2205 Hex Nut

   duplex 2205                                      
               Typical Composition ( %)
 

C	Cr	Ni	Mo	N	Others
0.020	22.1	5.6	3.1	0.18	S=0.001
PREN = [Cr%] = 3.3 [Mo%] = 16 [N%] ≥ 34

 
                   duplex 2205
             Physical Properties  
 

Temperature °F		68	212	392	572
Density	lb/in3	0.278	--	--	--
Modulus of Elasticity	psi x 106	27.6	26.1	25.4	24.9
Linear Expansion (681T4F-T)	10-6/°F	--	7.5	7.8	8.1
Thermal Conductivity	Btu/h ft. °F	8.7	9.2	9.8	10.4
Heat Capacity	Btu/lb/°F	0.112	0.119	0.127	0.134
Electrical Resistivity	in x 10-6	33.5	35.4	37.4	39.4

 
              duplex 2205
                 Mechanical Properties  
 

	ASTM A 240	Typical
Yield Strength 0.2%, ksi	65 min.	74
Tensile Strength, ksi	90 min.	105
Elongation %	25 min.	30
Hardness HB	293 max.	256

 
 Structure 
The chemical analysis of 2205 is optimized to obtain a typical 50 a/ 50 g microstructure after solution annealing treatment at 1900°/1922°F (1040°/1080°C).
Heat treatments performed above 2000°F may result in an increase of ferrite content.
Like all duplex stainless steels, 2205 is susceptible to precipitation of intermetallic phases, usually referred to as sigma phase. Intermetallic phases precipitate in the range of 1300°F to 1800°F, with the most rapid precipitation occurring at about 1600°F. Thus, it is prudent to have 2205 pass a test for the absence of intermetallic phases, such as those in ASTM A 923.
 
Processing
Hot Forming
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. Alloy 2205 is quite soft at these temperatures and is readily formed. Above this range, 2205 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 Forming
Alloy 2205 is readily sheared and cold formed on equipment suited to working stainless steels. However, because of the high strength and rapid work hardening of 2205, forces substantially higher than those for austenitic steels are required to cold form 2205. Also because of the high strength, a somewhat larger allowance must be made for springback.
 
Heat Treatment
Alloy 2205 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.