Duplex Couplings in 2205 and UNS S31803
FAV is the manufacturer of Duplex Pipe Fitting with configurations like Duplex Hex Nipple, Duplex reducing bushing, Duplex Coupling, Duplex Pipe Adapters.
Duplex stainless steels are becoming more common. They are being offered by all the major stainless steel mills for a number of reasons:
- Higher strength leading to weight saving
- Greater corrosion resistance particularly stress corrosion cracking
- Better price stability
- Lower price
The combination of chromium, molybdenum and nitrogen convey the good resistance of 2205 to chloride pitting and crevice corrosion. This resistance is extremely important for services such as marine environments, brackish water, bleaching operations, closed loop water systems and some food processing applications. The high chromium, molybdenum and nitrogen contents of 2205 provide corrosion resistance superior to common stainless steels, such as, 316L and 317L in most environments.
The advantage of a duplex structure is that it combines the favorable qualities of a ferritic alloy (stress corrosion cracking resistance and high strength) with those of an austenitic alloy (ease of fabrication and corrosion resistance).
2205 duplex stainless steel is a cost effective solution for many applications where the 300 series stainless steels are susceptible to chloride stress corrosion cracking. Stress corrosion cracking occurs when stainless steels are subjected to tensile stress, while in contact with solutions containing chlorides. Increasing temperatures also increase the susceptibility of stainless steels to stress corrosion cracking.
What are the characteristics of Duplex Couplings?
- High resistance to chloride stress corrosion cracking
- Resistance to chloride pitting and crevice corrosion
- Good general corrosion resistance
- Good sulphide stress corrosion resistance
- High Strength
- Good weldability and workability
In what applications is Duplex Couplings used?
- Chemical process vessels, piping and heat exchangers
- Pulp mill digesters, bleach washers, chip pre-steaming vessels
- Food processing equipment
- Oil field piping and heat exchangers
- Flue gas desulfurization equipment
Advantages of Duplex Couplings
- Variety of styles , shapes and sizes
- Sizes available from 1/8” to 2” NPT.
- Options of Precision thread end connections
- Very effective seal between pipes.