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S31700 (317)
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Introduction:
Molybdenum enhances the corrosion performance of stainless
steel in seawater and many other chemicals.
It will be noted that Euronorm only includes the low
carbon version and that the basic composition differs
from that of ASTM and JIS.
This 3.5%Mo type steel has even better resistance
to discolouration than 2.5%Mo (UNS S31600)
type in marine atmosphere exposures (Sweden). Similar
superiority exists to pitting in cool seawater (PREN
about 31), but risk of crevice attack still exists.
Metallurgy:
This steel, with 3.5%Mo is part of a series
with nominally 2.25, 2.75, 3.5, 4.5 and 6.5% Mo.
Conditions where the steels are not quickly taken
through the temperature range 900-500°C - eg.
slow cooling or large section heat treatments, high
heat input welding, service exposures - can allow
carbide precipitation and increased risk of embrittling
sigma formation in high Mo steels. Consideration should
be given to low carbon grades and to rapid cooling.
Composition:
| Element |
Minimum
(%) |
Maximum
(%) |
| Chromium |
18.00 |
20.00 |
| Nickel |
11.00 |
15.00 |
| Molybdenum |
3.00 |
4.00 |
| Nitrogen |
- |
0.10 |
| Manganese |
- |
2.00 |
| Carbon |
- |
0.08 |
|
Similiar Specifications:
ASTM UNS S31700 317
18-20%Cr, 11-15%Ni, 3-4%Mo, <0.10%N, <2%Mn,
<0.08%C
BS 317S16
17.5-19.5%Cr, 12-15%Ni, 3-4%Mo, <2%Mn, <0.06%C
JIS SUS 317
18-20%Cr, 11-15%Ni, 3-4%Mo, <2%Mn, <0.08%C
Applications:
Power station condensers.
Chemical tankers.
Dyeing equipment.
Chemical, textile, paper industries.
Product Forms:
Plate,sheet & strip
ASTM UNS S31700 317 167, 240, 480
BS 317S16 1449/2
JIS SUS 317 4304, 4305, 4307
Bar & long products
ASTM UNS S31700 317 276, 479, 484
JIS SUS 317 4303, 4311
Forgings & others
ASTM UNS S31700 317 314, 473, 484, 182, 403
Tube and/or pipe
JIS SUS 317 3463, 3459
ASTM UNS S31700 317 213, 249, 269, 450, 511, 554,
632
Pipe
ASTM UNS S31700 317 312, 409, 530, 813, 814
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Page Last Modified: 7/04/06 17:54
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