ASTM A312 Tp321 Seamless Pipe & SS 321 Welded Tubes Manufacturer, Supplier, Exporter & Stockist in India
Amardeep Steel Centre LLP is a manufacturer, supplier, exporter, and stockist of Stainless Steel 321 Pipes & Tubes in India, operating from Mumbai with ready stock across the complete SS 321 product range. We supply ASTM A312 TP321 Seamless Pipe, SS 321 Welded Pipe, ERW Pipe, and EFW Pipe in sizes from ½" NB to 24" NB, schedules 5S through XXS, in round, square, rectangular, and custom forms.
Our inventory is sourced from India's leading mills as well as Japanese, Korean, and European producers including Outokumpu and Aperam, ensuring material traceability and consistent chemistry across every heat. Every supply comes with EN 10204 3.1 Mill Test Certificates as standard. IBR Form III-D certification, third-party inspection by Bureau Veritas, SGS, TUV, or Lloyds, and NABL-approved laboratory test reports are available on request.
We export SS 321 Pipe & Tube to the USA, UAE, Saudi Arabia, UK, Germany, Singapore, Australia, and 50+ countries on FOB, CIF, and CNF terms. Procurement engineers and project managers can request a confirmed price with lead time and documentation details by contacting our sales team directly.
What is Stainless Steel 321 Pipe?
Stainless Steel 321 Pipe is a titanium-stabilized austenitic stainless steel pipe belonging to the AISI 300 series. Its base composition 17–19% chromium and 9–12% nickel is similar to grade 304, but with one critical addition: titanium, present at a minimum of five times the combined carbon and nitrogen content (5×[C+N]), up to a maximum of 0.70%.
This titanium addition gives SS 321 a property that standard 304 and 316 do not possess: immunity to sensitization. When austenitic stainless steels are exposed to temperatures between 427°C and 816°C (800–1500°F) during welding, slow cooling, or sustained service carbon migrates to grain boundaries and combines with chromium to form chromium carbides (Cr₂₃C₆). The zones immediately surrounding these carbides become depleted of chromium below the 11% passive film threshold, leaving them vulnerable to intergranular corrosion. This is the failure mode known as sensitization or weld decay.
Titanium prevents this by bonding with available carbon before chromium can, forming stable titanium carbides instead. The chromium remains in solution, the passive film stays intact, and the material retains its full corrosion resistance — before and after welding, and throughout high-temperature service up to 870°C (1598°F).
Commercially, SS 321 pipe is produced in seamless form under ASTM A312 TP321 and ASTM A376, and in welded form under ASTM A312 and ASTM A358. It is also known as UNS S32100, DIN/WNR 1.4541, EN X6CrNiTi18-10, and JIS SUS 321 all referring to the same alloy under different standardization systems.
Stainless Steel 321 Pipe Specifications
|
Parameter |
Detail |
|
ASTM/ASME Standard |
ASTM A312 / ASME SA312 (seamless & welded austenitic pipe) ASTM A213 / ASME SA213 (seamless ferritic and austenitic alloy-steel tubes) ASTM A249 / ASME SA249 (welded austenitic steel boiler tubes) ASTM A269 / ASME SA269 (seamless and welded austenitic stainless steel tubing) ASTM A358 / ASME SA358 (electric fusion welded) ASTM A376 (seamless austenitic pipe for high temperature) ASTM A813 / A814 (single-seam welded austenitic) |
|
Dimensional Standard |
ANSI/ASME B36.19M, ANSI/ASME B36.10M |
|
Outside Diameter (Seamless) |
6.0 mm OD up to 323.8 mm OD (½" NB to 12" NPS) |
|
Outside Diameter (Welded / ERW) |
6.35 mm OD up to 914.4 mm OD (up to 24" NB ex-stock; up to 36" special order) |
|
Wall Thickness Range |
0.3 mm to 50 mm |
|
Schedule Range |
SCH 5S, SCH 10S, SCH 20S, SCH 40S, SCH 80S, SCH 160, XXS |
|
Pipe Types Available |
Seamless, ERW, Welded, EFW, CDW, LSAW, Fabricated |
|
Pipe Forms |
Round, Square, Rectangular, U-Shape, Coiled, Hydraulic, Pancake Coil, Hexagonal |
|
Length Options |
Single Random (4–7 m), Double Random (7–14 m), Cut Length |
|
End Types |
Plain End (PE), Beveled End (BE), Threaded End |
|
Surface Finish |
2B, No.1, No.4, No.8 Mirror, Polished, Electropolished, Bright Annealed, Annealed & Pickled |
|
Delivery Condition |
Annealed and Pickled, Bright Annealed, Cold Drawn, Polished |
|
Mill Origins Available |
Indian Mills, Japanese Mills, Korean Mills, European Mills (Outokumpu, Aperam, POSCO) |
|
HSN Code |
73044900 (seamless pipes and tubes), 73069090 (welded pipes and tubes) |
For dimensional weights and schedule thicknesses, use our Steel Weight Calculator or refer to the Pipe Dimension reference page.
