Product Introduction
ASTM A358 TP321 Class 1 EFW Stainless Steel Pipe
ASTM A358 TP321 Class 1 EFW (Electric Fusion Welded) Stainless Steel Pipe is manufactured from stabilized austenitic stainless steel containing titanium additions to improve resistance to intergranular corrosion at elevated temperatures. The material is designed for high-temperature pressure service where long-term thermal stability and oxidation resistance are required.
Produced according to ASTM A358 / ASME SA358 specifications, TP321 EFW pipe is widely used in petrochemical plants, refinery units, power generation facilities, heat recovery systems, and process piping exposed to temperatures ranging from 425°C to 900°C. The electric fusion welding process enables the production of large-diameter pipes while maintaining structural integrity and dimensional consistency.
Technical Specifications
| Item |
Specification |
| Standard |
ASTM A358 / ASME SA358 |
| Material Grade |
TP321 / UNS S32100 |
| Pipe Type |
Electric Fusion Welded (EFW) |
| Class |
Class 1 |
| Manufacturing Process |
Electric Fusion Welding |
| Outside Diameter |
1/8" – 64" NB |
| Wall Thickness |
SCH 5S – SCH XXS |
| Length |
Random Length / Fixed Length |
| Inspection |
UT, RT, HT, PMI Available |
| Surface Finish |
Pickled, Passivated |
| Certification |
EN10204 3.1 / Third Party Inspection |
Product Advantages
Why Choose TP321 EFW Stainless Steel Pipe?
- High Temperature Stability
Titanium stabilization minimizes carbide precipitation and improves resistance to intergranular corrosion after prolonged exposure to elevated temperatures.
- Suitable for Large Diameter Fabrication
The EFW manufacturing process allows production of large-diameter pipes up to 64 inches while maintaining weld quality and dimensional accuracy.
The chromium-nickel stainless steel composition provides reliable resistance to oxidation and process media in petrochemical environments.
UT, RT, HT, PMI and third-party inspection can be provided according to project requirements.
Main Features of UNS S32750 Super Duplex Stainless Steel
- UNS S32750 has excellent corrosion resistance in a wide variety of corrosive chemicals
- Outstanding resistance to pitting and crevice corrosion in seawater and other chloride containing environments, with Critical Pitting Temperature exceeding 50°C
- High strength compared to austenitic and 22%Cr duplex stainless steels
- Excellent ductility and impact strength at both ambient and sub-zero temperatures
- High resistance to abrasion, erosion and cavitation erosion
- Excellent resistance to stress corrosion cracking in chloride containing environments
- UNS S32750 is listed in NACE MR 01 75 for sour service
- ASME Approval for Pressure Vessel application
Duplex Stainless Steel Pipe Application:
- Chemical processing, Transport and Storage.
- Oil and gas exploration and offshore rigs.
- Oil and gas refining.
- Marine environments.
- Pollution control equipment.
- Pulp and paper manufacturing
- Chemical process Plant
Chemical Composition of A358 TP321
| Grade |
C
max
|
Si
max
|
Mn
max
|
P
max
|
S
max
|
Cr |
Ni |
Mo |
N |
| UNS S32750 |
0.030 |
0.8 |
1.2 |
0.030 |
0.015 |
24.0-26.0 |
6.0-8.0 |
3.0-5.0 |
0.24-0.32 |
| UNS S31803 |
0.030 |
1.0 |
2.0 |
0.020 |
0.020 |
21.0-23.0 |
4.5-6.5 |
2.5-3.5 |
0.08-0.20 |
| UNS S31500 |
0.030 |
1.0 |
1.2-2.0 |
0.030 |
0.030 |
18.0-19.0 |
4.5-5.5 |
2.5-3.5 |
0.05-0.10 |
Physical Properties of A358 TP321
| Grade |
Y.S.MPa min |
T.S.Mpa min |
Elongation % |
Hardness HRC |
| UNS S32750 |
550 |
800 |
15 |
20 |
| UNS S31803 |
450 |
620 |
25 |
20 |
| UNS S31500 |
440 |
630 |
30 |
20 |
Frequently Asked Questions
1. What is the difference between TP321 and TP304?
TP321 contains titanium stabilizing elements that improve resistance to intergranular corrosion under high-temperature service conditions.
2. What does Class 1 mean in ASTM A358?
Class 1 pipes are welded using filler metal without subsequent radiographic examination requirements specified for higher classes.
3. What industries use TP321 EFW pipes?
Petrochemical, refinery, power generation, heat exchanger manufacturing, and thermal processing industries.
4. Can TP321 EFW pipes be supplied with third-party inspection?
Yes. BV, SGS, TUV, DNV and other third-party inspections are commonly available.
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