2205 Duplex Stainless Steel Round Bar
2205 Duplex (UNS S32205/S31803) is a dual-phase stainless steel round bar offering double the yield strength of 316L and immunity to chloride stress corrosion cracking. PREN ≥ 34. Supplied per ASTM A276 with EN 10204 3.1 MTC.
| Material | Duplex Stainless Steel (Austenitic-Ferritic) |
|---|---|
| Grade / Standard | 2205 / UNS S32205 / F51 |
| Diameter | 3mm - 500mm |
| Length | 3m / 4m / 5m / 6m (or cut to length) |
| Delivery Condition | hot_rolled / cold_rolled |
| Surface Treatment | shot_blasting / coated |
| MOQ | 1 Ton |
| Delivery Time | 15-30 Days / Select Sizes In Stock |
| Loading Port | Tianjin / Shanghai / Qingdao |
Overview of 2205 Duplex Stainless Steel Round Bar
2205 is the most widely specified duplex stainless steel grade on the market, characterized by its advanced two-phase microstructure consisting of approximately 50% austenite and 50% ferrite. Specified under ASTM A276 / ASTM A479 / EN 10088-3 standards with dual UNS designations S31803 and the modern, higher-alloyed S32205, 2205 duplex stainless steel round bar offers a formidable combination of high mechanical strength and outstanding corrosion resistance. With a nominal composition of 22% Chromium, 5% Nickel, 3% Molybdenum, and a deliberate nitrogen addition, this grade bridges the performance gap between standard 300-series austenitic grades and highly expensive superalloys.
The most defining characteristic of the 2205 duplex round bar is its remarkable yield strength, which is roughly twice that of standard 316L stainless steel. For mechanical engineers, this translates to the ability to design much smaller, lighter pump shafts and fasteners that can handle the same load with reduced deflection and vibration. Furthermore, the dual-phase structure provides virtually complete immunity to chloride stress corrosion cracking (SCC)—a common and catastrophic failure mode for austenitic stainless steels in warm, chloride-rich environments. It is the definitive material choice for high-stress applications in offshore oil and gas, desalination, chemical processing, and marine engineering.
Key Features and Manufacturing Methods
Manufacturing 2205 duplex stainless steel round bar requires strict metallurgical control to ensure the critical 50/50 austenite-ferrite phase balance. Hot rolled (HR) bars (typically 16mm to 500mm) are produced from premium S32205 billets and are predominantly used as feedstock for heavy forging, machining flanges, and large valve bodies. Cold drawn (CD) bars (3mm to 100mm) are pulled through precision dies to improve dimensional tolerances (h9/h11), surface finish, and mechanical strength. For high-precision dynamic applications like electric motor shafts and high-pressure pump spindles, we provide peeled, turned, and centerless ground bars (up to 300mm) that achieve exact h6/h7 tolerances with a pristine, defect-free surface.
Because duplex stainless steel is prone to forming brittle intermetallic phases (like sigma phase) if cooled improperly, every 2205 bar undergoes a strict solution annealing process between 1040°C and 1080°C, followed by rapid water quenching. To guarantee peak performance in harsh environments, every batch is subjected to comprehensive testing beyond standard stainless grades. This includes ferrite phase balance testing (ASTM E562), Charpy V-notch impact testing at low temperatures (-46°C), ultrasonic testing (UT) for internal soundness, and verification of a Pitting Resistance Equivalent Number (PREN) of ≥ 34.
Main Applications of 2205 Duplex Stainless Steel Round Bar
Because of its immense strength and exceptional resistance to chloride environments, 2205 duplex stainless steel round bar is a vital raw material across heavy industry. In the Oil and Gas sector, it is heavily machined into valve stems, high-pressure pump shafts, choke valve internals, and specialized fasteners used in subsea equipment and topside platforms handling sour gas (H2S). The Water Treatment industry specifies 2205 round bar for high-pressure pump impellers and shafts in Seawater Reverse Osmosis (SWRO) desalination plants, where both intense mechanical stress and corrosive saltwater are present.
In the Chemical Processing Industry (CPI), 2205 bar is used to manufacture agitator shafts, mixer paddles, and centrifuge components that process organic acids, caustic solutions, and chloride-bearing fluids that would cause 316L to fail via stress corrosion cracking. The Marine industry utilizes it for high-strength propeller shafts, rudder stocks, tie bars, and rigging hardware. Additionally, due to its high strength-to-weight ratio, it is used for structural architectural components like tension rods and pedestrian bridge fittings in coastal salt-spray zones.
Why Choose Us for 2205 Duplex Stainless Steel Round Bar
Shandong Tanglu Metal Material Co., Ltd. is a specialized supplier of premium duplex and super duplex bar products. Sourced from globally recognized, ISO 9001, PED, and NORSOK M-650 qualified Chinese mills, our 2205 duplex round bars guarantee uncompromising quality. We strictly adhere to the S32205 chemistry, ensuring the upper limits of Chromium, Molybdenum, and Nitrogen are maintained to guarantee a PREN of 34 or higher, providing superior pitting corrosion resistance for your mission-critical machined components.
