Unlike ferritic and austenitic alloy grades, what makes duplex alloys special is that they have a mixed microstructure consisting of both ferrite and austenite in an equal proportion. In other words, Duplex 2205 Fasteners often have properties seen in both alloy classes. Duplex stainless steel grades were designed with the intention of overcoming the shortcomings of both ferritic as well as austenitic stainless steel classes. Being a nitrogen enhanced grade, the 2205 duplex stainless steel bolts have superior resistance to pitting as well as crevice corrosion. And in comparison to regular stainless steel grades like 304 stainless steel, duplex steels tend to be much more resilient to chlorine induced stress related corrosion cracking.

Duplex 2205 Fasteners

Duplex 2205 Fasteners

The Duplex 2205 hex nuts are particularly useful in building pieces of equipment to be used in Flue gas desulfurization due to several of its advantageous properties. For instance, the Duplex 2205 studs have good weldability characteristics and are known to resist sulphide related stress corrosion. Usually, a corrosive environment of these sorts can be seen in exhaust flue gases of fossil-fuel power plants during the removal of sulfur dioxide from processes such as waste incineration during the emissions of other sulfur oxide emitting.


As opposed to conventional stainless steel grade, the UNS S31803 Hex Bolts do not crack under the stress of these corrosive compounds, which would indicate that duplex alloys often outperform austenitic grades. The hardness of Duplex 2205 Bolts is a property which has been inherited by the ferritic structure present in the alloy. Hence, the Duplex 2205 threaded rod is an alloy that is considered to be a valued addition to not only in equipment of Flue gas desulfurization but also Oil field piping and heat exchangers as well.

Duplex 2205 hex nuts Standard Dimensions

Duplex 2205 hex nuts Standard Dimensions

Minimal Size / Dia. of Basic Major Thread F G H
Across Flats Width

Across Corners Width

Thick
Max Basic Min Min Max Basic Min Max
2-3/4 2.7500 4.125 4-1/8 3.988 4.546 4.763 2-3/8 2.319 2.431
1/4 .2500 .438 7/16 .428 .488 .505 7/32 .212 .226
5/16 .3125 .500 1/2 .489 .557 .577 17/64 .258 .273
3/8 .3750 .562 9/16 .551 .628 .650 21/64 .479 .337
1/2 .5000 .750 3/4 .736 .840 .866 7/16 .427 .448
7/16 .4375 .688 11/16 .675 .768 .794 3/8 .365 .385
9/16 .5625 .875 7/8 .861 .982 1.010 31/64 .473 .496
7/8 .8750 1.312 1-5/16 1.269 1.447 1.516 3/4 .724 .776
5/8 .6250 .938 15/16 .922 1.051 1.083 35/64 .535 .559
3/4 .7500 1.125 1-1/8 1.088 1.240 1.299 41/64 .617 .665
1 1.0000 1.500 1-1/2 1.450 1.653 1.732 55/64 .831 .887
1-1/8 1.1250 1.688 1-11/16 1.631 1.859 1.949 31/32 .939 .999
1-3/8 1.3750 2.062 2-1/16 1.994 2.273 2.382 1-11/64 1.138 1.206
2 2.0000 3.000 3 2.900 3.306 3.464 1-23/32 1.675 1.763
1-1/2 1.500 2.250 2-1/4 2.175 2.480 2.598 1-9/32 1.245 1.ASTM A194 GR. 8
1-5/8 1.6250 2.438 2-7/16 2.356 2.686 2.815 1-25/64 1.353 1.429
2-1/4 2.2500 3.375 3-3/8 3.263 3.719 3.897 1-15/16 1.890 1.986
1-3/4 1.7500 2.625 2-5/8 2.538 2.893 3.031 1-1/2 1.460 1.540
2-1/2 2.5000 3.750 3-3/4 3.625 4.133 4.330 2-5/32 2.105 2.209

Physical Properties of Duplex 2205 threaded rod

Density (Kg / M3) Modulus of Elasticity (GPa) Poisson’s Ratio Thermal Conductivity (W/moC) Thermal Capacity (I/KgoC) Electrical Resistivity
7800 200 0.3 15 500 0.80

UNS S32205 Hex Bolts Composition Chart

Gr. UNS C Cr Ni P Si S Mo N Mn
2205 S32205 < 0.03 22.0-23.0 4.5-6.5 0.03 max 1 max 0.02 max 3.0-3.5 0.14-0.20 < 2.0

Mechanical Characteristics of Duplex 2205 studs

Gr. YS (MPa) UTS (MPa) % Elongation Hardness(BHN)
2205 450 min. 655 min. 25 min. 293 max.

Equivalent material grade of 2205 Stainless steel screws

Duplex
Common Name
Related Specifications
DIN
UNS
ASTM/ ASME
2205
SAF 2205®
1.4462
S32205
A479/ SA479

Duplex 2205 Fasteners grades and specifications

Sizing 3/6 inch upto 2 inch | M3 – M56
Standard ASTM A479/ ASME SA479
Lengths M02 to M152.4
In Form of: Round, Threading, Hex, Square as per Gauge Etc.