Duplex Steel S31803 Pipes

Duplex Steel 31803 pipes are also known as UNS S31803 or SAF 2205 and are a dual-phase alloy combining austenitic and ferritic microstructures in a near-equal ratio. This two-phase structure gives the material roughly twice the yield strength of standard austenitic grades like 304 or 316. The grade offers outstanding resistance to chloride stress corrosion cracking, pitting, and crevice corrosion, making it a practical choice for aggressive chemical and marine environments. Industries including oil and gas, chemical processing, marine engineering, and water treatment rely on it for its strength, long service life, and lower material cost per unit of performance.

Duplex Steel 31803 Stainless Steel Pipe Price

The price of Duplex Steel S31803 pipes in India depends on pipe type, dimensions, finish grade, and order quantity. Below are 3 key price factors every buyer should review before sourcing.

Approximate price range

S31803 seamless pipes are priced between INR 450 and INR 950 per kg in India. Welded and ERW variants are more affordable, ranging from INR 300 to INR 650 per kg. Pricing shifts with wall thickness and outer diameter.

Cost per foot (approx.)

A standard 1-inch S31803 seamless pipe (Schedule 40) costs approximately INR 180 to INR 380 per foot. The final figure varies by supplier, surface finish, and any required third-party testing.

Factors affecting price

Raw material cost: The key elements used are chromium, molybdenum, and nickel. Global fluctuations in these metals directly affect the pipe cost.

Pipe type and finish: Seamless pipes carry a higher price than welded variants. Polished or pickled finishes add a premium over standard mill finishes.

Order volume and dimensions: Bulk orders reduce the cost per kilogram. Custom sizes, high tolerances, and special certifications like PED or NACE raise the overall cost.

Available Types of Duplex Steel 31803 Stainless Steel Pipes

Duplex Steel S31803 pipes are available in 5 standard types, each suited to specific pressure, fabrication, and installation requirements.

Duplex Steel 31803 EFW pipes
Duplex Steel 31803 seamless pipes
Duplex Steel 31803 welded pipes
Duplex Steel 31803 ERW pipes
Duplex Steel 31803 custom pipes

Stainless Steel Duplex Steel 31803 Pipe Specifications

The table below covers the standard manufacturing parameters for S31803 pipes per ASTM and ASME specifications. Confirm exact dimensions and schedules with your supplier before placing an order.

Parameter	Standard / Range
Standard	ASTM A790 / ASME SA790
Grades	UNS S31803 / S32205
Outer Diameter (OD)	6.35 mm to 323.85 mm
Pipe schedules	Sch 5S to Sch XXS
Forms available	Seamless, Welded, EFW, ERW, Custom
Wall thickness	1.0 mm to 25 mm
Finish	Plain, Pickled, Polished (2B, No.4, BA)

Chemical Composition of Duplex Steel 31803 Stainless Steel Pipes

The chemical composition below defines the corrosion resistance and mechanical performance of S31803 pipes. The dual-phase microstructure is achieved through balanced chromium, molybdenum, and nitrogen content.

Grade	C	Mn	Si	P	S	Cr	Mo	Ni	N	Fe
Duplex Steel S31803	0.030 max	2.00 max	1.00 max	0.030 max	0.020 max	22–23	3–3.5	4.50–6.50	0.14–0.20	63.72 min

Mechanical Properties Of Stainless Steel Duplex Steel 31803 Pipes

These 5 mechanical property values define the structural and load-bearing capability of S31803 pipes tested under standard conditions.

Density	Melting Point (°C)	Tensile Strength	Yield Strength (0.2% Offset)	Elongation
7.8 g/cm³	1350 °C (2460 °F)	Psi – 116,000 \| MPa – 800	Psi – 80,000 \| MPa – 550	15%

Size and Schedule Chart of ASTM A790 UNS S31803

The table below provides details of the duplex steel S31803 pipes' size and schedule chart.

