Product Overview – Why TP321 Instead of 304 or 316?
When stainless steel piping operates continuously between 425°C and 900°C, chromium carbide precipitation can reduce corrosion resistance.
TP321 solves this problem by adding titanium, which stabilizes the structure and prevents sensitization.
This makes SS 321 seamless pipes suitable for thermal processing, exhaust systems, and refinery piping.
Standard & International Identification -ASTM A312 TP321 Seamless Pipe
Standard
ASTM A312 / ASME SA312
Grade
TP321
UNS
S32100
EN
1.4541
Technical Specifications – ASTM A312 TP321 Seamless Pipe
| Manufacturing Type : | Seamless |
| Available Sizes: | 1/8″ NB to 24″ NB |
| Wall Thickness: | SCH 5S to SCH XXS |
| Pipe Length: | 6m, 12m, Custom Length |
| End Type : | Plain End (PE), Beveled End (BE) |
| Testing : | Hydrostatic Test, PMI,NDT |
| Certification : | EN 10204 3.1 / 3.2 MTC |
| Dimensional compliance: | ASME B36.19M. |
All specifications are in accordance of ASTM A312 / ASME SA312 standards. Mechanical and chemical values are as per standard limits. Mill Test Certificates (MTC) available upon request.
Chemical Composition of ASTM A312 TP321 Seamless Pipe
(As per ASTM specification)
| Element | Max (%) |
|---|---|
| Carbon (C) | 0.08% |
| Manganese (Mn) | 2.00 % |
| Silicon (Si) | 1.00 % |
| Phosphorus (P) | 0.045 % |
| Sulfur (S) | 0.030 % |
| Chromium (Cr) | 17.0 – 19.0 % |
| Nickel (Ni) | 9.0 – 12.0 % |
| Titanium (Ti): | Minimum 5 × Carbon content |
| Iron (Fe) | Balance |
Note: Titanium binds carbon to prevent chromium depletion at grain boundaries.
Mechanical Properties of SS 321 Seamless Pipes
| Property | Minimum Value |
|---|---|
| Tensile Strength | ≥ 515 MPa |
| Yield Strength | ≥ 205 MPa |
| Elongation | ≥ 35% |
Performance Characteristics of SS 321 Seamless Pipes
SS 321 seamless pipes provide:
🔸 Improved resistance to intergranular corrosion
🔸 Better structural stability during continuous high temperature exposure
🔸 Good oxidation resistance up to approximately 870°C
🔸 Suitable for thermal cycling applications
This is why TP321 is preferred over 304 in elevated temperature service.
Applications of ASTM A312 SS TP 321 Seamless Pipes
- 🔸Refinery piping systems
- 🔸Aircraft exhaust manifolds
- 🔸Petrochemical pipelines
- 🔸Heat exchangers
- 🔸Boiler components
- 🔸Thermal processing equipment
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Commercial Section – For Buyers
If your project involves high temperature processing or continuous heat exposure, selecting the correct stainless steel grade is critical to prevent long-term corrosion failures.
We supply ASTM A312 TP321 seamless stainless steel pipes from Mumbai with full MTC certification and project-ready stock availability.
We supply ASTM A312 TP321 seamless stainless steel pipes from Mumbai with full MTC certification and project-ready stock availability.