JN Duplex 2205 Stainless Steel for Sale

Duplex 2205 stainless steel is a two-phase alloy - roughly half ferrite, half austenite - that delivers about twice the yield strength of 316L and far better resistance to chloride pitting and stress corrosion cracking, while costing noticeably less than super duplex 2507 or a 6-moly super-austenitic grade. That combination is why 2205 has become the default upgrade whenever 316L fails in chloride service, and the default value choice whenever super duplex has been over-specified.

JN supplies 2205 in both chemistries - UNS S31803 (F51) and the tighter UNS S32205 (F60) - across plate, sheet, pipe, tube, round bar, flanges and forged fittings. Material is delivered solution annealed and water quenched to ASTM A240, ASTM A790, ASTM A789, ASTM A182, A276, A479 and A815, with EN 10204 3.1 or 3.2 certification and NACE MR0175 / ISO 15156-3 compliance available on request. Start from the duplex and super duplex stainless steel hub if you are still deciding between the duplex families.

What Is 2205 Duplex Stainless Steel?

2205 is a ferritic-austenitic stainless steel - about half ferrite and half austenite - with roughly 22 percent chromium, 5-6 percent nickel, 3 percent molybdenum and 0.14-0.20 percent nitrogen in the S32205 chemistry. The mixed structure is what gives it about twice the yield strength of an austenitic grade and much better resistance to chloride stress corrosion cracking.

The ferrite phase carries the strength and the resistance to stress corrosion cracking; the austenite phase carries toughness and ductility. Because 2205 sits in both camps, it behaves differently from the 300-series stainless most buyers are used to: it is magnetic, it work-hardens faster, its springback on bending is larger, and it has a hard ceiling on service temperature. None of those are defects - they are simply the trade you make for the strength and the chloride performance.

JN Duplex Steel 2205 products are supplied and certified as follows:

• UNS S31803 and S32205, ASTM grades F51 and F60, EN 1.4462 (WNR 1.4462)
• ASTM A182, A240, A276, A479, A789, A790 and A815; ASME SA182, SA240, SA479, SA789, SA790 and SA815
• NORSOK MDS D45 grade F51; EN 10088-3
• NACE MR0175 / ISO 15156-3 for sour service, in the solution-annealed condition
• EN 10204 3.1 mill certificate as standard, 3.2 third-party witness on request

In most environments 2205 offers high general corrosion resistance. The high chromium content handles oxidising acids, while the molybdenum and nickel content handles reducing acids. Its resistance to chloride pitting and crevice corrosion sits between that of 316L stainless steel and that of super duplex 2507.

What Is the Difference Between S31803 and S32205?

S32205 is the tighter, higher-alloy version of S31803: more chromium, more molybdenum and more nitrogen, all inside narrower bands. The mechanical minimums are identical, so the upgrade is chemical - and it shows up as a higher pitting resistance equivalent number and more consistent corrosion behaviour.

This matters commercially because the word "2205" on a drawing does not tell the mill which chemistry you want. If the equipment sees chlorides, seawater, brine or sour gas, specify UNS S32205 and require the calculated PREN on the certificate. If the duty is mild and the driver is strength, S31803 will do the job at a lower price. Where the risk is unclear, ask for dual certification to both designations, which most mills can supply from a single heat.

Both designations carry the same forging grade family - S31803 is F51 and S32205 is F60 - and both are recognised across the whole duplex product-form standard set. See what is duplex S31803 and a guide to duplex stainless steel S32205 for the full chemistry discussion, and 2205 versus super duplex 2507 for the next step up.

What Grade Is Duplex Stainless Steel?

Duplex stainless steel is a family of grades, not a single grade. The family splits into four tiers - lean, standard, super and hyper duplex - and 2205 sits in the standard tier. Pick the tier by the PREN you need, not by the name on the datasheet.

The tiers are separated mainly by chromium, molybdenum and nitrogen, which is exactly what the PREN formula rewards. Lean grades trade corrosion resistance for lower and more stable cost; standard grades such as 2205 balance the two; super and hyper grades push chloride performance as far as a stainless steel can go before you have to move to a nickel alloy. The full naming logic is set out in the numbering system for duplex stainless steels.