Equivalent Grades of Stainless Steel 321 Pipe
|
Standard |
UNS No. |
ASTM |
Werkstoff Nr. |
EN / Euronorm |
JIS (Japanese) |
Swedish SS |
Old British BS |
|
SS 321 |
S32100 |
TP321 |
1.4541 |
X6CrNiTi18-10 |
SUS 321 |
2337 |
321S31 (58B, 58C) |
|
SS 321H |
S32109 |
TP321H |
1.4878 |
X6CrNiTi18-10 |
SUS 321H |
— |
321S51 |
SS 321 Pipe Chemical Composition (ASTM A312 TP321 / UNS S32100)
|
Element |
SS 321 (min) |
SS 321 (max) |
SS 321H (min) |
SS 321H (max) |
|
Carbon (C) |
— |
0.08% |
0.04% |
0.08% |
|
Manganese (Mn) |
— |
2.00% |
— |
2.00% |
|
Silicon (Si) |
— |
1.00% |
— |
0.75% |
|
Phosphorus (P) |
— |
0.045% |
— |
0.045% |
|
Sulphur (S) |
— |
0.030% |
— |
0.030% |
|
Chromium (Cr) |
17.0% |
19.0% |
17.0% |
19.0% |
|
Nickel (Ni) |
9.00% |
12.00% |
9.00% |
12.00% |
|
Nitrogen (N) |
— |
0.10% |
— |
0.10% |
|
Titanium (Ti) |
5×(C+N) min |
0.70% max |
5×(C+N) min |
0.70% max |
SS 321 Pipe Mechanical Properties
|
Property |
SS 321 |
SS 321H |
|
Tensile Strength (MPa min) |
515 |
515 |
|
Yield Strength 0.2% Proof (MPa min) |
205 |
205 |
|
Elongation in 50mm (% min) |
40% |
35% |
|
Hardness Rockwell B (max) |
95 HRB |
95 HRB |
|
Hardness Brinell (max) |
217 HB |
217 HB |
Physical Properties of SS 321 Pipe (Grade 321)
Stainless steel 316 pipe prices in India vary by size, schedule, manufacturing process (seamless vs. welded), surface finish, and order quantity.
|
Property |
Value |
|
Density |
8027 kg/m³ (8.027 g/cm³) |
|
Melting Point |
1398–1454°C (2548–2650°F) |
|
Elastic Modulus |
193 GPa |
|
Mean Thermal Expansion (0–100°C) |
16.6 µm/m·°C |
|
Mean Thermal Expansion (0–315°C) |
17.2 µm/m·°C |
|
Mean Thermal Expansion (0–538°C) |
18.6 µm/m·°C |
|
Thermal Conductivity at 100°C |
16.1 W/m·K |
|
Thermal Conductivity at 500°C |
22.2 W/m·K |
|
Electrical Resistivity |
720 nΩ·m |
|
Specific Heat (0–100°C) |
500 J/kg·K |
Why Titanium Stabilization Matters in SS 321 Pipe
The core engineering advantage of 321 stainless steel pipe over standard 304 or 316 is its resistance to a failure mechanism called sensitization. When any austenitic stainless steel is held or slowly cooled through the temperature range of 427–816°C (800–1500°F) — as happens during welding or high-temperature service — carbon atoms diffuse through the grain structure and combine with chromium at grain boundaries to form chromium carbides (Cr₂₃C₆).
