UNS Number S31803, S32205

Duplex 2205 is a nitrogen enhanced duplex stainless steel that was developed to combat common corrosion problems encountered with the 300 series stainless steels. “Duplex” describes a family of stainless steels that are neither fully austenitic, like 304 stainless, nor purely ferritic, like 430 stainless. The structure of 2205 duplex stainless steel consists of austenite pools surrounded by a continuous ferrite phase. In the annealed condition, 2205 contains approximately 40-50% ferrite. Often referred to as the work horse grade, 2205 is the most widely used grade in the duplex family of stainless steels.
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).
Usage of 2205 Duplex stainless steel should be limited to temperatures below 600° F.  Extended elevated temperature exposure can embrittle 2205 stainless.

Available Forms of Duplex 2205 at Rooplaxmi Steels:

• Sheet
• Plate
• Bar
• Pipe & Tube (welded & seamless)
• Fittings
• Wire

 

Characteristics of Duplex 2205:

•           High resistance to chloride stress corrosion cracking
•           Resistance to chloride pitting and crevice corrosion
•           Good general corrosion resistance
•           Good sulfide stress corrosion resistance
•           High Strength
•           Good weldability and workability

 

Duplex 2205 Chemical Composition, %:

Cr	Ni	Mo	C	N	Mn	Si	P
22.0-23.0	4.50-6.50	3.00-3.50	0.03 max	0.14-0.20	2.00 max	1.00 max	0.03 max

S	Fe
0.02 max	Balance

 

Application of Duplex 2205:

•           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

Machining and Fabrication with Duplex 2205:

Fabrication of Duplex 2205 should be done only with tools dedicated to stainless steel materials. Tooling and work surfaces must be thoroughly cleaned before use. These precautions are necessary to avoid cross contamination of stainless steel by easily corroded metals that may discolour the surface of the fabricated product.
Duplex stainless steel cannot be hardened by heat treatment. They can however be work hardened.
Solution treatment or annealing can be done by rapid cooling after heating to around 1100°C.
Although machinable, the high strengths of Duplex stainless steel makes machining difficult. As an example, machining of 2205 is around 20% slower than for 304.
Duplex stainless steel have good weldability. All standard welding processes can be used. They are not quite as easily welded as the austenitic grades but low thermal expansion in duplex grades reduces distortion and residual stresses after welding. The recommended filler material for 2205 stainless steel is 2209.

Duplex 2205 ASTM Specification:

Pipe Smls	Pipe Welded	Tube Smls	Tube Welded	Sheet / Plate	Bar	Fitting
A790	A790	A789	A789	A240	A276	A182

Welding Wire Designations:
USA AWS A5.9 – ER2205 , ER 2209

 

Mechanical Properties of Duplex 2205:

Ultimate Tensile Strength	95 ksi minimum
Yield	(0.2 % offset) 65 ksi minimum