The material loss upon erosion was measured for several iron-chromium alloys. Two types of erodent material were used: spherical glass beads and sharp particles of crushed glass. For erosion with glass beads the erosion resistance (defined as the reciprocal of material loss rate) was linearly dependent on hardness. This is in accordance with the erosion behavior of pure metals, but contrary to the erosion behavior of alloys of constant composition that were subjected to different heat treatments. For erosion with crushed glass, however, no correlation existed between hardness and erosion resistance. Instead, the erosion resistance depended on alloy composition rather than on hardness and increased with the chromium content of the alloy. The difference in erosion behavior for the two types of erodent particles suggested that two different material removal mechanisms were involved. This was confirmed by SEM micrographs of the eroded surfaces, which showed that for erosion with glass beads the mechanism of material removal was deformation-induced flaking of surface layers, or peening, whereas for erosion with crushed glass it was cutting or chopping

Buckley, D. H.

Salik, J.

English

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NASA NASA-TP-2354 19840020896 f
Technical i
Paper --
2354
July 1984
Erosion of Iron-Chromium
Alloys by Glass Particles
Joshua Salik and
Donald H. Buckley
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https://ntrs.nasa.gov/search.jsp?R=19840020896 2020-03-20T22:39:37+00:00Z

NASA
Technical
Paper
2354
1984
Erosion of Iron-Chromium
Alloys by Glass Particles
Joshua Salik and
Donald H. Buckley
Lewis Research Center
Cleveland, Ohio
National Aeronautics
and Space Administration
Scientific and Technical
Information Branch

