Defining Reliable Flow Solutions for Harsh Corrosive Environments – by Womic Steel
Solving Real Pipeline Problems in Corrosive and High-Stress Conditions
In environments where chloride-induced corrosion, stress corrosion cracking, and high mechanical loads coexist, selecting the wrong pipe material leads to premature failure, unplanned shutdowns, and escalating lifecycle costs. This is exactly where ASTM A789 / ASTM A790 S31803 duplex stainless steel pipes demonstrate their true value.
At Womic Steel, we manufacture and supply S31803 duplex stainless steel seamless and welded pipes not as a commodity product, but as a fully engineered pipeline solution, designed to perform reliably in offshore, chemical, desalination, and energy applications.
Technical Foundation: ASTM A789 / A790 and Global Material Alignment
ASTM A789 and ASTM A790 are the core international standards governing duplex stainless steel pipes for pressure and corrosion-resistant service.
ASTM A789 covers seamless and welded duplex stainless steel tubes for general corrosive service.
ASTM A790 extends these requirements to pipes intended for pressure, high-temperature, and structural pipeline applications, making it the primary reference for process piping systems.
The steel grade UNS S31803 represents a classic 22Cr duplex stainless steel, engineered to achieve an approximately 50% austenite and 50% ferrite microstructure, delivering a superior balance of strength and corrosion resistance.
Globally, S31803 is equivalent to:
EN 1.4462 / X2CrNiMoN22-5-3
ISO 3183 Duplex Class
GB/T 20878 022Cr22Ni5Mo3N
Womic Steel ensures full material consistency across all standards through strict chemical composition control and heat treatment discipline.
Chemical Composition of ASTM A789 / A790 S31803 Duplex Stainless Steel Pipes
(UNS S31803 – Typical Chemical Composition)
|
Element |
ASTM A789 / A790 Requirement (%) |
Womic Steel Internal Control (%) |
Function & Technical Significance |
| Carbon (C) | ≤ 0.030 | ≤ 0.025 | Low carbon minimizes carbide precipitation and improves corrosion resistance |
| Silicon (Si) | ≤ 1.00 | ≤ 0.80 | Improves oxidation resistance and molten metal fluidity |
| Manganese (Mn) | ≤ 2.00 | ≤ 1.50 | Enhances deoxidation and hot workability |
| Phosphorus (P) | ≤ 0.030 | ≤ 0.025 | Controlled to avoid embrittlement |
| Sulfur (S) | ≤ 0.020 | ≤ 0.010 | Low sulfur improves toughness and weld integrity |
| Chromium (Cr) | 21.0 – 23.0 | 21.5 – 22.8 | Primary element for corrosion and pitting resistance |
| Nickel (Ni) | 4.5 – 6.5 | 5.0 – 6.2 | Stabilizes austenite phase |
| Molybdenum (Mo) | 2.5 – 3.5 | 2.8 – 3.3 | Enhances resistance to pitting and crevice corrosion |
| Nitrogen (N) | 0.08 – 0.20 | 0.14 – 0.18 | Increases strength and improves pitting resistance (PREN) |
| Iron (Fe) | Balance | Balance | Structural matrix |
Technical Note:
Through tight nitrogen and chromium control, Womic Steel ensures a stable PREN value ≥ 35, critical for seawater and chloride-rich environments.
Mechanical Properties of ASTM A789 / A790 S31803 Duplex Stainless Steel Pipes
(Solution Annealed Condition)
|
Property |
ASTM A789 / A790 Minimum Requirement |
Typical Womic Steel Performance |
| Tensile Strength (Rm) | ≥ 620 MPa | 650 – 750 MPa |
| Yield Strength (Rp0.2) | ≥ 450 MPa | 480 – 550 MPa |
| Elongation (A) | ≥ 25 % | ≥ 30 % |
| Hardness | ≤ 290 HB | 250 – 280 HB |
| Impact Toughness (optional, project-based) | As specified | Fully compliant when required |
| Ferrite Content | Not numerically fixed | Controlled to optimal duplex range |
Engineering Advantage:
Compared to austenitic grades such as 316L, S31803 offers nearly double the yield strength, enabling thinner wall design, reduced system weight, and higher pressure efficiency.
