Duplex 2205 vs Super Duplex 2507: Composition, PREN, Strength & When to Use Each
This comparison sets duplex 2205 (UNS S32205) against super duplex 2507 (UNS S32750), both austenitic-ferritic stainless steels known simply as "duplex" grades. 2205 is the workhorse of the family: a PREN around 34 to 36, well suited to moderate-chloride service. 2507, on the other hand, is a super duplex grade. Its PREN runs above 40. Yield strength sits roughly 20 to 25% higher than 2205's, and it holds up far better against warm-seawater pitting, crevice attack and chloride stress-corrosion cracking. That performance comes at a higher price, though. Pick the grade based on the service conditions, not the reverse. One clarification is needed here: 2205 and 2507 refer strictly to duplex stainless-steel alloy grades used in instrumentation fluid systems. They aren't unrelated part numbers, resistor codes, or product model numbers.
Crestflo makes instrumentation tube fittings, valves and tubing in both grades. That's what keeps this comparison grounded rather than theoretical: one supplier can hand you either alloy as a drop-in instrumentation component. Reviewed by the Crestflo Engineering Team.
Duplex 2205 & Super Duplex 2507: Also Known As (UNS S32205, S32750, 1.4462, 1.4410)
Both grades go by several equivalent names, and buyers often specify them differently depending on the standard they follow. Duplex 2205 shows up as UNS S32205. It's also listed under the older, slightly leaner nitrogen chemistry as UNS S31803. You'll find it as Werkstoff 1.4462, as EN X2CrNiMoN22-5-3, as the "22-5-3" duplex, as Alloy 2205, and under Sandvik's trade name SAF 2205® (a trademark of Sandvik/Alleima). Super duplex 2507, meanwhile, carries its own set of names: UNS S32750, Werkstoff 1.4410, EN X2CrNiMoN25-7-4, the "25-7-4" super duplex, Alloy 2507, and Sandvik's SAF 2507® (also a trademark of Sandvik/Alleima).
One thing needs to be said plainly: Zeron 100® is UNS S32760 (Werkstoff 1.4501), a super duplex bearing copper and tungsten that's related to but distinct from 2507/S32750. Don't confuse the two. 2507 isn't Zeron 100; think of S32760 as a separate super-duplex cousin. For the full single-alloy datasheets, see Duplex 2205 (UNS S32205) and Super Duplex 2507 (UNS S32750).
At-a-Glance: Duplex 2205 vs Super Duplex 2507 Comparison Table
| Attribute | Duplex 2205 | Super Duplex 2507 |
|---|---|---|
| Class | Duplex (austenitic-ferritic) stainless | Super duplex stainless |
| UNS | S32205 (legacy S31803) | S32750 |
| Werkstoff / EN | 1.4462 · X2CrNiMoN22-5-3 | 1.4410 · X2CrNiMoN25-7-4 |
| Common trade name | SAF 2205® (Sandvik) | SAF 2507® (Sandvik) |
| Chromium (Cr) | ~22–23% | ~24–26% |
| Nickel (Ni) | ~4.5–6.5% | ~6–8% |
| Molybdenum (Mo) | ~3.0–3.5% | ~3–5% |
| Nitrogen (N) | ~0.14–0.20% | ~0.24–0.32% |
| PREN (Cr + 3.3Mo + 16N) | ~34–36 | ~42–43 (>40) |
| Min 0.2% yield | ~450 MPa (65 ksi) | ~550 MPa (80 ksi) |
| Min tensile | ~620 MPa (90 ksi) | ~795–800 MPa (116 ksi) |
| Relative strength | Baseline | ~20–25% higher yield |
| Chloride pitting resistance | Good (moderate chloride) | Superior (warm/marine seawater) |
| Chloride SCC resistance | High | Very high |
| Max continuous service temp | ~≤300 °C (sigma / 475 °C embrittlement above) | ~≤300 °C (same duplex limit) |
| Weldability | Good, standard duplex procedure | More sensitive; tight heat-input control |
| Machinability | Moderate | Harder to machine |
| Density | ~7.8 g/cm³ | ~7.8 g/cm³ |
| Thermal expansion (20–100 °C) | ~13.5 µm/m·°C | ~13 µm/m·°C |
| Magnetic response | Ferromagnetic | Ferromagnetic |
| Relative cost | Lower (workhorse) | Higher (more Ni/Mo/N) |
Values are standard published alloy figures per the applicable ASTM/EN specifications, and they can be adjusted to requirement. Both grades are ferromagnetic.