This depletion of chromium from the areas immediately adjacent to grain boundaries reduces their chromium content below the 11% threshold needed for passive film formation. The result is a network of chromium-depleted zones running through the material that are highly susceptible to intergranular corrosion — sometimes called weld decay or knife-line attack. In pipework this causes catastrophic failure that is invisible from the surface.
Titanium solves this problem by acting as a carbon getter. With a higher affinity for carbon than chromium has, titanium preferentially bonds with available carbon at elevated temperatures to form titanium carbides (TiC), leaving chromium free to maintain the protective passive film throughout the grain structure. The ASTM specification a312 tp321 requires titanium at a minimum of 5 times the carbon and nitrogen content (5×[C+N]) to ensure complete stabilization, up to a maximum of 0.70%.
For standard 304 pipe performance data, see our Stainless Steel 304 Pipes & Tubes page.
321 vs 321H Stainless Steel — Key Differences
Buyers choosing between tp321 material and TP321H should understand that both share the same base composition but differ significantly in high-temperature performance:
|
Property |
SS 321 |
SS 321H |
|
Carbon Content |
0.08% max |
0.04–0.08% (controlled range) |
|
Grain Size Requirement |
None |
ASTM No. 7 or coarser |
|
Creep Strength |
Standard |
Superior (higher C + coarse grain) |
|
Best for temperatures above |
538°C (1000°F) |
593°C (1100°F) sustained |
|
Typical applications |
Heat exchangers, food processing, exhaust systems |
Superheater tubes, power boilers, pressure vessels |
|
ASTM Spec (pipe) |
A312 TP321 |
A312 TP321H |
|
Price |
Standard |
Premium (10–15% typically) |
For sustained elevated-temperature service in boilers and power plants, see Stainless Steel 321H Pipes & Tubes.
321 vs 316 Stainless Steel Pipe — Key Differences
|
Property |
SS 321 |
SS 316 |
|
Stabilizer |
Titanium (Ti) |
Molybdenum (Mo, 2–3%) |
|
High-temperature performance |
Superior (sensitization resistant) |
Good to ~760°C; sensitizes above |
|
Pitting / crevice corrosion |
Good |
Excellent (Mo provides superior Cl⁻ resistance) |
|
Marine environments |
Good |
Preferred (higher Mo content) |
|
Post-weld service |
Preferred (no PWHT needed) |
Requires solution annealing for sensitized service |
|
Cost |
Moderate |
Higher (Mo is expensive) |
|
Density |
7.9 g/cm³ |
7.8 g/cm³ |
For applications where chloride pitting resistance is the primary concern, see our Stainless Steel 316 Pipes & Tubes or Stainless Steel 316H Pipes & Tubes.
Types of Stainless Steel 321 Pipes & Tubes
Stainless Steel 321 Pipes & Tubes are manufactured in a wide range of types, each suited to specific pressure requirements, temperature conditions, dimensional tolerances, and end-use applications. All of the following types are available from Amardeep Steel Centre in Mumbai.
