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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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1.4462
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Introduction:
A widely used duplex steel with a PREN about 34. Duplex
steels combine high strength and corrosion resistance.
With a near equal mix of austenite and ferrite, they
give yield strengths 30% higher and tensile strengths
marginally higher than comparable nitrogen-containing
austenitics. Their resistance to stress-corrosion
cracking in neutral chlorides is superior to that
of the 18/10 and 18/12/3 austenites. In high chloride
acidic or moderately sour environments where hydrogen
or sulphide stress cracking is more likely, higher
alloyed austenitcs need also to be considered.
Impact values are high and transition temperatures
of base materials vary around -50°C. However,
the proportion and orientation of ferrite in welds
and base materials may significantly affect toughness
at subzero temperatures.
Exposure to moderate and high temperatures and less
rapid cooling may cause embrittlement. Accordingly,
design stress values in ASME II and BS 5500-1991 do
not extend above 300-315°C for S31803/S39205/X2
CrNiMoN 22 5 3.
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 |
21.00 |
23.00 |
| Nickel |
4.50 |
6.50 |
| Molybdenum |
2.50 |
3.50 |
| Nitrogen |
0.08 |
0.20 |
| Manganese |
- |
2.00 |
| Carbon |
- |
0.03 |
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Similiar Specifications:
ASTM UNS S31803
21-23%Cr, 4.5-6.5%Ni, 2.5-3.5%Mo, 0.08-0.20%N,
<2%Mn, <0.03%C
BS 318S13
21-23%Cr, 4.5-6.5%Ni, 2.5-3.5%Mo, 0.08-0.20%N, <2%Mn,
<0.03%C
DIN/SEW X2 CrNiMoN 22
5 3 1.4462
21-23%Cr, 4.5-6.5%Ni, 2.5-3.5%Mo, 0.08-0.20%N, <2%Mn,
<0.03%C
Applications:
Offshore piping and tubing.
Chemical tankers.
Chemical and petrochemical industries.
Flue gas desulphurization - scrubbers and chimneys.
Plup and paper - press rolls and filter washers.
Product Forms:
Plate,sheet
& strip
ASTM UNS S31803
240, 480
BS 318S13 1501/3
Bar & long products
ASTM UNS S31803
276
Forgings & others
ASTM UNS S31803
182, 815
Tube
ASTM UNS S31803
789
Pipe
ASTM UNS S31803
790
General
BS 318S13 5500
DIN/SEW X2
CrNiMoN 22 5 3 1.4462 SEW400
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Page Last Modified: 7/04/06 17:21
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