2205 Stainless Steel 1.4426（UNS32205/UNS31803）

What is 2205 stainless steel?

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.

2205 stainless steel 1.4462 Products Form

• Bar
• forgings
• sheet
• plate
• pipe
• tube
• closed die forgings
• flanges and welding consumabless

Applications for 2205 stainless steel

• Chemical processing, transport and storage – pressure vessels, tanks, piping, and heat exchangers
• Oil and gas exploration and processing equipment – piping, tubing, and heat exchangers
• Marine and other high chloride environments
• Effluent scrubbing systems
• Pulp and paper industry – digesters, bleaching equipment, and stock-handling systems
• Cargo tanks for ships and trucks
• Food processing equipment
• Biofuels plants

Equivalents of grade 2205

Grade	UNS No	Old British		Euronorm		SwedishSS	JapaneseJIS
		BS	En	No	Name
2205	S31803 / S32205	318S13	–	1.4462	X2CrNiMoN22-5-3	2377	SUS 329J3

Composition ranges for 2205 grade of stainless steel

	C	Mn	Si	P	S	Cr	Mo	Ni	N
2205 (S31803)	0.03 max	2.0 max	1.0 max	0.03 max	0.02 max	min: 21.0 max: 23.0	min: 2.5 max: 3.5	min: 4.5 max: 6.5	min: 0.08 max: 0.20
2205 (S32205)	0.03 max	2.0 max	1.0 max	0.03 max	0.02 max	min: 22.0 max: 23.0	min: 3.0 max: 3.5	min: 4.5 max: 6.5	min: 0.14 max: 0.20

Mechanical Properties

Grade	Tensile Str (MPa) min	Yield Strength 0.2% Proof (MPa) min	Elongation (% in 50mm) min	Hardness
				Rockwell C (HR C)	Brinell (HB)
2205	621	448	25	31 max	293 max

Physical Properties

Grade	Density (kg/m3)	Elastic Modulus(GPa)	Mean Co-eff of Thermal Expansion (μm/m/°C)			Thermal Conductivity (W/m.K)		Specific Heat 0-100°C( J/kg.K)	Electrical Resistivity (nΩ.m)
			0-100°C	0-315°C	0-538°C	at 100°C	at 500°C
2205	7800	190	13.7	14.2	–	19	–	418	850

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.

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.

Heat Resistance

2205 Duplex Stainless Steel is remarkable for its superior heat resistance; it can be used in applications involving temperatures up to 300°C. This makes it a perfect choice for uses such as steam turbine parts, exhaust manifolds and petrochemical processing equipment. Its heat resistance is achieved through the balanced chemical composition of chromium, molybdenum, nitrogen and other elements. It also has a high tensile strength and good weldability, so its durability speaks for itself. Making 2205 Duplex Stainless Steel the right material solution for many critical components.

Heat Treatment

2205 duplex stainless steel should be annealed at 1900°F minimum, followed by rapid cooling, ideally by water quenching. This treatment applies to both solution annealing and stress relieving. Stress relief treatments at any lower temperature carry the risk of precipitation of detrimental intermetallic or nonmetallic phases.

Hot working

Forming below 600°F is recommended whenever possible. When hot forming is required, the workpiece should be heated uniformly and worked in the range of 1750 to 2250°F. 2205 duplex stainless steel is quite soft at these temperatures and is readily formed. Above this range, 2205 duplex stainless steel is subject to hot tearing. Immediately below this range, the austenite becomes substantially stronger than the ferrite and may cause cracking, a particular danger to “cold” edges. Below 1700°F there can be rapid formation of intermetallic phases because of the combination of temperature and deformation. Whenever hot forming is done, it should be followed by a full solution anneal at 1900°F minimum and rapid quench to restore phase balance, toughness, and corrosion resistance. Stress relieving is not required or recommended; however, if it must be performed, the material should receive a full solution anneal at 1900°F minimum, followed by rapid cooling or water quenching.

Cold working

Duplex 2205 has shown good formability in a variety of fabrications. The high strength of Duplex 2205 can pose problems. Even when the equipment has sufficient power, allowance must be made for higher spring-back caused by the grade’s high strength.

Machinability:

Duplex 2205 is somewhat more difficult to machine than the 300 series austenitic stainless steels. Higher cutting forces are required and more rapid tool wear is typical. Some guidelines for machining are: A) Use powerful, rigid machines with extremely strong rigid mounting of tools and work piece, B) Minimize vibration by keeping the tool extension as short as possible, C) Use a nose radius on the tool, no longer than necessary, for carbides that have a sharp edge while still providing adequate strength, D) Design machining sequences to always provide for a depth of cut below the work hardened layer resulting from the previous passes.

Welding

2205 steel is easily weldable by the common methods but it should not be welded in the absence of filler metal because it may produce ferrite phases. Since 1554.6 metal qualifies the welding of stainless steel 2205 alloy with the help of 2209 rods or electrodes that make sure that the metal has been deposited equally. The nitrogen is included as the shielding material to support in guarantee the sufficient austenite in the shape.