Stainless Steel 321H Pipes & Tubes Supplier | ASTM A312 TP321H

Q: How does 321H compare to 347H for high-temperature service?

Both 321h stainless steel pipe and 347H Pipes are stabilised high-carbon austenitic grades with superior creep properties. 321H uses titanium as the stabiliser; 347H uses niobium. 347H is generally preferred when welding with filler metal, since niobium transfers across the arc while titanium does not. 321H is preferred where titanium stabilisation is specified by the client or code. Both grades are widely used in power generation and petrochemical superheater service.

Stainless Steel 321H Pipes & Tubes Manufacturer, Supplier & Exporter in India

ASTM A312 / ASME SA312UNS S32109WNR 1.4878½" NB – 24" NB SeamlessSCH 5 to XXSEN 10204 3.1 MTCIBR ApprovedReady Stock Mumbai

Amardeep Steel Centre LLP is a leading manufacturer, exporter, and supplier of Stainless Steel 321H Pipes & Tubes in India. SS 321H (UNS S32109 / WNR 1.4878) is a titanium-stabilised austenitic stainless steel with a higher and controlled carbon content of 0.04–0.10% — compared to the 0.08% maximum of standard grade 321. This elevated carbon specification, combined with a mandatory coarser grain size of ASTM No. 7 or above, delivers superior creep resistance and greater strength at elevated temperatures above 537°C (1000°F), making 321H stainless steel pipe the material of choice for the most demanding high-temperature service environments.

We supply stainless steel 321H pipes and tubes in seamless, welded, ERW, and EFW forms across a wide range of sizes, schedules, and finishes all backed by complete documentation and ready stock available at our Mumbai warehouse for fast worldwide dispatch. As a recognised ss 321h efw pipe dealer with direct mill access, we can supply large-diameter EFW pipes from 6" NB to 100" NB manufactured to ASTM A358.

Specification of Stainless Steel 321H Pipes & Tubes

Parameter	Details
International Standard	ASTM A312 / ASME SA312 TP321H
Other Standards	ASTM A213, ASTM A249, ASTM A269, ASTM A358, ASME SA249
UNS No.	S32109
Werkstoff Nr. (DIN)	1.4878
Japanese JIS	SUS 321H
Seamless Pipe Size	½" NB to 24" NB (OD: 4 mm to 219 mm)
Welded / EFW / ERW Pipe Size	½" NB to 100" NB (OD: 5 mm to 2540 mm)
Wall Thickness	SCH 5, 10S, 10, 20, 30, 40S, 40, 80, 80S, XS, 120, 140, 160, XXS
Types	Seamless, ERW, EFW, Welded, LSAW, CDW, Fabricated, Seam-Welded
Form	Round, Square, Rectangular, Hydraulic, U-Bend
Length	Single Random, Double Random, Custom Cut Lengths (Plain End, Beveled End, Threaded)
Finish / Condition	Annealed & Pickled, Bright Annealed, Polished (2B, No. 1, No. 4, No. 8 Mirror), Cold Drawn
Delivery Condition	Hot Finished, Cold Drawn, Annealed
Grain Size (321H mandatory)	ASTM No. 7 or coarser

For dimensional weights across schedules, see our Steel Weight Calculator or the Pipe Dimension reference page.

Chemical Composition of SS 321H Pipes & Tubes

Grade	C	Mn	Si	P	S	Cr	Ni	N	Ti
321H	0.04–0.10	2.00 max	0.75 max	0.045 max	0.030 max	17.0–19.0	9.0–12.0	0.10 max	4×(C+N) min / 0.70 max
321 (ref)	0.08 max	2.00 max	0.75 max	0.045 max	0.030 max	17.0–19.0	9.0–12.0	0.10 max	5×(C+N) min / 0.70 max

The controlled minimum carbon of 0.04% in tp 321h combined with the mandatory ASTM No. 7 or coarser grain size — is what separates ss 321h pipe from standard 321 and gives it the elevated creep and stress rupture properties required for sustained high-temperature service. Standard 321 has no minimum carbon requirement and no grain size control.