JN is a leading duplex 2205 and super duplex 2507 manufacturer and supplier in China, with a professional sales team that will help you order high-quality duplex stainless steel at factory price. Tell us the medium, the chloride level, the temperature and the design code and we will recommend the tier, not just the grade.

What Are the Chemical Composition Limits for 2205?

The contractual composition limits for 2205 plate, sheet and strip come from ASTM A240: carbon 0.030 percent maximum, chromium 21.0-23.0 percent for S31803 and 22.0-23.0 percent for S32205, nickel 4.5-6.5 percent, molybdenum 2.5-3.5 or 3.0-3.5 percent, and nitrogen 0.08-0.20 or 0.14-0.20 percent. Everything else is iron and residuals.

Two practical points follow from that table. First, nitrogen is the cheapest element in the alloy and the most powerful per unit - every 0.01 percent of nitrogen adds 0.16 to the PREN while also stabilising the austenite phase and raising strength. Second, the low carbon and low sulfur limits are what keep the heat treatable and weldable, so a certificate showing carbon at 0.020 percent or below is a good sign, not a waste of alloy.

What Are the Mechanical Properties of 2205?

At room temperature ASTM A240 requires a minimum yield strength of 450 MPa (65 ksi), a minimum tensile strength of 620 MPa (90 ksi) for S31803 and 655 MPa (95 ksi) for S32205, a minimum elongation of 25 percent, and a maximum hardness of 293 HBW or 31 HRC. The 450 MPa yield is the headline number: it is roughly 2.6 times the 170 MPa minimum of 316L.

Elevated temperature is where duplex stops behaving like austenitic stainless. Strength falls steadily above about 100 degC and the alloy has a hard service ceiling that no amount of over-thickness will fix. The two measurement records below come from the original JN data set and are reproduced unchanged.

What Are the Physical Properties of 2205?

2205 has a density of 7.8 g/cm3, a thermal expansion coefficient of about 13.7 x 10^-6 per degC between 20 and 100 degC, a thermal conductivity of about 19 W/m.K at 100 degC, and it is magnetic. The expansion figure sits much closer to carbon steel than to austenitic stainless, which simplifies mixed-material designs.

How Corrosion-Resistant Is 2205?

2205 resists chloride pitting, crevice corrosion and stress corrosion cracking far better than 316L, and it handles oxidising and reducing acids, acetic and formic acid, and caustic service. Where it stops is warm, stagnant, high-chloride water - that is the boundary where super duplex takes over.

Pitting and crevice corrosion

The pitting resistance equivalent number is the standard screening yardstick: PREN = %Cr + 3.3 x %Mo + 16 x %N. Run on the S32205 minimum chemistry it gives about 34, and as supplied it typically lands at 34-36. Critically pitting temperature measured by ASTM G48 ferric chloride testing moves with surface finish, weld condition and test method, so the number on a datasheet is not a guarantee. For chloride duty, require the calculated PREN on the mill certificate and, where the risk justifies it, an actual G48 result.

Stress corrosion cracking

Chloride stress corrosion cracking is the failure mode that most often ends a 316L vessel or pipe run, usually above about 50 degC in the presence of chlorides and tensile stress. 2205 resists it because the ferritic phase interrupts crack propagation; the laboratory threshold temperature for 2205 is far higher. In practice 2205 removes chloride SCC from the risk register for most cooling water, firewater and process duties.

Acid and process media

The high chromium content handles oxidising acids such as nitric acid; the molybdenum and nickel handle reducing acids such as dilute sulfuric and phosphoric acid. 2205 is a recognised material for acetic acid and formic acid duty, and it is a standard choice in flue gas desulphurisation scrubbers and in the digester and bleach-plant sections of pulp and paper mills. For hydrochloric acid, hot concentrated sulfuric acid or severe acid-chloride mixes, step up to a nickel alloy - see Hastelloy C276 and the nickel alloy pipe selection by acid type guide.

If your duty is seawater specifically, read what alloy should I use for seawater piping and the super duplex S32750 desalination guide, and compare against the marine engineering and chemical equipment application pages.

What Temperature Range Can 2205 Handle?

