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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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X4 CrNiMoN 27 5 2
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Introduction:
This was one of the earliest duplex steels which is
reflected in its higher permitted carbon content.
Its resistance to pitting (PREN about 32) and to crevice
corrosion is below that of superduplex steels, therefore
use in seawater is limited.
Exposure to moderate and high temperature and less
rapid cooling may cause embrittlement. Accordingly,
design stress values in ASME II do not extend above
260°C for S32900.
Impact values are high at room temperature. However,
the proportion and orientation of ferrite in welds
and base material may significantly affect toughness
at subzero temperatures. The SEW/DIN grade, 1.4460,
differs considerably in respect of N, C and Ni contents
to the ASTM and JIS grades.
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 the compositions 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 cold
work
Composition:
| Element |
Minimum
(%) |
Maximum
(%) |
| Chromium |
25.00 |
28.00 |
| Nickel |
4.50 |
6.00 |
| Molybdenum |
1.30 |
2.00 |
| Nitrogen |
0.05 |
0.20 |
| Manganese |
- |
2.00 |
| Carbon |
- |
0.05 |
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Similiar Specifications:
ASTM UNS S32900 329
23-28%Cr, 2.5-5.0%Ni, 1.0-2.0%Mo, <1%Mn, <0.08%C
DIN/SEW X4 CrNiMoN 27 5 2 1.4460
25-28%Cr, 4.5-6.0%Ni, 1.3-2.0%Mo, 0.05-0.20%N, <2%Mn,
<0.05%C
JIS SUS 329 J1
23-28%Cr, 3-6%Ni, 1-3%Mo, <1.5%Mn, <0.08%C
Product Forms:
Plate,sheet & strip
ASTM UNS S32900
329 240, 480
JIS SUS 329 J1 4304, 4305
Bar & long products
JIS SUS 329 J1 4303, 4318
Forgings & others
JIS SUS 329 J1 4319
Tube and/or pipe
JIS SUS 329 J1 3463, 3459
ASTM UNS S32900
329 789
Pipe
ASTM UNS S32900
329 790
General
DIN/SEW X4 CrNiMoN
27 5 2 1.4460 SEW400
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Page Last Modified: 10/04/06 11:28
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