ASME SA789 / ASME SA790 Duplex Stainless Steel Pipe and tube, materials for the Oil and Gas, Petrochemical and Power Industry.

• Customization: Available
• Type: Stainless Steel Pipes
• Standard: ASTM, AISI, GB, EN, GOST9941
• Model NO.: Super Duplex
• Grade: 300 Series
• Certification: ISO
• Shape: Round
• Technique: Cold Rolled
• Surface Treatment: AP/BA/Polishing/Sand Blasting/Shot Blasting
• Material: Stainless Steel
• Section Shape: Round
• Test: Hydraulic Test/NDT
• Delivery Time: Stock 7 Days; MTO 30 Days
• Trade Terms: EXW, FOB, CFR, CIF etc.
• Markings: According to A999/A999m
• Transport Package: Packed in Bundles or Plywooden Box
• Specification: S32750 S32205 S31803
• Trademark: GH-STEEL
• Origin: China
• HS Code: 7304419000
• Production Capacity: 2000 Tons Per Month

Product Description

Product Description

Product Name	Seamless Super Duplex Stainless Steel Pipe
Process	Seamless, formed through cold rolling or cold drawing, without weld seams, and with high structural uniformity.
Company	WENZHOU GUOHAO STEEL., LTD(Manufacturer & Exporter)
Grade	ASTM:  UNS S32205, UNS 31803,UNS S32750,UNS S32760
Standard	• ASTM A790 / ASME SA790,ASTM A789 / ASME SA789 • EN 10216-5 • GB/T 21833-2008,GB/T 14976-2012 • GOST 9941-81
Specification	Outer Diameter: • Nominal Pipe Size (NPS): 1/8 in to 24 in (corresponding to actual OD per ASME B36.19M/B36.10M) • Mechanical Tubing OD: 6.35 mm to 108.0 mm (1/4 in to 4¼ in), per ASTM A269/A511 tolerances • Metric OD Range: 6.0 mm to 630.0 mm — covering both seamless pipe and precision tubing applications
	Wall Thickness:  • Standard pipe schedules: SCH 10S, SCH 40S, SCH 80S, SCH 160, and SCH XXS • Tubing wall gauges: 10 BWG, 12 BWG, 14 BWG, 16 BWG, 18 BWG, and 20 BWG • Metric thickness range: 0.89 mm to 80.0 mm (covering both seamless pipe and precision tubing applications)
	Length: • Random lengths: 5–7 meters (typical range)  • Fixed lengths: 6.0 m, 6.096 m (20 ft), 6.1 m, or 12.0 m — subject to mill capability and order volume • Custom lengths: available upon request, subject to technical feasibility and minimum order requirements
Pipe End	•Plain End (PE)  •Beveled End (BE)
Surface Treatment Processes	• Acid Pickling   • Mechanical Polishing   • Bright Annealing (in Controlled Atmosphere)   • Sand Blasting   • Shot Blasting and Shot Peening
Tests and Inspections	Spectrochemical Analysis, Dimensional Inspection, Tensile Strength Testing, Flattening Test, Flaring Test, Hydrostatic Test, Eddy Current Testing, Ultrasonic Testing, Intergranular Corrosion Resistance Testing, Hardness Testing, and Grain Size Determination.
Weight Per Meter	2057 Duplex Stainless Steel Pipe Weight Calculation Formula=(OD-THK)*THK*0.02450 kg/m
Pipe's Markings	GH-STEEL SML PIPE ASTM A790 UNS S32205 3 IN SCH40S  HEAT/LOT NO:
Custom Processing Services Available	• Precision length cutting   • Cold bending (to specified radii and tolerances)   • Surface finishing: mechanical polishing (grit grades 180, 240, 320, 400, and 600)   • Surface conditioning: shot blasting or shot peening (per ASTM B851 / SAE AMS 2430)   • Hole-making: CNC drilling or precision punching   • Solvent-based degreasing (to remove oils, greases, and contaminants)   • Colour-coding application (per customer-specified scheme)
Delivery Time	For ready stock :7 days ;For MTO: 30 days
Payment Collection	We maintain a VTB Bank account, which helps to reduce cross - border collection fees and export - related costs.
Export license	We are a physical factory and can directly apply for export licenses for steel products and export them in compliance with regulations.
Price	All quotations are tax-inclusive, and pricing may be structured on a per-ton or per-meter basis.