Chemical Composition & Designations: UNS S32205 vs UNS S32750
Chemistry explains the performance gap between these two grades. Super duplex 2507 packs more chromium, molybdenum and nitrogen than duplex 2205 does; it's that richer alloying, nitrogen especially, that lifts its pitting resistance and strength.
| Element | Duplex 2205 (%) | Super Duplex 2507 (%) |
|---|---|---|
| Chromium (Cr) | ~22–23 | ~24–26 |
| Nickel (Ni) | ~4.5–6.5 | ~6–8 |
| Molybdenum (Mo) | ~3.0–3.5 | ~3–5 |
| Nitrogen (N) | ~0.14–0.20 | ~0.24–0.32 |
| Carbon (C, max) | ~0.030 | ~0.030 |
| Manganese (Mn, max) | ~2.0 | ~1.2 |
Compositions follow the standard published ranges set out in the applicable specifications; actual values depend on the standard in question and can be adjusted to requirement. Two points on designation matter here. First, S32205 replaced the older S31803. S31803 carries a wider, leaner nitrogen band. That's why modern 2205 is normally ordered against the tighter S32205 chemistry instead. Second, the "22-5-3" and "25-7-4" shorthand isn't arbitrary; it simply tracks the nominal Cr-Ni-Mo content of each grade. The ASTM equivalent for 2507 is UNS S32750 / Werkstoff 1.4410. For 2205, it's UNS S32205 / 1.4462.
PREN & Corrosion Resistance: Pitting, Crevice, Chloride & Seawater
PREN, the Pitting Resistance Equivalent Number, comes from a straightforward formula: PREN = %Cr + 3.3 × %Mo + 16 × %N. Run duplex 2205 through it and you land around 34–36. Super duplex 2507 comes in higher, roughly 42–43, well clear of the PREN 40 mark that separates the super-duplex class from standard duplex grades. The pattern holds beyond that single number, too. A higher PREN tracks with a higher critical pitting temperature (CPT) and a higher critical crevice temperature (CCT); 2507's CCT sits above 2205's. It also means better resistance to chloride-induced localized corrosion.
| Metric | Duplex 2205 | Super Duplex 2507 |
|---|---|---|
| PREN (Cr + 3.3Mo + 16N) | ~34–36 | ~42–43 (>40) |
| Chloride suitability | Moderate chloride, general process | Warm seawater / high chloride |
| Pitting resistance | Good | Superior |
| Crevice corrosion resistance | Good | Superior |
| Chloride SCC resistance | High | Very high |
| Critical pitting temperature (CPT, ASTM G48) | Lower than 2507 | Higher (warm-seawater capable) |
| Critical crevice temperature (CCT, ASTM G48) | Lower than 2507 | Higher |
| Sour service (NACE MR0175 / ISO 15156) | Within qualified limits | Higher-severity envelope |
2205 does the job in brackish water, general chemical process duty, and moderate chloride exposure. 2507 carries more chromium, molybdenum, and nitrogen. That extra alloying is what lets it stand up to warm seawater, subsea service, and high-chloride environments, conditions where 2205 would start to pit.
Both grades find use in sour service under NACE MR0175 / ISO 15156, though 2507 qualifies for a more severe envelope of chloride, temperature, and H2S partial pressure. Don't skip confirming the specific limits for your own conditions. For the full cross-alloy ranking, check the PREN comparison table and the corrosion-by-media alloy selector.
Mechanical Properties & Strength: Is 2507 Stronger Than 2205?
Yes, super duplex 2507 is genuinely stronger than duplex 2205. Its minimum 0.2% proof (yield) strength runs about 550 MPa (80 ksi), roughly 20-25% above 2205's ~450 MPa (65 ksi) minimum. Tensile strength follows the same pattern: 2507's minimum sits near 795-800 MPa (116 ksi), well ahead of 2205's ~620 MPa (90 ksi). Both figures dwarf standard austenitic grades like 316/316L. That's the real payoff of 2507's extra strength: thinner walls at a given design pressure, or a higher pressure rating for the same wall thickness.
| Property | Duplex 2205 | Super Duplex 2507 |
|---|---|---|
| Min 0.2% yield strength | ~450 MPa (65 ksi) | ~550 MPa (80 ksi) |
| Min tensile strength | ~620 MPa (90 ksi) | ~795–800 MPa (116 ksi) |
| Elongation (min) | ~25% | ~15% |
| Hardness | Per applicable spec (annealed) | Per applicable spec (annealed) |
Mechanical minimums come straight from the standard published values in the applicable ASTM/EN product specification. That said, they can be adjusted to fit your requirement.