Plan on about -50 degC to 300 degC (-58 degF to 572 degF) for continuous service. Above roughly 300 degC, 475 degC embrittlement and sigma-phase precipitation - not strength - become the governing limit, and no amount of extra thickness changes that.

The practical rule for a specification writer is simple: state the maximum design temperature, state that the material is to be supplied solution annealed, and state that no post-weld heat treatment is permitted. Those three lines remove almost every elevated-temperature failure mode for duplex.

How Do You Form, Machine and Heat-Treat 2205?

2205 forms and machines well, but it needs more force than 316L because of its yield strength, roughly two to three times the springback, and a mandatory solution anneal after hot work or after any thermal excursion into the 600-900 degC band.

Hot forming

Heat the entire workpiece as a whole and work it between 1750 degF and 2250 degF (955-1230 degC). 2205 is very soft in this window. Above it, the alloy is prone to hot tearing; below it, the austenite phase fractures. After hot forming, solution anneal immediately at 1900 degF (1040 degC) minimum and water quench to restore phase balance, toughness and corrosion resistance.

Cold forming

2205 can be cut and cold formed, but because of its high strength and hardness it needs more forming force than austenitic steel and demands explicit springback allowance. Use a larger bend radius than you would for 316L, expect roughly two to three times the springback, and remember that heavy cold work raises strength and hardness while reducing ductility - which will show up on the certificate if the material is not re-annealed.

Heat treatment

Anneal at 1900 degF (1040 degC) minimum, then rapidly cool by water quenching. Processing below 1900 degC risks precipitation of harmful metallic or non-metallic phases. Stress relieving in the 600-900 degC band is not permitted: if stress relief is required, re-solution anneal the whole component instead.

Machinability

On high-speed steel tooling, cutting speeds for 2205 are essentially the same as for 316L; with carbide tooling, reduce cutting speed by about 20 percent relative to 316L. Use rigid setups, positive rake geometry, constant feed and plenty of coolant, because 2205 work-hardens and will punish a dwelling tool.

How Do You Weld 2205 Duplex Stainless Steel?

Weld 2205 with ER2209 filler, at 0.5-2.5 kJ/mm heat input, with interpass temperature held at 150 degC or below, argon back-purged, and no post-weld heat treatment. The goal is not just a strong joint - it is a weld metal and a heat-affected zone that still have roughly balanced ferrite and austenite.

Duplex 2205 has very good weldability, but the weld procedure exists to protect the phase balance rather than to achieve strength. Filler metal is deliberately over-alloyed in nickel - about 9 percent against 5-6 percent in the base metal - so that the fast-cooling weld metal still transforms enough austenite. Heat input that is too low leaves an excessively ferritic bead; heat input that is too high, or too many passes at too high an interpass temperature, lets sigma and chromium nitride precipitate.

Target ferrite in the finished weld metal is normally 30-70 percent, measured by magnetic gauge or by point count to ASTM E562, and the qualification should include a Charpy test and an ASTM A923 check where the code or the duty calls for it. Finish by removing heat tint and passivating - a weld that looks clean but carries a straw-coloured oxide film will pit in chloride service.

2205 Versus 316L, 904L, 254SMO and Super Duplex 2507: Which Should You Buy?

Buy 316L for mild duty at the lowest price, 2205 when chloride resistance and strength both matter, 904L or 254SMO when the acid duty - not strength - governs, and super duplex 2507 when the chloride load exceeds what a PREN of about 35 can carry. The table below is the short form of that decision.

Two comparisons are worth reading in full before you commit: duplex 2205 versus super duplex 2507 for the chloride boundary, and 904L versus 254SMO versus 316L for the acid-driven decision.

What Are the Benefits of Duplex Stainless Steel?

The three benefits that matter commercially are roughly double the yield strength of 304 or 316L, far better resistance to chloride pitting and stress corrosion cracking, and a lower alloy surcharge exposure than the super-austenitic grades. The cost of those benefits is a hard temperature ceiling and a stricter fabrication procedure.

