Super Duplex 2507 (S32750)

What is Super Duplex 2507 and its applications?

Super Duplex 2507 (UNS S32750) is a chromium-nickel-molybdenum stainless steel containing nitrogen and both ferritic and austenitic phases. It combines high strength with resistance to chloride attack and is used in seawater systems, offshore equipment and chemical processing.

Seawater cooling: Pumps, valves and associated connections exposed to salt water.
Desalination: Brine-handling equipment where chloride concentration and crevices govern material selection.
Offshore process equipment: Mechanical components requiring corrosion resistance and high strength.

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Engineering Application & Selection Guide

Chromium, molybdenum and nitrogen support localized-corrosion resistance; nitrogen also strengthens the austenite. The useful properties depend on preserving the duplex microstructure through the manufacturing and heat-treatment route.

2507 stud bolts — For a seawater flange enquiry, include water temperature, chlorination, periods of stagnation and any cathodic protection.
2507 hex bolts — On coated offshore structures, identify which surfaces are electrically connected and where seawater can collect beneath washers.
2507 hex nuts — Specify the mating bolt condition, thread fit and required load capacity rather than selecting the nut by chemistry alone.

Compare Duplex 2205 when assessing whether the extra alloying is justified. A high PREN does not establish a safe crevice temperature or immunity to hydrogen-related cracking under cathodic protection. Include the proposed heat treatment and inspection requirements with the drawing; see duplex heat-treatment and inspection guidance.

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Super Duplex 2507 Composition

Composition limits · wt.%

ElementWeight %

Cr: 24–26%
Ni: 6–8%
Mo: 3–5%
N: 0.24–0.32%
Cu: ≤0.50%
C: ≤0.03%
Mn: ≤1.20%
P: ≤0.035%
S: ≤0.020%
Si: ≤0.80%

ASTM / ASME specifications by product form

Finished-product requirements

Specify the finished-fastener mechanical requirements, condition and inspection separately from the starting-stock specification.

Super Duplex 2507 hex bolt requirements ↗

Fasteners · dimensional references

Product	Reference
Hex bolts	ISO 4014 / ISO 4017 · ASME B18.2.1
Threaded studs	DIN 976-1 · ASME B18.31.2
Hex nuts	ISO 4032 · ASME B18.2.2
Socket head screws	ISO 4762 · ASME B18.3
Flat washers	ISO 7089 / ISO 7090 · ASME B18.21.1
Custom fasteners	Customer drawing

Raw-material specifications

Product form / scope	Reference
Bar & shapes · Specify grade, condition and order requirements.	ASTM A276
Plate, sheet & strip	ASTM A240 / ASME SA240
Grade and composition reference · Specify the applicable revision.	GB/T 20878

Dimensions do not define material or finished-part compliance. Specify the grade, condition and applicable requirements.

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Super Duplex 2507 Mechanical Properties

Reference sample and condition

Data basis: Catalogue reference minimums
Sample size: ≤50.8 mm
Gauge length: A5, as labelled in supplied table

Key properties	Value
Tensile strength	≥800 MPa
0.2% yield strength	≥550 MPa
Elongation	≥15%

Supplied technical reference · Scanned PDF page 1 · printed page 13

Super Duplex 2507 Physical Properties

Property	Value	Unit
Density	7.79	g/cm³
Melting range	1396–1450	°C

Procurement and application guide

Specify the material and final condition

Confirm section size, solution treatment and the actual corrosion environment.

Material forms in the technical reference: Bar · Wire · Strip · Sheet · Plate · Pipe & tube · Machined parts.

Define the finished-part acceptance

Include the material or bolting specification, required final condition, dimensions and quantity. State the service medium, temperature and loading where known. Agree the required tests, inspection coverage and acceptance criteria for the finished part.

Start with the information you have

Send a drawing or share the product form and dimensions. Identify any undecided requirements for review rather than copying a typical property value into the purchase order.

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