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S31803 Duplex Stainless Steel Pipes from China | Trusted Suppliers & Factory for Fast Shipping

ZONSUN STEEL is a leading China supplier and factory specializing in S31803 duplex stainless steel pipes. As a professional stockist and exporter, we adhere to international standards, ensuring high-quality products for our customers. With a robust inventory available for immediate shipment, we guarantee fast delivery to meet your project timelines. Trust ZONSUN STEEL for all your duplex stainless steel needs

Product Detail

Introduction

ASTM A790/A790M S31803 duplex stainless steel pipes combine austenitic and ferritic microstructures, delivering twice the strength of 316L with exceptional resistance to chloride-induced stress corrosion cracking (SCC). Ideal for harsh offshore, chemical, and marine applications, this alloy balances cost-efficiency with premium performance.

Key Features

Dual-Phase Strength Yield strength ≥450 MPa, nearly double conventional stainless steels (e.g., 304/316), reducing wall thickness and material costs.

Enhanced Corrosion Resistance 21%-23% Cr, 2.5%-3.5% Mo, and 4.5%-6.5% Ni combat pitting/crevice corrosion in seawater, acids, and sour gas (H₂S) environments (PREN ≥35).

Thermal Stability Performs reliably from -50°C to 300°C (-58°F to 572°F), suitable for subsea and high-pressure systems.

Material Specification

Standard ASTM A790/A790M

O.D 1/8" NB TO 32" NB , (10.29MM-812.80MM) ,(Customization Available)

W.T SCH 10S, SCH 40S, SCH 80S, SCH160, SCH XXS (Customization Available)

Application

Oil & Gas Pipelines (Including Sour Service)
Chemical & Petrochemical Processing
Desalination & Water Treatment Plants
Marine & Offshore Structures
Power Plants (Including Flue Gas Desulfurization)
Pulp & Paper Industry
Heat Exchangers & Condensers

End Plain End, Beveled End, Threaded

Processing Cut-to-length; Polishing.

Inspection

100% PMI (Positive Material Identification) Tested
EN 10204 3.1/3.2 Mill Test Certificate
Third-Party Inspection Accepted (SGS, BV, TUV, etc.)
Ultrasonic Testing (UT) / Eddy Current Testing (ECT) Available
Hardness, Tensile, and Impact Testing as per ASTM Standards

Delivery Condition Cold Drawn, Annealed and Pickled/ Polished /Bright Annealed/ Sand blasting/ Shot Blasting.

Marking All SS SMLS Pipes are marked as follows: Standard, Grade, OD, Thickness, Length, Heat No. (Or as per the customer’s request)

Packing Packed in Wooden Boxes, plywood cases, Steel Strips Bundled, or as per Customers Requests

Specials Sizes and Specifications other than above can be customized on request.

Specification parameters

S31803 chemical composition

HEAT NO.		CHEMICAL COMPOSITION (%)
HEAT NO.		C	Mn	P	S	Si	Ni	Cr	Mo	N
STAND.	MIN.						4.50	21.00	2.50	0.08
STAND.	MAX.	0.03	2.00	0.03	0.020	1.00	6.50	23.00	3.50	0.20

S31803 Mechanical Properties

Mechanical Properties
Grade	Tensile Strength (MPa) min	Yield Strength 0.2% Proof (MPa) min	Elongation (% in 50mm) min	Hardness
Grade	Tensile Strength (MPa) min	Yield Strength 0.2% Proof (MPa) min	Elongation (% in 50mm) min	HRW	HRC
S31803	620	450	25	290	30

Equivalent Grades - (ASTM A790/A790M S31803 Equivalent Grades)

ASTM A790/A790M S31803 (UNS S31803) Equivalent Grades
ISO	EN (Europe)	DIN (Germany)	JIS (Japan)	GB (China)	UNS (USA)	AISI/SAE
X2CrNiMoN22-5-3 (ISO 15510)	1.4462 (EN 10088-2)	X2CrNiMoN22-5-3 (DIN 17440)	SUS 329J3L (JIS G3463)	022Cr22Ni5Mo3N (GB/T 21833)	S31803	Duplex 2205 (Commercial Name)

