Super-Austenitic Stainless Steel

Austenitic | Martensitic | Ferritic | Duplex | Super Duplex | Superaustenitic | Superferritic | Precipitation Hardening
Superaustenitic stainless steel have the same structure as the common austenitic alloys, but they have enhanced levels of elements such as chromium, nickel, molybdenum, copper, and nitrogen, which give them superior strength and corrosion resistance.

Super-austenitic stainless steel alloys are characterized by their high nickel and molybdenum contents plus nitrogen. The most common of the alloys are 904L, AL-6XN, 254 SMO, 25-6MO and 1925 hMO.Super-austenitic metal designed to resist crevice corrosion, pitting, chloride-induced corrosion, and stress corrosion cracking. It can also withstand alkaline and salt solutions, protecting against metallic contami- nation of product and preventing rapid degradation of the fluid transfer system

These alloys have a face-centered cubic crystal structure similar to other austenitic stainless steel and are non-magnetic and their magnetic permeability remains low even after severe cold forming. The nitrogen addition provides the alloy with improved resistance to pitting and crevice corrosion, a greater resistance to localized corrosion in oxidizing chlorides and reducing solutions plus higher strength. Nitrogen also helps to significantly reduce the potential formation of harmful secondary phases during welding.

904L Stainless Steel Pipe
Super-Austenitic Stainless Steel Pipe

Superaustenitic Stainless Steel Mechanical Properties and Physical Properties

Alloy
(UNS)
End UseComposition
nominal wt%
StandardDensity
lb/in3 (g/cm3)
Tensile Strength
ksi. (MPa)
0.2% Yield Strength
ksi. (MPa)
Elong
ation %
Hardness
N08020Flue gas scrubbers,
Sulphuric acid tanks and racks, Process piping,
Heat exchanger,
Manufacture of solvents/explosives
/plastics/synthetic fibers/organic chemicals
/pharmaceuticals
C 0.07 max,
Mn 2.0 max,
P 0.045 max,
S 0.035 max,
Si 1.0 max,
Cr 19.0-21.0,
Ni 32.0-38.0,
Mo 2.0-3.0,
Cu 3.0-4.0,
Cb+Ta (8xC)min-1.0 max,
Fe balance
ASTM
B463 ASME SB-463
0.292
(8.09)
80 min
(550 min)
35 min
(240 min)
30 min95 Rockwell B max
S34565Desalination,
seawater piping,
offshore oil production,
pollution control (FGD)
C 0.03 max,
Mn 5.0-7.0,
P 0.03 max,
S 0.01 max,
Si 1.0 max,
Cr 23.0-25.0,
Ni 16.0-18.0,
Mo 4.0-5.0,
N 0.4-0.6,
Cb 0.1 max,
Fe balance
ASTM A240 ASME SA2400.29
(8.03)
115 min
(795 min)
60 min
(415 min)
35 min100 Rockwell B max
904L / N08904High efficiency
furnace vent pipe,
pulp & paper
processing equipment,
welding
 electrodes and fittings.
C 0.02 max,
Mn 2.0 max,
P 0.045 max,
S 0.035 max,
Si 1.0 max,
Cr 19.0-23.0,
Ni 23.0-28.0,
Mo 4.0-5.0,
N 0.1 max,
Cu 1.0-2.0,
Fe Balance
ASTM A240 ASME SB6250.287
(7.95)
71 min
(490 min)
31 min
(220 min)
35 min90 Rockwell B max
N08367Desalination,
seawater piping and
critical components on
offshore oil platforms
C 0.030 max,
Mn 2.0 max,
P 0.040 max,
S 0.030 max,
Si 1.0 max,
Cr 20.0-22.0,
Ni 23.5-25.5,
Mo 6.0-7.0,
N 0.18-0.25,
Cu 0.75 max,
Fe Balance (PREN 50.0 min)
ASTM A240, ASTM B688 ASME
SA240,
ASME
SB688
0.291
(8.06)
100 min (Sheet) / 95 min (Plate)
(690 min / 655 min)
45 min
(310 min)
30 min100 Rockwell B max
N08367Desalination,
seawater piping and
critical components on
offshore oil platforms.
C 0.030 max,
Mn 2.0 max,
P 0.040 max,
S 0.030 max,
Si 1.0 max,
Cr 20.0-22.0,
Ni 23.5-25.5,
Mo 6.0-7.0,
N 0.18-0.25,
Cu 0.75 max,
Fe Balance
ASTM A240, ASTM B688 ASME SA-240, ASME SB6880.291
(8.06)
100 min (sheet) / 95 min (plate)
(690 min / 655 min)
45 min
(310 min)
30 min100 Rockwell B max
JS700?
N08700
Wet scrubbers in
municipal incinerators,
wet-process
phosphoric acid plants, chlorine dioxide pulp bleaching
C 0.04 max,
Mn 2.0 max,
P 0.04 max,
S 0.03 max,
Si 1.0 max,
Cr 19.0-23.0,
Ni 24.0-26.0,
Mo 4.3-5.0,
Cu 0.5,
Cb (8xC)min-0.4 max,
Fe Balance
ASTM A240 ASTM B5990.287
(7.95)
80 min
(550 min)
35 min
(240 min)
30 min90 Rockwell B max

