ASTM G75-07(2013)
(Test Method)Standard Test Method for Determination of Slurry Abrasivity (Miller Number) and Slurry Abrasion Response of Materials (SAR Number)
Standard Test Method for Determination of Slurry Abrasivity (Miller Number) and Slurry Abrasion Response of Materials (SAR Number)
SIGNIFICANCE AND USE
5.1 The Miller Number5 is an index of the relative abrasivity of slurries. Its primary purpose is to rank the abrasivity of slurries in terms of the wear of a standard reference material. The wear damage on the standard wear block is worse as the Miller Number gets higher.
5.2 The SAR Number is an index of the relative abrasion response of materials as tested in any particular slurry of interest. The SAR Number is a generalized form of the Miller Number applicable to materials other than the reference material used for the Miller Number determination. A major purpose is to rank construction materials for use in a system for pumping and fluid handling equipment for a particular slurry. It can also be used to rank the abrasivity of various slurries against any selected construction material other than the reference material specified for a Miller Number determination. The slurry damage on the specimen of material being tested is worse as the SAR Number gets higher.
5.3 Experience has shown that slurries with a Miller Number or a SAR Number of approximately 50 or lower can be pumped with minor abrasive damage to the system. Above a number of 50, precautions must be observed and greater damage from abrasion is to be expected. Accordingly, the Miller Number and the SAR Number provide information about the slurry or the material that may be useful in the selection of pumps and other equipment and to predict the life expectancy of liquid-end parts of the pumps involved.
5.4 The SAR Number can be used to determine the most suitable materials for certain slurry systems.
SCOPE
1.1 This test method covers a single laboratory procedure that can be used to develop data from which either the relative abrasivity of any slurry (Miller Number) or the response of different materials to the abrasivity of different slurries (SAR Number), can be determined.
1.2 The test data obtained by this procedure is used to calculate either a number related to the rate of mass loss of duplicate standard-shaped 27 % chromium iron wear blocks when run for a period of time in the slurry of interest (Miller Number), or to calculate a number related to the rate of mass loss (converted to volume loss) of duplicate standard-shaped wear specimens of any material of interest when run for a period of time in any slurry of interest (SAR Number).
1.3 The requirement for a finished flat wearing surface on the test specimen for a SAR Number test may preclude application of the procedure where thin (0.051 to 0.127-mm), hard, wear-resistant coatings will not allow for surface finishing. The 6 hours total duration of the SAR Number Test may not allow establishment of a consistent rate-of-mass-loss of the unfinished surface.
1.4 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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Standards Content (Sample)
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Designation: G75 − 07(Reapproved 2013)
Standard Test Method for
Determination of Slurry Abrasivity (Miller Number) and
Slurry Abrasion Response of Materials (SAR Number)
ThisstandardisissuedunderthefixeddesignationG75;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginal
adoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscript
epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 2.2 Military Standard:
MIL-R-6855CRubber, Synthetic, Sheets, Strips, Molded or
1.1 This test method covers a single laboratory procedure
Extruded Shapes
that can be used to develop data from which either the relative
abrasivity of any slurry (Miller Number) or the response of
3. Terminology
different materials to the abrasivity of different slurries (SAR
3.1 Definitions:
Number), can be determined.
3.1.1 Definitions used in this test method are in accordance
1.2 The test data obtained by this procedure is used to
with Terminology G40 as follows:
calculate either a number related to the rate of mass loss of
3.1.2 abrasive wear—wear due to hard particles or hard
duplicate standard-shaped 27% chromium iron wear blocks
protuberancesforcedagainstandmovingalongasolidsurface.
when run for a period of time in the slurry of interest (Miller
Number), or to calculate a number related to the rate of mass
3.1.3 corrosive wear—wear in which chemical or electro-
loss (converted to volume loss) of duplicate standard-shaped
chemical reaction with the environment is significant.
wear specimens of any material of interest when run for a
3.1.4 abrasion-corrosion—a synergistic process involving
period of time in any slurry of interest (SAR Number).