The comparison that buyers ask for most often is against 304 plate: 2205 has enough plastic toughness and more than double the yield strength, which is why duplex storage tanks and pressure vessels have walls 30 to 50 percent thinner than the austenitic equivalent. It also resists local rusting well, and its corrosion fatigue and wear corrosion behaviour exceeds austenitic stainless steels of comparable alloy content.

What Are the Main Applications of 2205?

2205 is bought for five markets: oil and gas, chemical processing, marine and desalination, pollution control and FGD, and pressure-containing equipment such as vessels, tanks and heat exchangers. In every one of them the buying reason is the same - chlorides plus pressure.

• Oil and gas: flowlines, manifolds, separators, risers, process piping, valves and wellhead equipment, both topside and subsea, including sour service under NACE MR0175 / ISO 15156-3. See the best alloy for offshore oil and gas pipelines.
• Chemical processing: reactors, storage tanks, heat exchangers and pipework handling phosphoric acid, acetic and formic acid, caustic and chloride-contaminated process streams. The duplex structure resists pitting and crevice corrosion in strong acid environments. Cross-check against the chemical equipment page.
• Marine and shipbuilding: seawater piping, ballast and cargo tanks, hull components exposed to seawater, and desalination balance-of-plant pipework. Compare with the marine engineering and seawater piping guides.
• Desalination and water treatment: evaporator shells, brine recirculation lines, RO skid pipework and reverse-osmosis high-pressure manifolds.
• Pollution control: flue gas desulphurisation absorbers and outlet ducting, effluent scrubbers, and wastewater treatment systems, where corrosion fatigue and stress corrosion resistance handle corrosive waste streams.
• Pulp and paper: digesters, bleach plant washers and liquor tanks.
• Pressure equipment and storage: storage tanks and pressure vessels to ASME VIII, where the higher allowable stress translates directly into thinner plate and lower weld volume.

In short, 2205 has many excellent properties and is a high-performance, multi-purpose stainless steel material. For any inquiry about 2205 stainless steel - pricing, availability or technical selection - contact JN directly.

Which Standards and Product Forms Apply to 2205?

Name the product standard on the order. Plate and sheet are ASTM A240, pipe is A790, tube is A789, flanges and forged fittings are A182 grades F51 and F60, bar is A276 or A479, and wrought butt-welding fittings are A815. Each has an ASME SA equivalent for coded pressure work.

Product forms stocked and made to order include plate and sheet, seamless and welded pipe, tube, round bar, flanges to ASME B16.5, forged fittings, and butt-welding fittings such as elbows, tees and reducers - for example the S32205 short radius elbow. Cut-to-length plate, bevelling, polishing and export packing are available on the same order.

What Does 2205 Cost and What Drives the Price?

2205 costs more per kilogram than 316L and less than most super-austenitic and super duplex grades, and it is usually the cheapest option per unit of strength. The price you actually pay is driven by the alloy surcharges, the form and thickness, the certification package and the quantity.

The value argument for 2205 is not that it is cheap per kilogram. It is that a strength-governed vessel or pipe run needs roughly half the wall thickness of a 316L design, so less material, less weld metal, less weight and less freight can more than offset the higher unit price. Ask JN to price the same duty in 316L, 2205 and 2507 and compare the installed number, not the kilogram number.

How Do You Specify 2205 on a Purchase Order?

Eight decisions remove almost every dispute: the UNS number, the standard and edition, the dimensions, the condition of supply, the corrosion acceptance criteria, the sour-service clause, the documentation package, and inspection plus Incoterms.

How to specify duplex 2205 on a purchase order

An eight-step checklist that removes the ambiguity that causes most 2205 order disputes.

