ASTM D6770-07(2019)

Standard Test Method for Abrasion Resistance of Textile Webbing (Hex Bar Method)

SIGNIFICANCE AND USE
5.1 The measurement of the resistance to abrasion of textile webbing is very complex. The resistance to abrasion is affected by many factors that include the inherent mechanical properties of the fibers; the dimensions of the fibers; the structure of the yarns; the construction of the webbing; the type, kind, and amount of treatment added to the fibers, yarns, or webbing; the nature of the abradant; the variable action of the abradant over the specimen area abraded; the tension on the specimen; the pressure between the specimen and the abradant; and the dimensional changes in the specimen.  
5.2 The resistance of textile webbing to abrasion as measured by this test method does not include all the factors which account for wear performance or durability in actual use. While the abrasion resistance stated in terms of the number of cycles and durability (defined as the ability to withstand deterioration or wearing out in use, including the effects of abrasion) are frequently related, the relationship varies with different end uses. Different factors may be necessary in any calculation of predicted durability from specific abrasion data.  
5.3 Laboratory tests may be reliable as an indication of relative end use in cases where the difference in abrasion resistance of various materials is large, but they should not be relied upon where differences in laboratory test findings are small. In general, the results should not be relied upon for prediction of performance during actual wear life for specific end uses unless there are data showing the specific relationship between laboratory abrasion tests and actual wear in the intended end use.  
5.4 While there has not been extensive interlaboratory testing prior to development of this standard, there has been some quality control testing by manufacturers. An intralaboratory test was conducted to initiate this test method, using a single product. This data will be used to determine a preliminary statement on precision and b...
SCOPE
1.1 This test method covers the determination of abrasion resistance of textile webbing using a hex bar abrasion tester.  
1.1.1 The resistance is expressed as a percentage of retained break strength.  
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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.  
1.3 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.

General Information

• Status: Historical
• Publication Date: 30-Nov-2019
• ICS: 59.080.30 - Textile fabrics
• Technical Committee: D13 - Textiles
• Drafting Committee: D13.60 - Fabric Physical Test Methods B

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation: D6770 − 07 (Reapproved 2019)
Standard Test Method for
Abrasion Resistance of Textile Webbing (Hex Bar Method)
This standard is issued under the fixed designation D6770; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 3.2 The following terms are relevant to this standard:
abrasion, abrasion cycle, breaking force, standard atmosphere
1.1 This test method covers the determination of abrasion
for preconditioning textiles, standard atmosphere for testing
resistance of textile webbing using a hex bar abrasion tester.
textiles, stroke, in hex bar abrasion testing, webbing.
1.1.1 Theresistanceisexpressedasapercentageofretained
break strength.
3.3 For all other terminology related to textiles, refer to
1.2 This standard does not purport to address all of the Terminology D123.
safety concerns, if any, associated with its use. It is the
responsibility of the user of this standard to establish appro-
4. Summary of Test Method
priate safety, health, and environmental practices and deter-
4.1 Abrasionresistanceismeasuredbysubjectingthespeci-
mine the applicability of regulatory limitations prior to use.
men to unidirectional reciprocal rubbing over a specific bar
1.3 This international standard was developed in accor-
under specified conditions of tension, stroke length and time.
dance with internationally recognized principles on standard-
Resistance to abrasion is evaluated by determining the percent
ization established in the Decision on Principles for the
retention of breaking force of an abraded specimen compared
Development of International Standards, Guides and Recom-
to an unabraded specimen.
mendations issued by the World Trade Organization Technical
Barriers to Trade (TBT) Committee.
