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Monday 26 October 2020
  • S31803 Duplex Data sheet
  • S31803 Duplex Data sheet
  • S31803 Duplex Data sheet
  • S31803 Duplex Data sheet
  • S31803 Duplex Data sheet
  • S31803 Duplex Data sheet
  • S31803 Duplex Data sheet
  • S31803 Duplex Data sheet

 

Alloy

UNS Number

SAE Number

Super duplex

S31803

UNS S31803

 

 

GENERAL PROPERTIES

UNS S31803 is a duplex grade with a ferritic-austenitic microstructure. The alloy consists of around 40-50% ferrite in the annealed condition. The duplex microstructure has the high strength of the ferritic grades whilst retaining the corrosion resistance of the austenitic grades. It is not uncommon to see the metal used as a practical solution to chloride-induced stress cracking.

It has superior resistance to chloride pitting and crevice corrosion as compared to 317L stainless steel. The alloy has outstanding corrosion resistance to seawater and most concentrations of sulphuric acid. In addition, it is also resistant to sulphide stress corrosion cracking (sour-gas environments).

 

RESISTANCE TO CORROSION

UNS S31803 is resistant to intergranular corrosion. It has better corrosion resistance than that of other austenitic stainless grades such as 316, with higher resistance to stress corrosion cracking to that of either 304 or 316 stainless grades. Pitting corrosion and crevice corrosion is higher than that of 316. Due to its higher corrosion resistance UNS S31803 has better fatigue strength in corrosive environments than that of other austenitic stainless steel specifications.

PHYSICAL PROPERTIES

Melting Point

Density

Specific Gravity

Modulus of Elasticity
in Tension

 1420 – 1465 ℃

    7.8g/cm3

7.8

200 GPa

MECHANICAL PROPERTIES

Alloy

Tensile Strength
Minimum
(psi)

Yield Strength
Minimum 0.2% offset

(psi)

% Elongation
in 2" Minimum

       

S31803

90,000

65,000

25

CHEMICAL PROPERTIES

Alloy

C

Si

Mn

P

Cr

Ni

S

N

Mo

S31803

0.03

1.0

2.0

0.035

21.0-23.0

4.5-6.5

0.015

0.1-0.22

2.5-3.5

 

WELDING

UNS S31803 (1.4462, F51) has good weldability similar to that of other stainless steel types. Low thermal expansion reduces residual stresses after welding. Use duplex welding electrodes similar to that of the parent steel when welding UNS S31083. Electric arc welding processes are suitable though oxyacetylene welding is not recommended due to the possibility of carbon pick up in the weld area of the UNS S31803. Whilst post weld annealing is not a requirement for many applications it will give optimum corrosion resistance in severe service conditions. We recommend you contact your welding consumables supplier who should provide you full assistance and information of welding UNS S31803 duplex.

HEAT TREATMENT

UNS S31803 (1.4462, F51) cannot be hardened by conventional heat treatment, though it is a work hardening steel. Duplex can be solution annealed at 1020-1100ºC, water quench.

Contact Us

 

contact phoneT: + 44 (0)1902 409316
Fusion House
The Crescent
Willenhall
West Midlands
WV13 2QR

F: + 44 (0)1902 409304
E: sales@quest4alloys.com