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Utilizing 26 high-precision cold rolling mills and 6 cold drawing machines, we ensure dimensional accuracy and superior mechanical properties.
S31803 Duplex Stainless Steel Tubing
High Strength Dual-Phase Alloy | UNS S31803 / 2205 | Superior SCC Resistance
ASTM A789 / A790 | PREN ≥ 34 | Phase BalancedRelated Products
Introduction
S31803 Duplex Stainless Steel Tubing represents a sophisticated metallurgical leap, offering a dual-phase microstructure that harmoniously balances austenite and ferrite in approximately equal proportions. Often referred to as "2205" Duplex due to its 22% Chromium and 5% Nickel composition, S31803 (UNS S31803) is specifically engineered to provide a high-performance alternative to standard 300-series austenitic steels. By leveraging the high strength of the ferritic phase alongside the superior corrosion resistance of the austenitic phase, this tubing delivers nearly double the yield strength of TP316L while providing exceptional resistance to localized corrosion, particularly chloride-induced stress corrosion cracking (SCC), which remains a primary failure mode in offshore and petrochemical piping systems.
The manufacturing of S31803 seamless tubing requires extreme precision in thermal management. The performance of the alloy is entirely dependent on maintaining the delicate 50/50 phase balance. Our production process utilizes advanced cold-working followed by a strictly controlled solution annealing heat treatment, typically between 1020°C and 1100°C, followed by rapid water quenching. This rapid cooling is essential to prevent the formation of detrimental intermetallic phases, such as Sigma phase, which can severely compromise the material's impact toughness and corrosion resistance. The result is a seamless tube with a highly refined grain structure that offers superior fatigue strength, making it ideal for high-pressure subsea umbilicals and heat exchanger tubes subject to constant mechanical vibration and thermal cycling. The absence of a longitudinal weld seam in our tubes ensures 100% metallurgical integrity, providing a 20% safety increase in allowable working pressure according to modern pressure vessel codes.
From a chemical standpoint, the high Chromium (21-23%), Molybdenum (2.5-3.5%), and Nitrogen (0.08-0.20%) content of S31803 results in a Pitting Resistance Equivalent Number (PREN) typically exceeding 34. This makes the tubing effectively immune to pitting and crevice corrosion in brackish water, seawater, and aggressive chemical environments containing hydrogen sulfide (H2S). The Nitrogen addition is particularly critical, as it enhances the pitting resistance of the austenitic phase and improves the overall weldability of the alloy. In the petrochemical and refining industries, S31803 is the material of choice for heat exchangers and process piping where sour gas and high chloride levels are present. Its superior erosion-corrosion resistance also makes it highly effective for transporting slurries or high-velocity fluids in desalination plants and industrial waste treatment facilities.
Moreover, the economic value of S31803 is significant. Due to its higher mechanical strength, engineers can often specify a thinner wall thickness for the same pressure rating compared to standard austenitic grades, leading to substantial weight savings in offshore platform deck loads and reduced overall material costs. Compliance with international standards such as ASTM A789 and A790 ensures that our S31803 seamless tubes meet the rigorous requirements of the global energy sector. By choosing our duplex solutions, industrial operators are investing in a future-proof material that offers the ultimate combination of high mechanical reliability, exceptional corrosion immunity, and reduced Total Cost of Ownership (TCO) in the world's most unforgiving operating environments.
Specifications
| Material | S31803 / S2205 / 1.4462 |
| Standards | ASTM A789, A790, EN 10216-5 |
| OD Range | 6.0mm - 406.4mm |
| WT Range | 1.0mm - 30.0mm |
| Phase | 40-60% Ferrite Balance |
Chemical Composition
| C | Cr | Ni | Mo | N |
| ≤.03 | 21-23 | 4.5-6.5 | 2.5-3.5 | .08-.20 |
PREN ≥ 34 Dual Phase
Mechanical Performance
Quality Control
| NDT | 100% ET & UT Testing |
| Corrosion | ASTM G48 Pitting Test |
| Heat Tx | Solution Anneal & Quench |
Industrial Applications
Oil & Gas Subsea umbilicals and flowlines
Desalination High-pressure RO evaporator tubes
Chemical Plants Chloride-heavy heat exchangers
Strategic Advantages
Double Strength
Yield strength twice that of austenitic 316L, allowing thinner walls.
SCC Immunity
Excellent resistance to chloride stress corrosion cracking.
High PREN
Pitting resistance exceeds most 300-series grades in seawater.
Fatigue Life
Higher endurance limits under mechanical and thermal stress.
About Jiangsu Jend Tube Co.,Ltd.
As China S31803 Duplex Stainless Steel Tubing Manufacturers and Wholesale S31803 Duplex Stainless Steel Tubing Factory, Established in 2011 and is a manufacturing enterprise with a complete manufacturing cycle from raw material selection to finished product delivery. The company currently has more than 100 employees, covers an area of 30015 square meters, and has a registered capital of 48 million yuan, annual production capacity of 3800 tons.
