UNS S31803 pipe fittings used for?

UNS S31803 Pipes is a ferritic-austenitic microstructured duplex steel. In its annealed state, the alloy contains roughly 40-50 percent ferrite. The duplex microstructure combines the strength of ferritic steels with the corrosion resistance of austenitic steels. The metal is frequently employed as a viable remedy for chloride-induced stress cracking. UNS S31803 Pipe Fittings is two-phase stainless steel that has properties such as ferritic, austenitic, 22 percent chromium, 3% molybdenum, and 5 to 6% nickel alloyed stainless steel. 

Metco Overseas is the leading manufacturer and supplier of UNS S31803 Pipes in India. We supply them at the most competitive price in the market compared to others. We supply them at the customized size as required by the Clients. In this article, we will understand the properties and application of UNS S31803 Pipe Fittings.

Properties of UNS S31803 Pipes

Resistance to corrosion:

Intergranular corrosion is not a problem for UNS S31803. It has stronger corrosion resistance than other austenitic stainless grades like 316, as well as better stress corrosion cracking resistance than either 304 or 316 stainless grades. The rate of pitting and crevice corrosion is higher in 316 than in 316. UNS S31803 has stronger fatigue strength in corrosive conditions than other austenitic stainless steel specifications because of its higher corrosion resistance.


The weldability of UNS S31803 (1.4462, F51) is comparable to that of other stainless steel grades. After welding, residual stresses are reduced by low thermal expansion. When welding UNS S31083, use duplex welding electrodes that are identical to the parent steel. Although oxyacetylene welding is not suggested due to the likelihood of carbon pick-up in the UNS S31803 welding region, electric arc welding procedures are suitable. While post-weld annealing isn’t required in many applications, it does provide the best corrosion protection in extreme conditions.

Heat Temperatures:

Despite being a work hardening steel, UNS S31803 (1.4462, F51) cannot be hardened by standard heat treatment. Duplex can be water quenched after solution annealing at 1020–1100 oC.

Applications of UNS S31803 Pipe Fittings:

Duplex UNS S31803 is used in the upstream production of high chloride oil and gas liquids, among other things. Duplex UNS S31803 can also be utilized in a variety of other applications, including:

  • Scrubbers for FGD gas
  • Systems that use seawater
  • Vessels, pipes, and heat exchangers are used in chemical processes.
  • Pumps and valves for seawater
  • The pipework in the oilfield
  • Digesters for pulp mills and bleach scrubbers
  • Feed processing machinery

I hope this article has helped you come across the UNS S31803 Pipe Fittings in detail. Contact us now for more information about Metco Overseas.

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