1. Step 1 - Name the UNS number, not the nickname. Write UNS S32205 (or S31803) on the order, and state whether dual certification to both is acceptable. '2205' alone is ambiguous between two chemistries with different corrosion performance.
2. Step 2 - Name the standard and the edition. Cite the product standard - ASTM A240 for plate, A790 for pipe, A789 for tube, A182 for forgings and flanges, A276 or A479 for bar, A815 for wrought fittings - plus the ASME SA equivalent when the item goes into a coded pressure boundary.
3. Step 3 - Fix the dimensions, finish and quantity. Give thickness or schedule, width and length or nominal pipe size, surface finish, tolerances and the exact quantity, plus whether cut-to-length, bevelling or test coupons are required.
4. Step 4 - State the condition of supply. Require solution annealed at 1040 degC minimum and water quenched. This single line protects you against material supplied in a sensitised or sigma-contaminated condition.
5. Step 5 - Add the corrosion acceptance criteria. Require the calculated PREN on the certificate, a ferrite measurement, and an ASTM A923 test when the duty or the code calls for evidence that no detrimental intermetallic phase is present.
6. Step 6 - Add the sour-service clause if H2S is present. Reference NACE MR0175 / ISO 15156-3 by edition, cap hardness below the ASTM A240 maximum, and require the heat treatment record to prove the annealed condition.
7. Step 7 - Specify the documentation package. Ask for EN 10204 3.1 as standard and 3.2 when third-party witness is needed, plus PMI or spectro verification on delivery if the risk of mix-up is real.
8. Step 8 - Close with inspection, packing and Incoterms. State the inspection hold points, the export packing standard, the marking requirement (heat number traceable to the certificate) and the delivery term - EXW, FOB, CFR or CIF - with the named port.

How Do You Verify a 2205 Mill Test Report?

Run five checks in order: the UNS number matches the drawing, every element is inside the ASTM band, the calculated PREN is where the specification promised, the solution-anneal temperature is 1040 degC or higher with a water quench, and the hardness is under the applicable maximum. Any single failure sends the certificate back to the mill.

Key Takeaways

• Specify the UNS number. "2205" covers two chemistries; S32205 is the tighter, higher-PREN one and the right default for chloride, seawater and sour duty.
• 2205 roughly doubles the strength of 316L. A 450 MPa minimum yield against about 170 MPa means 30-50 percent thinner walls on strength-governed vessels and pipe.
• PREN is the number to put on the certificate. Around 34-36 for S32205 as supplied, against 24-26 for 316L and 40-42 for super duplex 2507.
• There is a hard temperature ceiling. Plan on -50 degC to 300 degC, avoid the 425-525 degC embrittlement band and the 600-900 degC sigma band, and never stress relieve.
• Welding is procedural. ER2209 filler, 0.5-2.5 kJ/mm heat input, 150 degC maximum interpass, argon purge, no post-weld heat treatment, heat tint removed and passivated.
• Buy on installed cost, not kilogram cost. 2205 usually wins on cost per unit of strength even when it loses on price per kilogram.
• Certificate discipline protects the asset. UNS number, chemistry, PREN, anneal temperature and hardness are the five checks that catch almost every bad heat.

Related Products

• Super Duplex S32750 / F53 - the step up when chlorides exceed 2205
• Super Duplex S32760 / F55 - tungsten-bearing super duplex for seawater
• Duplex S32205 / F60 - the tighter 2205 chemistry, stocked
• Duplex S31803 / F51 - the general-purpose 2205 chemistry
• Duplex steel pipe - seamless and welded pipe to A790
• Duplex sheet and plate - plate and sheet to A240
• Duplex round bars - bar to A276 and A479
• ASTM A182 S32205 flanges - F60 flanges and forged fittings
• Inconel 625 - when the duty needs a nickel alloy rather than duplex
• Hastelloy C276 - for hydrochloric and hot acid service

Frequently Asked Questions

Is 2205 the same as S31803 and S32205?

No. "2205" is the trade nickname for the whole family; S31803 and S32205 are two different UNS chemistries inside it. S32205 is the tighter, higher-alloy version: chromium 22.0-23.0 percent against 21.0-23.0 percent, molybdenum 3.0-3.5 percent against 2.5-3.5 percent, and nitrogen 0.14-0.20 percent against 0.08-0.20 percent. That tighter band raises the pitting resistance equivalent number, so S32205 is the safer buy for chloride and seawater duty. Always name the UNS number on the order.

Can you weld 2205 to 316 stainless steel?

Yes, you can weld them together, but always use ER2209 filler metal. Regular 316 filler will not work well because 2205 is stronger and more corrosion-resistant. The ER2209 filler creates a strong joint that balances both materials. Never weld them without filler metal, because an autogenous weld leaves a ferrite-rich, low-toughness bead that becomes a corrosion initiation site.

