing Process
The manufacturing of a Stainless Steel TP347 Seamless Tubes is a precise, multi-step process:
- Heating: A solid billet of Stainless Steel 347 is heated to a high temperature.
- Piercing: A piercing mill pushes a mandrel through the center of the heated billet to form a hollow shell.
- Drawing and Sizing: The hollow shell is then rolled and drawn to reduce its diameter and wall thickness to the desired dimensions.
- Heat Treatment: The tube is solution annealed to achieve its specified metallurgical properties and to ensure optimal performance.
- Finishing: The tube is cut to length, straightened, and subjected to rigorous testing to ensure it meets the highest standards for performance and reliability. This meticulous process ensures that every seamless Stainless Steel 347 tube is built to withstand the most extreme operating conditions
