ASTM G76-95(2000)
(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.
General Information
Relations
Standards Content (Sample)
NOTICE: This standard has either been superseded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
Designation: G 76 – 95 (Reapproved 2000)
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 3.1.2 impingement—a process resulting in a continuing
succession of impacts between (liquid or solid) particles and a
1.1 This test method covers the determination of material
solid surface.
loss by gas-entrained solid particle impingement erosion with
3.2 Definitions of Terms Specific to This Standard:
jetnozzle type erosion equipment. This test method may be
3.2.1 erosion value—the volume loss of specimen material
used in the laboratory to measure the solid particle erosion of
divided by the total mass of abrasive particles that impacted the
different materials and has been used as a screening test for
3 −1
specimen (mm ·g ).
ranking solid particle erosion rates of materials in simulated
3 −1
3.2.2 Normalized Erosion Rate—erosion value (mm ·g )
service environments (1, 2). Actual erosion service involves
3 −1
of specimen material divided by erosion value (mm ·g )of
particle sizes, velocities, attack angles, environments, etc., that
reference material.
will vary over a wide range (3-5). Hence, any single laboratory
test may not be sufficient to evaluate expected service perfor-
4. Summary of Practice
mance. This test method describes one well characterized
4.1 This test method utilizes a repeated impact erosion
procedure for solid particle impingement erosion measurement
approach involving a small nozzle delivering a stream of gas
for which interlaboratory test results are available.
containing abrasive particles which impacts the surface of a
1.2 This standard does not purport to address all of the
test specimen. A standard set of test conditions is described.
safety concerns, if any, associated with its use. It is the
However, deviations from some of the standard conditions are
responsibility of the user of this standard to establish appro-
permitted if described thoroughly. This allows for laboratory
priate safety and health practices and determine the applica-
scale erosion measurements under a range of conditions.
bility of regulatory limitations prior to use.
Methods are described for preparing the specimens, conducting
2. Referenced Documents the erosion exposure, and reporting the results.
2.1 ASTM Standards:
5. Significance and Use
E 122 Practice for Choice of Sample Size to Estimate a
3 5.1 The significance of this test method in any overall
Measure of Quality for a Lot or Process
measurements program to assess the erosion behavior of
G 40 Terminology Relating to Wear and Erosion
materials will depend on many factors concerning the condi-
2.2 American National Standard:
tions of service applications. The users of this test method
ANSI B74.10 Grading of Abrasive Microgrits
should determine the degree of correlation of the results
3. Terminology obtained with those from field performance or results using
other test systems and methods. This test method may be used
3.1 Definitions:
to rank the erosion resistance of materials under the specified
3.1.1 erosion—progressive loss of original material from a
conditions of testing.
solid surface due to mechanical interaction between that
surface and a fluid, a multicomponent fluid, or impinging liquid
6. Apparatus
or solid particles.
6.1 The apparatus is capable of eroding material from a test
specimen under well controlled exposure conditions. A sche-
This practice is under the jurisdiction of ASTM Committee G02 on Wear and
matic drawing of the exit nozzle and the particle-gas supply
Erosion and is the direct responsibility of Subcommittee G02.10 on Erosion by
system is shown in Fig. 1. Deviations from this design are
Solids and Liquids.
permitted; however, adequate system characterization and
Current edition approved Feb. 15, 1995. Published April 1995. Originally
control of critical parameters are required. Deviations in nozzle
published as G 76 – 83. Last previous edition G 76 – 83 (1989)e .
Boldface numbers in parentheses refer to references at the end of this test
design and dimensions must be documented. Nozzle length to
method.
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.
NOTICE: This standard has either been superseded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
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
diameter ratio should be 25:1 or greater in order to achieve an
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.
FIG. 2 Microstructure of 1020 Steel Reference Material
6.4 A method to measure the particle velocity shall be
ASTM Grain Size 9
available for use with the erosion equipment. Examples of
accepted methods are high-speed photography (6), rotating
series shall be tested periodically using specified (see Section
double-disk (7), and laser velocimeter (8). Particle velocity
9) 50 μm A1 O particles to verify the satisfactory performance
2 3
shall be measured at the location to be occupied by the
of the apparatus. It is recommended that performance be
specimen and under the conditions of the test.
verified using this reference material every 50 tests during a
measurement series, and also at the beginning of each new test
7. Test Materials and Sampling
series whenever the apparatus has been idle for some time. The
7.1 This test method can be used over a range of specimen
recommended composition, heat treatment, and hardness range
sizes and configurations. One convenient specimen configura-
for this steel are listed in Table 1. The use of a steel of different
tion is a rectangular strip approximately 10 by 30 by 2 mm
composition may lead to different erosion results. A photomi-
thick. Larger specimens and other shapes can be used where
crograph of the specified A1 O particles is shown in Fig. 3.
2 3
necessary, but must be documented.
The range of erosion results to be expected for this steel under
7.2 The abrasive material to be used shall be uniform in
the standard test conditions specified in Section 9 is shown in
essential characteristics such as particle size, moisture, chemi-
Table 2 and is based on interlaboratory test results.
cal composition, etc.
8.2 Calibration at standard test conditions is recommended
7.3 Sampling of material for the purpose of obtaining
even if the apparatus is operated at other test conditions.
representative test specimens shall be done in accordance with
8.3 In any test program the particle velocity and particle
acceptable statistical practice. Practice E 122 shall be con-
feed rate shall be measured at frequent intervals, typically
sulted.
every ten tests, to ensure constancy of conditions.
8. Calibration of Apparatus
9. Standard Test Conditions
8.1 Specimens fabricated from Type 1020 steel (see Table 1
9.1 This test method defines the following standard condi-
and Fig. 2) equivalent to that used in the interlaboratory test
tions.
7 8
A source for the recommended nozzle (tungsten carbide) is Kennametal, Inc., Supporting data are available from ASTM Headquarters. Request
Latrobe, PA. RR:G02–1003.
NOTICE: This standard has either been superseded and replaced by a new version or discontinued.
Contact ASTM International (www.astm.org) for the latest information.
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 caref
...
Questions, Comments and Discussion
Ask us and Technical Secretary will try to provide an answer. You can facilitate discussion about the standard in here.