Mechanical Properties of SS 321H Seamless & Welded Pipes

Grade	Tensile Strength (MPa) min	Yield Strength 0.2% (MPa) min	Elongation (% in 50 mm) min	Hardness Rockwell B max	Brinell (HB) max
321H	515	205	40	95	217
321 (ref)	515	205	40	95	217

Note: While room-temperature tensile properties of SS 321H and 321 are identical, 321H's superior high-temperature performance becomes measurable above 537°C through improved creep strength, stress rupture life, and long-term stability — properties not captured in the standard room-temperature test.

Physical Properties of SS 321H

Property	Value
Density	8.0 g/cm³
Melting Point	1454°C (2650°F)
Elastic Modulus	193 GPa
Thermal Conductivity (at 100°C)	16.1 W/m·K
Mean Coeff. of Thermal Expansion (0–100°C)	16.6 µm/m·°C
Specific Heat (0–100°C)	500 J/kg·K
Electrical Resistivity	720 nΩ·m

Grade Specification Comparison — UNS S32109 Pipe Equivalent

Stainless steel 316 pipe prices in India vary by size, schedule, manufacturing process (seamless vs. welded), surface finish, and order quantity.

Grade	UNS No.	Old British BS	Euronorm No.	Euronorm Name	Swedish SS	Japanese JIS
321H	S32109	321S51	1.4878	X10CrNiTi18-10	—	SUS 321H
321	S32100	321S31	1.4541	X6CrNiTi18-10	2337	SUS 321

For the full comparison between these grades and related high-temperature stainless steels, see our Stainless Steel 321 Pipes & Tubes page

SS 321H Pipe Weight Chart (Selected Sizes — Schedule 40 STD)

Nominal Size (inch)	OD (mm)	Wall Thickness (mm)	Schedule	Weight (kg/m)	Weight (lbs/ft)
½"	21	2.769	40 STD	1.268	0.851
½"	21	3.734	80 XS	1.621	1.088
¾"	27	2.870	40 STD	1.684	1.131
1"	33	3.378	40 STD	2.501	1.679
1½"	48	3.683	40 STD	4.048	2.718
2"	60	3.912	40 STD	5.441	3.653
3"	89	5.486	40 STD	11.284	7.576
4"	114	6.020	40 STD	16.073	10.790
6"	168	7.112	40 STD	28.263	18.974
8"	219	8.179	40 STD	42.352	28.554
10"	273	9.271	40 STD	63.301	40.483
12"	324	10.312	40 STD	79.727	53.525

For Schedule 40 and Schedule 80 full size and weight data, see our dedicated schedule pages.

AISI 321H Schedule 40 Pipe — Pressure Rating (psi)

Pipe Size (in)	OD (in)	Wall Thickness (in)	100°F	200°F	400°F	600°F	700°F
1"	1.315	0.133	2205	2205	2047	1783	1703
1½"	1.900	0.145	1629	1629	1512	1317	1287
2"	2.375	0.154	1371	1371	1272	1108	1083
3"	3.500	0.216	1301	1301	1208	1052	1028
4"	4.500	0.237	1102	1102	1023	891	871
6"	6.625	0.280	877	877	814	709	693
8"	8.625	0.322	771	771	716	623	610
10"	10.750	0.365	699	699	649	565	553

Note: The sustained high-temperature creep strength advantage of 321H stainless steel pipe over standard 321 becomes operationally significant above 537°C (1000°F) in applications like superheater tubes and power plant steam headers, where allowable stress values from ASME Code Cases must be applied.

