ASTM A358 TP321H EFW pipes are electric fusion welded stainless steel pipes designed for high-temperature and corrosive environments. Made from titanium-stabilized 321H stainless steel (UNS S32109), they offer improved creep resistance, high-temperature strength, and excellent resistance to intergranular corrosion in power, petrochemical, and industrial applications.
What is ASTM A358 TP321H EFW Pipe?
ASTM A358 TP321H is a high-carbon, titanium-stabilized austenitic stainless steel pipe manufactured using the electric fusion welded (EFW) process.
Compared with standard 321:
- Higher carbon content → improved high-temperature strength
- Titanium stabilization → prevents intergranular corrosion
- Suitable for long-term high-temperature service
ASTM A358 / ASME SA358 Standard Overview
ASTM A358 covers electric-fusion-welded austenitic stainless steel pipes for:
- High-temperature service
- Corrosive environments
- General industrial applications
Available Grades:
- TP304 / 304L / 304H
- TP316 / 316L / 316Ti
- TP309S / 310S
- TP321 / 321H
- TP347 / 347H
Grade selection depends on temperature and corrosion conditions
ASTM A358 Pipe Classes (Class 1–5)
- Class 1: Double welded + full radiographic inspection
- Class 2: Double welded, no RT required
- Class 3: Single welded + full RT
- Class 4: Same as Class 3, internal weld may be autogenous
- Class 5: Double welded + spot RT
Higher class = stricter inspection and reliability
Product Specifications
- Material Grade: TP321H (UNS S32109)
- Standard: ASTM A358 / ASME SA358
- Process: EFW (Electric Fusion Welded)
- OD: 10.3 mm – 1219 mm
- Wall Thickness: 1.24 mm – 59.54 mm
- Length: 6 m or customized
Pipe Ends
- Plain End
- Beveled End
- Threaded End
Chemical Composition – 321H Stainless Steel (%)
| Element | Content |
|---|---|
| C | 0.04 – 0.10 |
| Mn | ≤ 2.00 |
| Si | ≤ 0.75 |
| P | ≤ 0.045 |
| S | ≤ 0.030 |
| Cr | 17.0 – 19.0 |
| Ni | 9.0 – 12.0 |
| Ti | ≥ 4(C+N) |
Titanium stabilizes the structure and prevents carbide precipitation
Mechanical Properties
- Tensile Strength: ≥ 515 MPa
- Yield Strength: ≥ 205 MPa
- Elongation: ≥ 40%
- Hardness: ≤ 95 HRB
Grain size requirement: ASTM No.7 or coarser (high-temp performance)
Physical Properties
| Property | Value |
|---|---|
| Density | 8027 kg/m³ |
| Elastic Modulus | 193 GPa |
| Thermal Expansion | 16.6 µm/m/°C |
| Thermal Conductivity | 16.1 W/m·K |
| Specific Heat | 500 J/kg·K |
Advantages of TP321H EFW Pipes
- Excellent high-temperature strength
- Strong creep resistance
- Superior resistance to intergranular corrosion
- Good weldability
- Long service life in harsh environments
Applications of ASTM A358 TP321H Pipes
Power Plants
- Superheater tubes
- Boiler piping
- Steam pipelines
Petrochemical Industry
- Process piping
- Heat exchangers
- Refinery systems
Oil & Gas
- High-temperature pipelines
- Offshore processing systems
Industrial Equipment
- Pressure vessels
- Furnace piping
- Chemical plants
Summary of ASTM A358 TP321H Pipes
- Standard: ASTM A358 / ASME SA358
- Grade: TP321H (UNS S32109)
- Process: EFW
- Feature: High-temp strength + corrosion resistance
- Application: Power, petrochemical, oil & gas
FAQ: ASTM A358 TP321H Pipes
Q1: What is ASTM A358 TP321H pipe used for?
Used in high-temperature and corrosive environments such as power plants and refineries.
Q2: What is the difference between 321 and 321H?
321H has higher carbon content, providing better high-temperature strength.
Q3: What is EFW pipe?
EFW (Electric Fusion Welded) pipe is produced by melting the edges and welding them together, suitable for thick-wall and high-performance applications.
Q4: What temperature can TP321H handle?
Suitable for elevated temperatures, typically up to 800°C depending on service conditions.
How to Order ASTM A358 TP321H Pipes
Example:
ASTM A358 TP321H EFW Pipe, NPS 10, SCH 40S, BE, Length 6m
Required Information:
- Standard (ASTM / ASME)
- Grade (TP321H)
- Size (NPS / OD)
- Wall thickness
- Pipe class (1–5)
- End type
Related Products
ASTM A312 TP321 Seamless Pipes
ASTM A358 TP347H Pipes
All pipes can be supplied with EN 10204 3.1 Mill Test Certificate (MTC) and seaworthy export packaging.