both abrasive wear and corrosion in which each of these
1.3 The requirement for a finished flat wearing surface on processes is affected by the simultaneous action of the other
the test specimen for a SAR Number test may preclude and, in many cases is thereby accelerated.
application of the procedure where thin (0.051 to 0.127-mm),
3.1.5 cumulative erosion-time curve—a plot of cumulative
hard, wear-resistant coatings will not allow for surface finish-
erosion versus cumulative exposure duration, usually deter-
ing. The 6 hours total duration of the SAR Number Test may
mined by periodic interruption of the test and weighing of the
notallowestablishmentofaconsistentrate-of-mass-lossofthe
specimen. This is the primary record of an erosion test. Most
unfinished surface.
other characteristics, such as the incubation period, maximum
1.4 This standard does not purport to address all of the
erosionrate,terminalerosionrate,anderosionrate-timecurve,
safety concerns, if any, associated with its use. It is the are derived from it.
responsibility of the user of this standard to establish appro-
3.1.6 erosion—progressive loss of original material from a
priate safety and health practices and determine the applica-
solid surface due to mechanical interaction between that
bility of regulatory limitations prior to use.
surface and a fluid, a multi-component fluid, or impinging
liquid or solid particles.
2. Referenced Documents
3.1.7 erosion-corrosion—a conjoint action involving corro-
2.1 ASTM Standards:
sion and erosion in the presence of a corrosive substance.
G40Terminology Relating to Wear and Erosion
3.1.8 instantaneous erosion rate—the slope of a tangent to
the cumulative erosion-time curve at a specified point on that
curve.
This test method is under the jurisdiction of ASTM Committee G02 on Wear
and Erosion and is the direct responsibility of Subcommittee G02.30 on Abrasive 3.2 Definitions of Terms Specific to This Standard:
Wear.
3.2.1 mass concentration—the mass of solid particles per
Current edition approved Nov. 15, 2013. Published November 2013. Originally
unit mass of mixture, expressed in percent.
approved in 1982. Last previous edition approved in 2007 as G75–07. DOI:
10.1520/G0075-07R13.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
Standards volume information, refer to the standard’s Document Summary page on AvailablefromStandardizationDocumentsOrderDesk,Bldg.4SectionD,700
the ASTM website. Robbins Ave., Philadelphia, PA 19111-5094, Attn: NPODS.
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G75 − 07 (2013)
3.2.2 Miller Number—a measure of slurry abrasivity as
related to the instantaneous rate of mass loss of a standard
metalwearblockataspecifictimeonthecumulativeabrasion-
corrosion time curve.
3.2.3 SAR Number—a measure of the relative abrasion
response of any material in any slurry, as related to the
instantaneousrateofmass-lossofaspecimenataspecifictime
on the cumulative abrasion-corrosion time curve, converted to
volume or thickness loss rate.
3.2.4 slurry—amixtureofsolidparticlesinliquid,ofsucha
consistency as to be capable of being pumped like a liquid.
3.2.5 slurry abrasivity—therelativetendencyofaparticular
moving slurry to produce abrasive and corrosive wear com-
FIG. 1 Miller Number Machine
pared with other slurries.
4. Summary of Test Method
slurries in terms of the wear of a standard reference material.
4.1 The relative effect of slurry abrasivity in both the Miller The wear damage on the standard wear block is worse as the
Number and the SAR Number is determined by using the Miller Number gets higher.
measured mass loss of a standard-shaped 27% chrome iron
5.2 The SAR Number is an index of the relative abrasion
metal wear block (Miller Number); or a metal, ceramic,
response of materials as tested in any particular slurry of
composite, plastic, or elastomer wear specimen (SAR
interest. The SAR Number is a generalized form of the Miller
Number), driven in a reciprocating motion by a rotating crank,
Number applicable to materials other than the reference
riding in the bottom of a trough containing the slurry.Adirect
material used for the Miller Number determination. A major
load is applied to the wear block or wear specimen. For each
purposeistorankconstructionmaterialsforuseinasystemfor
test, the bottom of the trough is equipped with a new piece of
pumpingandfluidhandlingequipmentforaparticularslurry.It
a sheet of Neoprene to act as a lap. The interior of the trough
can also be used to rank the abrasivity of various slurries
hasaflat-bottomedortruncated“V”shapetroughthatconfines
against any selected construction material other than the
the slurry particles to the path taken by the wear block or wear
reference material specified for a Miller Number determina-
specimen. At one end of each stroke, the wear block wear
tion. The slurry damage on the specimen of material being
specimenisliftedoffthelapbyacamactionforsufficienttime
tested is worse as the SAR Number gets higher.