5. Significance and Use
2. Referenced Documents
5.1 The measurement of the resistance to abrasion of textile
2.1 ASTM Standards:
webbingisverycomplex.Theresistancetoabrasionisaffected
D123Terminology Relating to Textiles
bymanyfactorsthatincludetheinherentmechanicalproperties
D1776/D1776MPractice for Conditioning and Testing Tex-
of the fibers; the dimensions of the fibers; the structure of the
tiles
yarns; the construction of the webbing; the type, kind, and
D4850Terminology Relating to Fabrics and Fabric Test
amountoftreatmentaddedtothefibers,yarns,orwebbing;the
Methods
nature of the abradant; the variable action of the abradant over
2.2 Other Standard:
the specimen area abraded; the tension on the specimen; the
Federal Standard 191A, Method 4108 “Strength and
pressure between the specimen and the abradant; and the
Elongation, Breaking;TextileWebbing,Tape and Braided
dimensional changes in the specimen.
Items”
5.2 The resistance of textile webbing to abrasion as mea-
suredbythistestmethoddoesnotincludeallthefactorswhich
3. Terminology
accountforwearperformanceordurabilityinactualuse.While
3.1 For all terminology relating to Fabrics, refer to Termi-
the abrasion resistance stated in terms of the number of cycles
nology D4850.
and durability (defined as the ability to withstand deterioration
or wearing out in use, including the effects of abrasion) are
ThistestmethodisunderthejurisdictionofASTMCommitteeD13onTextiles frequently related, the relationship varies with different end
and is the direct responsibility of Subcommittee D13.60 on Fabric Test Methods,
uses. Different factors may be necessary in any calculation of
Specific.
predicted durability from specific abrasion data.
Current edition approved Dec. 1, 2019. Published December 2019. Originally
approved in 2002. Last previous edition approved in 2015 as D6770–07(2015).
5.3 Laboratory tests may be reliable as an indication of
DOI: 10.1520/D6770-07R19.
relative end use in cases where the difference in abrasion
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
resistance of various materials is large, but they should not be
Standards volume information, refer to the standard’s Document Summary page on
relied upon where differences in laboratory test findings are
the ASTM website.
small. In general, the results should not be relied upon for
Available from Superintendent of Documents, Government Printing Office,
Washington, DC 20402. prediction of performance during actual wear life for specific
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D6770 − 07 (2019)
endusesunlesstherearedatashowingthespecificrelationship catingmotionofthewebbingoverastandardizedhexbar.One
between laboratory abrasion tests and actual wear in the end of each specimen is attached to the mechanism and the
intended end use. other end passing over a hexagonal steel rod is attached to a
weight.Thehexagonalrodissofixedastosubjectthewebbing
5.4 While there has not been extensive interlaboratory
specimentoabrasionontwoadjacentedgesasthedrummoves
testing prior to development of this standard, there has been
the specimen across the rod. One example of such a mecha-
some quality control testing by manufacturers.An intralabora-
nism is a reciprocating drum as illustrated in Fig. 1.
tory test was conducted to initiate this test method, using a
6.1.1 Mass “B” shall be 900 660g(2lb 6 2 oz) for
single product. This data will be used to determine a prelimi-
webbing with breaking strengths up to 4500 N (1000 lb), 1800
nary statement on precision and bias. Subsequent to approval
660g(4lb 6 2 oz) for breaking strengths of 4500 to 13500
ofthisstandard,aformalizedinterlaboratoryprocedurewillbe
N(1000to3000lb)and2400 660g(5.2 62lb)forbreaking
initiated under the direction of a professional statistician and
strengths over 13500 N (3000 lb).
will produce a research report. Samples used in this controlled
6.1.2 Steel hexagonal rods “C” shall be 6.35 6 0.03 mm
test will be representative of end use applications.