ASTM A312/A312M Standard Cold Machining size Deviation Permitted

ASTM A312/A312M-09 Standard Permitted Tolerance of WT and OD
Nominal Outside Diameter		Allowable deviation	Nominal wall thickness		Allowable deviation
1/8”—1 1/2“	(10.29—48.26)	+0.4 -0.8	1/8”—1 1/2“	(10.29-73.03) all of t	+20 -12.5
>1 1/2“—4”	(48.26—114.3)	±0.8	3“—18”	(88.9-457.2) t/D=5%	+22.5 -12.5
>4”—8"	(114.3—219.08)	+1.6 -0.8	3“—18”	(88.9-457.2) t/D>5%	+15 -12.5
>8“—18"	(219.08—457.2)	+2.4 -0.8	≥20"	=508 t of wld pipe	+17.5 -12.5
>18”—26“	(457.2—660.4)	+3.2 -0.8	≥20"	=508 t/D=5%	+22.5 -12.5
>26”—34”	(660.4—863.6)	+4.0 -0.8	≥20"	=508 t/D>5%	+15 -12.5
>34“—48"	(863.6—1219.2)	+4.8 -0.8
Thin wall pipe (t/D=3%) ovality condition: Any cross section in a steel pipe Dmax Dmin=1.5% nominal, and (Dmax Dmin)/ 2 conforms to the stipulated diameter tolerance range.

Comparison Table Of American Standard Dimensions - (ANSI B36.19 & ANSI B36.10) (This data refers to ASTM A312)

OD DN	IN	OD MM	ANSI B36.19										ANSI B36.10
			Nominal diameter in inches
			5s		10s		Sched.40s		Sched.40	Sched.80s		Sched.80	10		20		30		Standard
			mm	Kg/m	mm	Kg/m	mm	Kg/m	mm	mm	Kg/m	mm	mm	Kg/m	mm	Kg/m	mm	Kg/m	mm	Kg/m
6	1/8"	10.29	-	-	1.24	0.281	1.73	371	1.73	2.41	0.467	2.41	-	-	-	-	-	-	1.73	0.371
8	1/4"	13.72	-	-	1.65	0.499	2.24	0.644	2	3.02	0.809	3.02	-	-	-	-	-	-	2.24	0.644
10	3/8"	17.14	-	-	1.65	0.64	2.31	0.858	2.31	3.2	1.118	3.2	-	-	-	-	-	-	2.31	0.858
15	1/2"	21.34	1.65	0.814	2.11	1.016	2.77	1.26	2.77	3.73	1.62	3.73	-	-	-	-	-	-	2.77	1.26
20	3/4"	26.67	1.65	1.034	2.11	1.298	2.87	1.68	2.87	3.91	2.19	3.91	-	-	-	-	-	-	2.87	1.68
25	1"	33.4	1.65	1.312	2.77	2.125	3.38	2.5	3.38	4.55	3.23	4.55	-	-	-	-	-	-	3.36	2.5
32	1 1/4"	42.16	1.65	1.674	2.77	2.732	3.56	3.38	3.56	4.85	4.46	4.85	-	-	-	-	-	-	3.56	3.38
40	1 1/2"	48.26	1.65	1.926	2.77	3.155	3.68	4.05	3.68	5.08	5.4	5.08	-	-	-	-	-	-	3.68	4.05
50	2"	60.32	1.65	2.424	2.77	3.992	3.91	5.43	3.91	5.54	7.47	5.54	-	-	-	-	-	-	3.91	5.43
65	2 1/2"	73.02	2.11	3.747	3.05	5.345	5.16	8.62	5.16	7.01	11.4	7.01	-	-	-	-	-	-	5.16	8.62
80	3"	88.9	2.11	4.585	3.05	6.557	5.49	11.28	5.49	7.62	15.25	7.62	-	-	-	-	-	-	5.49	11.28
90	3 1/2"	101.6	2.11	5.272	3.05	7.526	5.74	13.56	5.74	8.08	18.62	8.08	-	-	-	-	-	-	5.74	13.56
100	4"	114.3	2.11	5.945	3.05	8.496	6.02	16.06	6.02	8.56	22.29	8.56	-	-	-	-	-	-	6.02	16.06
125	5"	141.3	2.77	9.639	3.4	11.74	6.55	21.76	6.55	9.52	30.92	9.52	-	-	-	-	-	-	6.55	21.76
150	6"	168.28	2.77	11.514	3.4	14.037	7.11	28.23	7.11	10.97	42.52	10.97	-	-	-	-	-	-	7.11	28.23
200	8"	219.08	2.77	15.049	3.76	20.334	8.18	42.49	8.18	12.7	64.57	12.7	-	-	6.35	33.28	7.04	36.8	8.18	42.4
250	10"	273.05	3.4	23.028	4.19	28.29	9.27	60.24	9.27	12.7	81.46	15.09	-	-	6.35	41.7	7.8	51	9.27	60.24
300	12"	323.85	3.96	31.806	4.57	36.633	9.52	73.76	10.31	12.7	97.36	17.48	-	-	6.35	49.68	8.38	65.14	9.52	73.76
350	14"	355.6	3.98	34.99	4.78	42.102	9.52	-	11.13	-	-	19.05	6.35	54.63	7.92	67.98	9.52	81.21	9.52	81.21
400	16"	406.4	4.19	42.35	4.78	48.22	9.52	-	12.7	-	-	21.44	6.35	62.58	7.92	77.9	9.52	93.13	9.52	93.18
450	18"	457.2	4.19	47.7	4.78	54.3	9.52	-	14.27	-	-	23.82	6.35	70.5	7.92	87.8	11.13	122.12	9.52	105.05
500	20"	508	4.77	60.32	5.54	69.766	9.52	-	15.09	-	-	26.19	6.35	78.47	9.52	116.97	12.7	155	9.52	116.97
550	22"	558.8	4.77	-	5.54	-	9.52	-	-	-	-	28.58	6.35	86.42	9.52	128.89	12.7	170.86	9.52	128.89
600	24"	609.6	5.54	84.1	6.35	96.215	9.52	-	17.48	-	-	30.96	6.35	96.215	9.52	140.8	14.7	209.54	9.52	140.81
650	26"	660.4	-	-	-	-	9.52	-	-	-	-	-	7.92	127.58	12.7	202.65	-	-	9.52	152.73
700	28"	711.2	-	-	-	-	9.52	-	-	-	-	-	7.92	137.52	12.7	218.54	15.88	271.94	9.52	164.65
750	30"	762	6.35	120.59	7.92	147.45	9.52	-	-	-	-	-	7.92	147.45	12.7	234.44	15.88	291.81	9.52	176.57
800	32"	812	-	-	-	-	9.52	-	17.48	-	-	-	7.92	157.39	12.7	250.33	15.88	311.67	9.52	188.5
850	34"	863.6	-	-	-	-	9.52	-	17.48	-	-	-	7.92	167.32	12.7	266.22	15.88	331.54	9.52	200.42
900	36"	914.4	-	-	-	-	9.52	-	19.05	-	-	-	7.92	177.26	12.7	282.18	15.88	351.41	9.52	212.34