The company has passed ISO9001:2015 quality certification, domestic pressure vessel TS certification, and foreign pressure vessel PED certification. With rich experience and mature technology, we have been expanding our market internationally. At present, our products are exported to more than 50 countries and regions including Europe, America, Southeast Asia, and the Middle East.
The company adheres to different production norms and standards such as the American standard (ASTM), the European standard (EN), the German standard (DIN), the Japanese standard (JIS), the Russian standard (GOST), and the Chinese standard (GB).
Our company specializes in and customizes various specifications of Martensite TP410 (0Cr13, 1Cr13), Ferrite TP405 (1Cr13Al), TP430 (1Cr17), TP444 (0Cr18Mo2), TP439, TP409 (0Cr11Ti), It is also proficient in manufacturing Austenitic seamless stainless steel pipes of series such as TP304(L/H), TP316(L/H/Ti), TP310S, TP317, TP321(H) and TP347(H). Duplex such as S31803, S2205, S32750, S32304, and Nickel-based alloys Monel400, Monel600, Monel800, GH3030, 904L, Inconel 625, etc.
The company mainly produces seamless steel pipes with the following specifications: outer diameter: 3.18mm to 406.4mm, wall thickness: 0.3mm to 20mm, and the longest length is 25000mm. Additionally, it can customize seamless steel pipes with special materials and specifications according to customer requirements. The company attaches great importance to scientific innovation. The staff of the company vigorously develop technological research and development.
Jiangsu Jend Tube Co.,Ltd. will continuously accumulate professional knowledge and capabilities, striving to become a leader in the domestic market and even the world market. Strive to be the most reassuring pipe manufacturing enterprise for customers.
Precision Manufacturing and Process Optimization
We rely on precision equipment and optimized production technologies to achieve outstanding mechanical performance and consistent product quality.
Cold Rolling and Cold Drawing
Solution Heat Treatment
Natural gas solution treatment furnaces and BA solution treatment furnaces optimize the material's grain structure, enhancing corrosion resistance.
Precision Straightening and Polishing
10 straightening machines and 8 finishing polishing machines guarantee product surface smoothness and dimensional accuracy.
Automated Inspection and Quality Assurance
Real-time monitoring systems ensure the stable quality of every batch of products.
Usage & Installation Tips
Welding Shield
Use Nitrogen-enhanced shielding gas (e.g., Ar+2% N2) to maintain austenite balance in the weld root.
Temperature Limit
Avoid service above 300°C (572°F) to prevent "475°C embrittlement" of the ferritic phase.
Value-Added Services
U-Bending
Custom U-tubes for high-pressure exchangers with stress-relief.
IGC Testing
ASTM A262 and G48 corrosion testing for verification.
Phase Check
Metallographic phase balance report for every heat number.
Logistics & Terms
30% T/T / L/C. Delivered in heavy-duty IPPC plywood cases with VCI rust-inhibitor protection for ocean freight.
Standards
ASTM A789/A790
NACE MR0175
PED 2014/68/EU
ISO 9001
Frequently Asked Questions
What is Duplex S31803?
It is a stainless steel with a mixed microstructure of austenite and ferrite (approx. 50/50), offering higher strength and superior SCC resistance.
How much stronger is S31803 than TP316L?
S31803 has nearly double the yield strength of standard austenitic grades, allowing for thinner wall designs and weight savings.
What is the PREN value for S31803?
The Pitting Resistance Equivalent Number (PREN) is typically ≥ 34, offering much better protection in seawater than 316L (PREN ~24).
Is S31803 magnetic?
Yes, unlike 300-series steels, duplex grades are magnetic due to their ferrite content.
What is the maximum operating temperature?
Duplex steels are generally limited to below 300°C (572°F) to avoid the risk of embrittlement of the ferritic phase.
Is it resistant to Stress Corrosion Cracking (SCC)?
Yes, the ferritic phase provides excellent immunity to chloride-induced SCC, making it ideal for offshore and chemical plants.
Can S31803 be welded?
Yes, but it requires careful control of heat input and specific filler metals (like 22.9.3.L) to maintain the phase balance.
Do you provide phase balance reports?
Yes, we provide metallographic analysis to confirm the 40-60% ferrite/austenite ratio for every batch.
What are typical subsea applications?
It is widely used for subsea umbilicals, heat exchangers, and flowlines due to its pressure integrity and corrosion resistance.
What is the MOQ?
Standard MOQ is 500kg-1000kg depending on sizing, though we carry stock for standard project requirements.
Upgrade to Duplex Performance
Contact our technical team for S31803/2205 sizing and corrosion-resistance data.
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