Temperature Limits: Why Neither Duplex Grade Is a High-Temperature Alloy
2205 and 2507 both belong to the duplex family, and they share the same ceiling on service temperature. Continuous use tops out around 300 °C, since running hotter than that for extended periods invites 475 °C (885 °F) embrittlement and sigma-phase precipitation. Both mechanisms eat away at toughness and corrosion resistance. Neither grade is a high-temperature alloy, though. If the application calls for elevated temperatures, you'll want a nickel alloy instead. Duplex steels hold up fine at the cold end too, keeping good toughness at ambient and moderately low temperatures. Still, don't skip checking the minimum design temperature for your project.
Weldability, Machinability & Fabrication of 2205 vs 2507
You can weld both grades with matching or over-alloyed duplex filler, though 2507 asks for tighter discipline. Its chemistry runs richer, and that makes it more sensitive to heat input during welding. Interpass temperature and heat input need close control to protect the austenite-ferrite balance and keep sigma-phase or nitride precipitation out of the heat-affected zone. 2205 is more forgiving; its procedure window is simply wider. Machining tells a similar story. Both grades outmuscle austenitic stainless on the machine tool, a result of their high strength and work-hardening, but 2507 is the tougher of the two to cut. None of this falls on the buyer's plate for instrumentation components, though. Those fabrication factors get handled in-house.
Cost & Availability: Is 2507 More Expensive Than 2205?
Yes, super duplex 2507 usually costs more than duplex 2205. The reason comes down to higher nickel, molybdenum and nitrogen content, plus the tighter fabrication control the alloy demands. Duplex 2205 stays the cheaper, more widely available workhorse, and it's the default choice whenever its corrosion resistance is enough for the job. 2507 carries a premium, but that premium only makes sense when the application truly calls for super-duplex performance. For numbers on lead time and cost after tariffs, check the alloy lead-time & cost benchmark.
Standards & Product-Form Specs: ASTM A789, A790, A182, A276, A479
Both duplex grades share the same family of ASTM product-form specifications. That's a real convenience when you're drafting a spec that has to cover tube, forging and bar all at once.
| Product form | ASTM specification | Notes |
|---|---|---|
| Seamless/welded tube | A789 | Duplex/super-duplex tubing |
| Seamless/welded pipe | A790 | Duplex/super-duplex pipe |
| Forgings / fittings | A182 | Forged components |
| Bar | A276 / A479 | Bar and shapes |
See the underlying ASTM A789 and ASTM A790 tube and pipe specifications. For sour service, both grades are qualified under NACE MR0175 / ISO 15156 within their respective limits; NORSOK M-630 / M-650 are commonly specified for offshore duplex where required. Crestflo states conformance to the standard approvals applicable to each product type, for instrumentation fittings that anchor is ASTM F1387; certificates are held under our ISO 9001 / 14001 / 45001 & PED certification.
When to Choose Duplex 2205 vs Super Duplex 2507
It all comes down to just how aggressive the chloride, pressure and sour-service conditions are. Check the guide below first, then confirm it against your own partial pressures and temperatures.
| Service condition | Recommended grade | Why |
|---|---|---|
| General process, moderate chloride | Duplex 2205 | Sufficient PREN (~34–36) at lower cost |
| Brackish water, cost-sensitive systems | Duplex 2205 | Workhorse economy and availability |
| Warm seawater, marine, high chloride | Super Duplex 2507 | PREN >40 resists pitting/crevice |
| Subsea & offshore hydraulics | Super Duplex 2507 | Chloride SCC margin, higher strength |
| Aggressive sour service (NACE) | Super Duplex 2507 | Wider qualified H2S/chloride envelope |
| Higher design pressure, thinner wall | Super Duplex 2507 | ~20–25% higher yield strength |
Crestflo generally recommends 2205 for moderate-chloride, general-process work where cost matters. Step up to 2507 once you're dealing with warm seawater, subsea conditions, high chloride levels, or tougher sour service. If 2507 still doesn't cut it, take a look at 254 SMO vs super duplex vs AL-6XN.
For a broader, class-level comparison, see duplex vs super duplex. If you need workflow-driven selection instead, check the sour-service grade selection guide or the offshore / chloride selection guide. You'll find these grades used most often in offshore, subsea, and oil & gas work.
