Seamless Stainless Steel TP321H Pipe
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 pipes are indispensable for mission-critical applications in superheater coils, power plant boilers, and high-temperature refinery infrastructure. Through advanced cold-drawing and precise solution annealing, GZH guarantees a uniform grain structure and maximum durability for demanding thermal cycling conditions.
What Is a Seamless Stainless Steel TP321H Pipe?
TP321H SeamlessStainlesssteel pipe is a cylindrical tube crafted from a single, solid billet of stainless steel. Like other seamless products, it has no weld joint, which ensures superior structural integrity and reliability.
The"321H"designation signifies a high-carbon version of the 321 grade. The higher carbon content provides significantly improved creep rupture strength, which is crucial for components that must endure continuous stress under extreme heat without deforming over time. This makes 321H a top choice for high-temperature structural applications. It retains the same excellent resistance to oxidation, scaling, and intergranular corrosion as the standard 321 grade, thanks to its titanium stabilization.
Key Features and Advantages
TP321H Stainless Steel seamless pipes offer a unique combination of benefits that make them invaluable in the most demanding industries:
Superior Creep Rupture Strength: The high carbon content is the primary differentiator, providing enhanced strength and resistance to deformation under sustained high temperatures. This is critical for long-term reliability.
Exceptional Resistance to Intergranular Corrosion: The titanium stabilization prevents carbide precipitation during welding and high-temperature service, ensuring the material retains its corrosion-fighting properties in all conditions.
Excellent High-Temperature Performance: It performs exceptionally well in temperatures up to 870°C (1600°F), with better high-temperature strength and creep resistance than the standard 321 grade.
High Pressure Tolerance: The seamless construction eliminates a potential weak point, allowing the pipe to safely handle high internal pressures, which is critical in many high-temperature processes.
Product Specifications and Data
To provide a comprehensive overview of this high-performance material, here are the detailed technical specifications and performance data for 321H stainless steel.
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 Pipe Size Tolerance Size Chart :
| Standard | OD(D) | Tolerance（MM) | Thickness(S) | Tolerance(MM) | Length | Tolerance | |
| MM | Common | High | MM | MM | |||
| ASTM A312 | D≤48.3 | +0.4/-0.8 | 10.3 | +20%-12.5% | +6.0/0 | ||
| 48.3 | ±0.8 | 88.9 | +22.5%/-12.5% | ||||
| 114.3 | +1.6/-0.8 | 88.9 | +15%/-12.5% | ||||
| 219.1 | +2.4/-0.8 | D≥508, t/D≤5%,SMLS | +22.5%/-12.5% | ||||
| 457.2 | +3.2/-0.8 | D≥508, t/D>5%,SMLS | +15%/-12.5% | ||||
| 660.4 | +4.0/-0.8 | D≥508, WELD | +17.5%/-12.5% | ||||
| 863.6 | +4.8/-0.8 | ||||||
| JIS 3459 Hot-Finished Smls Pipe | D＜50 | ±0.51 | S＜4 | ±0.5 | |||
| D≥50 | ±1.0% | S≥4 | ±12.5% | ||||
| JIS 3459 Cold-Finished | D＜30 | ±0.3 | S＜2 | ±0.2 | |||
| D≥30 | ±1.0% | S≥2 | ±10.0% | ||||
| JIS G3463 Hot-Finished Smls Pipe | 100 | +0.4/-0.8 | D＜100，S<2 | / | D<50, L<7M | +7/0 | |
| D＜100，2≤S<2.4 | +40%/0 | D<50,7< L<10M | +10/0 | ||||
| D＜100，2.4≤S<3.8 | +35%/0 | ||||||
| D＜100，3.8≤S<4.6 | +33%/0 | ||||||
| D＜100，4.6≤S | +28%/0 | D<50,10< L<13M | +13/0 | ||||
| 100≤D<120 | +0.4/-1.2 | D>100, S＜2 | / | ||||
| 120≤D<160 | D>100，2≤S<2.4 | / | D<50,13M< L | +15/0 | |||
| 160≤D<200 | +0.4/-1.8 | D>100，2.4≤S<3.8 | +35%/0 | ||||
| 200≤D | +0.4/-2.4 | D>100，3.8≤S<4.6 | +33%/0 | D>50,7< L<7M | +10/0 | ||
| D>100，4.6≤S | +28%/0 | ||||||
| JIS G3463 Cold-finished | <60 | +0.4/-0.8 | D<40, S<2.0 | +0.4/0 | |||
| 60≤D<80 | ±0.3 | D<40, S≥2.0 | +20%/0 | D>50,7< L<10M | +13/0 | ||
| 80≤D<100 | ±0.4 | D≥40 | +22%/0 | ||||
| 100≤D<120 | +0.4/-0.6 | ||||||
| 120≤D<160 | +0.4/-0.8 | D>50,10M< L | +15/0 | ||||
| 160≤D<200 | +0.4/-1.2 | ||||||
| 200≤D | +0.4/-1.6 | ||||||
| GB/T 14975 冷拔(扎)钢管 | D<12.7 | ±0.3 | ±0.1 | 所有壁厚，普通级PA | +12.5%/-10% | ||
| 12.7 | ±0.15 | ||||||
| 38.1 | ±0.4 | ±0.3 | |||||
| 88.9 | ±0.9% | ±0.4 | |||||
| 139.7 | ±0.8 | 所有壁厚，高级PC | ±10% | ||||
| 203.2 | ±1.1 | ||||||
| 219.1 | ±1.6 | ||||||
| D≥323.9 | ±0.5% | ||||||
| GB/T 14976 冷拔(轧)钢管 | 6 | ±0.2 | ±0.15 | S≤3 | ±12%(10% /0高级PC) | ||
| 10≤D<30 | ±0.2 | ±0.2 | |||||
| 30≤D<50 | ±0.2 | ±0.3 | S>3 | +12.5%/-10%(10%/0高级PC) | |||
| 50≤D<219 | 0.85% | 0.75% | |||||
| D>219 | 0.9% | 0.8% | Smin, all | +22%/0(+20%/0高级PC) | |||
Common Applications
The enhanced creep resistance of TP321H stainless steel seamless pipes makes them a preferred choice for:
Aerospace: Used in jet engine parts, exhaust manifolds, and afterburners where components must endure high temperatures and loads over extended periods.
Chemical Processing: In systems handling corrosive chemicals and gases at high temperatures under structural load.
Thermal Oxidizers and Boilers: For components that are exposed to high heat and corrosive conditions, such as boiler tubes and hangers.
Refineries: Used in piping for high-temperature and high-pressure applications.
Manufacturing Process
The manufacturing of a TP321H seamless pipe is a precise, multi-step process:
- Heating: A solid steel billet 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.
- Rolling and Sizing: The hollow shell is then rolled and drawn to reduce its diameter and wall thickness to the desired dimensions.
- Finishing: The pipe is cut to length, heat-treated, and subjected to finishing processes like pickling to achieve its final state.
This meticulous process ensures that every 321H seamless pipe meets the highest standards for performance and reliability in the most demanding applications.
