ASTM G75-95
(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)
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 are 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 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 respionsibility 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 75 – 95
Standard Test Method for
Determination of Slurry Abrasivity (Miller Number) and
Slurry Abrasion Response of Materials (SAR Number)
This standard is issued under the fixed designation G 75; 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 accordance with Terminology G 40 as follows:
3.1.1 abrasive wear—wear due to hard particles or hard
1.1 This test method covers a single laboratory procedure
protuberances forced against and moving along a solid surface.
that can be used to develop data from which either the relative
3.1.2 corrosive wear—wear in which chemical or electro-
abrasivity of any slurry (Miller Number) or the response of
chemical reaction with the environment is significant.
different materials to the abrasivity of different slurries (SAR
3.1.3 cumulative erosion-time curve—a plot of cumulative
Number), can be determined.
erosion versus cumulative exposure duration, usually deter-
1.2 The test data obtained by this procedure are used to
mined by periodic interruption of the test and weighing of the
calculate either a number related to the rate of mass loss of
specimen. This is the primary record of an erosion test. Most
duplicate standard-shaped 27 % chromium iron wear blocks
other characteristics, such as the incubation period, maximum
when run for a period of time in the slurry of interest (Miller
erosion rate, terminal erosion rate, and erosion rate-time curve,
Number), or to calculate a number related to the rate of mass
are derived from it.
loss (converted to volume loss) of duplicate standard-shaped
3.1.4 erosion—progressive loss of original material from a
specimens of any material of interest when run for a period of
solid surface due to mechanical interaction between that
time in any slurry of interest (SAR Number).
surface and a fluid, a multi-component fluid, or impinging
1.3 The requirement for a finished flat wearing surface on
liquid or solid particles.
the test specimen for a SAR Number test may preclude
3.1.5 erosion-corrosion—a conjoint action involving corro-
application of the procedure where thin (0.002 to 0.005-in. or
sion and erosion in the presence of a corrosive substance.
0.051 to 0.127-mm), hard, wear-resistant coatings will not
3.1.6 instantaneous erosion rate—the slope of a tangent to
allow for surface finishing. The 6-h total duration of the SAR
the cumulative erosion-time curve at a specified point on that
Number Test may not allow establishment of a consistent
curve.
rate-of-mass-loss of the unfinished surface.
3.2 Definitions of Terms Specific to This Standard:
1.4 This standard does not purport to address all of the
3.2.1 abrasion-corrosion—a conjoint action involving abra-
safety concerns, if any, associated with its use. It is the
sion and corrosion.
responsibility of the user of this standard to establish appro-
3.2.2 mass concentration—the mass of solid particles per
priate safety and health practices and determine the applica-
unit mass of mixture, expressed in percent.
bility of regulatory limitations prior to use.
3.2.3 Miller Number—a measure of slurry abrasivity as
2. Referenced Documents
related to the instantaneous rate of mass loss of a standard
metal wear block at a specific time on the cumulative abrasion-
2.1 ASTM Standards:
corrosion time curve.
G 40 Terminology Relating to Wear and Erosion
3.2.4 SAR Number—a measure of the relative abrasion
2.2 Military Standard:
response of any material in any slurry, as related to the
MIL-R-6855C Rubber, Synthetic, Sheets, Strips, Molded or
instantaneous rate of mass-loss of a specimen at a specific time
Extruded Shapes
on the cumulative abrasion-corrosion time curve, converted to
3. Terminology
volume or thickness loss rate.
3.2.5 slurry—a mixture of solid particles in liquid, of such
3.1 Definitions—Definitions used in this test method are in
a consistency as to be capable of being pumped like a liquid.
3.2.6 slurry abrasivity—the relative tendency of a particular
This test method is under the jurisdiction of ASTM Committee G-2 on Wear
moving slurry to produce abrasive and corrosive wear com-
and Erosion and is the direct responsibility of Subcommittee G02.30 on Abrasive
pared with other slurries.
Wear.
Current edition approved Jan. 30, 1995. Published March 1995. Originally
published as G 75 – 82. Last previous edition G 75 – 94. 4. Summary of Test Method
Annual Book of ASTM Standards, Vol 03.02.
3 4.1 The relative effect of slurry abrasivity in both the Miller
Available from Standardization Documents Order Desk, Bldg. 4 Section D, 700
Number and the SAR Number is determined by using the
Robbins Ave., Philadelphia, PA 19111-5094, Attn: NPODS.
Copyright © ASTM, 100 Barr Harbor Drive, West Conshohocken, PA 19428-2959, United States.
