Tensile
Strength
Mpa
Min |
0.2 % Yield
Strength
Mpa
Min |
Elongation
in 50mm
%
Min |
Hardness
HB
Max |
620 |
448 |
25 |
290 |
Tensile
Strength
Mpa |
Yield
Strength
Mpa |
Elongation
in 50mm
% |
Charpy
V
Impact
J |
Hardness |
HB |
Rc |
650 - 900 |
570 |
30 |
130 |
235 |
23 |
While the oxidation resistance
of 2205 is good at high temperature as with other duplex
stainless steel grades, it is subject to embrittlement when
exposed to temperatures above 300 oC even for short periods.
It is subject to embrittlement at 475 oC when exposed for
2 hours only, also between 370 oC and 540 oC over a longer
period.
Precipitation of sigma phase will also occur above 650 oC
resulting in decreased ductility and corrosion resistance.
*2205 is therefore not recommended
for use at temperatures above 300 oC.
Test
Temperature
oC
|
Tensile
Strength
Mpa
|
Yield
Strength
Mpa
|
Charpy V Notch
Impact
After 100 Hours at Temp.
J |
315 |
650 |
390 |
45 |
370 |
640 |
375 |
22 |
480 |
|
|
5 |
N.B. Should embrittlement
occur then annealing is required to rectify. |
2205 is not recommended for use at
temperatures below -50 oC, again due to its embrittling
effect resulting in low ductility.
N.B. Unlike high temperature exposure
however, the embrittling effect of low temperature exposure
is not permanent, existing only for the duration at low
temperature.
Test Temperature
oC |
Impact Test
Charpy V-Notch |
25 |
160 |
0 |
60 |
-20 |
30 |
-45 |
15 |
Cold bending will be extremely difficult due to the high
yield strength. Any cold working causing more than 10% deformation
should be followed by annealing.
Hot bending should be performed at 950 oC - 1000 oC followed
by annealing.
2205 has superior resistance to general corrosion in most
media than 316L or 317L austenitic stainless steel grades
2205 has a much higher resistance to stress corrosion cracking
than 304L or 316L austenitic stainless steel grades.
2205 has a higher resistance to pitting corrosion than 316L
or 317L austenitic stainless steel grades.
2205 has a higher resistance to crevice corrosion and erosion
corrosion than 316L austenitic stainless steel grade.
2205 has better fatigue strength in corrosive environments
than the standard austenitic stainless steel grades due
to its higher strength and higher corrosion resistance.
N.B. For optimum corrosion resistance, surfaces must be
free of scale and foreign particles.
Finished parts should be passivated.
Heat uniformly to 1150 oC. Hold until temperature is uniform
throughout the section.
Do not forge below 900 oC.
Finished forgings should be air cooled.
Finally forgings will require to be annealed
in order to obtain optimum mechanical properties and corrosion
resistance.
Heat to 1020 oC - 1100 oC. Hold until temperature is uniform
throughout the section. *Soak as required.
Quench in water to obtain optimum corrosion resistance.
*Actual soaking time should be long enough
to ensure that the part is heated thoroughly throughout
its section to the required temperature, 30 minutes per
25mm of section may be used as a guide.
Please consult your heat treater for best
results.
The machinability of 2205 in the annealed as supplied condition
is lower than either 304 and 316 due to it's higher yield
strength (approximately double).
Typically 80% as machinable as the standard 304 and 316
grades, but lower against the improved machinability 304
and 316 grades.
N.B. All machining should be carried out
as per machine manufacturers recommendations for suitable
tool type, feeds and speeds.
2205 is readily weldable by the various standard electric
arc welding processes.
Oxcyacetylene welding is however not recommended due to
the possibility of carbon pick up in the weld area.
Welding of 2205 should always be carried out using duplex
stainless electrodes* similar to the parent metal.
No pre-heat or post-heat is required.
Post weld annealing, while not necessary
for many applications, will however provide optimum corrosion
resistance in severe service conditions.
|
