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X2CrNiMoN25-7-4 (Super Duplex 2507)

Super duplex 2507 β€” PRE=42-45, yield strength 550 MPa. For the most aggressive chloride and acid environments: subsea, desalination and chemical plant.

Stainless Steels Super Duplex Stainless Steel ENX2CrNiMoN25-7-4 DIN1.4410 UNSS32750 ASTMA240 / A276 UNS S32750 +12
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Description

X2CrNiMoN25-7-4 (EN 1.4410 / UNS S32750 β€” Super Duplex 2507) per EN 10088. PRE (Pitting Resistance Equivalent) = 42-45, which is among the highest of any duplex grade. Yield strength Rp0.2 >=550 MPa β€” 25% above standard 2205 duplex. Extraordinary resistance to chloride pitting, crevice corrosion and SCC. Standard for the most demanding offshore, desalination and chemical plant applications where 2205 is insufficient.

Key Properties β€” Solution Annealed (plate)
Rm (Tensile Strength)
795
MPa
Re / Rp0.2 (Yield)
550
MPa
Aβ‚… (Elongation)
β‰₯ 15.0
%
Hardness
β€” – 310
HB
E (Young's Modulus)
200
GPa
Density
7.80
g/cmΒ³
Main Designations (16)
Standard BodyDesignationCountry / RegionNote
EN X2CrNiMoN25-7-4 European Union
DIN 1.4410 Germany
UNS S32750 USA (UNS)
ASTM A240 / A276 UNS S32750 USA
BS EN 2507 UK
JIS SUS329J4L Japan
GOST 08H25N7AM3 (nearest) Russia / CIS
UNI X2CrNiMoN25-7-4 Italy
NF Z2CND25-7-03-AZ France
SS 2328 Sweden
PN X2CrNiMoN25-7-4 Poland
UNS S32750 USA (UNS)
GB 022Cr25Ni7Mo4N China
JUS C.4750SD Yugoslavia / Serbia Super duplex Cr-Ni-Mo-N stainless (nearest JUS equiv.)
ISO X2CrNiMoN25-7-4 International
ASME SA-240 UNS S32750 USA
Standards (16)
#Standard BodyDesignationCountry / RegionNote
1 EN X2CrNiMoN25-7-4 European Union β€”
2 DIN 1.4410 Germany β€”
3 UNS S32750 USA (UNS) β€”
4 ASTM A240 / A276 UNS S32750 USA β€”
5 BS EN 2507 UK β€”
6 JIS SUS329J4L Japan β€”
7 GOST 08H25N7AM3 (nearest) Russia / CIS β€”
8 UNI X2CrNiMoN25-7-4 Italy β€”
9 NF Z2CND25-7-03-AZ France β€”
10 SS 2328 Sweden β€”
11 PN X2CrNiMoN25-7-4 Poland β€”
12 UNS S32750 USA (UNS) β€”
13 GB 022Cr25Ni7Mo4N China β€”
14 JUS C.4750SD Yugoslavia / Serbia Super duplex Cr-Ni-Mo-N stainless (nearest JUS equiv.)
15 ISO X2CrNiMoN25-7-4 International β€”
16 ASME SA-240 UNS S32750 USA β€”
All values in wt.%
C
Carbon
≀ 0.0300
Si
Silicon
≀ 0.8000
Mn
Manganese
≀ 1.2000
Cr
Chromium
24.0000 – 26.0000
Ni
Nickel
6.0000 – 8.0000
Mo
Molybdenum
3.5000 – 4.5000
N
Nitrogen
0.2400 – 0.3200
Cu
Copper
≀ 0.5000
ElementSymbolMin %Max %Typical %
Carbon C β€” 0.0300 0.0150
Silicon Si β€” 0.8000 0.4000
Manganese Mn β€” 1.2000 0.8000
Chromium Cr 24.0000 26.0000 25.0000
Nickel Ni 6.0000 8.0000 7.0000
Molybdenum Mo 3.5000 4.5000 3.8000
Nitrogen N 0.2400 0.3200 0.2700
Copper Cu β€” 0.5000 0.1000
Mechanical Properties
ConditionCode Rm min
MPa		Rm max
MPa		 Re min
MPa		Re max
MPa		 Aβ‚… min
%		 Z
%		 KV
J		 HB minHB max HRC minHRC max E
GPa
Solution Annealed (plate) +AT 795 β€” 550 β€” 15.0 β€” β€” β€” 310 β€” β€” 200.0
Physical Properties
Density
7.800
g/cmΒ³
Melting Point
1350–1410
Β°C
Young's Modulus
200.0
GPa
Poisson's Ratio
0.300
β€”
Thermal Conductivity
14.0
W/mΒ·K
Thermal Expansion
13.00
Γ—10⁻⁢ /K
Specific Heat
480
J/kgΒ·K
Electrical Resistivity
0.8600
¡Ω·m
Magnetic
Yes
 
Heat Treatment
Solution Annealing
Temperature:1040Β°C – 1120Β°C
Medium:Rapid water quench
Duration:Sufficient
Cooling:Water quench β€” MUST be rapid
Hardness After:HB 310 max
Rapid quench absolutely mandatory. Slow cooling causes sigma and alpha-prime embrittlement.
AVOID sustained exposure
Temperature:700Β°C – 955Β°C
Medium:N/A
Duration:N/A
Cooling:N/A
Hardness After:N/A
Sigma phase forms rapidly at 700-955 C. Chi phase at 600-800 C. NEVER allow prolonged exposure in this range.
Machinability
Machinability Rating
relative to AISI B1112 = 100%
35.0%
Very Difficult
Turning Speed (HSS)
12
m/min
Turning Speed (Carbide)
75
m/min
Feed Rate (Turning)
0.090
mm/rev
Drilling Speed (HSS)
8
m/min
Milling Speed (Carbide)
80
m/min
CoolantHigh-pressure flood coolant mandatory
Chip FormationShort-medium chips; very high cutting forces vs 2205
Tool MaterialCarbide M10/P10 TiAlN coated; reduce speed ~30% vs 2205
Surface FinishRa 0.4-1.6 um
Very difficult to machine β€” hardest standard duplex grade. Cutting forces 40-50% higher than 316L. Maintain constant chip load, heavy coolant. Rating ~35% vs B1112.
Applications
Subsea Oil & Gas
Manifolds, wellheads, X-mas tree bodies and subsea valve bodies in the most aggressive sour service.
Desalination
High-pressure RO pressure vessels, membranes housings and seawater intake strainers.
Chemical Process
Reactors, heat exchangers and piping in chloride-containing acid service where 2205 fails.
Technical Notes
βœ…
2507 vs 2205
PRE 2507=42-45 vs 2205=35. Use 2507 when: chlorides >1000 ppm at >80 C, strong acid service, or when 2205 has known pitting or SCC failures.
⚠️
Max Service Temperature
Maximum continuous service: 300 C. Above this temperature impact toughness drops rapidly.
πŸ”₯
Weldability
Good but demanding. Use 2509 filler (ER2594). Interpass max 150 C. Heat input 1.0-2.5 kJ/mm.