ASTM G134-17(2023)
(Test Method)Standard Test Method for Erosion of Solid Materials by Cavitating Liquid Jet
Standard Test Method for Erosion of Solid Materials by Cavitating Liquid Jet
SIGNIFICANCE AND USE
5.1 This test method may be used to estimate the relative resistances of materials to cavitation erosion, as may be encountered for instance in pumps, hydraulic turbines, valves, hydraulic dynamometers and couplings, bearings, diesel engine cylinder liners, ship propellers, hydrofoils, internal flow passages, and various components of fluid power systems or fuel systems of diesel engines. It can also be used to compare erosion produced by different liquids under the conditions simulated by the test. Its general applications are similar to those of Test Method G32.
5.2 In this test method cavitation is generated in a flowing system. Both the velocity of flow which causes the formation of cavities and the chamber pressure in which they collapse can be changed easily and independently, so it is possible to study the effects of various parameters separately. Cavitation conditions can be controlled easily and precisely. Furthermore, if tests are performed at constant cavitation number (σ), it is possible, by suitably altering the pressures, to accelerate or slow down the testing process (see 11.2 and Fig. A2.2).
5.3 This test method with standard conditions should not be used to rank materials for applications where electrochemical corrosion or solid particle impingement plays a major role. However, it could be adapted to evaluate erosion-corrosion effects if the appropriate liquid and cavitation number, for the service conditions of interest, are used (see 11.1).
5.4 For metallic materials, this test method could also be used as a screening test for applications subjected to high-speed liquid drop impingement, if the use of Practice G73 is not feasible. However, this is not recommended for elastomeric coatings, composites, or other nonmetallic aerospace materials.
5.5 The mechanisms of cavitation erosion and liquid impingement erosion are not fully understood and may vary, depending on the detailed nature, scale, and intensity of the liquid/solid interaction...
SCOPE
1.1 This test method covers a test that can be used to compare the cavitation erosion resistance of solid materials. A submerged cavitating jet, issuing from a nozzle, impinges on a test specimen placed in its path so that cavities collapse on it, thereby causing erosion. The test is carried out under specified conditions in a specified liquid, usually water. This test method can also be used to compare the cavitation erosion capability of various liquids.
1.2 This test method specifies the nozzle and nozzle holder shape and size, the specimen size and its method of mounting, and the minimum test chamber size. Procedures are described for selecting the standoff distance and one of several standard test conditions. Deviation from some of these conditions is permitted where appropriate and if properly documented. Guidance is given on setting up a suitable apparatus, test and reporting procedures, and the precautions to be taken. Standard reference materials are specified; these must be used to verify the operation of the facility and to define the normalized erosion resistance of other materials.
1.3 Two types of tests are encompassed, one using test liquids which can be run to waste, for example, tap water, and the other using liquids which must be recirculated, for example, reagent water or various oils. Slightly different test circuits are required for each type.
1.4 This test method provides an alternative to Test Method G32. In that method, cavitation is induced by vibrating a submerged specimen at high frequency (20 kHz) with a specified amplitude. In the present method, cavitation is generated in a flowing system so that both the jet velocity and the downstream pressure (which causes the bubble collapse) can be varied independently.
1.5 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.6 This standard does not purport to addres...
General Information
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Standards Content (Sample)
This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: G134 − 17 (Reapproved 2023)
Standard Test Method for
Erosion of Solid Materials by Cavitating Liquid Jet
This standard is issued under the fixed designation G134; 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 (´) indicates an editorial change since the last revision or reapproval.