We maintain a strategic inventory of 2205 round bars from 3mm up to 300mm in hot rolled, peeled, and centerless ground conditions, ready to support urgent offshore maintenance and chemical plant turnarounds. Our quality assurance team guarantees that every batch undergoes 100% PMI testing, ultrasonic non-destructive testing (UT), and microstructure analysis to confirm the absence of intermetallic phases and verify the 40-60% ferrite ratio. Every order complies with NACE MR0175/ISO 15156 for sour service and is supplied with an EN 10204 3.1 Mill Test Certificate, with third-party inspection (DNV, ABS, LR, SGS) and EN 10204 3.2 certification seamlessly coordinated upon request.
📐 Dimension & Size Table
| Diameter (mm) | Length (m) | Weight (kg/m) | Tolerance |
|---|---|---|---|
| 10 | 3 / 6 | 0.623 | h9 / h11 (CD) |
| 12 | 3 / 6 | 0.897 | h9 / h11 (CD) |
| 16 | 3 / 6 | 1.594 | h9 / h11 (CD) |
| 20 | 3 / 6 | 2.491 | h9 / h11 (CD) |
| 25 | 3 / 6 | 3.892 | h9 / h11 (CD) |
| 30 | 3 / 6 | 5.605 | h9 / h11 (CD) |
| 40 | 3 / 6 | 9.964 | h9 / h11 (CD) |
| 50 | 3 / 6 | 15.570 | h9 / h11 (CD) |
| 60 | 3 / 6 | 22.420 | h9 / h11 (CD) |
| 80 | 3 / 6 | 39.860 | h9 / h11 (CD) |
| 100 | 3 / 6 | 62.280 | h9 / h11 (CD) |
| 120 | 3 / 6 | 89.680 | ± 1.0mm (HR) |
| 150 | 3 / 6 | 140.130 | ± 1.5mm (HR) |
| 200 | 3 / 6 | 249.120 | ± 2.0mm (HR) |
| 250 | 3 / 6 | 389.250 | ± 2.5mm (HR) |
| 300 | 3 / 6 | 560.520 | ± 3.0mm (HR) |
| 400 | 3 / 6 | 996.480 | ± 4.0mm (HR) |
| 500 | 3 / 6 | 1556.870 | ± 5.0mm (HR) |
* Custom sizes available upon request. Tolerances per relevant international standards.
🔬 Chemical Composition
| Element | Min | Max | Display Value | Note |
|---|---|---|---|---|
| C | - | 0.030 | ≤0.030 | Low carbon to prevent sensitization |
| Cr | 22.00 | 23.00 | 22.00-23.00 | High Cr for superior oxidation & pitting resistance |
| Ni | 4.50 | 6.50 | 4.50-6.50 | Controls ferrite-austenite phase balance |
| Mo | 3.00 | 3.50 | 3.00-3.50 | Crucial for chloride pitting resistance |
| N | 0.14 | 0.20 | 0.14-0.20 | Increases strength and PREN, stabilizes austenite |
| Mn | - | 2.00 | ≤2.00 | |
| Si | - | 1.00 | ≤1.00 | |
| P | - | 0.030 | ≤0.030 | |
| S | - | 0.020 | ≤0.020 |
* Chemical composition may vary by heat, thickness and specification. Please refer to the actual mill test certificate.
⚙️ Mechanical Properties
| Property | Value | Unit | Test Condition |
|---|---|---|---|
| Tensile Strength (Rm) | ≥655 | MPa | Solution annealed & quenched |
| Yield Strength (Rp0.2) | ≥450 | MPa | Almost double that of 316L (≥170 MPa) |
| Elongation (A) | ≥25 | % | Gauge length 50mm |
| Hardness (HBW) | ≤293 | HBW | Max 31 HRC (per NACE MR0175 limits) |
| PREN | ≥34 | - | PREN = %Cr + 3.3x%Mo + 16x%N |
| Impact Strength (Charpy V) | ≥40 | J | At -46°C (-50°F) |
| Microstructure | 40-60 | % | Ferrite/Austenite balance (ASTM E562) |
| Density | 7.80 | g/cm³ | Reference value |
* Values shown are minimum requirements unless otherwise stated.
📦 Commercial Information
| Packaging | 2205 Duplex round bars are packaged to premium export standards suitable for high-value alloys. Bars are bundled in hexagonal shapes using heavy-duty steel strapping over protective wood/plastic spacers to prevent surface contamination from carbon steel. For precision centerless ground or bright cold-drawn bars, each shaft is individually wrapped in VCI (Volatile Corrosion Inhibitor) film to prevent salt air corrosion, then securely packed into ISPM-15 fumigated wooden crates. This ensures absolute protection of the tight dimensional tolerances (h6/h7) and surface finish during long-distance oceanic freight. |
|---|---|
| Payment Terms | T/T (Telegraphic Transfer),L/C (Letter of Credit),D/P (Documents against Payment) |
| Price Term | FOB,CFR,CIF,EXW |
| Supply Capacity | 800 Tons/Month (Duplex & Super Duplex Bars) |
| Loading Port | Tianjin / Shanghai / Qingdao |
Why Choose Our 2205 Duplex Stainless Steel Round Bar?