Duplex stainless steel is a class of stainless steels characterized by a two-phase microstructure comprising approximately equal volume fractions of austenite and ferrite. This dual-phase architecture imparts a unique balance of high mechanical strength and superior corrosion resistance—particularly against chloride-induced stress corrosion cracking—making duplex grades a preferred material solution for demanding industrial applications, including offshore, chemical processing, and desalination environments.
Developed specifically to overcome the susceptibility of fully austenitic stainless steels to chloride stress corrosion cracking, duplex stainless steels retain favorable ductility and weldability while offering significantly higher yield strength (typically 2–3 times that of standard austenitic grades such as AISI 304 or 316) and enhanced resistance to pitting and crevice corrosion.
Super duplex stainless steel represents an advanced evolution of the duplex stainless steel family, engineered with elevated alloying element concentrations—particularly chromium, molybdenum, and nitrogen—to meet the demanding requirements of highly aggressive service environments. As a result, it is classified both as a high-chromium stainless steel and a high-molybdenum corrosion-resistant alloy.
Super duplex stainless steel offers higher strength, superior resistance to pitting and crevice corrosion, and excellent performance in chloride environments. Its dual-phase (austenite/ferrite) microstructure is retained, but increased chromium, molybdenum, and nitrogen raise the PREN well above that of standard duplex grades.
The Chemical Composition of Duplex Stainlesss Steel Seamless Tube/Pipe
Grade	C (max)	Mn (max)	P (max)	S (max)	Si (max)	Cr	Ni	Mo	Others
UNS S31803	0.030	2.00	0.030	0.020	1.00	21.0~23.0	4.5~6.5	2.5~3.5	N:0.08~0.20
UNS S32205	0.030	2.00	0.030	0.020	1.00	22~23.0	4.5~6.5	3.0~3.5	N:0.14~0.20
UNS S32750	0.030	1.20	0.035	0.020	0.80	24.0~26.0	6.0~8.0	3.0~5.0	N:0.24~0.32 Cu≤0.5
UNS S32760	0.030	1.00	0.030	0.010	1.00	24.0~26.0	6.0~8.0	3.0~4.0	N:0.20~0.30 Cu:0.5~1.00 W:0.5~1.00
Mechanical Properties of  Duplex Stainlesss Steel Seamless Tube/Pipe
Grade		Tensile Strength, Min		Yield Strength, Min		Elognation		Hardness
UNS S31803		620 Mpa		450 Mpa		25%		30 HRC Max
UNS S32205		655 Mpa		485 Mpa		25%		30HRC Max
UNS S32750		800 Mpa		550 Mpa		15%		32 HRC Max
UNS S32760		750 Mpa		550 Mpa		25%		32 HRC Max
Equivalent Grade of Duplex Stainless Steel:
UNS NO. / USA			EN No. / EU			GB / China
UNS S31803			1.4462 (X2CrNiMoN22-5-3)			S22253 (022Cr22Ni5Mo3N)
UNS S32205 / 2205			1.4462 (X2CrNiMoN22-5-3)			S22053 (022Cr23Ni5Mo3N)
UNS S32750   / 2507			1.4410 (X2CrNiMoN25-7-4)			S25073 (022Cr25Ni7Mo4N)
UNS S32760			1.4501 (X2CrNiMoCuWN25-7-4)			S27603 (022Cr25Ni7Mo4WCuN)
ASTM A789, ASTM A790; GOST 9941–2022; EN 10216-5; GB/T 21833 — Standard dimensional tolerances for duplex stainless steel seamless tubes
Standard	Outside Diameter Tolerance(mm)		Thickness Tolerance				Length Tolerance (mm)
ASTM A790	10.29≤D≤48.26	+0.4/-0.8	10.3≤T≤73		T:+20%/ -12.5%		L:+6/-0
			88.9≤T≤457 T/D≤5%		T:+22.5%/-12.5%
	48.26<D≤114.3	±0.80	88.9≤T≤457 T/D>5%		T:+15%/-12.5%
	114.3<D≤219.1	+1.6/-0.8	508above T/D<5%		T:+22.5%/-12.5%
	219.1<D≤457.2	+2.4/-0.8	508above T/D>5%		T:+15%/-12.5%
ASTM A789	D<12.7	±0.13	T:±15%				L:+3.2/-0 L:+4.8/-0
	12.7<D≤38.1	±0.13	T:±10%
	38.1<D≤88.9	±0.25
	88.9<D≤139.7	±0.38
	139.7<D≤203.2	±0.76
EN10216-5	D3	±0.75%/±0.30	T3		T:±10%/ ±0.20mm		L≤6m,+5/-0 6<L≤12m,+10/-0
	D4	±0.5%/±0.10	T4		T:±7.5% / ±0.15mm
GOST 9941-2022 (except 06XH28MAT)	D<10	Normal:±0.30 High:±0.20 Higher:±0.15	T<0.3		Normal:±0.05 mm High:±0.03 mm		L:+15/-0
	10<D≤30	Normal:±0.40 High:±0.30 Higher:±0.20	0.3<T≤0.4		Normal:±0.07 mm High:±0.05 mm
	30<D≤95	Normal:±1.2% High:±1% Higher:±0.8%	0.4<T≤0.6		Normal:±0.10 mm High:±0.07 mm
			0.6<T≤1.0		Normal:±0.15 mm High:±0.10 mm
	D>95   D/S<40	Normal:±1.2% High:±1% Higher:±0.8%	1<T≤3 D/S<40		Normal:+12.5%/-15% High:+12.5%/-10% Higher:±10%
			3<T≤7 D/S >40		Normal:+12.5%/-15% High:±12.5%
	D>95   D/S >40	Normal:±1.5% High:±1.2% Higher:±1.0%	T>7 D<325		Normal:+12.5%/-10% High:±10%
			T>7 D>325		Normal:+12.5%/-15% High:±12.5%
GB/T 21833-2020	6≤D≤10	Normal:±0.2% High:±0.15%	T≤3.0		Normal:±12% High:±10%		L:+10/-0
	10<D≤30	Normal:±0.3% High:±0.2%
	30<D≤50	Normal:±0.4% High:±0.3%	T>3.0		Normal:+12.5%/-10% High:±10%
	50<D≤219	Normal:±0.85% High:±0.75%
	D>219	Normal:±0.9% High:±0.8%