Types of Stainless Steel 321H Pipes & Tubes

Amardeep Steel Centre manufactures and supplies SS 321H pipes and tubes across all major product forms:

SS 321H Seamless Pipes
SS 321H Welded Pipes
SS 321H ERW Pipes
SS 321H EFW Pipes
SS 321H LSAW Pipes
SS 321H Seamless Tubes
SS 321H Square Pipes
SS 321H Rectangular Pipes
SS 321H U-Bend Tubes
SS 321H Capillary Tubes
SS 321H Instrumentation Tubes
SS 321H Coiled Tubing
SS 321H Heat Exchanger Tubes
SS 321H Hydraulic Tubes
SS 321H Electropolished Pipes
SS 321H Large Diameter Fabricated Pipes

Applications of SS 321H Pipes & Tubes

Stainless Steel 321H's titanium stabilisation and elevated, controlled carbon content make 321h pipe and ss 321h tube the material of choice wherever service temperatures fall in the carbide precipitation range of 427°C to 816°C (800°F to 1500°F) and especially for sustained service above 537°C (1000°F) where creep properties determine component life. Typical industries and end uses include:

Petroleum refineries
Boiler tubes & high-pressure steam pipes
Heat exchangers & condensers
High-temperature chemical process equipment
Heavy-duty exhaust manifolds
Aerospace structural tubing
Power generation (superheaters)
Furnace components
Cryogenic service (excellent low-temp toughness)
Pharmaceutical & food-grade pipework

Why Choose Amardeep Steel Centre for SS 321H Pipes?

Manufacturer & exporter since 1984 – 40+ years of expertise
PED 97/23/EC, AD 2000-Merkblatt W0 certified manufacturing unit
ISO 9001, ISO 14001, OHSAS 18001 certified
Ready stock in Mumbai for fast delivery
EN 10204 3.1 MTC supplied as standard
IBR Form III-D available on request
Third-party inspection: SGS, Bureau Veritas, Lloyds, TÜV
NABL-approved lab test reports
Custom sizes, schedules & lengths on request
Worldwide export capability

Corrosion Resistance & Heat Treatment of SS 321H

Corrosion Resistance

SS 321H pipe offers corrosion resistance equivalent to Grade 304 in the annealed condition. It is superior to 304 when a weldment has not been post-weld annealed, or when the application involves continuous service in the 425–900°C range. 321h stainless steel pipe is immune to intergranular corrosion when heated within the carbide precipitation range because titanium ties up carbon and nitrogen as stable carbides and nitrides, preventing grain-boundary chromium depletion — the mechanism that causes weld decay in unstabilised grades like 304. For a detailed comparison with other high-temperature grades, see Stainless Steel 321 Pipes & Tubes and Stainless Steel 316H Pipes & Tubes.

Heat Treatment

SS 321H pipe cannot be hardened by thermal treatment. Three heat treatment conditions are relevant:

Solution Annealing: Heat to 950–1120°C and cool rapidly (water quench or forced air). This dissolves any chromium carbides or sigma phase and restores maximum corrosion resistance and ductility. As-supplied tp 321h pipe is normally delivered in the annealed and pickled condition.
Stabilising Anneal: Heat to 870–900°C for 1 hour per 25 mm of thickness and air cool. Recommended before placing 321h pipe into severe service above 425°C. This treatment ensures all available carbon is locked in stable titanium carbides before the component enters service.
Stress Relief: Heat to 700°C for 1–2 hours and air cool. Partial stress relief for cold-formed or cold-drawn ss 321h tube without entering the sensitization range.

For further reading on heat treatment of austenitic stainless steels, see our blog: Difference Between Annealing and Tempering.

Test Certificates & Documentation for SS 321H Pipes

EN 10204 3.1 Mill Test Certificate (MTC)
EN 10204 3.2 (Third-Party Witnessed)
Chemical & Mechanical Test Reports
IBR Form III-D (on request)
NABL-Approved Lab Reports
100% Radiography Test Reports
PMI (Positive Material Identification) Reports
Hydrostatic Test Reports
Third-Party Inspection Reports (SGS, BV, Lloyds, TÜV)

SS 321H Pipe Price

The price of 321h stainless steel pipe varies by form (seamless vs welded vs EFW), size, schedule, surface finish, quantity, and mill origin. As a direct ss 321h efw pipe dealer with access to Indian, Japanese, Korean, and European mills, Amardeep Steel Centre offers competitive pricing with full documentation. Contact us at sales@amardeepsteel.com or +91-22-67439130 for a confirmed quotation.