1. Scope 1.6 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
1.1 This test method covers a test that can be used to
responsibility of the user of this standard to establish appro-
compare the cavitation erosion resistance of solid materials. A
priate safety, health, and environmental practices and deter-
submerged cavitating jet, issuing from a nozzle, impinges on a
mine the applicability of regulatory limitations prior to use.
test specimen placed in its path so that cavities collapse on it,
1.7 This international standard was developed in accor-
thereby causing erosion. The test is carried out under specified
dance with internationally recognized principles on standard-
conditions in a specified liquid, usually water. This test method
ization established in the Decision on Principles for the
can also be used to compare the cavitation erosion capability of
Development of International Standards, Guides and Recom-
various liquids.
mendations issued by the World Trade Organization Technical
1.2 This test method specifies the nozzle and nozzle holder
Barriers to Trade (TBT) Committee.
shape and size, the specimen size and its method of mounting,
and the minimum test chamber size. Procedures are described
2. Referenced Documents
for selecting the standoff distance and one of several standard
2.1 ASTM Standards:
test conditions. Deviation from some of these conditions is
A276/A276M Specification for Stainless Steel Bars and
permitted where appropriate and if properly documented.
Shapes
Guidance is given on setting up a suitable apparatus, test and
B160 Specification for Nickel Rod and Bar
reporting procedures, and the precautions to be taken. Standard
B211 Specification for Aluminum and Aluminum-Alloy
reference materials are specified; these must be used to verify
Rolled or Cold-Finished Bar, Rod, and Wire (Metric)
the operation of the facility and to define the normalized
B0211_B0211M
erosion resistance of other materials.
D1193 Specification for Reagent Water
1.3 Two types of tests are encompassed, one using test
E691 Practice for Conducting an Interlaboratory Study to
liquids which can be run to waste, for example, tap water, and
Determine the Precision of a Test Method
the other using liquids which must be recirculated, for
G32 Test Method for Cavitation Erosion Using Vibratory
example, reagent water or various oils. Slightly different test
Apparatus
circuits are required for each type.
G40 Terminology Relating to Wear and Erosion
G73 Test Method for Liquid Impingement Erosion Using
1.4 This test method provides an alternative to Test Method
Rotating Apparatus
G32. In that method, cavitation is induced by vibrating a
submerged specimen at high frequency (20 kHz) with a 2.2 ASTM Adjuncts:
Manufacturing Drawings of the Apparatus
specified amplitude. In the present method, cavitation is
generated in a flowing system so that both the jet velocity and
3. Terminology
the downstream pressure (which causes the bubble collapse)
can be varied independently.
3.1 See Terminology G40 for definitions of terms relating to
cavitation erosion. For convenience, definitions of some im-
1.5 The values stated in SI units are to be regarded as
portant terms used in this test method are reproduced below.
standard. No other units of measurement are included in this
standard.
3.2 Definitions:
1 2
This test method is under the jurisdiction of ASTM Committee G02 on Wear For referenced ASTM standards, visit the ASTM website, www.astm.org, or
and Erosion and is the direct responsibility of Subcommittee G02.10 on Erosion by contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Solids and Liquids. Standards volume information, refer to the standard’s Document Summary page on
Current edition approved June 1, 2023. Published June 2023. Originally the ASTM website.
approved in 1995. Last previous edition approved in 2017 as G134 – 17. DOI: Available from ASTM International Headquarters. Order Adjunct No.
10.1520/G0134-17R23. ADJG0134.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
G134 − 17 (2023)
3.2.1 cavitation, n—the formation and subsequent collapse, maximum-slope portion of the cumulative erosion-time curve.)
within a liquid, of cavities or bubbles that contain vapor or a G40
mixture of vapor and gas.
3.2.8 maximum erosion rate, n—in cavitation and liquid
3.2.1.1 Discussion—Cavitation originates from a local de-
impingement erosion, the maximum instantaneous erosion rate
crease in hydrostatic pressure in the liquid, usually produced
in a test that exhibits such a maximum followed by decreasing
by motion of the liquid (see flow cavitation) or of a solid
erosion rates. (See also erosion rate-time pattern.)
boundary (see vibratory cavitation). It is distinguished in this
3.2.8.1 Discussion—Occurrence of such a maximum is
way from boiling, which originates from an increase in liquid
typical of many cavitation and liquid impingement tests. In
temperature.
