OXIDE DISPERSION STRENGTHENED AUSTENITIC STAINLESS STEEL

1. OXIDE DISPERSION STRENGTHENED
AUSTENITIC STAINLESS STEEL
Presented by
Suresh Beera
12ETMM11
M.Tech/Ph.D
Materials Engineering
SEST, UoH
10/24/2014
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2. CONTENTS
 Introduction to Stainless steels
 Austenitic stainless steels
 Oxide dispersion strengthening
 ODS procedure
 Comparisons with non ODS steels
 Microstructure of ODS steel
 applications
 Advantages & disadvantages
 Summary
 References
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3. Stainless Steel
• Add Chromium to steel
• Above 13%, it precipitates
at the surface,
• Forms a Cr2O3 layer
Which doesn’t corrode.
•Martensitic (Heat Treated)
•Duplex (Mo and Ni)
•Ferrite (with Mo)
•Austenitic (with Ni, Mn)
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4. AUSTENITIC STAINLESS STEELS when
compare to a typical carbon steel.
•high ductility,
•low yield stress
•relatively high ultimate tensile strength
•good corrosion resistance,
A carbon steel on cooling transforms from
Austenite to a mixture of ferrite and
cementite.
type 304 typically contain 18Cr and 8Ni
wt% (18/8 stainless) type 316 which
contains up to 3 wt% Mo, offers an
improved general and pitting corrosion
resistance,
They contain a maximum of 0.15% carbon,
a minimum of 16% chromium and sufficient
nickel and/or manganese to retain an
austenitic structure at all temperatures
from the cryogenic region to the melting
point of the alloy
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5. What Is An Oxide Dispersion Strengthened (ODS)
Alloy?
Oxide dispersion strengthened alloys (ODS alloys) typically
consist of a high temperature metal matrix - such as iron
aluminide, iron chromium, iron-chromium-aluminium, nickel
chromium or nickel aluminide - with small (5-50nm) oxide
particles of alumina (Al2O3) or yttria (Y2O3) dispersed within
it.
Iron-based and nickel-based oxide dispersion strengthened
alloys exhibit good corrosion resistance and mechanical
properties at elevated temperatures.
These alloys also show excellent creep resistance, and
partly from the very large elongated grain structure
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6. The composition of two commercially-available oxide
dispersion strengthened (ODS) alloys (one iron-based,
the other nickel-based)
Composition (wt%)
Name Ni Fe Cr Al Ti C Yttrium
Oxide
INCONEL
MA754
78 1.0 20 0.3 0.5 0.05 0.6
INCOLOY
MA956
- 74 20 4.5 0.5 0.05 0.5
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7. HOW ARE OXIDE DISPERSION STRENGTHENED
(ODS) ALLOYS PRODUCED?
yttria
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8. A Comparison Of Commercial ODS
Steels & ferritic/martensitic steels
A comparison of the yield stress
as a function of test temperature
for the three commercial ODS
steels and the non-ODS
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9. A comparison of the ultimate tensile
strength as a function of test temperature
for the three commercial ODS steels and
the non-ODS
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10. MICRO STRUCTURE OF STAINLESS STEEL 316L &
MECHANICAL ALLOYED 316L
a b
SEM Images of (a) AISI 316L Stainless Steel, (b) Ti,
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11. C
(d) MA Powders Composed of 99.4
wt% AISI 316L Stainless Steel,
0.3 wt% Ti ,
0.3 wt% Y2O3
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(c) Y2O3

12. Applications
0xide dispersion strengthened alloys (ODS)
are used for high temperature turbine blades
and heat exchanger tubing.Alloys of nickel
are the most common but work is being done
on iron aluminum alloys.
ODS steels are used in nuclear
applications.
ODS materials are used on space crafts as
a layer designed to protect the vehicle
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13. ADVANTAGES:
Can be machined, brazed, formed, cut with available
processes.
Develops a protective oxide layer that is self-healing.
Allows the design of thin-walled structures (sandwich).
Resistant to harsh weather conditions in the troposphere
Low maintenance cost.
DISADVANTAGES:
It has a higher expansion coefficient than other materials,
causing higher thermal stresses.
Lower maximum allowable temperature.
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14. Summary
ODS steels can by produced by mechanical alloying process,
hot isostatic pressing, and rolling.
ODS austenitic stainless steel , exhibit good corrosion
resistance, creep resistance and mechanical properties at
elevated temperatures
Yield strength and tensile strength of ODS Steels is higher
than ferritic/martensitic steels
Changes in Micro structure of Mechanical Alloying Stainless
Steel 316L was observed
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15. REFERENCES
Elements of metallurgy and engineering alloys f.C.
Campbell, editor, p 573.148,441-445
F.C. Campbell, manuf acturin g technology for aerospace
structu ral mat erials, elsevier scientific, 2006
Oxide dispersion-strengthened steels: a comparison of
experimental and commercial steels―r. L. Klueh, j. P.
Shingledecker, r. W. Swindeman, and d. T. Hoelzer (oak ridge
national laboratory)
Oxide dispersion strengthened steels: a comparison of
microstructure features of some commercial steels with
Applying of doppler broadening spectroscopy
J. Veterníková, s. Kilpeläine, v. Slugen, f. Tuomisto
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16. THANK YOU
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