(0.250 6 0.001 in.) when measured across opposite flat sides
5.5 These general observations apply to most webbings that
and the radius shall be 0.5 6 0.2 mm (0.020 6 0.008 in.).The
are used in automotive, aerospace, industrial, and military
steel shall have a cold drawn finish and a Rockwell Hardness
applications.
of B-91 to B-101. The edges of the hexagonal rods shall not
5.6 This test method can be used for acceptance testing of
have any burrs, nicks or scale.
commercial shipments but comparisons should be made with
6.1.3 The mechanism “D” shall have a nominal outside
caution because estimates of between-laboratory precision are
diameter of 400 mm (16 in.) or be some mechanism able to
incomplete.
produceareciprocatingmotionofatleast300mm(12in.)over
thehexrodwithasuitablemeansforattachingthespecimento
5.7 If there are differences of practical significance between
be tested without damage to the specimen.
reported test results for two laboratories (or more), compara-
6.1.4 Thecrank-arm“F”shallbeattachedtothemechanism
tive tests should be performed to determine if there is a
statistical bias between them, using competent statistical assis- “D” and to the driver disk “E” in such a manner that when the
specimen is attached to the mechanism, the specimen during
tance. As a minimum, use samples for such comparative tests
thatareashomogenousaspossible,drawnfromthesamelotof the test will oscillate over the hexagonal rod the required
distance during each stroke and at the required rate (see 10.4).
material as the samples that resulted in disparate results during
initialtesting,andrandomlyassignedinequalnumberstoeach
6.1.5 The hexagonal rod shall be so placed that specimen
laboratory. The test results from the laboratories involved “A” with the weight attached to one end and the other end
shouldbecomparedusingastatisticaltestforunpaireddata,at
passing over the hexagonal rod and attached to the drive
a probability level chosen prior to the testing series. If bias is mechanism will form an angle of 85 6 2° “H”.
found, either its cause must be found and corrected, or future
6.2 Tensile Testing Machine , CRE-Type equipped with
test results must be adjusted in consideration of the known
split-drum webbing clamps as described in Federal Test
bias.
Method 191A, Method 4108.
6. Apparatus
6.1 Webbing Abrasion Tester—The webbing abrasion tester
consists of a suitable mechanism that will provide a recipro- Apparatus and accessories are commercially available.
FIG. 1 Webbing Abrasion Tester
D6770 − 07 (2019)
7. Sampling and Test Specimens rateof1 6.03strokes(0.5cycles)persecondfor5000strokes
(2500 cycles). One single stroke is 300 6 25 mm (12 6 1 in.)
7.1 Lot Sample—Take a lot sample as directed in the
in one direction only.
applicable material specification. In absence of such a specifi-
cation randomly select five rolls or pieces to constitute the lot 10.5 After the machine has stopped at the predetermined
sample.
number of cycles remove the test specimens from the abrading
machine.
7.2 Laboratory Sampling Unit—As a laboratory sampling
unit take from each roll or piece one piece of webbing that is
10.6 Continue as directed in 10.2 – 10.5 until all the
2.8 m (3.0 yd) in length.
required specimens have been abraded for each laboratory
sampling unit.
7.3 Test Specimens—From each laboratory sampling unit,
cut 2 test specimens 1.4 m (1.5 yd) in length. Mark one
10.7 Determinethebreakingforceoftheabradedspecimens
specimen “A” for abraded and the other “U” for unabraded.
(A) and the unabraded specimens (U) for each laboratory
7.3.1 When the lot or shipment consists of less than 5 rolls
sampling unit in the lot to the nearest 1% as directed in
or pieces, randomly select 5 test specimens that represent all
Fed-Std-191A, Method 4108 set as follows:
rolls or pieces in the lot or shipment.
10.7.1 Attach the split drum webbing clamps in the tensile
tester and set the distance between them to 250 mm (10 in.)
7.4 Ensurespecimensarefreeoffolds,creases,orwrinkles.
center to center.
Avoidgettingoil,water,grease,andsoforth,onthespecimens
10.7.2 Setthetestingspeedto75 625mm(3 61in./min).
when handling.
8. Conditioning 11. Calculation
8.1 Conditionthetestspecimenstomoistureequilibriumfor
11.1 Calculate the average breaking force for the lot of the
testing in the standard atmosphere for testing textiles in
abraded test specimens from the results of the laboratory
accordance with Practice D1776/D1776M or, if applicable, in
sampling units.
the specified atmosphere in which the testing is to be per-
11.2 Calculate the average breaking force for the lot of the
formed.
unabraded test specimens from the results of the laboratory
8.2 In the event of dispute concerning the results of tests
sampling units.
that may be affected by the moisture content, test specimens
11.3 Calculate the percentage of retained breaking force to
shall be preconditioned by bringing them to approximate
the nearest 1 % for the lot using Eq 1:
moisture equilibrium in the standard atmosphere for precondi-
100A
tioning textiles in accordance with Practice D1776/D1776M.