Both Grades, One Supplier: 2205 & 2507 Instrumentation Fittings, Valves & Tubing
Crestflo supplies duplex 2205 and super duplex 2507 alike, both as instrumentation components rather than mill product. What's on offer: compression and tube fittings with end connections up to 2 inches, or 50 mm, in outer diameter, available with single or double ferrules, hardened or non-hardened. Instrumentation valves round out the range, along with instrumentation tubing.
| Form | Duplex 2205 | Super Duplex 2507 |
|---|---|---|
| Tube fittings | 2205 tube fittings | 2507 tube fittings |
| Instrumentation valves | 2205 valves | 2507 valves |
| Tubing | 2205 tubing | 2507 tubing |
Compression tube fittings go through ASTM F1387 testing for dimensional interchange with major brands. That means either grade fits straight into an existing Swagelok®, Parker® or Hy-Lok® layout, no rework needed. Each part carries a heat-number mark with EN 10204 3.1 MTC (3.2 available on request), giving you full traceability. Both grades ship NACE MR0175 / ISO 15156 compliant.
Stock and delivery follow our standard model: ready stock for standard items, made-to-order for specials, 6–8 week delivery. Origin is Indian; US and European melt is available on request, with full material traceability. For details, see origin & compliance. We Engineer Confidence.
Ready to price out 2205 or 2507 fittings? Request a quote, request a sample, or talk to an engineer at Crestflo. Switching over from another brand? Our engineering team can put together a Swagelok®/Parker® cross-reference for you.
Frequently Asked Questions: 2205 vs 2507
Is 2205 duplex or super duplex?
Duplex 2205 (UNS S32205) is a standard duplex stainless steel, the workhorse of the industry, with a PREN around 34–36. It's not a super duplex.
Is 2507 a duplex or super duplex steel?
2507 (UNS S32750) is a super duplex stainless steel. It packs more chromium, molybdenum and nitrogen than 2205, and its PREN sits above 40.
What is the main difference between 2205 and 2507?
2507 packs more chromium, molybdenum and nitrogen than 2205 does. The payoff shows up in the numbers: a PREN above 40, versus 34–36 for its cousin, plus roughly 20–25% higher yield strength. It also holds up better against warm-seawater pitting, crevice corrosion and chloride stress-corrosion cracking. None of that comes cheap, though.
Which is better, 2205 or 2507?
Neither one's clearly better. 2205 handles moderate-chloride, general-process work where cost is a real concern. 2507, on the other hand, is built for warm seawater, subsea installations, high-chloride environments and the harsher sour-service conditions. Pick the grade based on what the service actually demands.
What is the equivalent material for 2507 stainless steel?
2507 corresponds to UNS S32750, Werkstoff 1.4410, EN X2CrNiMoN25-7-4, and SAF 2507®, a trademark held by Sandvik. Zeron 100 (UNS S32760) belongs to the same super duplex family, but it isn't the same alloy as 2507.
What ASTM grade is duplex 2205 equivalent to?
2205 is UNS S32205 (the older, leaner grade was S31803) and Werkstoff 1.4462. You'll find its product forms under ASTM A789 / A790 for tube and pipe, A182 for forgings, and A276 / A479 for bar.
What are the PREN values for 2205 and 2507?
PREN adds %Cr to 3.3 times %Mo, then 16 times %N. Duplex 2205 lands around 34–36. Super duplex 2507 climbs higher, roughly 42–43, well above the 40 mark that separates the two grades.
Can both grades be used in sour service (NACE MR0175 / ISO 15156)?
Both get used in sour service, each within its own qualified limits. 2507 handles a tougher range, though, covering higher chloride levels, temperature and H2S partial pressure. Check the specific limits that apply to your application before proceeding.
What is the temperature limit for 2205 and 2507?
Both grades are duplex, and continuous service tops out around 300 °C. Push past that ceiling and you're courting 475 °C embrittlement and sigma-phase formation. Neither one is a high-temperature alloy.
Does Crestflo supply both 2205 and 2507 fittings, valves and tubing?
Yes. Crestflo carries instrumentation compression and tube fittings up to 2" OD, plus valves and tubing in both grades. Ferrules can be hardened or non-hardened, and the line meets ASTM F1387 interchange. Every order ships with an EN 10204 3.1 MTC.
What is the lead time and origin for 2205 and 2507 components?
The framing ships as ready stock for standard items; specials are made to order, with 6–8 week delivery. Origin is Indian, though US or European melt is available on request, and full material traceability comes standard. TAA eligibility is covered on the origin and compliance page.