Manufacturing Process: Seamless and Welded Excellence
Seamless Pipe Production
Seamless S31803 pipes are produced through hot piercing, elongation, and precision cold finishing processes. This route ensures uniform wall thickness, excellent surface quality, and superior pressure resistance, especially for high-integrity pipelines.
Welded Pipe Production
For welded pipes, Womic Steel employs high-precision TIG and Plasma welding technologies, using duplex-grade filler control to ensure weld metal corrosion resistance matches the base material. Post-weld solution annealing is mandatory, restoring duplex phase balance and eliminating residual stress.
Both seamless and welded pipes undergo identical final inspection and certification standards.
Heat Treatment and Ferrite Control Technology
Proper heat treatment is critical for duplex stainless steel performance. Womic Steel applies solution annealing typically within 1070–1120°C, followed by rapid water quenching. This process:
Dissolves harmful intermetallic phases
Restores optimal austenite–ferrite balance
Maximizes corrosion resistance and toughness
Ferrite content is verified using metallographic analysis and ferrite measurement instruments, ensuring compliance with both ASTM requirements and project-specific specifications.
Inspection, Testing, and Full Traceability
Every ASTM A789 / A790 S31803 pipe supplied by Womic Steel is subjected to a complete inspection chain, including:
l Chemical composition analysis
l Tensile and mechanical testing
l Hydrostatic or pneumatic pressure testing
l Ultrasonic testing (UT) and eddy current testing (ET)
l Ferrite content verification
l ASTM G48 Method A pitting corrosion testing when required
Each pipe is fully traceable, with EN 10204 3.1 or 3.2 material certificates issued per customer or project requirements.
Production Capacity, Flexible Supply, and Zero MOQ Policy
Womic Steel maintains strategic inventories of duplex stainless steel raw materials and semi-finished products, enabling us to support both large EPC projects and small-volume urgent orders.
There is no minimum order quantity. Even a single pipe can be supplied with full certification, making us a practical partner for maintenance, replacement, and pilot projects.
Typical lead times:
Stock sizes: short delivery
Customized production: optimized scheduling with transparent timelines
Processing, Packaging, and Global Logistics Advantages
Fabrication and Processing Services
In addition to ASTM A789 / A790 S31803 duplex stainless steel pipes, Womic Steel provides flexible fabrication and processing services, allowing customers to receive semi-finished or ready-to-install components according to project drawings.
Typical services include pipe prefabrication spools, welded assemblies, and machined components, helping reduce on-site workload and installation time.
Available Processing Scope
|
Service Type |
Capability |
| Pipe Cutting | Fixed length, project-based cutting |
| Beveling & End Machining | Welding preparation per ASME / ISO |
| Welding & Prefabrication | Pipe spools, welded pipe assemblies |
| Drilling & Hole Making | Instrument holes, branch openings |
| Bending | Cold bending with controlled radius |
| Forming & Machining | Slotting, special openings, custom parts |
All fabrication work is performed under qualified welding procedures and dimensional control, ensuring material integrity and compliance with project specifications.
For export delivery, pipes are protected using VCI anti-corrosion materials, PE wrapping, reinforced bundling, and seaworthy packaging, ensuring cleanliness and corrosion protection during long-distance transport.
Our logistics team works closely with major shipping lines, securing stable vessel space and competitive freight solutions for global delivery.
Application Fields of S31803 Duplex Stainless Steel Pipes
Womic Steel ASTM A789 / A790 S31803 pipes are widely used in:
l Oil & gas production and processing
l Offshore and subsea systems
l Chemical and petrochemical plants
l Desalination and seawater handling systems
l Pulp & paper industry
l Marine and shipbuilding applications
Choosing Womic Steel Means Choosing Reliability
Selecting Womic Steel means choosing more than a compliant material. It means selecting a fully transparent manufacturing system, verified metallurgy, rigorous testing, flexible supply, and dependable global delivery—combined into one reliable pipeline solution.
We pride ourselves on our customization services, fast production cycles, and global delivery network, ensuring your specific needs are met with precision and excellence.
Website: www.womicsteel.com
Email: sales@womicsteel.com
Tel/WhatsApp/WeChat: Victor: +86-15575100681 or Jack: +86-18390957568
Post time: Feb-05-2026