some instances, it occurs as an instantaneous maximum, in
3.2.1.2 Discussion—The term cavitation, by itself, should others as a steady-state maximum which persists for some
not be used to denote the damage or erosion of a solid surface time. G40
that can be caused by it; this effect of cavitation is termed
3.2.9 normalized erosion resistance, N , n—in cavitation
e
cavitation damage or cavitation erosion. To erode a solid
and liquid impingement erosion, a measure of the erosion
surface, bubbles or cavities must collapse on or near that
resistance of a test material relative to that of a specified
surface. G40
reference material, calculated by dividing the volume loss rate
of the reference material by that of the test material, when both
3.2.2 cavitation erosion, n—progressive loss of original
are similarly tested and similarly analyzed. By “similarly
material from a solid surface due to continued exposure to
analyzed,” it is meant that the two erosion rates must be
cavitation. G40
determined for corresponding portions of the erosion rate time
3.2.3 cumulative erosion, n—in cavitation and impingement
pattern; for instance, the maximum erosion rate or the terminal
erosion, the total amount of material lost from a solid surface
erosion rate.
during all exposure periods since it was first exposed to
3.2.9.1 Discussion—A recommended complete wording has
cavitation or impingement as a newly-finished surface. (More
the form, “The normalized erosion resistance of (test material)
specific terms that may be used are cumulative mass loss,
relative to (reference material) based on (criterion of data
cumulative volume loss, or cumulative mean depth of erosion.
analysis) is (numerical value).” G40
See also cumulative erosion-time curve.)
3.2.10 normalized incubation resistance, N , n—the nomi-
o
3.2.3.1 Discussion—Unless otherwise indicated by the
nal incubation period of a test material, divided by the nominal
context, it is implied that the conditions of cavitation or
incubation period of a specified reference material similarly
impingement have remained the same throughout all exposure
tested and similarly analyzed. (See also normalized erosion
periods, with no intermediate refinishing of the surface. G40
resistance.) G40
3.2.4 cumulative erosion rate, n—the cumulative erosion at
3.2.11 terminal erosion rate, n—in cavitation or liquid
a specified point in an erosion test divided by the correspond-
impingement erosion, the final steady-state erosion rate that is
ing cumulative exposure duration; that is, the slope of a line
reached (or appears to be approached asymptotically) after the
from the origin to the specified point on the cumulative
erosion rate has declined from its maximum value. (See also
erosion-time curve. (Synonym: average erosion rate) G40
terminal period and erosion rate-time pattern.) G40
3.2.5 cumulative erosion-time curve, n—in cavitation and
3.3 Definitions of Terms Specific to This Standard:
impingement erosion, a plot of cumulative erosion versus
3.3.1 cavitating jet, n—a continuous liquid jet (usually
cumulative exposure duration, usually determined by periodic
submerged) in which cavitation is induced by the nozzle design
interruption of the test and weighing of the specimen. This is
or sometimes by a center body. See also jet cavitation.
the primary record of an erosion test. Most other
3.3.2 cavitation number, σ—a dimensionless number that
characteristics, such as the incubation period, maximum ero-
measures the tendency for cavitation to occur in a flowing
sion rate, terminal erosion rate, and erosion rate-time curve, are
stream of liquid, and that, for the purpose of this test method,
derived from it. G40
is defined by the following equation. All pressures are absolute.
3.2.6 flow cavitation, n—cavitation caused by a decrease in
p 2 p
~ !
d v
local pressure induced by changes in velocity of a flowing
σ 5 (1)
liquid. Typically, this may be caused by flow around an
ρV
obstacle or through a constriction, or relative to a blade or foil.
A cavitation cloud or “cavitating wake” generally trails from
where:
some point adjacent to the obstacle or constriction to some
p = vapor pressure,
v
distance downstream, the bubbles being formed at one place
p = static pressure in the downstream chamber,
d
and collapsing at another. G40
V = jet velocity, and
ρ = liquid density.
3.2.7 incubation period, n—in cavitation and impingement
erosion, the initial stage of the erosion rate-time pattern during
3.3.2.1 For liquid flow through any orifice:
which the erosion rate is zero or negligible compared to later
stages. Also, the exposure duration associated with this stage.