Summary solution heat treatment causes a substantial increase in
resistance to erosion with glass beads (ref. 9) but has no
The material loss upon erosion was measured for sev- effect on resistance to erosion with crushed glass. There
eral iron-chromium alloys. Two types of erodent material thus seems to be little hope of improving resistance to
were used: spherical glass beads and sharp particles of erosion with sharp particles by heat treating. Another
crushed glass. For erosion with glass beads the erosion approach to this problem is presented herein, namely,
resistance (defined as the reciprocal of material loss rate) increasing erosion resistance by changing the chemical
was linearly dependent on hardness. This was in composition of the eroded material.
accordance with the erosion behavior of pure metals, but The materials selected for this study were iron-
contrary to the erosion behavior of alloys of constant chromium alloys. These alloys are the basis for stainless
composition that were subjected to different heat steels, and thus studying their erosion behavior may give
treatments. For erosion with crushed glass, however, no useful information for applying this important class of
correlation existed between hardness and erosion construction materials in erosive conditions. Also, this
resistance. Instead, the erosion resistance depended on study may indicate the extent of the usefulness of
alloy composition rather than on hardness and increased chromium diffusion coating, an established industrial
with the chromium content of the alloy. The difference in process (ref. 10), for protection against erosion.
erosion behavior for the two types of erodent particles The friction and wear behavior of these alloys in
suggested that two different material removal contact with an abrasive grit of silicon carbide (as well as
mechanisms were involved. This was confirmed by SEM with themselves) was investigated by Miyoshi and
micrographs of the eroded surfaces, which showed that Buckley (ref. 11). They found that the height of grooves
for erosion with glass beads the mechanism of material formed in these materials as a result of sliding against
removal was deformation-induced flaking of surface silicon carbide depends on the chromium content of the
layers, or peening, whereas for erosion with crushed glass alloys and reaches a minimum at 14 wt °70chromium.
it was cutting or chopping. These results were interpreted as due to atomic size misfit
between iron and chromium, following Stephens and
Witzke (ref. 12). It was of interest to compare these
findings with erosion results.
Introduction
In spite of the recent interest in the erosion of materials Materials
by solid particles and its mechanisms (for an excellent
review, see ref. 1), little work concerning the-effect of The alloys used in this investigation were prepared
material properties on erosion resistance has been from 99.9 percent pure iron and 99.7 percent pure
reported. The available literature consists mainly of chromium. The starting materials were placed in zirconia
comparative studies of the erosion resistance of various molds and then induction melted in an argon
materials (refs. 2 to 6). The effect of the microstructures atmosphere. Alloys containing 1, 9, 14, and 19 wt o70
of 1020 and 1075 steels on their, erosion behavior was chromium were used. Before samples were prepared, the
studied by Levy (ref. 7). alloys were annealed in a vacuum furnace at 460° C and a
In a study of the effect of various heat treatments on pressure of 34/_Pa (4.5 x 10-3 torr) for 5 hours.
the erosion resistance of 1045 steel (ref. 8), it was found Two types of erodent particles were employed: glass
that although quenching and formation of martensite beads with an average diameter of 15 #m and crushed
considerably increase the resistance to erosion with glass glass. Figure 1 shows micrographs of the two types of
beads, they have no observable effect on the resistance to erodent particles.
erosion with crushed glass, which represents more X-ray diffraction patterns were taken by using a
realistic erosion conditions. Similar results were obtained copper source operated at a voltage of 45 kV and a
for heat treatment of the 6061 aluminum alloy, where current of 40 mA with a nickel filter.
The Rockwell A hardness values of the samples are between hardness and erosion resistance. Previous
given in table I. Hardness was highest for the Fe-19Cr studies (refs. 2, 8, and 9) show no correlation between
alloy. To check whether this variation in hardness was hardness and erosion resistance for alloys of constant
due to formation of intermetallic compounds, X-ray composition subjected to different heat treatments. On
diffraction patterns of the samples were taken (fig. 2). the other hand, a comparative study of the erosion of
These diffractograms, as wellas computer analysis of the different pure metals with angular silicon carbide
diffraction results, show that the X-ray diffraction particles (ref. 2) yielded a relation between hardness and
patterns of the various Fe-Cr alloys were essentially erosion resistance.
identical to the X-ray pattern of pure iron. In other The results expressed in terms of the volume of the
words, no intermetallic compound was observed and the material removed are presented in figure 3. Comparison
alloys formed a series of solid solutions. The variation in with the results obtained by Miyoshi and Buckley
hardness was thus due to solid solution hardening and (ref. 11) for the abrasion wear of iron-chromium alloys
softening effects, by silicon carbide (fig. 5) shows a considerable similarity
as well as some differences. Thus the groove height in
abrasion reached a minimum, and so did the material loss
Experimental Procedure in erosion. These minima, however, seem to appear at
somewhat different compositions. Also, the erosion rate
The hardness of the samples was measured by means for the Fe-lCr alloy was found to be higher than that of
of the Rockwell A hardness test. This test, rather than pure iron, whereas no such effect was observed by
a microhardness test, was selected to eliminate the possi- Miyoshi and Buckley.
bility of erroneous hardness values due to specimen For erosion with crushed glass, no correlation was
preparation, found between hardness and erosion resistance (fig. 6).
Specimens were eroded in an industrial sandblasting Rather, the main factor dominating the resistance to
apparatus. Argon at a pressure of 0.54 MPa was used as erosion with crushed glass seemed to be the chromium
the driving gas in order to minimize corrosion effects, content of the alloys. This is an encouraging observation
The nozzle diameter was 1.18 mm. The specimen surface since it provides us with a means of improving the erosion
was perpendicular to the stream of particles and at a resistance, namely, alloying.
distance of 13 mm from the nozzle. The erodent particle The different effects of chemical composition and
