Seamless Stainless Steel TP321 Pipe
Distinguished by the strategic addition of Titanium (Ti), our TP321 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 heat exchanger tubes, petrochemical refinery infrastructure, and power plant boilers. Through advanced cold-drawing and precise solution annealing, GZH ensures every pipe maintains a uniform microstructure and optimized mechanical strength for demanding thermal cycling conditions.
"For applications requiring higher creep resistance at temperatures above 1000°F, we recommend TP321H (UNS S32109) with optimized carbon content."
What Is a Seamless Stainless Steel TP321 Pipe?
Seamless Stainless Steel TP321 Pipe is a cylindrical tube crafted from a single, solid billet of stainless steel. Like other seamless products, it has no weld joint, ensuring maximum structural integrity and high-pressure ratings.
The"321"designation signifies an austenitic stainless steel stabilized with a titanium addition. While a low-carbon grade like 304L is excellent for preventing intergranular corrosion during welding, it can still be vulnerable to"sensitization"(carbide precipitation) if exposed to high temperatures for a long time. The titanium in 321 binds with carbon, preventing chromium from forming carbides at the grain boundaries. This stabilization ensures that the pipe maintains its superior corrosion resistance even after being exposed to high temperatures up to 870°C (1600°F).
Key Features and Advantages
Seamless TP321 Stainless Steel Pipe offer a unique combination of benefits that make them invaluable in demanding applications:
Exceptional Resistance to Intergranular Corrosion: The addition of titanium prevents carbide precipitation during welding and high-temperature service. This is the primary advantage, ensuring the material retains its corrosion-fighting properties in the weld zone and throughout its service life.
Superior High-Temperature Performance: It provides better high-temperature strength and creep resistance than 304 stainless steel, making it suitable for a wide range of thermal applications.
Excellent Corrosion Resistance: It offers good general corrosion resistance, similar to 304, in various atmospheric and chemical environments.
High Pressure Tolerance: The seamless construction provides a uniform, robust structure that safely handles high internal pressures.
Product Specifications and Data
To provide a comprehensive overview of this high-performance material, here are the detailed technical specifications and performance data for 321 stainless steel.
Table 1: Chemical Composition of Stainless Steel 321
The composition of Stainless Steel 321 is carefully balanced to achieve its superior high-temperature stability and corrosion resistance.
| Cr | Ni | P | S | Ti | Mn | Si | C |
| 17.00 - 19.00 | 9.00 - 12.00 | ≤ 0.045 | ≤ 0.030 | ≥ 5xC | ≤ 2.00 | ≤ 1.00 | ≤ 0.08 |
Note: The titanium content must be at least five times the carbon content to ensure stabilization.
Table 2: Typical Mechanical Properties of Stainless Steel 321
Stainless Steel 321 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 321
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 combination of superior corrosion resistance and high-temperature stability makes Seamless Stainless Steel TP321 Pipe a preferred choice for:
Aerospace: Used in jet engine parts, exhaust stacks, and manifolds due to its high-temperature strength.
Chemical Processing: In systems handling corrosive chemicals and gases at high temperatures.
Thermal Oxidizers and Boilers: For components that are exposed to high heat and corrosive conditions.
Food Processing: In environments where cleanliness is crucial and piping is exposed to heat.
Manufacturing Process
The manufacturing of a TP321 Stainless Steel 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 321 seamless pipe meets the highest standards for performance and reliability in the most demanding applications.