AR 5 (1)
U
9. Preparation and Calibration of Test Apparatus
where:
9.1 Ensurethetestmachineisonalevel,sturdysurfaceand
AR = abrasion resistance, %,
free from vibration.
A = average breaking force of the abraded specimens, N
(lb), and
9.2 For hexagonal rods a manufacturer’s certificate of com-
U = average breaking force of the unabraded specimens, N
pliance shall be acceptable as to the requirements as described
(lb).
in 6.1.2.
11.3.1 When data are automatically computer processed,
10. Procedure
calculationsaregenerallycontainedintheassociatedsoftware.
10.1 Condition the “A” test specimens in the standard It is recommended that computer-processed data be verified
atmosphere for testing textiles, in accordance with Section 8. againstknownpropertyvaluesanditssoftwaredescribedinthe
report.
10.2 Attach the required mass (6.1.1) to one end of the test
specimen,passtheotherendoverthehexagonalrodandattach
12. Report
tothedrum.Thelengthofthetestspecimensshallbeadjusted,
without altering the original length, so that the test specimens
12.1 Report that the abrasion resistance was determined in
will oscillate across the hexagon rod and each end of the
accordance with Test Method D6770. Describe the material or
abraded area will be equidistant from the ends of the test
product sampled.
specimens.
12.2 Report the following information for the laboratory
10.3 The edges of each new hexagonal rod shall be identi-
sampling unit and for the lot as applicable to a material
fied as 1 through 6, and rotated after each use so that no
specification or contract order:
abrading edges are used more than once. Use edge 1 and two
12.2.1 Abrasion resistance, percent retained in breaking
foronetestspecimen,edge3and4forasecondtestspecimen,
force.
edges 5 and 6 for a third test specimen, and then discard the
12.2.2 Breaking force of abraded test specimens.
rod.
12.2.3 Breaking force of unabraded test specimens.
10.4 Oscillate the mechanism so that the test specimens are 12.2.4 For computer-processed data, identify the program
given a 300 6 25 mm (12 6 1 in.) traverse over the rod at the (software) used.
D6770 − 07 (2019)
13. Precision and Bias 13.3 Bias—Theprocedureofthistestmethodprovidesatest
value that can be defined only in terms of this test method.
13.1 An intralaboratory test was conducted for the determi-
Thereisnoindependent,refereemethodbywhichbiasmaybe
nation of precision and bias of this test method. The results of
determined. No known bias has been determined for this test
the test are attached as Table 1.
method.
NOTE 1—Because the intralaboratory test included less than the
recommended five laboratories, estimates of precision data may be either
underestimated or overestimated to a considerable extent and should be 14. Keywords
used with special caution.
14.1 hex-bar abrasion resistance webbing
13.2 Precision—A statement on the precision of this test
method is being developed. The results will be included when
available.
D6770 − 07 (2019)
TABLE 1 Raw Data from Intralaboratory Test
Material 1—Before Abrasion Material 2—After Abrasion
Total Opr.
Lab. Opr. Test 1 Test 2 Test 3 Test 4 Test 5 Opr. Sum Test 1 Test 2 Test 3 Test 4 Test 5 Opr. Sum
Sum
Set 1 1 4.720 4.820 4.600 4.700 4.600 23.440 4.620 4.460 4.680 4.600 4.620 22.980 46.420
2 4.600 4.720 4.700 4.720 4.680 23.420 4.640 4.600 4.580 4.680 4.600 23.100 46.520
3 4.580 4.720 4.720 4.560 4
...