velocities and flow rates under these conditions were hardness on resistance to erosion with glass beads, as
measured by Rao et al. (ref. 13) and reported to be 101 compared with erosion with crushed glass, are another
m/sec and 0.76 g/sec for glass beads and 68 m/sec and manifestation of the fact that two different material
0.26 g/sec for crushed glass. Reproducible mass-loss removal mechanisms are involved in these two cases. As
results were obtained with a variation not exceeding ±3 was already pointed out for the erosion of 1045 steel
percent. (refs. 8 and 14) and 6061 aluminum alloy and copper (ref.
14), the main mechanism of material removal for erosion
with glass beads is deformation-induced flaking of
Results and Discussion surface layers, or peening; whereas for erosion with sharp
particles, it is cutting or chopping. This can be clearly
The data for erosion with glass beads are also listed in seen in the SEM micrographs of the surface of the
table I and plotted in figures 3 and 4. The most notable Fe-9Cr alloy eroded by these two types of erodent
feature of the results is the existence of a linear relation particles (fig. 7).
Conclusions References
The main conclusion of this study of the material loss 1. Schmitt, G. F., Jr.: Liquid and Solid Particle Impact Erosion.
upon erosion of several iron-chromium alloys is that the Wear Control Handbook, M. B. Peterson and W. O. Winer, eds.,
resistance of some materials to erosion with sharp AmericanSocietyofMechanicalEngineers,1980,pp. 231-282.
particles could be improved by changing their 2. Finnie, Ialn; Wolak, Jan; and Kabil, Yehia: Erosion of Metals bySolid Particles. J. Mater., vol. 2, no. 3, Sept. 1967, pp. 682-700.
composition. This is in contrast to mechanical and heat 3. Ascarelli,Paolo: Relation Between the Erosion by Solid Particles
treatments, which were previously shown to have little or and the Physical Properties of Metals. AMMRC TR 71--47, Army
no effect on resistance to erosion with crushed glass. Materials and Mechanics Research Center, 1971. (AD-738162.)
Another finding is that the resistance of iron- 4. Hansen,J. S.: Relative Erosion Resistance of Several Materials.
chromium alloys to erosion with spherical particles Erosion:Preventionand UsefulApplications,ASTM-STP-664,W. F. Adler, ed., American Society for Testing Materials, 1979,
increased linearly with hardness. This is in accordance pp. 148-162.
with the erosion resistance of pure metals, but contrary to 5. Jones, M. H.; and Lewis, R.: Solid Particle Erosion of a Selection
results obtained for alloys of constant composition that ofAlloySteels. Proceedings of the Fifth International Conference
were subjected to different heat treatments, on Erosion by Liquid and Solid Impact, University of Cambridge,
1979, pp. 52-1--52-9.
For erosion with sharp angular particles, however, 6. Soderberg, S.; et al.: Erosion Classification of Materials Using a
there was no correlation between hardness and erosion Centrifugal Erosion Tester. Tribol..Int., vol. 14, no. 6, Dec. 1981,
resistance. In this case erosion resistance depended on the pp. 333-343.
alloy composition and increased with chromium content. 7. Levy, Alan V.: The Solid Particle Erosion Behavior of Steel as a
The difference in behavior for the two types of erodent Function of Microstructure. Wear, vol. 68, no. 3, May 15, 1981,
particles demonstrated once again that the material pp. 269-287.8. Salik, Joshua; and Buckley, Donald H.: Effect of Mechanical
removal mechanisms in these two cases are different. For Surface and Heat Treatments on Erosion Resistance. NASA
spherical erodent particles the mechanism was TM-81540,1981.
deformation-induced flaking of surface layers, whereas 9. Salik, Joshua; Buckley, Donald H.; and Bralnard, William A.:
for sharp erodent particles it was cutting or chopping. The Effect of Mechanical Surface and Heat Treatments on the
Erosion Resistance of 6061Aluminum Alloy. Wear, vol. 65, no. 3,
Jan. l, 1981, pp. 351-358.
10. Wesley, W. A.: Nickel and Chromium Coatings. Corrosion
Handbook, H. H. Uhlig, ed., John Wiley & Sons, Inc., 1948, pp.
817-829.
11. Miyoshi, Kazuhisa; and Buckley, Donald H.: Friction and Wear
Characteristics of Iron-Chromium Alloys in Contact with
Themselves and Silicon Carbide. NASA TP-1387, 1979.
12. Stephens, Joseph R.; and Witzke, Walter R.: Alloy Softening in
Binary Iron Solid Solutions. J. Less Common Met., vol. 48, 1976,
pp. 285-308.
13. Rao, P. Veerabhadra; Young, Stanley G.; and Buckley, Donald
H.: A Study of the Nature of Solid Particle Impact and Shape on
the Erosion Morphology of Ductile Metals. NASA TM-82933,
1982.
Lewis Research Center 14. Rao, P. V.; Young, S. G.; and Buckley, D. H.: Morphology of
National Aeronautics and Space Administration Ductile Metals Eroded by a Jet of Spherical Particles Impinging at
Cleveland, Ohio, April 25, 1984 Normal Incidence, Wear, vol. 85, 1983, 223-237.
TABLE 1.--HARDNESS AND EI¢O_51ONDAtA UP Pe-_r /_.LLU¥_
OF DIFFERENT COMPOSITIONS
Alloy Hardness Material loss in 15-min Material loss in 15-min
(Rockwell A) erosion test with glass erosion test with crushed
beads glass
Mass, Atoms, Volume, Mass, Atoms, Volume,
mg g-atom mm3 mg g-atom mm3
Pure Fe 32 46.0 0.000824 5.84 41.3 0.000739 5.25
Fe-lCr 30 56.9 .001020 7.29 37.4 .000670 4.79
Fe-9Cr 61 17.7 .000319 2.27 35.8 .000645 4.58
Fe-14Cr 56 22.8 .000412 2.93 33.1 .000598 4.26
Fe-19Cr 40 33.1 .000601 4,27 30.5 .000553 3.94
(a) Glass beads.
(b) Crushed glass.
Figure 1.--SEM micrographs of erodent particles used in this study.
4
3000 2000
2430 1620
1920 1280
1410 980
1080 120
150 5OO
480 320
210 180
120 80
30 20
3240 -- 1620
2560-- 1280
1960-- 980
1440-- 720
I000 5OO
640 320
360 _ 180
160 8O
40 _t 20
40 50 60 70 80 90 100 40 .50 60 70 80 90 100
29 29
2OO0
1620
1280
980
72O
5o0
-= 320
180
80
20
40 50 6O 70 80 9O i00
20
(a) Pure Fe.
(b) Fe-lCr.
(c) Fe-gCr.
(d) Fe-14Cr.
(e) Fe-19Cr.
Figure 2.--X-ray diffractograms of the alloys used in this study.
20 m 4 --
o/,,,
15 -- _ 0 Erosionresistance _D Ch
"_ 3 --
o -
_. ._, 2 --
0- 1 -_ I I I I
20 30 40 50 60 ;0
Hardness(RockwellA)
Figure 3.--Erosion resistance and chromium content as functions of hardness for various Fe-Or alloys eroded by glass beads.
.8--
8 --
Load,
0 g
0 10
._ []E
.
_6-- =_"
._. .__
_4 _
_ .2
o
>
z I i I I
0 5 10 15 20 0 5 10 15 20
Chromiumcontent,wt % Chromiumcontent, wt%
Figure 4.--Material loss as function of chromium content for various Figure 5.--Height of grooves caused by sliding of silicon carbide rider
Fe-Cr alloys eroded by glass beads, in mineral oil on Fe-Cr alloys as function of chromium content a/nd
load. (From ref. 11.)
80 --
11--
A
_0-$
"_lO --
_9 j
/ D Hardness2O
s _" I I I I
5 10 15 20
Chromiumcontent,wt%
Figure 6.--Erosion resistanceand hardnessas functions of chromium content for various Fe-Cr alloys erodedby crushed glass.
6
(a) Erodent, glass beads.
(b) Erodent, crushed glass.
Figure 7.--SEM micrographs of surface of Fe-9Cr alloy eroded with glass beads and crushed glass.