NOMINAL	OD	SCH-5S		SCH-10S		SCH-10		SCH-20		SCH-30		SCH- 40S/STD		SCH-40		SCH-60
PIPE SIZE		THICK	KG/ MTR	THICK	KG/ MTR	THICK	KG/ MTR	THICK	KG/ MTR	THICK	KG/ MTR	THICK	KG/ MTR	THICK	KG/ MTR	THICK	KG/ MTR
1 /8''	10.3			1.24	0.279							1.73	0.386
1/4''	13.7			1.65	0.5							2.24	0.63	2.24	0.63
3/8''	17.1			1.65	0.64							2.31	0.85	2.31	0.85
1/2''	21.3	1.65	0.81	2.11	1.02							2.77	1.27	2.77	1.27
3/4''	26.7	1.65	1.03	2.11	1.3							2.87	1.68	2.87	1.68
1''	33.4	1.65	1.31	2.77	2.13							3.38	2.5	3.38	2.5
1 1/4''	42.2	1.65	1.68	2.77	2.73							3.56	3.39	3.56	3.39
1 1/2''	48.3	1.65	1.93	2.77	3.16							3.67	4.05	3.67	4.05
2''	60.3	1.65	2.42	2.77	3.99							3.91	5.44	3.91	5.44
2 1/2''	73	2.11	3.75	3.05	5.35							5.16	8.63	5.16	8.63
3''	88.9	2.11	4.59	3.05	6.56							5.49	11.29	5.49	11.29
3 1/2''	101.6	2.11	5.26	3.05	7.53							5.74	13.57	5.74	13.57
4''	114.3	2.11	5.93	3.05	8.54							6.02	16.07	6.02	16.07
5''	141.3	2.77	9.61	3.4	11.74							6.55	21.77	6.55	21.77
6''	168.3	2.77	11.48	3.4	14.04							7.11	28.26	7.11	28.26
8''	219.1	2.77	14.9	3.4	20.12			6.35	33.31	7.07	36.81	8.18	42.55	8.18	42.55	10.31	53.08
10''	273	3.4	22.95	4.19	28.2			6.35	41.77	7.8	51.03	9.27	60.3	9.27	60.3	12.7	81.55
12''	323.8	3.96	31.71	4.57	36.53			6.35	49.73	8.38	65.2	9.53	73.88	10.31	79.73	14.28	108.9
14''	355.6	3.96	34.87	4.78	41.99	6.35	54.69	7.92	67.9	9.53	81.33	9.53	81.33	11.13	94.55	15.09	126.7
16''	406.4	4.19	42.2	4.78	48.07	6.35	62.64	7.92	77.83	9.53	93.27	9.53	93.27	12.7	123.3	16.66	160.1
18''	457.2	4.19	47.53	4.78	54.15	6.35	70.57	7.92	87.71	11.13	122.3	9.53	105.1	14.27	155.8	19.05	205.7
20''	508	4.78	60.23	5.54	69.7	6.35	78.55	9.53	117.1	12.7	155.1	9.53	117.1	15.09	183.4	20.62	247.8
22''	558.9	4.78	65.8	5.54	75.75	6.35	85.54	9.53	129.1	12.7	171	9.53	129.1			22.23	234.2
24''	609.6	5.54	83.8	6.35	95.92	6.35	94.53	9.53	141.1	14.27	209.5	9.53	141.1	17.48	255.4	24.61	235.2
26''	660.4					7.92	127.3	12.7	202.7			9.53	152.8
28''	711.2					7.92	137.3	12.7	218.6	15.88	271.2	9.53	164.8
30''	762	6.35	120.15	7.92	149.55	7.92	147.2	12.7	234.6	15.88	291.1	9.53	176.8
32''	812.8					7.92	157.2	12.7	250.6	15.88	312.1	9.53	188.8	17.48	342.9
34''	853.6					7.92	167.2	12.7	266.6	15.88	329.1	9.53	200.3	17.48	364.9
36''	914.4					7.92	176.9	12.7	282.2	15.88	351.7	9.53	212.5	19.05	420.4
38''	965					9.53	226	12.7	301
40''	1016					9.53	238	12.7	317
42''	1067					9.53	251	12.7	333
44''	1118					9.53	263	12.7	349
46''	1168					9.53	275	12.7	365