This document is not an ASTM standard and is intended only to provide the user of an ASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation: D6770 − 07 (Reapproved 2015) D6770 − 07 (Reapproved 2019)
Standard Test Method for
Abrasion Resistance of Textile Webbing (Hex Bar Method)
This standard is issued under the fixed designation D6770; 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
1.1 This test method covers the determination of abrasion resistance of textile webbing using a hex bar abrasion tester.
1.1.1 The resistance is expressed as a percentage of retained break strength.
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 safety, health, and healthenvironmental practices and determine the
applicability of regulatory limitations prior to use.
1.3 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.
2. Referenced Documents
2.1 ASTM Standards:
D123 Terminology Relating to Textiles
D1776D1776/D1776M Practice for Conditioning and Testing Textiles
D4850 Terminology Relating to Fabrics and Fabric Test Methods
2.2 Other Standard:
Federal Standard 191,191A, Method 4108 “Strength and Elongation, Breaking; Textile Webbing, Tape and Braided Items”
3. Terminology
3.1 For all terminology relating to Fabrics, refer to Terminology D4850.
3.2 The following terms are relevant to this standard: abrasion, abrasion cycle, breaking force, standard atmosphere for
preconditioning textiles, standard atmosphere for testing textiles, stroke, in hex bar abrasion testing, webbing.
3.3 For all other terminology related to textiles, refer to Terminology D123.
4. Summary of Test Method
4.1 Abrasion resistance is measured by subjecting the specimen to unidirectional reciprocal rubbing over a specific bar under
specified conditions of tension, stroke length and time. Resistance to abrasion is evaluated by determining the percent retention
of breaking force of an abraded specimen compared to an unabraded specimen.
5. Significance and Use
5.1 The measurement of the resistance to abrasion of textile webbing is very complex. The resistance to abrasion is affected by
many factors that include the inherent mechanical properties of the fibers; the dimensions of the fibers; the structure of the yarns;
the construction of the webbing; the type, kind, and amount of treatment added to the fibers, yarns, or webbing; the nature of the
abradant; the variable action of the abradant over the specimen area abraded; the tension on the specimen; the pressure between
the specimen and the abradant; and the dimensional changes in the specimen.
This test method is under the jurisdiction of ASTM Committee D13 on Textiles and is the direct responsibility of Subcommittee D13.60 on Fabric Test Methods, Specific.
Current edition approved July 1, 2015Dec. 1, 2019. Published September 2015December 2019. Originally approved in 2002. Last previous edition approved in 20112015
as D6770–07(2011).D6770–07(2015). DOI: 10.1520/D6770-07R15.10.1520/D6770-07R19.
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Available from Superintendent of Documents, Government Printing Office, Washington, DC 20402.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
D6770 − 07 (2019)
5.2 The resistance of textile webbing to abrasion as measured by this test method does not include all the factors which account
for wear performance or durability in actual use. While the abrasion resistance stated in terms of the number of cycles and
durability (defined as the ability to withstand deterioration or wearing out in use, including the effects of abrasion) are frequently
related, the relationship varies with different end uses. Different factors may be necessary in any calculation of predicted durability
from specific abrasion data.
5.3 Laboratory tests may be reliable as an indication of relative end use in cases where the difference in abrasion resistance of
various materials is large, but they should not be relied upon where differences in laboratory test findings are small. In general,
the results should not be relied upon for prediction of performance during actual wear life for specific end uses unless there are
data showing the specific relationship between laboratory abrasion tests and actual wear in the intended end use.
5.4 While there has not been extensive interlaboratory testing prior to development of this standard, there has been some quality
control testing by manufacturers. An intralaboratory test was conducted to initiate this test method, using a single product. This
data will be used to determine a preliminary statement on precision and bias. Subsequent to approval of this standard, a formalized
interlaboratory procedure will be initiated under the direction of a professional statistician and will produce a research report.
Samples used in this controlled test will be representative of end use applications.
5.5 These general observations apply to most webbings that are used in automotive, aerospace, industrial, and military
applications.
