ASTM G76-95
(Test Method)Standard Test Method for Conducting Erosion Tests by Solid Particle Impingement Using Gas Jets
Standard Test Method for Conducting Erosion Tests by Solid Particle Impingement Using Gas Jets
SCOPE
1.1 This practice covers the determination of material loss by gas-entrained solid particle impingement erosion with jet- nozzle type erosion equipment. This practice may be used in the laboratory to measure the solid particle erosion of different materials and has been used as a screening test for ranking solid particle erosion rates of materials in simulated service environments (1, 2). Actual erosion service involves particle sizes, velocities, attack angles, environments, etc., that will vary over a wide range (3-5). Hence, any single laboratory test may not be sufficient to evaluate expected service performance. This practice describes one well characterized procedure for solid particle impingement erosion measurement for which interlaboratory test results are available.
1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
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Designation: G 76 – 95
Standard Test Method for
Conducting Erosion Tests by Solid Particle Impingement
Using Gas Jets
This standard is issued under the fixed designation G 76; the number immediately following the designation indicates the year of original
adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript
epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope succession of impacts between (liquid or solid) particles and a
solid surface.
1.1 This test method covers the determination of material
3.2 Definitions of Terms Specific to This Standard:
loss by gas-entrained solid particle impingement erosion with
3.2.1 erosion value—the volume loss of specimen material
jetnozzle type erosion equipment. This test method may be
divided by the total mass of abrasive particles that impacted the
used in the laboratory to measure the solid particle erosion of
3 −1
specimen (mm ·g ).
different materials and has been used as a screening test for
3 −1
3.2.2 Normalized Erosion Rate—erosion value (mm ·g )
ranking solid particle erosion rates of materials in simulated
3 −1
of specimen material divided by erosion value (mm ·g )of
service environments (1, 2). Actual erosion service involves
reference material.
particle sizes, velocities, attack angles, environments, etc., that
will vary over a wide range (3-5). Hence, any single laboratory
4. Summary of Practice
test may not be sufficient to evaluate expected service perfor-
4.1 This test method utilizes a repeated impact erosion
mance. This test method describes one well characterized
approach involving a small nozzle delivering a stream of gas
procedure for solid particle impingement erosion measurement
containing abrasive particles which impacts the surface of a
for which interlaboratory test results are available.
test specimen. A standard set of test conditions is described.
1.2 This standard does not purport to address all of the
However, deviations from some of the standard conditions are
safety concerns, if any, associated with its use. It is the
permitted if described thoroughly. This allows for laboratory
responsibility of the user of this standard to establish appro-
scale erosion measurements under a range of conditions.
priate safety and health practices and determine the applica-
Methods are described for preparing the specimens, conducting
bility of regulatory limitations prior to use.
the erosion exposure, and reporting the results.
2. Referenced Documents
5. Significance and Use
2.1 ASTM Standards:
5.1 The significance of this test method in any overall
E 122 Practice for Choice of Sample Size to Estimate a
3 measurements program to assess the erosion behavior of
Measure of Quality for a Lot or Process
materials will depend on many factors concerning the condi-
G 40 Terminology Relating to Wear and Erosion
tions of service applications. The users of this test method
2.2 American National Standard:
should determine the degree of correlation of the results
ANSI B74.10 Grading of Abrasive Microgrits
obtained with those from field performance or results using
3. Terminology other test systems and methods. This test method may be used
to rank the erosion resistance of materials under the specified
3.1 Definitions:
conditions of testing.
3.1.1 erosion—progressive loss of original material from a
solid surface due to mechanical interaction between that
6. Apparatus
surface and a fluid, a multicomponent fluid, or impinging liquid
6.1 The apparatus is capable of eroding material from a test
or solid particles.
specimen under well controlled exposure conditions. A sche-
3.1.2 impingement—a process resulting in a continuing
matic drawing of the exit nozzle and the particle-gas supply
system is shown in Fig. 1. Deviations from this design are
This practice is under the jurisdiction of ASTM Committee G-2 on Wear and
permitted; however, adequate system characterization and
Erosion and is the direct responsibility of Subcommittee G02.10 on Erosion by
control of critical parameters are required. Deviations in nozzle
Solids and Liquids.
design and dimensions must be documented. Nozzle length to
Current edition approved Feb. 15, 1995. Published April 1995. Originally
published as G 76 – 83. Last previous edition G 76 – 83 (1989)e .
diameter ratio should be 25:1 or greater in order to achieve an
Boldface numbers in parentheses refer to references at the end of this practice.
Annual Book of ASTM Standards, Vol 14.02.
Annual Book of ASTM Standards, Vol 03.02.
5 6
Available from American National Standards Institute, 11 West 42nd Street, A commercial apparatus is available from Falex Corp., 1020 Airpark Dr., Sugar
13th Floor, New York, NY 10036. Grove, IL 60554.