NOMINAL	OD	SCH- 80S/XS		SCH-80		SCH-100		SCH-120		SCH-140		SCH-160		SCH-XXS
PIPE SIZE		THICK	KG/ MTR	THICK	KG/ MTR	THICK	KG/ MTR	THICK	KG/ MTR	THICK	KG/ MTR	THICK	KG/ MTR	THICK	KG/ MTR
1 /8''	10.3	2.41	0.473
1/4''	13.7	3.02	0.8	3.02	0.8
3/8''	17.1	3.2	1.1	3.2	1.1
1/2''	21.3	3.73	1.62	3.73	1.62							4.78	1.95	7.47	2.55
3/4''	26.7	3.91	2.2	3.91	2.2							5.56	2.9	7.82	3.64
1''	33.4	4.55	3.24	4.55	3.24							6.35	4.42	9.09	5.45
1 1/4''	42.2	4.85	4.42	4.85	4.42							6.35	5.61	9.7	7.77
1 1/2''	48.3	5.08	5.41	5.08	5.41							7.14	7.25	10.15	9.53
2''	60.3	5.54	7.48	5.54	7.48							8.74	11.11	11.07	13.44
2 1/2''	73	7.01	11.41	7.01	11.41							9.53	14.92	14.02	20.39
3''	88.9	7.62	15.27	7.62	15.27							11.13	21.35	15.24	27.58
3 1/2''	101.6	8.08	18.63	8.08	18.63
4''	114.3	8.56	22.32	8.56	22.32			11.13	28.32			13.49	33.54	17.12	41.03
5''	141.3	9.53	30.97	9.53	30.97			12.7	40.28			15.88	49.11	19.05	57.43
6''	168.3	10.97	42.56	10.97	42.56			14.27	54.2			18.26	67.56	21.95	79.22
8''	219.1	12.7	64.64	12.7	64.64	15.09	75.92	18.26	90.44	20.62	100.9	23.01	111.2	22.23	107.9
10''	273	12.7	81.55	15.09	96.01	18.26	114.7	21.44	133	25.4	155.1	28.58	172.3	25.4	155.1
12''	323.8	12.7	97.4	17.48	132	21.44	159.9	25.4	186.9	28.58	208.1	35.32	252.69	25.4	186.3
14''	355.6	12.7	107.3	19.05	158.1	21.83	194.9	27.79	224.5	31.75	253.5	35.71	281.7
16''	406.4	12.7	123.3	21.44	203.5	25.19	245.5	30.96	286.6	36.53	333.1	40.49	365.3
18''	457.2	12.7	139.1	23.83	254.5	28.36	309.6	34.93	363.6	39.67	408.2	45.24	459.3
20''	508	12.7	155.1	26.19	311.1	31.54	331.5	38.1	441.4	44.45	508.1	50.01	564.8
22''	558.9	12.7	171	28.58	373.8	34.93	451.4	41.28	527	47.63	600.6	53.9	675.2
24''	609.6	12.7	187	30.96	442	36.89	547.7	46.02	640	52.37	720.1	59.64	808.2
26''	660.4	12.7	202.7
28''	711.2	12.7	218.6
30''	762	12.7	234.6
32''	812.8	12.7	250.6
34''	853.6	12.7	266.6
36''	914.4	12.7	282.2
38''	965
40''	1016
42''	1067
44''	1118
46''	1168

Key Features of SS Duplex Steel 31803 Pipes

S31803 pipes offer 8 performance advantages that make them the go-to material in high-pressure and corrosion-critical applications.

Excellent corrosion resistance
High-temperature resistance
High strength and durability
Attractive and modern appearance
Easy fabrication
Hygienic and easy to clean
Low maintenance requirements
Excellent chemical compatibility

Applications of Duplex Steel 31803 Pipes

S31803 pipes are used across 8 industries where strength, corrosion resistance, and long service life are non-negotiable.

Chemical processing applications
Oil and gas transportation
Food and beverage processing
Pharmaceutical manufacturing
Water treatment systems
Construction and architectural uses
Marine and coastal applications
Medical equipment manufacturing

How to Choose the Right SS Duplex Steel 31803 Pipe Supplier

Choosing the right supplier affects product quality, delivery reliability, and long-term cost. Evaluate potential suppliers on these 6 criteria before committing to an order.

Evaluate the manufacturer's technical expertise: A capable supplier should have in-house metallurgical knowledge of duplex grades. Ask for technical data sheets, mill test reports, and previous project references for the S31803 supply.

Check grade availability and product range: Confirm that the supplier stocks S31803 in the pipe types, OD ranges, and schedules you need. A wide product range reduces the need for multiple sourcing points.

Verify quality certifications and testing capabilities: Look for at least an ISO 9001 certification. Suppliers with NACE, PED, or third‑party inspection approvals are a better choice for critical projects.

Examine the strength of raw material sourcing: The finished pipe’s performance depends on using good-quality materials from reliable mills. Ask the supplier for documents that show where their materials come from.

Assess customisation capabilities: Some applications require nonstandard lengths, specific surface treatments, or cut-to-length pipes. A reliable supplier with in-house processing prevents delays related to outsourcing.

Review delivery timelines and supply capacity: For project-critical timelines, confirm stock availability and dispatch lead times before placing orders. A supplier with a dedicated warehouse inventory reduces risk.