How do you weld 2205 duplex stainless steel?

Weld 2205 with ER2209 or E2209 filler, keep heat input in the 0.5-2.5 kJ/mm band, hold interpass temperature at 150 degC (302 degF) or below, and back-purge with pure argon so the root does not oxidise. Control the temperature well and let the metal cool below 150 degC between passes. After welding, remove heat tint with pickling paste or a nitric-hydrofluoric acid bath and passivate. Do not apply post-weld heat treatment; if a thermal treatment is required the whole component must be re-solution-annealed.

Is 2205 duplex stainless steel magnetic?

Yes, 2205 duplex stainless steel is partly magnetic. This happens because about half of the microstructure is ferrite, which is ferromagnetic, while the austenite half is not. The magnetism is normal and does not mean the steel is low quality or will rust easily. It still performs very well in seawater and in chemical process duty.

What is the PREN of 2205 and why does it matter?

PREN means pitting resistance equivalent number, calculated as PREN = percent chromium + 3.3 x percent molybdenum + 16 x percent nitrogen. As supplied, S31803 typically lands around 30-34 and S32205 around 34-36, against roughly 24-26 for 316L and 40 or more for super duplex 2507. It is a screening tool, not a certification value - ASTM A240 does not impose a minimum PREN - but asking for the calculated PREN on the mill test report is the cheapest way to prove that the heat you received is really seawater-grade duplex.

Is 2205 suitable for seawater service?

2205 is suitable for many seawater duties such as ballast and cargo tanks, firewater and cooling-water lines, heat exchanger shells and desalination balance-of-plant pipework, provided the water is flowing and not stagnant. For warm, stagnant or chlorinated seawater, or for creviced joints that cannot be inspected, step up to super duplex or a 6-molybdenum super-austenitic grade.

What is the maximum service temperature for 2205?

In practice continuous service is capped at about 300 degC (572 degF), and design codes often stop at 250-300 degC. Above roughly 300 degC long-term exposure causes 475 degC embrittlement, and between about 600 degC and 900 degC (1110-1650 degF) sigma and chi intermetallic phases precipitate and destroy both toughness and corrosion resistance. Below the freezing end, 2205 stays tough to about -50 degC (-58 degF) with 100 J or better Charpy energy, but it is not a cryogenic alloy - use austenitic grades below that.

Is 2205 compliant with NACE MR0175 for sour service?

Solution-annealed S31803 and S32205 are listed in NACE MR0175 / ISO 15156-3 for sour (H2S-containing) service subject to the hardness and environmental limits of the edition in force. The practical consequences are: order in the solution-annealed condition only, require hardness well under the ASTM A240 maximum of 31 HRC, and name the exact edition of MR0175 or ISO 15156-3 on the purchase order so that there is no argument later.

Does 2205 need post-weld heat treatment?

No. Duplex 2205 welds are used in the as-welded condition; post-weld heat treatment is not applied because reheating into the 600-900 degC range precipitates sigma phase. If a stress relief is unavoidable on code grounds, the only safe route is a full re-solution anneal at 1040 degC (1900 degF) minimum followed by a water quench, which means treating the whole fabrication, not just the weld.

How does 2205 compare with 316L for pressure vessels and tanks?

2205 roughly doubles the allowable design strength: 450 MPa minimum yield against about 170 MPa for 316L. That lets you cut plate thickness by roughly 30 to 50 percent on a strength-governed vessel, which cuts weld metal, weight, lifting cost and often total cost, even though 2205 costs more per kilogram. It also removes the chloride stress corrosion cracking risk that limits 316L to about 50 degC in chloride-bearing water.

When should I upgrade from 2205 to super duplex 2507?

Upgrade when the chloride load, the temperature or the stagnation risk exceeds what a PREN of about 35 can carry: warm seawater above roughly 30 to 40 degC, concentrated brines, aerated acidic chloride, or any crevice that cannot be inspected or flushed. Super duplex 2507 (UNS S32750, F53) carries a PREN around 40-42 and a 550 MPa minimum yield, so it also buys extra strength.

Can 2205 be hot formed and cold formed?