to allow fresh slurry material to flow under the wear block or
5.3 Experience has shown that slurries with a Miller Num-
wear specimen.The wear block/wear specimen holder is made
ber or a SAR Number of approximately 50 or lower can be
of plastic, as are the toughs, so that electrolysis inherent in
pumped with minor abrasive damage to the system. Above a
certain slurries is minimized.
number of 50, precautions must be observed and greater
4.2 The test consists of measuring the mass loss of a part
damage from abrasion is to be expected. Accordingly, the
that is referred to either a wear block or wear specimen to be
Miller Number and the SAR Number provide information
consistent with Section G34 of Form and Style for ASTM
about the slurry or the material that may be useful in the
Standards.Standardwearblocksof27%chromeironareused
selection of pumps and other equipment and to predict the life
fortheMillerNumbertestwheretheslurryisthespecimenand
expectancy of liquid-end parts of the pumps involved.
the results are the relative abrasivity of the slurry. Wear
5.4 The SAR Number can be used to determine the most
specimens are used in the SAR Number test where the test
suitable materials for certain slurry systems.
resultsaretherelativewearrateofdifferentwearspecimensin
a given slurry.
6. Apparatus
4.3 Thistestmethodwasoriginallydevelopedasa16-htest
6.1 Figs. 1 and 2 show the arrangement of a typical test
to be run in 4-h increments. However, experience has shown
machine.
that the extended test length is unnecessary and it has been
6.2 Description of Machine:
established that a 6-h test, run in 2-h increments, gives
6.2.1 The drive mechanism provides a horizontal recipro-
essentially equivalent results. The current revision is based on
cating harmonic motion to the wear block/wear specimen arm
the shorter test procedure.
of203.2-mmtravel.Thearmisfreelypivotedtoacrossheadat
5. Significance and Use
a point that results in the arm being parallel (level) to the
5.1 The Miller Number is an index of the relative abrasiv-
ity of slurries. Its primary purpose is to rank the abrasivity of
The sole source of supply of the machine and parts, including laps and wear
blocks, known to the committee at this time is Falex Friction and Wear Test
Neoprene is a registered trademark of E. I. du Pont de Nemours and Co., Machines, 1020 Airport Dr., Sugar Grove, IL 60554. If you are aware of alternate
Wilmington, DE 19898. suppliers, please provide this information to ASTM Headquarters. Your comments
5 1
“The Miller Number—A New Slurry Rating Index,” AIME Paper 73-B-300, will receive careful attention at a meeting of the responsible technical committee
SME Meeting, Pittsburgh, PA, 1973. which you may attend.
G75 − 07 (2013)
FIG. 3 Wear Block or Wear Specimen Dimensions
7. Reagents and Materials
7.1 The reference material for the Miller Number is a
proprietaryalloy ofthetypecommonlyusedinpipelinepump
applications. The nominal composition of this chromium-iron
wear block reference material is: Carbon-2.5%, Manganese-
1.0%, Silicone-0.6%, Nickel-0.25%, Chromium-28%, Mo-
FIG. 2 Miller Number Machine Slurry Trough Cross-Section
lybdenum-0.3%, Vanadium-0.8%, Iron-balance.
7.1.1 The material is obtainable in the form of a centrifu-
gallycastcylinder,approximately183-mmoutsidediameterby
152-mm inside diameter by 305 mm long.
crosshead ways in the operating position. The crosshead is 7.1.2 In this case the following heat-treat procedure and
connected to a crank, rotating at 48 r/min, by an appropriate specimen preparation procedure should be followed:
connecting rod. 7.1.2.1 Anneal 24 h, turn and bore, approximately 179-mm
outside diameter by 164-mm inside diameter.