Austenitic Stainless Steel / Super Austenitic Stainless Steel Comparison Chart

China GBISO Unified Digital CodeASTM / ASME GradeUNS CodeEN CodeCompany Commercial Grade
06Cr19Ni10S30408304S304001.4301
07Cr19Ni10S30409304HS304091.4948
022Cr19Ni10S30403304LS304031.4307
022Cr19Ni10NS30453304LNS304531.4311
Super304S30432Super304H(NSSMC)
06Cr18Ni11TiS32168321S321001.4541
07Cr18Ni11TiS32169321HS321091.494
06Cr17Ni12Mo2S31608316S316001.4401
022Cr17Ni12Mo2S31603316LS316031.4404
022Cr17Ni12Mo2NS31653316LNS316531.4406
06Cr17Ni12Mo3TiS31668316TiS316351.4571
00Cr17Ni14Mo2316LMoD/316LUGS316031.4435
022Cr19Ni13Mo3S31703317LS317031.4438
022Cr19Ni16Mo5NS31723317LMNS317251.4439
06Cr25Ni20S31008310SS310081.4845
00Cr19Ni11304LS304031.43073RE12(Sandvik)
310LS310021.43352RE10(Sandvik)
20Cr25Ni20S31020310HS310091.4821
16Cr25Ni20Si2S383403141.4841
022Cr25Ni22Mo2NS31053310MoLNS310501.44662RE69(Sandvik)
310HCbNS31042HR3C(NSSMC)
07Cr18Ni11NbS34749347HS347091.4942
347HFGS34710
015Cr21Ni26M5Cu2S31782904LN089041.45392RK65(Sandvik)
015Cr20Ni18Mo6CuNS31252S31254S312541.4547254 SMO (Sandvik)
00Cr20Ni24Mo6NN08367N08367AL6XN, AL6XN plus(ATI)
00Cr21Ni25Mo6CuNN08926N089261.4529
015Cr24Ni22Mo8Mn3CuNS32652S32654S326541.4652654SMO(Outokumpu)
00Cr22Ni27Mo7CuNS31277S31277

Related References:
Austenitic Stainless Steel
Superaustenitic Stainless Steel
Austenitic stainless steel for timber fixings
Austenitic Stainless Steel Grades Comparison Table
Effect of Austenitic Steel Composition and Heat Treatment
Compared Austenitic and Duplex Steel strength and vulnerable
Stress Relieving Heat Treatment for Austenitic Stainless Steel
Mechanism Measurement of Work Hardening Austenitic Steel
Composition Effect Magnetic Permeability of Austenitic Steel
Effect of Cold Work and Heat Treatment of Austenitic Stainless Steel

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