Yes to both. Hot form between 1750 degF and 2250 degF (955-1230 degC) with the whole workpiece heated, then solution anneal at 1900 degF (1040 degC) minimum and water quench to restore phase balance. Cold forming is possible but 2205 needs higher forming loads than 316L because of its yield strength, and springback is roughly two to three times that of austenitic grades, so allow extra overbend and use a larger bend radius.

Is 2205 more expensive than 316L, and is it worth it?

Per kilogram, yes - 2205 usually carries a noticeable premium over 316L because of the higher chromium, molybdenum and nitrogen content and the tighter melt control. Per unit of strength it is usually cheaper, because you buy roughly half the thickness for the same design load. The break-even normally arrives as soon as wall thickness is strength-governed rather than corrosion-governed.

What certifications should I require with a 2205 order?

Ask for an EN 10204 3.1 mill test certificate as the minimum, or 3.2 when a third party (SGS, BV, TUV, DNV, Lloyd's) must witness. The certificate should show the UNS number, the heat number, the full chemical analysis, the calculated PREN, the mechanical test results, the solution-anneal temperature, the ferrite count, intergranular corrosion test results to ASTM A923 when specified, and the NACE MR0175 / ISO 15156-3 statement if the duty is sour.

What is the difference between duplex 2205 and lean duplex 2101 or 2304?

Lean duplex grades such as UNS S32101 (2101) and UNS S32304 (2304) cut nickel and molybdenum to reduce cost and price volatility. They still beat 316L on yield strength, but their PREN sits around 25-30, below the 34-36 of 2205, so they are a strength-and-cost play for mild environments rather than a corrosion upgrade. Use 2205 when chlorides are the reason you are leaving 316L behind.

Does 2205 rust?

2205 resists rust far better than 316L, but it is stainless, not stain-free. It will discolour or pit if heat tint from welding is left on the surface, if free iron from carbon steel tooling is embedded in it, or if it sits under a stagnant chloride deposit. Removing heat tint by pickling, passivating after fabrication and keeping the surface free of iron contamination prevents almost every real-world rust complaint.

Which filler metal should I use for 2205?

Use ER2209 bare wire for GTAW and GMAW, E2209-16 or E2209-17 covered electrodes for SMAW, and a 2209 flux-wire combination for submerged arc. The ISO designation is 22 9 3 N L. The filler is deliberately over-alloyed in nickel - around 9 percent against 5-6 percent in the base metal - so that the weld metal re-balances to roughly equal ferrite and austenite as it cools.

What product forms and sizes can JN supply in 2205?

JN supplies duplex 2205 as plate and sheet to ASTM A240, seamless and welded pipe to ASTM A790, tube to ASTM A789, round bar to ASTM A276 and A479, forgings, flanges and forged fittings to ASTM A182 grade F51 and F60, and wrought butt-welding fittings to ASTM A815. Cut-to-length plate, bevelling, third-party inspection and export packing are available on the same order.

How do I read a 2205 mill test report?

Work through five checks in order. First, does the UNS number match the one on the drawing? Second, is every element inside the ASTM A240 band for that UNS? Third, what is the calculated PREN, and is it where the specification said it would be? Fourth, is the solution-anneal temperature at 1040 degC minimum with a water quench? Fifth, is the hardness under the maximum and, for sour service, under the NACE limit? A certificate that fails any one of the five should go back to the mill.

How fast can JN ship 2205?

Lead time depends on form and quantity. Common sizes of 2205 plate, pipe and bar are normally held or sourced within one to three weeks, while large-diameter pipe, heavy plate, forged flanges and made-to-order fittings typically run four to eight weeks including solution annealing, testing and packing. Send the UNS number, form, dimensions, quantity, standard and destination port and JN will confirm a firm ex-works or FOB date.

Glossary

Duplex stainless steel

A stainless steel whose microstructure is a mix of ferrite and austenite, typically close to half and half, combining the strength of the ferritic phase with the toughness of the austenitic phase.

PREN

Pitting resistance equivalent number, calculated as percent Cr + 3.3 x percent Mo + 16 x percent N. A screening index for chloride pitting resistance, not a code requirement.

