Seamless Stainless Steel TP321H Tube
Distinguished by an optimized carbon content (0.04–0.10%) and strategic Titanium (Ti) stabilization, our TP321H tubing prevents sensitization and intergranular corrosion while maintaining enhanced mechanical properties at temperatures exceeding 538°C (1000°F). These tubes are indispensable for mission-critical applications in superheater coils, heat exchanger tubing, and high-pressure steam systems. Through advanced cold-drawing and precise solution annealing,GZH guarantees a uniform grain size and maximum durability for demanding thermal cycling conditions.
"The 'H' in TP321H stands for high carbon, which is specifically controlled to provide higher creep-rupture strength at temperatures above 1000°F (537°C) compared to standard TP321."
What Is a Seamless Stainless Steel TP321H Tube?
Seamless Stainless Steel TP321H Tube is a high-performance, precision-engineered tube crafted from a single, solid billet of a titanium-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"321H"designation refers to a specific grade that is a high-carbon version of Stainless Steel 321. This higher carbon content (0.04-0.10%) provides enhanced creep and stress-rupture properties at elevated temperatures, making it a preferred choice for applications where long-term high-temperature strength and stability are critical. Like Stainless Steel 321, it is stabilized with titanium to prevent the formation of chromium carbide precipitates and subsequent intergranular corrosion.
Key Features and Advantages
Seamless Stainless Steel 321H Tube offer a unique combination of benefits that make them invaluable in demanding high-temperature environments:
Excellent High-Temperature Strength: The higher carbon content provides superior creep and stress-rupture properties, ensuring long-term structural stability at temperatures exceeding 1100°F (593°C).
High-Temperature Stability: The titanium 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.
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 321H.
Table 1: Chemical Composition of Stainless Steel 321H
The composition of Stainless Steel 321H is carefully balanced to achieve its superior high-temperature strength and corrosion resistance.
| Cr | Ni | P | S | Ti | Mn | Si | C |
| 17.00 - 19.00 | 9.00 - 12.00 | ≤ 0.045 | ≤ 0.030 | ≥ 4xC | ≤ 2.00 | ≤ 1.00 | 0.04 - 0.10 |
Note: The titanium content must be at least four times the carbon content to ensure stabilization.
Table 2: Typical Mechanical Properties of Stainless Steel 321H
Stainless Steel 321H is specifically designed to maintain its strength and shape in high-temperature, high-stress environments.
| Property | Value (Annealed) |
| Tensile Strength | ≥ 515 MPa |
| Yield Strength | ≥ 205 MPa |
| Elongation | ≥ 40% |
| Hardness | ≤ 201 HBW |
Table 3: Typical Physical Properties of Stainless Steel 321H
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 strength and excellent corrosion resistance of Seamless Stainless Steel TP321H Tube makes them a preferred choice for:
Power Generation: Used in superheater and reheater tubes for boilers where long-term high-temperature stability is critical.
Aerospace: In jet engine components, afterburners, and exhaust manifold tubing.
Chemical and Petrochemical Processing: For furnace parts, heat exchangers, and expansion joints where temperatures are in the carbide precipitation range.
Heat Treating Industry: In muffles, retorts, and other furnace fixtures.
ManufacturingProcess
The manufacturing of a Seamless SS321H Tube is a precise, multi-step process:
- Heating: A solid billet of Stainless Steel 321H 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 at a high temperature to achieve the 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 321H tube is built to withstand the most extreme operating conditions
