UNS S31803
UNS S31803 is a typical duplex stainless steel very similar to UNS S32205 except that it may have a bit lower content requirement of chromium, molybdenum and nitrogen. Generally, both UNS 31803 and S32205 can be called as “Duplex 2205” in practice.

ASTM A789 UNS S31803 seamless pipes, 33mm x 1mm.
1. Chemical Composition of UNS S31803
The Chemical Composition of S31803, % | |
---|---|
Carbon | 0-0.03 |
Chromium | 21.00-23.00 |
Manganese | ≤2.00 |
Silicon | ≤1.00 |
Phosphorous | 0-0.03 |
Sulphur | 0-0.02 |
Nickel | 4.50-6.50 |
Nitrogen | 0.08-0.20 |
Molybdenum | 2.50-3.50 |
Iron | Balance |
2. Mechanical Properties of UNS S31803
Tensile Strength,min. | Yield Strength,min. | Elongation,min. | Hardness Brinell, max |
---|---|---|---|
Mpa | Mpa | % | HB |
620 | 450 | 25 | 290 |
3. Physical Properties of UNS S31803

A floating ball valve with ASTM A182 F51 body.
Density | Thermal Expansion | Modulus of Elasticity | Thermal Conductivity | Electrical Resistivity |
---|---|---|---|---|
g/cm3 | K | Gpa | W/m.k | Ω.m |
7.805 | 13.7*10-6 | 200 | 19.0 | 0.085*10-6 |
4. Product Forms and Standards
Duplex stainless steel UNS S31803 can be supplied in the following forms:
- Plates, sheets & strips: ASTM A240;
- Bars and shapes: ASTM A276, A479;
- Seamless and weld pipe/ tubes: ASTM A789, A790, A928;
- Wrought duplex pipe fittings: ASTM A815;
- Forgings(flanges, fittings, valve parts): ASTM A182, ASTM A988.
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