Copyright © ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, United States.
G76
TABLE 1 Characteristics of Type 1020 Steel Reference Material
Annealed 15 min at 760°C (1400°F), air cooled.
Hardness: HRB 5 706 2.
Chemical Composition:
C 5 0.20 6 0.01 wt %
Mn 5 0.45 6 0.10
S 5 0.03 6 0.01
Si 5 0.16 0.05
P 5 0.01 6 0.01
FIG. 1 Schematic Drawing of Solid Particle Erosion Equipment
acceptable particle velocity distribution in the stream. The
recommended nozzle consists of a tube about 1.5 mm inner
diameter, 50 mm long, manufactured from an erosion resistant
material such as WC, A1 O , etc. Erosion of the nozzle during
2 3
service shall be monitored and shall not exceed 10 % increase
in the initial diameter.
6.2 Necessary features of the apparatus shall include a
means of controlling and adjusting the particle impact velocity,
particle flux, and the specimen location and orientation relative
to the impinging stream.
6.3 Various means can be provided for introducing particles
into the gas stream, including a vibrator-controlled hopper or a
screw-feed system. It is required that the system provide a
uniform particle feed and that it be adjustable to accommodate
desired particle flow values.
6.4 A method to measure the particle velocity shall be
available for use with the erosion equipment. Examples of FIG. 2 Microstructure of 1020 Steel Reference Material
ASTM Grain Size 9
accepted methods are high-speed photography (6), rotating
double-disk (7), and laser velocimeter (8). Particle velocity
series shall be tested periodically using specified (see Section
shall be measured at the location to be occupied by the
9) 50 μm A1 O particles to verify the satisfactory performance
specimen and under the conditions of the test.
2 3
of the apparatus. It is recommended that performance be
7. Test Materials and Sampling
verified using this reference material every 50 tests during a
measurement series, and also at the beginning of each new test
7.1 This test method can be used over a range of specimen
series whenever the apparatus has been idle for some time. The
sizes and configurations. One convenient specimen configura-
recommended composition, heat treatment, and hardness range
tion is a rectangular strip approximately 10 by 30 by 2 mm
for this steel are listed in Table 1. The use of a steel of different
thick. Larger specimens and other shapes can be used where
composition may lead to different erosion results. A photomi-
necessary, but must be documented.
crograph of the specified A1 O particles is shown in Fig. 3.
7.2 The abrasive material to be used shall be uniform in
2 3
The range of erosion results to be expected for this steel under
essential characteristics such as particle size, moisture, chemi-
the standard test conditions specified in Section 9 is shown in
cal composition, etc.
Table 2 and is based on interlaboratory test results.
7.3 Sampling of material for the purpose of obtaining
8.2 Calibration at standard test conditions is recommended
representative test specimens shall be done in accordance with
even if the apparatus is operated at other test conditions.
acceptable statistical practice. Practice E 122 shall be con-
8.3 In any test program the particle velocity and particle
sulted.
feed rate shall be measured at frequent intervals, typically
8. Calibration of Apparatus
every ten tests, to ensure constancy of conditions.
8.1 Specimens fabricated from Type 1020 steel (see Table 1
9. Standard Test Conditions
and Fig. 2) equivalent to that used in the interlaboratory test
9.1 This test method defines the following standard condi-
tions.
A source for the recommended nozzle (tungsten carbide) is Kennametal, Inc.,
Latrobe, PA.
Supporting data are available from ASTM Headquarters. Request
RR:G–2–1003.
G76
9.1.9 The distance from specimen surface to nozzle end
shall be 10 6 1 mm.
10. Optional Test Conditions
10.1 When test conditions or materials other than those
given in Section 9 are used, reference to this test method shall
clearly specify all test conditions and materials. It should be
noted that other conditions, for example, larger particle veloci-
ties, may adversely affect measurement precision.
11. Test Procedure
11.1 Establish and measure the particle velocity and particle
flow specified. Adjust equipment controls to obtain proper
velocity and flow conditions before inserting test specimens.
Particle flow rate values are determined by collecting and
subsequently weighing the abrasive exiting from the nozzle for
a measured time period.
11.2 Prepare the specimen surface if required to achieve
uniformity and adequate finish. Grinding through a series of
abrasive papers to 400 grit is usually adequate so long as all
surface scale is removed. A surface roughness of 1 μm (40 μin.)
rms or smaller is recommended. Clean the specimen surface
11 12
carefully. Weigh on an analytical balance to 60.01 mg.
11.3 Mount the specimen in proper location and orientation
FIG. 3 Photomicrograph of 50 μm A1 O Particles Used in
2 3
in the apparatus. Subject the specimen to particle impingement
Interlaboratory Testing
for a selected time interval, measured to an accuracy of 5 s.
Remove the specimen, clean carefully, reweigh and calcul
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