G75
FIG. 1 Miller Number Machine
measured mass loss of a standard-shaped metal block, driven in pumped with minor abrasive damage to the system. Above a
a reciprocating motion by a rotating crank, riding in the bottom number of 50, precautions must be observed and greater
of a tray containing the slurry. A direct load is applied to the damage from abrasion is to be expected. Accordingly, the
block. For each test, the bottom of the tray is equipped with a Miller Number and the SAR Number provide information
new piece of a sheet of neoprene to act as a lap. The interior about the slurry or the material that may be useful in the
of the tray has a flat-bottomed or truncated “V” shape formed selection of pumps and other equipment and to predict the life
by the filler, that confines the slurry particles to the path taken expectancy of liquid-end parts of the pumps involved.
by the wear block. At one end of each stroke, the block is lifted 5.4 The SAR Number can be used to determine the most
off the lap by a cam action for sufficient time to allow fresh suitable materials for certain slurry systems.
slurry material to flow under the block. The block holder is
6. Apparatus and Materials
made of plastic, as are the trays, so that electrolysis inherent in
6.1 Figs. 1 and 2 show the arrangement of a typical test
certain slurries is minimized.
machine.
4.2 This test method was originally developed as a 16-h test
to be run in 4-h increments. However, experience has shown
that the extended test length is unnecessary and it has been
established that a 6-h test, run in 2-h increments, gives
essentially equivalent results. The current revision is based on
the shorter test procedure.
5. Significance and Use
5.1 The Miller Number is an index of the relative abrasiv-
ity 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
FIG. 2 Miller Machine Layout
Number applicable to materials other than the reference
material used for the Miller Number determination. A major
6.2 Description of Machine:
purpose is to rank construction materials for use in a system for
6.2.1 The drive mechanism provides a horizontal recipro-
pumping a particular slurry. It can also be used to rank the
cating harmonic motion to the block arm of 200-mm (8-in.)
abrasivity of various slurries against any selected construction
travel. The arm is freely pivoted to a crosshead at a point that
material other than the reference material specified for a Miller
results in the arm being parallel (level) to the crosshead ways
Number determination. The slurry damage on the specimen of
in the operating position. The crosshead is connected to a
material being tested is worse as the SAR Number gets higher.
crank, rotating at 48 r/min, by an appropriate connecting rod.
5.3 Experience has shown that slurries with a Miller Num-
6.2.2 The apparatus includes two operating arms for an
ber or a SAR Number of approximately 50 or lower can be
averaging effect and as a check on the accuracy of measure-
ments. It is possible to combine four arms on one machine so
that two simultaneous tests can be run.
Neoprene is a registered trademark of E. I. du Pont de Nemours and Co.,
Wilmington, DE 19898.
5 6
“The Miller Number—A New Slurry Rating Index,” AIME Paper 73-B-300, Machine and parts, including laps and wear blocks, are available from Falex
SME Meeting, Pittsburgh, PA, 1973. Friction and Wear Test Machines, 2055 Comprehensive Dr., Aurora, IL 60505.
G75
6.2.3 Each arm is loaded with a mass so that the total 6.3.2 In this case the following heat-treat procedure and
downward force on the face of the wear block is 22.24 N (5 lb). specimen preparation procedure should be followed:
6.2.4 A cam is provided on the tray clamp to momentarily 6.3.2.1 Anneal 24 h, turn and bore, approximately 179-mm
lift each arm at the end of a stroke a distance of 0.8 mm ( ⁄32 outside diameter by 164-mm inside diameter (7.06-in. outside
in.) off the rubber lap. diameter by 6.44-in. inside diameter).
6.2.5 Plastic trays about 50 mm (2 in.) wide by 381 mm (15 6.3.2.2 Heat to 1010°C (1850°F), 60 min.
in.) long by 50 mm (2 in.) high are used. A separate tray is 6.3.2.3 Air cool, hardness 59 to 60 HRC.
required for each arm. 6.3.2.4 Grind to approximately 178-mm outside diameter by
6.2.6 A special reinforced molded elastomeric filler is used 165-mm inside diameter (7.00-in. outside diameter by 6.50-in.
to hold the lap in place in the bottom of the tray and to provide inside diameter).
a V-shaped flat-bottom trough for the length of the wear block 6.4 Using an abrasive wheel or wire EDM, cut 25.4-mm
travel. There is a slope of 45° at the cam end of one stroke to (1.0-in.) lengths or “rings” from the cylinder. Cut the rings into
generate a surge or back flow of fresh slurry under the lifted 15-mm (0.6-in.) wide segments. Grind the segments to the
block. This filler is shown in Fig. 3. shape shown in Fig. 4.