Lean duplex

A lower-alloy duplex grade with reduced nickel and molybdenum, for example UNS S32101 or S32304, sold on strength and price rather than maximum corrosion resistance.

Super duplex

A higher-alloy duplex grade with a PREN around 40 or above, for example UNS S32750 (F53) and UNS S32760 (F55).

Sigma phase

A hard, brittle iron-chromium-molybdenum intermetallic that precipitates between roughly 600 degC and 900 degC and destroys toughness and corrosion resistance.

475 degC embrittlement

Loss of toughness after long exposure near 475 degC (885 degF), caused by separation of the ferrite phase into iron-rich and chromium-rich domains.

Solution annealing

Heating to 1040 degC minimum and water quenching to dissolve precipitates and restore the designed ferrite-austenite balance.

Interpass temperature

The temperature of the weld area immediately before the next pass is deposited; for 2205 it is held at 150 degC or below.

Heat input

The arc energy delivered per unit length of weld, in kJ/mm. Too low promotes excess ferrite, too high promotes sigma phase.

ER2209

The matching nickel-enhanced filler metal for welding 2205, ISO designation 22 9 3 N L.

Ferrite number

A measure of the ferromagnetic ferrite fraction, measured magnetically or by point count to ASTM E562; 2205 weld metal is normally 30-70 percent ferrite.

EN 10204 3.1

A mill test certificate issued by the manufacturer confirming compliance with the order, signed by an authorised inspector independent of the production department.

EN 10204 3.2

A certificate confirmed by an independent third-party inspector or the purchaser's representative, in addition to the manufacturer's own 3.1 statement.

NACE MR0175 / ISO 15156-3

The oil and gas standard governing materials for use in H2S-containing (sour) environments; it lists duplex grades with hardness and environmental limits.

ASTM A923

The standard test methods used to detect detrimental intermetallic phase in duplex stainless steels - sodium hydroxide etch, Charpy impact and ferric chloride corrosion.

PMI

Positive material identification, usually handheld X-ray fluorescence, used to confirm the alloy chemistry of material on receipt or after fabrication.

Chloride stress corrosion cracking

Cracking caused by the combined action of tensile stress, chlorides and temperature; 2205 resists it far better than 316L.

Heat tint

The coloured oxide film left on and around a weld; it is chromium-depleted and must be removed by pickling before the component enters service.

References and Standards

1. ASTM A240/A240M - Standard specification for chromium and chromium-nickel stainless steel plate, sheet, and strip for pressure vessels and for general applications.
2. ASTM A182/A182M - Standard specification for forged or rolled alloy and stainless steel pipe flanges, forged fittings, and valves and parts for high-temperature service (grades F51 and F60).
3. ASTM A789/A789M and ASTM A790/A790M - Seamless and welded ferritic/austenitic stainless steel tubing and pipe.
4. ASTM A276 and ASTM A479 - Stainless steel bars and shapes; bars for use in boilers and pressure vessels.
5. ASTM A815/A815M - Wrought ferritic, ferritic/austenitic and martensitic stainless steel piping fittings.
6. ASTM A923 - Test methods for detecting detrimental intermetallic phase in duplex austenitic/ferritic stainless steels.
7. ASTM E562 - Test method for determining volume fraction by systematic manual point count (ferrite measurement).
8. ASTM G48 - Test methods for pitting and crevice corrosion resistance of stainless steels and related alloys by use of ferric chloride solution.
9. ASME Boiler and Pressure Vessel Code, Section II Part D - Material properties, including allowable stresses for duplex stainless steels.
10. ASME B31.3 - Process piping, including limits on the use of duplex stainless steels at elevated temperature.
11. NACE MR0175 / ISO 15156-3 - Petroleum and natural gas industries; materials for use in H2S-containing environments in oil and gas production; cracking-resistant CRAs and other alloys.
12. EN 10088-1 and EN 10088-3 - European stainless steel standards covering 1.4462 composition and semi-finished product delivery conditions.
13. EN 10204 - Metallic products; types of inspection documents, defining the 3.1 and 3.2 certificate levels.
14. NORSOK M-630 and NORSOK M-650 - Norwegian oil and gas material data sheets and qualification of manufacturers of special materials.