Use our Steel Weight Calculator to estimate material quantities before requesting a quotation.

Frequently Asked Questions – SS 321H Pipes & Tubes

What is the difference between SS 321 and SS 321H pipes?

SS 321H is the higher-carbon version of SS 321, with a carbon content of 0.04–0.10% versus 0.08% maximum for grade 321. This gives 321H improved creep resistance and greater tensile strength at elevated temperatures above 537°C (1000°F).

What standards cover Stainless Steel 321H Pipes?

SS 321H pipes are produced under ASTM A312 / ASME SA312 (seamless and welded pipes), ASTM A213 (seamless ferritic/austenitic alloy-steel boiler, superheater, and heat-exchanger tubes), ASTM A249 (welded austenitic steel boiler tubes), and ASTM A269 (seamless and welded austenitic stainless steel tubing).

What sizes are available in SS 321H seamless pipes?

We stock SS 321H seamless pipes from ½" NB to 24" NB (OD 4 mm to 219 mm), with wall thickness schedules from SCH 5 through to XXS. Custom OD sizes and lengths are manufactured on request.

What documentation is provided with SS 321H Pipes?

Standard supply includes EN 10204 3.1 MTC, chemical and mechanical test reports, NABL-approved lab reports, and hydrostatic test reports. IBR Form III-D and third-party inspection from agencies such as SGS, Bureau Veritas, Lloyd's, and TÜV are available on request.

What are the typical applications of SS 321H Pipes?

SS 321H pipes are used in petroleum refineries, high-pressure steam piping, boiler and superheater tubes, heat exchangers, exhaust manifolds, aerospace structural components, and high-temperature chemical process equipment wherever service temperatures range from 427°C to 816°C.

What is the delivery time for SS 321H Pipes from Amardeep Steel Centre?

For sizes available in our Mumbai ready stock, delivery is typically 2–5 business days. For non-stock or special sizes, delivery is within 10–25 working days depending on quantity and specifications.

Can SS 321H pipes be welded?

Yes. SS 321H can be welded using most standard processes. However, because titanium does not transfer well across a high-temperature welding arc, Grade 347 filler metal (niobium-stabilised) is typically recommended as the welding consumable. Post-weld annealing is not required.

What is the difference between 321H ERW pipe and 321H EFW pipe?

SS 321H ERW pipe is Electric Resistance Welded without filler metal, covering sizes up to 24" NB for moderate-pressure service per ASTM A312. SS 321H EFW pipe is Electric Fusion Welded with filler metal permitted, covering large diameters from 6" NB to 100" NB per ASTM A358 used for large-bore process piping and pressure vessels. Amardeep Steel Centre is a recognised SS 321H EFW pipe dealer with direct mill access for competitive pricing on both types.

How does 321H compare to 347H for high-temperature service?

Both 321H stainless steel pipe and 347H pipes are stabilised high-carbon austenitic grades with superior creep properties. 321H uses titanium as the stabiliser, while 347H uses niobium. Grade 347H is generally preferred when welding with filler metal because niobium transfers across the welding arc, whereas titanium does not. Grade 321H is preferred where titanium stabilisation is specified by the client or project code. Both grades are widely used in power generation and petrochemical superheater applications.

Get a Competitive Quote for SS 321H Pipes & Tubes

Amardeep Steel Centre supplies SS 321H Pipe & Tube with EN 10204 3.1 MTC, IBR Form III-D, and third-party inspection. Ready stock in Mumbai. Worldwide export.

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