Packing & Delivery

Company Profile

WENZHOU GUOHAO STEEL CO.,LTD

Wenzhou Guohao Steel Co., Ltd. is a Chinese manufacturer of high-performance stainless steel seamless pipes for construction, petrochemical, and offshore engineering.

We source raw materials from Tsingshan and Yongxing, and control the full production process—from cold rolling and solution annealing to fully automated eddy current and ultrasonic NDT—ensuring compliance with GB/T 14976, ASTM A312, GOST 9941 and EN 10216-5 on tensile strength, yield strength, elongation, dimensional tolerance, intergranular corrosion resistance, and uniform corrosion resistance.

We produce seamless tubes in austenitic (e.g., 304, 316L, 321, 310S), duplex (e.g., S32205, S32750), and nickel-based (e.g., Inconel 625, Hastelloy C-276, KhN78T) grades. All products are manufactured according to customer specifications, including outer diameter (OD), wall thickness, length, surface roughness, end finish, and packaging. Certificates of conformity are issued in accordance with EN 10204 Type 3.1 or 3.2, and third-party pre-shipment inspections are conducted by IAF-accredited bodies such as SGS or Bureau Veritas (BV).

FAQ

1.Q: Are you a manufacturer or trader?

A: We are manufacturers. We have our own factory to produce and process various kinds of stainless steel /nickel alloy pipes.

2.Q: Can we get some samples? Is there a charge?

A: Yes, we will provide you with the samples you want. The samples are free of charge, but the customer may have to pay the freight..

3.Q: Can we visit your factory?  

A: Of course, we welcome you to visit our factory on-site or visit our production line through online videos to learn more about our strength and quality. Once we have your schedule, we will arrange a professional sales team to follow up with you.

4.Q: How do you ensure the quality of the product?  

A: Our company's stainless steel pipe products are subject to full-process inspection in strict accordance with the enterprise quality manual. The factory inspection report is provided with the goods. If necessary, third-party inspections such as SGS can be accepted.

5.Q: What is your delivery time? 

A: Different products and procurement quantities have different delivery times. The product will be delivered as soon as possible on the basis of quality assurance. Usually, if the goods are in stock, it takes 3-10 days. Alternatively, if the goods are out of stock, it will take 25 to 45 days

6.Q: Can you arrange shipment?  

A: Of course, we have freight forwarders who have been cooperating for many years. We are VIP and can provide you with the most favorable prices and professional services.

7.Q: What if I don't have import experience?

A: We provide comprehensive import facilitation services to clients new to international procurement. Provided you hold a valid import license, our dedicated export compliance team will manage all end-to-end logistics coordination—including documentation preparation (e.g., commercial invoice, packing list, bill of lading), customs classification guidance, freight forwarding selection, and destination delivery oversight—to ensure secure, timely, and regulatory-compliant product delivery.

8.Q: Do you have an export license for steel products?

A: We are a factory and can directly apply for export licenses for steel products and export them in compliance with regulations.

9.Q: Do you have a VTB account?

A: We hold a VTB Bank (Russia) account, reducing cross-border collection fees and export-related costs.