Double Yield Strength of 316L
With a yield strength ≥ 450 MPa, 2205 is roughly twice as strong as standard austenitic grades. This allows engineers to design smaller diameter pump shafts and fasteners that reduce overall system weight while handling extreme mechanical loads.
Immunity to Chloride SCC
The dual-phase ferritic-austenitic structure provides virtually complete resistance to Chloride Stress Corrosion Cracking (SCC)—a common failure mode for 304 and 316 machined components in warm marine or chemical environments.
Excellent Pitting Resistance (PREN ≥34)
Highly alloyed with 22% Cr, 3% Mo, and Nitrogen, our S32205 bars deliver a guaranteed PREN of 34 or higher, vastly outperforming 316L in seawater, desalination plants, and harsh chemical streams.
NACE MR0175 / Sour Service Ready
Fully compliant with NACE standards for environments containing Hydrogen Sulfide (H2S), making it an indispensable material for machining offshore oil & gas valve internals and production manifold components.
Precision Ground & Phase Tested
Available in h6/h7 tolerances for high-speed dynamic applications. Every batch is solution annealed, rapidly quenched, and microscopically tested to ensure a perfect 40-60% phase balance without embrittling sigma phases.
🏭 Applications of 2205 Duplex Stainless Steel Round Bar
2205 Duplex stainless steel round bar is the ultimate raw material for machining components that endure extreme mechanical stress and corrosive environments simultaneously. In the Marine and Offshore industries, it is the standard for high-strength boat propeller shafts, rudder stocks, tie bars, and subsea fasteners where 316L lacks the required tensile strength or suffers from pitting. The Oil and Gas sector machines 2205 bars into high-pressure pump shafts, choke valve stems, and wellhead components exposed to sour gas (H2S), fully complying with NACE MR0175. The Water Treatment industry specifies 2205 centerless ground shafts for Seawater Reverse Osmosis (SWRO) desalination high-pressure pumps. In the Chemical Processing Industry (CPI), it is deployed for agitator shafts, centrifuge internals, and mixer paddles handling organic acids, caustic solutions, and chloride-bearing streams where SCC is a critical threat. Due to its exceptional strength-to-weight ratio, it is also utilized for high-load architectural tension rods and structural pins in coastal infrastructure.
📋 Quality & Certification
Our Certifications
- ✅ ISO 9001:2015
- ✅ ABS
- ✅ DNV GL
Mill Certificate Type
- 📋 EN 10204 3.1
- 📋 EN 10204 3.2
- 📋 Original Mill Certificate
❓ Frequently Asked Questions
What is a 2205 duplex stainless steel round bar?
A 2205 duplex round bar is a solid cylindrical bar made from a specialized stainless steel that contains a two-phase 'duplex' microstructure—roughly 50% austenite and 50% ferrite. This unique structure gives the bar the best characteristics of both phases: the high mechanical strength and SCC (Stress Corrosion Cracking) resistance of the ferritic phase, combined with the excellent general corrosion resistance, toughness, and ductility of the austenitic phase.
Why use 2205 round bar instead of 316L for pump shafts?
There are two major reasons: Strength and Chloride Resistance. 2205 has a yield strength of 450 MPa, which is more than double that of 316L. For pump and motor shafts, this higher strength significantly reduces shaft deflection and vibration under high loads, prolonging bearing and seal life. Alternatively, it allows engineers to design smaller, lighter shafts. Secondly, 316L is highly susceptible to Chloride Stress Corrosion Cracking and pitting in warm saltwater or chemical environments; 2205 is practically immune to SCC and has a much higher pitting resistance (PREN ≥ 34).
Is 2205 duplex stainless steel difficult to machine?
Yes, 2205 duplex is noticeably more challenging to machine than standard 304 or 316L. Its high yield strength and high work-hardening rate mean it generates significant cutting forces and heat, leading to faster tool wear. To successfully machine 2205 round bars, CNC operators must use rigid machine setups, high-quality carbide tooling with specific duplex geometries, heavy and continuous feed rates (to get under the work-hardened layer), and copious amounts of high-pressure coolant.
What is the difference between F51, S31803, and S32205?
These are different designations for essentially the same family of 2205 duplex stainless steel. F51 is the ASTM A182 forging specification designation. S31803 was the original UNS designation. However, engineers found that keeping the Cr, Mo, and N at the higher end of the S31803 specification yielded much better corrosion resistance. Thus, S32205 was created as a tighter specification with higher minimums. Reputable modern mills produce dual-certified material that meets both S31803 and S32205, guaranteeing superior PREN performance.
What are the temperature limitations for 2205 round bar applications?
2205 duplex has specific temperature operating windows. Its maximum continuous operating temperature is capped at approximately 300°C (572°F). Exposure to temperatures above this for extended periods causes '475°C embrittlement', where the ferrite phase becomes highly brittle and the bar loses impact toughness. On the cold side, 2205 maintains excellent Charpy impact toughness down to approximately -50°C (-58°F), after which it undergoes a ductile-to-brittle transition. For deep cryogenic processes, standard austenitic grades are preferred.
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2205 Duplex Stainless Steel Round Bar
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