ρ V 5 p 2 p (2)
u d
(Quantitatively it is sometimes defined as the intercept on the
time or exposure axis, of a straight line extension of the where:
G134 − 17 (2023)
accurately before testing begins and again during periodic
p = upstream pressure.
u
interruptions of the test, in order to obtain a history of mass
3.3.2.2 For erosion testing by this test method, the cavitat-
loss versus time (which is not linear). Appropriate interpreta-
ing flow in the nozzle is choked, so that the downstream
tion of the cumulative erosion-time curve derived from these
pressure, as seen by the flow, is equal to the vapor pressure.
measurements permits comparisons to be drawn between
The cavitation number thus reduces to:
different materials, different test conditions, or between differ-
p 2 p
ent liquids. A typical test rig can be built using a 2.5 kW pump
d v
σ 5 (3)
p 2 p
u d capable of producing 21 MPa pressure. The standard nozzle
bore diameter is 0.4 mm, but this may be changed if required
which for many liquids and at many temperatures can be
for specialized tests.
approximated by:
p
5. Significance and Use
d
σ 5 (4)
p
u
5.1 This test method may be used to estimate the relative
resistances of materials to cavitation erosion, as may be
since
encountered for instance in pumps, hydraulic turbines, valves,
p .p .p (5)
u d v
hydraulic dynamometers and couplings, bearings, diesel engine
3.3.3 jet cavitation, n—the cavitation generated in the vor-
cylinder liners, ship propellers, hydrofoils, internal flow
tices which travel in sequence singly or in clouds in the shear
passages, and various components of fluid power systems or
layer around a submerged jet. It can be amplified by the nozzle
fuel systems of diesel engines. It can also be used to compare
design so that vortices form in the vena contracta region inside
erosion produced by different liquids under the conditions
the nozzle.
simulated by the test. Its general applications are similar to
G32.
those of Test Method
3.3.4 stand-off distance, n—in this test method, the distance
between the inlet edge of the nozzle and the target face of the
5.2 In this test method cavitation is generated in a flowing
specimen. It is thus defined because the location and shape of
system. Both the velocity of flow which causes the formation
the inlet edge determine the location of the vena contracta and
of cavities and the chamber pressure in which they collapse can
the initiation of cavitation.
be changed easily and independently, so it is possible to study
the effects of various parameters separately. Cavitation condi-
3.3.5 tangent erosion rate, n—the slope of a straight line
tions can be controlled easily and precisely. Furthermore, if
drawn through the origin and tangent to the knee of the
cumulative erosion-time curve, when the shape of that curve tests are performed at constant cavitation number (σ), it is
possible, by suitably altering the pressures, to accelerate or
has the characteristic S-shape pattern that permits this. In such
cases, the tangent erosion rate also represents the maximum slow down the testing process (see 11.2 and Fig. A2.2).
cumulative erosion rate exhibited during the test.
5.3 This test method with standard conditions should not be
3.3.6 vena contracta, n—the smallest locally occurring di-
used to rank materials for applications where electrochemical
ameter of the main flow of a fluid after it enters into a nozzle corrosion or solid particle impingement plays a major role.
or orifice from a larger conduit or a reservoir. At this point the
However, it could be adapted to evaluate erosion-corrosion
main or primary flow is detached from the solid boundaries, effects if the appropriate liquid and cavitation number, for the
and vortices or recirculating secondary flow patterns are
service conditions of interest, are used (see 11.1).
formed in the intervening space.
5.4 For metallic materials, this test method could also be
used as a screening test for applications subjected to high-
4. Summary of Test Method
speed liquid drop impingement, if the use of Practice G73 is
4.1 This test method produces a submerged cavitating jet
not feasible. However, this is not recommended for elastomeric
which impinges upon a stationary specimen, also submerged,
coatings, composites, or other nonmetallic aerospace materials.
causing cavitation bubbles to collapse on that specimen
...
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