- SS 321 Seamless Pipe
- SS 321 Welded Pipe
- 321 ERW Pipe
- 321 EFW Pipe
- SS 321 CDW Tube
- 321 Square Tube
- 321 Rectangular Tube
- SS 321 Coiled Tube
- 321 U-Bend Tube
- SS 321 Capillary Tube
- SS 321 Boiler Tube
- 321 Heat Exchanger Tube
- SS 321 Sanitary Tube
- 321 Electropolished Pipe
- SS 321 Mirror Polished Pipe
- 321 Hydraulic Tube
- SS 321 Bright Annealed Tube
- 321 Ornamental Tube
- 321 Finned Tube
- SS 321 Handrail Tube
SS 321 Pipe Dimensions & Weight Chart (ASME B36.19M)
|
NPS |
OD (mm) |
Sch 5S WT (mm) |
Sch 10S WT (mm) |
Sch 40S WT (mm) |
Sch 80S WT (mm) |
Sch 160 WT (mm) |
XXS WT (mm) |
|
1/2" |
21.3 |
1.65 |
2.11 |
2.77 |
3.73 |
4.75 |
7.47 |
|
3/4" |
26.7 |
1.65 |
2.11 |
2.87 |
3.91 |
5.56 |
7.82 |
|
1" |
33.4 |
1.65 |
2.77 |
3.38 |
4.55 |
6.35 |
9.09 |
|
1¼" |
42.2 |
1.65 |
2.77 |
3.56 |
4.85 |
6.35 |
9.70 |
|
1½" |
48.3 |
1.65 |
2.77 |
3.68 |
5.08 |
7.14 |
11.10 |
|
2" |
60.3 |
1.65 |
2.77 |
3.91 |
5.54 |
8.74 |
11.07 |
|
2½" |
73.0 |
2.11 |
3.05 |
5.16 |
7.01 |
9.53 |
14.02 |
|
3" |
88.9 |
2.11 |
3.05 |
5.49 |
7.62 |
11.10 |
15.24 |
|
4" |
114.3 |
2.11 |
3.05 |
6.02 |
8.56 |
13.49 |
17.12 |
|
6" |
168.3 |
2.77 |
3.40 |
7.11 |
10.97 |
18.25 |
21.95 |
|
8" |
219.1 |
2.77 |
3.76 |
8.18 |
12.70 |
23.01 |
22.23 |
|
10" |
273.1 |
3.40 |
4.19 |
9.27 |
12.70 |
28.58 |
25.40 |
|
12" |
323.9 |
3.96 |
4.57 |
9.53 |
12.70 |
33.32 |
25.40 |
For Schedule 40 and Schedule 80 wall thickness and weight data, see our dedicated schedule pages. Use our Steel Weight Calculator to compute pipe weight per metre for any size and schedule combination.
Heat Treatment of SS 321 Pipe
SS 321 pipe is an austenitic stainless steel that cannot be hardened by heat treatment. However, two heat treatment procedures are relevant to its performance:
Solution Annealing
Solution annealing is performed by heating the material to 1010–1120°C (1850–2050°F), typically at 1065°C (1949°F), followed by rapid quenching in water or air cooling. This dissolves any chromium carbides or sigma phase that may have formed during manufacturing or processing, and restores full corrosion resistance and ductility. As-supplied SS 321 pipe is normally delivered in the annealed and pickled condition.
Stress Relief Annealing
Stress relief at temperatures above 400°C (752°F) in sensitization range should be avoided unless full solution annealing follows. For cold-formed or cold-drawn components, partial stress relief below 400°C may be performed, though it has limited effect.
Hot Working / Hot Bending
Hot bending and forming operations should be performed in the range of 950–1100°C (1742–2012°F). Following any hot working operation, a full solution anneal should be carried out to ensure corrosion resistance is fully restored. This re-dissolves any titanium or chromium carbides that may have precipitated during the hot working operation.
Note: SS 321 pipe should not be subjected to prolonged heat in the 425–870°C range without subsequent solution annealing, as the titanium stabilization only prevents sensitization during rapid thermal cycles — it does not eliminate the risk entirely under prolonged high-temperature exposure above 870°C.
For the difference between annealing and tempering procedures, see our blog: Difference Between Annealing and Tempering.