6.2.2 The apparatus includes two operating arms for an
7.1.2.2 Heat to 1010°C (1850°F), 60 min.
averaging effect and as a check on the accuracy of measure-
7.1.2.3 Air cool, hardness 59 to 60 HRC.
ments. It is possible to combine four arms on one machine so
7.1.2.4 Grindtoapproximately178-mmoutsidediameterby
that two simultaneous tests can be run.
165-mm inside diameter.
6.2.3 Each arm is loaded with a mass so that the total
7.2 Using an abrasive wheel or wire EDM, cut 25.4-mm
downward force on the face of the wear block or wear
lengths or “rings” from the cylinder. Cut the rings into 15-mm
specimen is 22.24 N (5 lb).
wide segments. Grind the segments to the shape shown in Fig.
6.2.4 A cam is provided on the trough cover plate to
3.
momentarily lift each arm at the end of a stroke to a distance
of 1 mm off the rubber lap. 7.3 As a final finish on the wearing surface, wet grind on
320-grit silicon carbide paper to remove machining damage.
6.2.5 Troughs about 50 mm wide by 381 mm long by 50
mm high are used.Aseparate trough is required for each arm.
7.4 The lap is a 3.18-mm thick sheet, 57.2 mm by 362 mm
6.2.6 Troughs as described above are machined into an
long of molded neoprene rubber specified as a Modified
elastomer material to form a slurry trough component that is
MIL-R-6855C,Class2,Grade80.TheDurometerspecification
used to hold the rubber lap in place between the bottom of the
of the Neoprene has been reduced from 80 65to80 6 3.The
trough and the base plate and to provide a V-shaped open
purpose of the tighter specification is to reduce variability
bottom trough for the length of the wear block or wear
observed in the initial interlaboratory test.
specimen travel. There is a slope of 45° at the cam end of one
7.5 The SAR Number wear specimen of any selected
stroketogenerateasurgeorbackflowoffreshslurryunderthe
candidate material is machined and ground to the shape shown
lifted wear block or wear specimen.
in Fig. 3.
6.2.7 Awear block/wear specimen holder is machined from
7.6 Isopropyl Alcohol.
plastic to about 50 mm by 50 mm by 12.7 mm with a
height-adjusting system and a slot to hold the wear block or
8. Preparation of Apparatus
wear specimen and a nonmetallic clamp-bolt to hold the wear
8.1 The following detailed description of the setup of the
block or wear specimen in alignment. See Fig. 3.
apparatus for the start of the test is appropriate for the
6.2.8 The wear block/wear specimen is mounted on the arm
in such a manner as to allow adjustment of the wear block or
Specimen available from Falex Friction andWearTest Machines, 1020Airport
wear specimen vertically and to establish parallelism with the
Dr., Sugar Grove, IL 60554. Falex is the sole source of supply known to the
flat rubber lap.
committee at this time. If you aware of alternative suppliers, please provide this
information to ASTM Headquarters. Your comments will receive careful consider-
6.2.9 Exceptforthewearblockorwearspecimenandstroke
ation at a meeting of the responsible technical committee, which you may attend.
length, dimensional tolerances of the machined parts are not 8
Proprietary of Woolley Tool and Manufacturing Co., P.O. Box 3505, Odessa,
critical and the tolerances can be in the order of 0.5% total. TX 79760.
G75 − 07 (2013)
commerciallyavailableunit.Forotherapparatustheprocedure
shouldbefollowedascloselyaspossible,particularlytoensure
the alignment required.
8.2 Wear Block or Wear Specimen Preparation:
8.2.1 Prepare duplicate wear block or wear specimens for
each test. The wear blocks, or wear specimens polished or
ground flat on the wearing surface, should be permanently
marked with an identification mark or number on one side.
8.2.2 The wear block/wear specimen holders are designed
to be adjustable so as to accept a wear block or wear specimen
of any thickness up to about 10 mm; therefore, it is possible to
rework the wear blocks or wear specimens and realize many
more runs, (except, of course, for coated or plated specimens).
8.2.3 The wear blocks or metallic wear specimens are
demagnetizedinitiallysoastominim
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