Frequently Asked Questions (FAQ)

What is ASTM A790 S31803?

ASTM A790 S31803 is a standard specification for seamless and welded duplex stainless steel pipes. It features a dual-phase microstructure consisting of both austenitic and ferritic stainless steel, which provides high mechanical strength and outstanding resistance to corrosion.

What are the mechanical properties of S31803 duplex pipes?

S31803 duplex stainless steel pipes provide a minimum tensile strength of 620 MPa and a minimum yield strength of 450 MPa (0.2% proof). It also offers a minimum elongation of 25% and a maximum hardness of 290 HRW / 30 HRC.

How does S31803 compare to standard 316L stainless steel?

S31803 duplex stainless steel delivers approximately twice the yield strength of conventional 316L stainless steel. Additionally, it offers significantly higher resistance to chloride-induced stress corrosion cracking (SCC) and localized pitting or crevice corrosion.

What are the equivalent grades of ASTM A790 S31803?

Equivalent grades include 1.4462 (EN/DIN), SUS 329J3L (JIS), X2CrNiMoN22-5-3 (ISO), and 022Cr22Ni5Mo3N (GB). It is also commercially known as Duplex 2205.

What testing is performed on S31803 duplex steel pipes?

Standard testing includes 100% PMI (Positive Material Identification) testing, Ultrasonic Testing (UT), Eddy Current Testing (ECT), and mechanical testing (hardness, tensile, and impact tests) in accordance with ASTM standards. Mill Test Certificates (EN 10204 3.1/3.2) are provided.

What is the temperature range for S31803 duplex stainless steel?

S31803 duplex stainless steel performs reliably at temperatures ranging from -50°C to 300°C (-58°F to 572°F), making it highly suitable for subsea, marine, and high-pressure processing systems.