6.5 As a final finish on the wearing surface, wet grind on
320-grit silicon carbide paper to remove machining damage.
1 1
6.6 The lap is a 3.18-mm ( ⁄8-in.) thick sheet, 2 ⁄4-in. wide
by xxx in. long. of molded neoprene rubber specified as a
MIL-R-6855C, Class 2, Grade 80.
6.7 The SAR Number test specimen of any selected candi-
date material is machined and ground to the shape shown in
Fig. 4.
FIG. 3 Tray Filler
7. Preparation of Apparatus
7.1 The following detailed description of the setup of the
6.2.7 A block or specimen holder is machined from plastic
apparatus for the start of the test is appropriate for the
to about 50 mm (2 in.) by 50 mm (2 in.) by 12.7 mm ( ⁄2 in.)
commercially available unit. For other apparatus the procedure
with a height-adjusting system and a slot to hold the block and
should be followed as closely as possible, particularly to ensure
a clamp-bolt to hold the block in alignment. See Fig. 4.
the alignment required.
6.2.8 The holder is mounted on the arm in such a manner as
7.2 Wear or Specimen Block Preparation:
to allow adjustment of the block vertically and to establish
7.2.1 Prepare duplicate wear or specimen blocks for each
parallelism with the flat rubber lap.
test. The blocks, polished or ground flat on the wearing surface,
should be permanently marked with an identification mark or
number on one side.
7.2.2 The block holders are designed to be adjustable so as
to accept a block of any thickness up to about 10 mm ( ⁄8 in.);
therefore, it is possible to rework the wear blocks and realize
many more runs, (except, of course, for coated or plated
specimens).
FIG. 4 Wear Block or Specimen Dimensions
7.2.3 The blocks are demagnetized initially so as to mini-
mize the magnetic effects in precision weighing and possible
6.2.9 Except for the block or specimen and stroke length,
effects in a magnetic slurry. Place the demagnetizer pole tip
dimensional tolerances of the machined parts are not critical
against the block. Move the tip over the entire block for a few
and the tolerances can be in the order of 0.5 % total.
seconds. Then move the demagnetizer slowly away and dis-
6.3 The reference material for the Miller Number is a
connect it from the power. Slow removal of the demagnetizer
proprietary alloy of the type commonly used in pipeline
is particularly important.
applications. The nominal composition of this chromium-iron
7.2.4 Scrub the blocks with detergent and water, rinse and
wear block reference material is: Carbon-2.5 %, Manganese-
dry with a clean cloth, then place under a heat lamp or blow dry
1.0 %, Silicone-0.6 %, Nickel-0.25 %, Chromium-28 %,
for about 5 min. Immediately after cooling, weigh each block
Molybdenum-0.3 %, Vanadium-0.8 %, Iron-balance.
to 0.1 mg and record the data.
6.3.1 The material is obtainable in the form of a centrifu-
7.3 Preparation of Duplicate Trays for Each Test:
gally cast cylinder, approximately 183-mm outside diameter by
7.3.1 Temporarily set the trays on the machine with those
152-mm inside diameter by 305 mm long (7.19-in. outside
two on the front having the interlocking edge facing frontward
diameter by 6.00-in. inside diameter by 12 in. long).
and those on the rear with the interlocking edges facing
rearward. This provides a stable support for the straight-edge
check to follow.
Specimen available from White Rock Engineering, Inc., P.O. Box 740095,
7.3.2 Place new neoprene laps in the trays, after removing
Dallas, TX 75374.
any protective coating prior to installation. Install a tray filler,
Proprietary of Woolley Tool and Manufacturing Co., P.O. Box 3505, Odessa,
TX 79760. (Fig. 3), with tapered or sloping end toward the left hand (Fig.
G75
1) of the machine. Then install the splash guards. Temporarily reduced to 100 g (3.5 oz) of solids and 100 g of liquid to
install the right and left tray clamps and move the trays so that prevent splashing.
the projections fit into tray-ends. Then tighten the nuts against 7.7.2 For the SAR Number, the solids concentration and
the clamps. liquid are usually specified by the user or the already mixed
7.4 Installation of Wear or Specimen Blocks—Duplicate slurry may be furnished. If a dry material sample is supplied,
blocks are installed in two selected holders. Place the arms on and no mixing instructions are furnished, distilled water should
the rack as shown in Fig. 5. Place the block in the jaws of the be used to mix a 50 % concentration and so
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