Duplex 2205 (S31803 / S32205)

UNS S32205 reference

Choose your UNS designation

Choose the UNS on your drawing or specification. S31803 and S32205 are distinct designations; dual certification requires supporting documents.

What is Duplex 2205 and its applications?

Duplex 2205 is a nitrogen-alloyed stainless steel with ferritic and austenitic phases. The 2205 family includes UNS S31803 and S32205. It is used in process and marine-related equipment where strength and chloride-corrosion resistance influence selection.

Chemical process equipment: Pumps, valves and associated mechanical components.
Pulp and paper: Equipment in compatible process streams.
Marine-related plant: Components selected against the actual chloride exposure and loading.

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Choose your Duplex 2205 product

Engineering Application & Selection Guide

Chromium, molybdenum and nitrogen contribute to corrosion resistance, while the duplex structure contributes strength. Processing must preserve an appropriate phase balance and avoid harmful intermetallic precipitation.

Duplex 2205 hex bolts — For coastal equipment, state the UNS designation, solution-treatment condition and inspection requirements.
Duplex 2205 stud bolts — For pressure joints, specify the service temperature and duration, and apply the project limits for toughness and phase stability.
Duplex 2205 socket head cap screws — For compact fluid controls, verify the final mechanical condition, thread engagement and bearing stresses.

S31803 and S32205 are not identical purchase descriptions. State the required UNS and substantiate any dual certification. Elevated-temperature exposure and cathodic protection need separate review; neither PREN nor yield strength justifies an automatic reduction in bolt size.

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Duplex 2205 Composition

Composition limits · wt.% · S32205 reference

ElementWeight %

Cr: 22–23%
Ni: 4.5–6.5%
Mo: 3.0–3.5%
N: 0.14–0.20%
C: ≤0.03%
Mn: ≤2.0%
P: ≤0.03%
S: ≤0.02%
Si: ≤1.0%

ASTM / ASME specifications by product form

Finished-product requirements

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

Duplex 2205 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 · S32205 reference shown; specify the required UNS.	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.

How to specify round bar, plate, wire and strip ↗

Duplex 2205 Mechanical Properties

Reference sample and condition

Data basis: Catalogue reference minimums
Gauge length: A5, as labelled in supplied table

S32205 reference. Do not assign these values to an unresolved S31803 condition.

Key properties	Value
Tensile strength	≥655 MPa
0.2% yield strength	≥450 MPa
Elongation	≥25%

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

Duplex 2205 Physical Properties

Property	Value	Unit
Density	7.88	g/cm³
Melting range	1398–1454	°C

Procurement and application guide

Specify the material and final condition

State S31803 or S32205 explicitly; dual certification requires documentation.

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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