We are stockists of 31803 duplex alloys in sheet, plate, and bar directly distributed globally from our UK stockholding warehouse, combined with our large capacity cutting capabilities we can meet requirements for many industries.

The following are the properties of 31803:

  • Stainless ferritic-austenitic Cr-Ni-Mo steel with nitrogen addition.
  • High corrosion resistance, especially against stress corrosion cracking in solutions containing chloride.
  • Good strength properties.
  • Resistant to intergranular corrosion in the temperature range up to 300°C.
  • Heat treatment subsequent to welding not necessary.
  • Surface condition for optimum corrosion resistance: pickled, heat treated free from scale or machined.
duplex-s31803[1]

Application

Components in the chemical industry, e.g. separator and heat exchanger parts, from the paper industry, oil and gas production, compressor parts, seawater desalination plants.

Technical Info

Chemical Composition (average %)

CSiMnCrMoNiN
0.0250.601.3022.603.205.800.17

Standards

EN / DINASTMUNSAFNOR
<1.4462 >
X2CrNiMoN22-5-3
A240S31803Z2CND22-5 Az

Hot Forming

Forging

1200 to 950°C / Air cooling

Heat Treatment

Solution annealing:

1020 to 1100°C
Water , air (thickness below 2mm)

Structure

Ferrite + Austenite

Mechanical Properties

Condition: solution annealed

ProductDimension
Size
mm
0.2% proof stress
N/mm2
min.
Tensile strength
N/mm2
Elongation A5
% min.
L    Q     T
Impact strength
(ISO-V)
J min.
L    Q     T
St≤ 160450650 – 88025   - –    - -100   - –    - -
Bl≤ 75460640 – 840252)  252)  - -90   60    - -

St = Bar ,
Bl = Sheet or plate
L = Longitudinal, Q = Transverse, T = Tangential
1) For sheet or plate < 3mm = A80mm specimen
The values for other products and dimensions shall be established by agreement.

Hight Temperature Properties

Condition: solution annealed

0.2% yield strength
N/mm² min.
Temperature
100°C150°C200°C250°C
360335315300

Welding

Good weldability. Welding is possible with all processes usual for stainless steels. We recommend depending on applications electric arc welding with covered electrodes, inert gas welding or SA-welding. Preheating and heat treatment after welding is not necessary. For high stressed heavy walled constructions the limited preheat temperature of 150°C maximum is recommendable. Maximum interpass temperature 150°C. Keep heat input low especially for small wall thicknesses. The TIG-process should be given reference for root welding.

Physical Properties

Thermal conductivity at ……………….. 20°C ………………15.0 ………W/(m.K)
Specific heat at …………………………..20°C ………………500 ……….J/(kg.K)
Electrical resistivity at …………………. 20°C ………………0.80 ………Ohm.mm2/m
Modulus of elasticity at ……………….. 20°C ………………200 x 103 N/mm2
Magnetic properties ……………………………………………..magnetic

Thermal expansion between
20°C and …°C, 10-6 m/(m.K) at
Temperature10-6 m/(m.K)
100°C13.0
200°C13.5
300°C14.0
Modulus of elasticity, 103 N/mm2 atTemperature103 N/mm2
20°C200
100°C194
200°C186
300°C180

As regards applications and processing steps that are not expressly mentioned in this product description/data sheet, the customer shall in each individual case be required to consult us.