Testing & Inspection of SS 321 Pipes & Tubes
All Stainless Steel 321 Pipe & Tube supplied by Amardeep Steel undergoes rigorous testing and inspection prior to dispatch. Available tests and documentation include:
|
Test Type |
Standard / Method |
Purpose |
|
Chemical Analysis |
OES / XRF Spectrometry |
Verify composition meets TP321 specification |
|
PMI (Positive Material Identification) |
XRF or OES handheld |
Confirm material grade at delivery |
|
Tensile / Yield Testing |
ASTM E8 / E21 |
Verify mechanical properties |
|
Hardness Test |
Rockwell B / Brinell |
Confirm hardness within spec (95 HRB max) |
|
Hydrostatic Test |
ASTM A312 requirements |
Pressure integrity of each pipe |
|
Ultrasonic Test (UT) |
ASTM E213 / EN 10246 |
Detect internal defects in seamless pipe |
|
Eddy Current Test (ECT) |
ASTM E426 |
Detect surface and near-surface defects |
|
Flattening Test |
ASTM A312 para. 13 |
Verify weld quality in welded pipes |
|
Reverse Flattening Test |
ASTM A312 |
Verify absence of laminations in welded seam |
|
Grain Size Determination |
ASTM E112 |
Required for TP321H to confirm ASTM No. 7 or coarser |
|
Intergranular Corrosion Test |
ASTM A262 Practice E |
Verify absence of sensitization |
|
Visual Inspection |
100% visual |
Surface finish, dimensional conformance |
|
Radiographic / X-Ray Test |
ASME IX (welds) |
Weld integrity for EFW pipe |
|
Third-Party Inspection (TPI) |
Bureau Veritas, SGS, TUV, Lloyds, Intertek |
Independent verification of test results on request |
SS 321 Pipe Price & Price Factors
The price of Stainless Steel 321 Pipe varies significantly based on several factors. The indicative FOB price ranges below are provided as a guide only — contact us for today's confirmed price with full documentation.
|
Product Type |
Indicative FOB Price Range |
|
SS 321 Welded Pipe (standard sizes) |
USD 1.00 – USD 2.50 per kg |
|
SS 321 ERW Pipe |
USD 1.20 – USD 3.00 per kg |
|
SS 321 Seamless Pipe (standard sizes) |
USD 2.00 – USD 5.00 per kg |
|
SS 321 Seamless Pipe (heavy wall / large OD) |
USD 4.00 – USD 17.00 per kg |
|
SS 321 EFW Pipe (large diameter) |
USD 2.60 – USD 4.00 per kg |
|
321 Stainless Steel Tubing (capillary / precision) |
USD 5.00 – USD 20.00 per kg |
Prices are indicative only and subject to change based on market conditions and raw material costs. Contact Amardeep Steel Centre at sales@amardeepsteel.com or +91-22-67439130 for a confirmed quotation.
Countries We Export Stainless Steel 321 Pipe To
Amardeep Steel Centre exports ss 321 pipe, 321 stainless steel tubing, and related products to 50+ countries worldwide. Export shipments come complete with country-specific documentation, SGS/BV pre-shipment inspection on request, and can be arranged on CIF, FOB, or CNF terms.
USA, UAE, Saudi Arabia, United Kingdom, Germany, Italy, France, Netherlands, Australia, Singapore, Malaysia, Brazil, South Africa, Kuwait, Oman, Qatar, Canada, Nigeria, Indonesia, Philippines
HSN Code: 73044900 (seamless) | 73069090 (welded) | IEC: Available | Shipping: Ex-Works Mumbai / FOB JNPT / CIF destination port
Frequently Asked Questions — Stainless Steel 321 Pipe
What is Stainless Steel 321 Pipe (TP321)?
Stainless Steel 321 Pipe (ASTM A312 TP321, UNS S32100) is a titanium-stabilized austenitic stainless steel pipe. Titanium is added at a minimum of 5 times the carbon content to prevent chromium carbide precipitation and intergranular corrosion in high-temperature service between 800–1500°F (427–816°C). It is available in seamless, welded, ERW, and EFW forms from ½" NB to 24" NB.