5.6 This test method can be used for acceptance testing of commercial shipments but comparisons should be made with caution
because estimates of between-laboratory precision are incomplete.
5.7 If there are differences of practical significance between reported test results for two laboratories (or more), comparative
tests should be performed to determine if there is a statistical bias between them, using competent statistical assistance. As a
minimum, use samples for such comparative tests that are as homogenous as possible, drawn from the same lot of material as the
samples that resulted in disparate results during initial testing, and randomly assigned in equal numbers to each laboratory. The
test results from the laboratories involved should be compared using a statistical test for unpaired data, at a probability level chosen
prior to the testing series. If bias is found, either its cause must be found and corrected, or future test results must be adjusted in
consideration of the known bias.
6. Apparatus
6.1 Webbing Abrasion Tester—The webbing abrasion tester consists of a suitable mechanism that will provide a reciprocating
motion of the webbing over a standardized hex bar. One end of each specimen is attached to the mechanism and the other end
passing over a hexagonal steel rod is attached to a weight. The hexagonal rod is so fixed as to subject the webbing specimen to
abrasion on two adjacent edges as the drum moves the specimen across the rod. One example of such a mechanism is a
reciprocating drum as illustrated in Fig. 1.
6.1.1 Mass “B” shall be 900 6 60 g (2 lb 6 2 oz) for webbing with breaking strengths up to 4500 N (1000 lb), 1800 6 60 g
(4 lb 6 2 oz) for breaking strengths of 4500 to 13 500 N (1000 to 3000 lb) and 2400 6 60 g (5.2 6 2 lb) for breaking strengths
over 13 500 N (3000 lb).
6.1.2 Steel hexagonal rods “C” shall be 6.35 6 0.03 mm (0.250 6 0.001 in.) when measured across opposite flat sides and the
radius shall be 0.5 6 0.2 mm (0.020 6 0.008 in.). The steel shall have a cold drawn finish and a Rockwell Hardness of B-91 to
B-101. The edges of the hexagonal rods shall not have any burrs, nicks or scale.
FIG. 1 Webbing Abrasion Tester
D6770 − 07 (2019)
6.1.3 The mechanism “D” shall have a nominal outside diameter of 400 mm (16 in.) or be some mechanism able to produce
a reciprocating motion of at least 300 mm (12 in.) over the hex rod with a suitable means for attaching the specimen to be tested
without damage to the specimen.
6.1.4 The crank-arm “F” shall be attached to the mechanism “D” and to the driver disk “E” in such a manner that when the
specimen is attached to the mechanism, the specimen during the test will oscillate over the hexagonal rod the required distance
during each stroke and at the required rate (see 10.4).
6.1.5 The hexagonal rod shall be so placed that specimen “A” with the weight attached to one end and the other end passing
over the hexagonal rod and attached to the drive mechanism will form an angle of 85 6 2° “H”.
6.2 Tensile Testing Machine , CRE-Type equipped with split-drum webbing clamps as described in Federal Test Method
191b,191A, Method 4108.
7. Sampling and Test Specimens
7.1 Lot Sample—Take a lot sample as directed in the applicable material specification. In absence of such a specification
randomly select five rolls or pieces to constitute the lot sample.
7.2 Laboratory Sampling Unit—As a laboratory sampling unit take from each roll or piece one piece of webbing that is 2.8 m
(3.0 yd) in length.
7.3 Test Specimens—From each laboratory sampling unit, cut 2 test specimens 1.4 m (1.5 yd) in length. Mark one specimen “A”
for abraded and the other “U” for unabraded.
7.3.1 When the lot or shipment consists of less than 5 rolls or pieces, randomly select 5 test specimens that represent all rolls
or pieces in the lot or shipment.
7.4 Ensure specimens are free of folds, creases, or wrinkles. Avoid getting oil, water, grease, and so forth, on the specimens
when handling.
8. Conditioning
8.1 Condition the test specimens to moisture equilibrium for testing in the standard atmosphere for testing textiles in accordance
with Practice D1776D1776/D1776M or, if applicable, in the specified atmosphere in which the testing is to be performed.
