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| Mailing Address |
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UKF Stainless Ltd
12 Buntsford Park Road
Bromsgrove
Worcestershire
B60 3DX
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| Telephone / Fax |
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| Tel: |
01527 578686 |
| Fax: |
01527 837792 |
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| Email |
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 info@ukfstainless.co.uk |
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S32304 / S39230
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Introduction:
This steel has the attributes of other duplex steels
- ie. high strength and good chloride stress corrosion
cracking resistance, but due to its economic lean
alloy content has a lower level of pitting and crevice-corrosion
resistance (PREN about 26). Tests rank it between
18Cr10Ni and 17Cr13Ni3Mo.
Exposure to moderate and higher temperatures and less
rapid cooling may cause embrittlement. Accordingly,
design stress values in ASME II do not extend above
315°C for S32304 / S39230 / X2
CrNiN 23 4.
Impact values are high at room temperature with transition
temperatures of base material around -100°C. However,
the proportion and orientation of ferrite in welds
and base material may affect toughness at subzero
temperatures.
Metallurgy:
When ferrite forming elements (Cr,Mo,Si,Nb)
are kept at high levels but austenite promoting elements
(Ni,Mn,N,C) are reduced, stainless steels with a mixed
or duplex microstructure are produced. Mixtures of
40-60% of either phase are near optimum.
Careful control of both composition and cooling rate
from high temperatures is necessary to prevent the
steel or weldment containing large amounts of ferrite
and/or traces of sigma phase that both embrittle and
impair corrosion resistance. Welding requires control
of heat-input and thermal cycles plus use of special
consumables enriched with nitrogen and/or nickel.
Duplex stainless steels may suffer severe embrittlement
due to sigma phase formation in the 550-900°C
range and from alpha prime in the 280-550°C range.
The period for embrittlement may be short or long
depending on composition, time, temperature and amount
of cold work.
Composition:
| Element |
Minimum
(%) |
Maximum
(%) |
| Chromium |
21.50 |
24.50 |
| Nickel |
3.00 |
5.50 |
| Molybdenum |
0.05 |
0.06 |
| Nitrogen |
0.05 |
0.20 |
| Manganese |
- |
2.50 |
| Carbon |
- |
0.03 |
| Copper |
0.05 |
0.60 |
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Similiar Specifications:
ASTM UNS S32304
21.5-24.5%Cr, 3-5.5%Ni, 0.05-0.60%Mo, 0.05-0.20%N,
<2.5%Mn, <0.03%C, 0.05-0.60%Cu
DIN/SEW X2
CrNiN 23 4 1.4362
21.5-24.5%Cr, 3.0-5.5%Ni, <0.6%Mo, 0.05-0.20%N,
<2.5%Mn, <0.03%C
Applications:
Structural - replacement for carbon steel in corrosive
service - eg. mine pit props, tubing, piping,
tensioning systems.
Pressure tubing
and reactors.
Module cladding
Product Forms:
Plate,sheet & strip
ASTM UNS S32304
240, 480
Tube
ASTM UNS S32304
789
Pipe
ASTM UNS S32304
790
General
DIN/SEW X2
CrNiN 23 4 1.4362 SEW400
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Page Last Modified: 7/04/06 17:56
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