What is the difference between 321 and 304 stainless steel pipe?
SS 321 pipe contains titanium as a stabilizing element (minimum 5× carbon content), preventing sensitization and intergranular corrosion after high-temperature service or welding—a failure mode that affects 304 without post-weld heat treatment. For ambient or low-temperature service, 304 is adequate and more economical. For high-temperature or post-weld corrosive service, 321 is the preferred grade.
What is the difference between 321 and 321H stainless steel?
SS 321H has a controlled carbon range of 0.04–0.08% and a mandatory ASTM No. 7 or coarser grain size requirement. The higher carbon content and coarser grain structure provide superior creep strength and stress-rupture properties above 593°C (1100°F). Grade 321 is suitable for general high-temperature service, while 321H is specified for prolonged elevated-temperature applications in boilers, power generation, and petrochemical industries.
What temperature can SS 321 pipe handle?
SS 321 pipe can be used continuously up to 870°C (1598°F). It is specifically designed to perform within the sensitization range of 427–816°C (800–1500°F). For sustained service above 870°C, SS 321H or SS 310 should be considered.
Is SS 321 pipe magnetic?
No. SS 321 is an austenitic stainless steel and is non-magnetic in the annealed condition. It cannot be hardened through heat treatment. Cold working may induce a small amount of martensite, resulting in slight magnetism, but this does not significantly affect corrosion resistance.
What certifications should SS 321 pipe come with?
SS 321 pipe should be supplied with an EN 10204 3.1 Mill Test Certificate (or EN 10204 3.2 for third-party witnessed inspection), chemical analysis report, mechanical test report, dimensional inspection report, and hydrostatic test report. For boiler applications in India, IBR Form III-D certification is required. Additional testing such as PMI, UT, and third-party inspection can be provided upon request.
What is the price of SS 321 pipe per kg in India?
SS 321 pipe prices in India generally range from approximately USD 1.00–2.50 per kg for welded pipes and USD 2.00–17.00 per kg for seamless pipes, depending on size, schedule, finish, quantity, and mill origin. Contact your supplier for current pricing, stock availability, and certification requirements.
Can SS 321 pipe be welded?
Yes. SS 321 pipe can be welded using TIG, MIG, SMAW, and SAW processes. Its titanium stabilization provides resistance to post-weld intergranular corrosion in most applications without requiring post-weld heat treatment. When filler metal is needed, TP347 (niobium-stabilized) filler is generally recommended because titanium does not transfer effectively across an electric arc.
Related Products
- Stainless Steel 321H Pipes & Tubes
- Stainless Steel 347H Pipes & Tubes
- Stainless Steel 347 Pipes & Tubes
- Stainless Steel 316H Pipes & Tubes
- Stainless Steel 316 Pipes & Tubes
- Stainless Steel 304 Pipes & Tubes
- Stainless Steel 304H Pipes & Tubes
- Stainless Steel 310 Pipes & Tubes
- Stainless Steel 310S Pipes & Tubes
- Stainless Steel 321 Plates, Sheets & Coils
- Stainless Steel 321H Plates, Sheets & Coils
- Stainless Steel 321 Buttweld Fittings
- Stainless Steel 321H Buttweld Fittings
- Stainless Steel 321 Forged Fittings
- Stainless Steel 321H Forged Fittings
- Stainless Steel 321H Flanges
- Stainless Steel 321 & 321H Pipe Fittings
Get a Competitive Quote for Stainless Steel 321 Pipes & Tubes
Amardeep Steel Centre supplies SS 321 Pipe & Tube in seamless, welded, ERW, and EFW forms with complete documentation including EN 10204 3.1 MTC, IBR Form III-D, and third-party inspection on request. Ready stock available in Mumbai with worldwide export capability.