1. Report No. 2. Government Accession No. 3. Recipient's Catalog No,
NASATP-2354
4. Title and Subtitle 5. Report Date
July 1984
Erosion of Iron-Chromium Alloys by Glass Particles 6. Performing Organization Code
506-53-1B
7. Author(s) 8. Performing Organization Report No.
E-1615
Joshua Salik and Donald H. Buckley
10.WorkUnitNo.
9. Performing Organization Name and Address
National Aeronautics and Space Administration 11. Contract or Grant No.
Lewis Research Center
Cleveland, Ohio 44135 13. Type of Report and Period Covered
12. Sponsoring Agency Name and Address Techni cal Paper
National Aeronautics and Space Administration
Washington, D.C. 20546 14.Sponsoring Agency Code
15. Supplementa_ Notes
Joshua Salik, National Research Council - NASAResearch Associate; Donald H.
Buckley, Lewis Research Center.
16. Abstract
The material loss upon erosion was measured for several iron-chromium alloys.
Two types of erodent material were used: spherical glass beads and sharp
particles of crushed glass. For erosion with glass beads the erosion
resistance (defined as the reciprocal of material loss rate) was linearly
dependent on hardness. This is in accordance with the erosion behavior of
pure metals, but contrary to the erosion behavior of alloys of constant
composition that were subjected to different heat treatments. For erosion
with crushed glass, however, no correlation existed between hardness and
erosion resistance. Instead, the erosion resistance depended on alloy
composition rather than on hardness and increased with the chromium content
of the alloy. The difference in erosion behavior for the two types of
erodent particles suggested that two different material removal mechanisms
were involved. This was confirmed by SEMmicrographs of the eroded surfaces,
which showed that for erosion with glass beads the mechanism of material
removal was deformation-induced flaking of surface layers, or peening,
whereas for erosion with crushed glass it was cutting or chopping.
17. Key Words (Suggested by Author(s)) 18. Distribution Statement
Erosion Unclassified - unlimited
Chromium STARCategory 26
Iron
Alloys
19. Security Classif. (of this report) 20. Security Classif. (of this page) 21. No. of pages 22. Price*
Unclassified Unclassified 9 A02
*For sale by the National Technical Information Service, Springfield, Virginia 22161 NASA-Langley, 1984

National Aeronauticsand THIRD-CLASS BULK RATE Postage and Fees Paid
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Erosion of iron-chromium alloys by glass particles

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