8.2 In the event of dispute concerning the results of tests that may be affected by the moisture content, test specimens shall be
preconditioned by bringing them to approximate moisture equilibrium in the standard atmosphere for preconditioning textiles in
accordance with Practice D1776D1776/D1776M.
9. Preparation and Calibration of Test Apparatus
9.1 Ensure the test machine is on a level, sturdy surface and free from vibration.
9.2 For hexagonal rods a manufacturer’s certificate of compliance shall be acceptable as to the requirements as described in
6.1.2.
10. Procedure
10.1 Condition the “A” test specimens in the standard atmosphere for testing textiles, in accordance with Section 8.
10.2 Attach the required mass (6.1.1) to one end of the test specimen, pass the other end over the hexagonal rod and attach to
the drum. The length of the test specimens shall be adjusted, without altering the original length, so that the test specimens will
oscillate across the hexagon rod and each end of the abraded area will be equidistant from the ends of the test specimens.
10.3 The edges of each new hexagonal rod shall be identified as 1 through 6, and rotated after each use so that no abrading edges
are used more than once. Use edge 1 and two for one test specimen, edge 3 and 4 for a second test specimen, edges 5 and 6 for
a third test specimen, and then discard the rod.
10.4 Oscillate the mechanism so that the test specimens are given a 300 6 25 mm (12 6 1 in.) traverse over the rod at the rate
of 1 6 .03 strokes (0.5 cycles) per second for 5000 strokes (2500 cycles). One single stroke is 300 6 25 mm (12 6 1 in.) in one
direction only.
10.5 After the machine has stopped at the predetermined number of cycles remove the test specimens from the abrading
machine.
10.6 Continue as directed in 10.2 – 10.5 until all the required specimens have been abraded for each laboratory sampling unit.
10.7 Determine the breaking force of the abraded specimens (A) and the unabraded specimens (U) for each laboratory sampling
unit in the lot to the nearest 1 % as directed in Fed-Std-191,Fed-Std-191A, Method 4108 set as follows:
Apparatus and accessories are commercially available.
D6770 − 07 (2019)
10.7.1 Attach the split drum webbing clamps in the tensile tester and set the distance between them to 250 mm (10 in.) center
to center.
10.7.2 Set the testing speed to 75 6 25 mm (3 6 1 in./min).
11. Calculation
11.1 Calculate the average breaking force for the lot of the abraded test specimens from the results of the laboratory sampling
units.
11.2 Calculate the average breaking force for the lot of the unabraded test specimens from the results of the laboratory sampling
units.
11.3 Calculate the percentage of retained breaking force to the nearest 1 % for the lot using Eq 1:
100A
AR 5 (1)
U
where:
AR = abrasion resistance, %,
A = average breaking force of the abraded specimens, N (lb), and
U = average breaking force of the unabraded specimens, N (lb).
11.3.1 When data are automatically computer processed, calculations are generally contained in the associated software. It is
recommended that computer-processed data be verified against known property values and its software described in the report.
12. Report
12.1 Report that the abrasion resistance was determined in accordance with Test Method D6770. Describe the material or
product sampled.
12.2 Report the following information for the laboratory sampling unit and for the lot as applicable to a material specification
or contract order:
12.2.1 Abrasion resistance, percent retained in breaking force.
12.2.2 Breaking force of abraded test specimens.
12.2.3 Breaking force of unabraded test specimens.
12.2.4 For computer-processed data, identify the program (software) used.
13. Precision and Bias
13.1 An intralaboratory test was conducted for the determination of precision and bias of this test method. The results of the
test are attached as Table 1.
NOTE 1—Because the intralaboratory test included less than the recommended five laboratories, estimates of precision data may be either
underestimated or overestimated to a considerable extent and should be used with special caution.
13.2 Precision—A statement on the precision of this test method is being developed. The results will be included when
available.
13.3 Bias—The procedure of this test method provides a test valu
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