ASTM D3762-98
(Test Method)Standard Test Method for Adhesive-Bonded Surface Durability of Aluminum (Wedge Test)
Standard Test Method for Adhesive-Bonded Surface Durability of Aluminum (Wedge Test)
SCOPE
1.1 This test method 2,3 simulates in a qualitative manner the forces and effects on an adhesive bond joint at metal-adhesive/primer interface. It has proven to be highly reliable in determining and predicting the environmental durability of adherend surface preparations. The method has proven to be correlatable with service performance in a manner that is much more reliable than conventional lap shear or peel tests (Note 2). Note 1-While this test method is intended for use in aluminum-to-aluminum applications it may be used for determining surface durability of other metals and plastics provided consideration is given to thickness and rigidity of the adherends. Note 2-This test method is not a quantitative fracture strength test method. To measure fracture strength see Practice D3433.
1.2 This standard does not purport to address all of the safety problems, 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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Designation: D 3762 – 98
AMERICAN SOCIETY FOR TESTING AND MATERIALS
100 Barr Harbor Dr., West Conshohocken, PA 19428
Reprinted from the Annual Book of ASTM Standards. Copyright ASTM
Standard Test Method for
Adhesive-Bonded Surface Durability of Aluminum (Wedge
1
Test)
This standard is issued under the fixed designation D 3762; 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 4. Summary of Test Method
,
2 3
1.1 This test method simulates in a qualitative manner the 4.1 A wedge is forced into the bondline of a flat-bonded
forces and effects on an adhesive bond joint at metal-adhesive/ aluminum specimen, thereby creating a tensile stress in the
primer interface. It has proven to be highly reliable in deter- region of the resulting crack tip. The stressed specimen is
mining and predicting the environmental durability of adher- exposed to an aqueous environment, usually at an elevated
end surface preparations. The method has proven to be temperature, or to an appropriate environment relative to the
correlatable with service performance in a manner that is much use of the bonded structure. The resulting crack growth with
more reliable than conventional lap shear or peel tests (Note 2). time and failure modes are then evaluated. Variations in
adherend surface quality are easily observable when the
NOTE 1—While this test method is intended for use in aluminum-to-
specimens are forcibly, if necessary, opened at the test conclu-
aluminum applications it may be used for determining surface durability
sion.
of other metals and plastics provided consideration is given to thickness
and rigidity of the adherends.
5. Significance and Use
NOTE 2—This test method is not a quantitative fracture strength test
5.1 The test is primarily qualitative, but is very discriminat-
method. To measure fracture strength see Test Method D 3433.
ing in determining variations in adherend surface preparation
1.2 The values stated in SI units are to be regarded as the
parameters and adhesive environmental durability. The test has
standard. The values given in parentheses are for information
found application in controlling surface preparation operations
only.
and in screening surface preparations, primer and adhesive
1.3 This standard does not purport to address all of the
systems for durability. In addition to determining crack growth
safety concerns, if any, associated with its use. It is the
rate and assigning a value to it, the adhesive–joint failure is
responsibility of the user of this standard to establish appro-
evaluated and reported. For example, adhesion failure; cohe-
priate safety and health practices and determine the applica-
sion failure; or adherend failure are noted after opening up the
bility of regulatory limitations prior to use.
specimen at the conclusion of the test period.
2. Referenced Documents
6. Apparatus
2.1 ASTM Standards:
6.1 Magnifier (preferably stereo binocular), 5 to 30-power.
4
D 907 Terminology of Adhesives
6.2 Marking Stylus, sharp-pointed, or triangular file.
D 3433 Test Method for Fracture Strength in Cleavage of
6.3 Wedges, aluminum or stainless steel.
4
Adhesives in Bonded Metal Joints
NOTE 3—Wedges are preferably of the same composition as the
adherends of the specimen being tested to reduce the possibility of
3. Terminology
electrolytic corrosion. Stainless steel wedges have been found to work
3.1 Definitions—Many of the terms used in this test method
well with many adherends and are very durable and reuseable.
are defined in Terminology D 907.
6.4 Scale, small, graduated in millimetres or hundredths of
an inch.
1
This test method is under the jurisdiction of ASTM Committee D-14 on
Adhesives and is the direct responsibility of Subcommittee D14.80 on Metal
7. Test Specimen
Bonding Adhesives.
7.1 Use a minimum of five 25.4 by 203-mm (1 by 8-in.)
Current edition approved May 10, 1998. Published March 1999. Originally
e1
published as D 3762–79. Last previous edition D 3762–79 (1993) .
specimens from a single assembly for each test (Fig. 1).
2
Marceau, J. A., Moji, Y., and McMillan, J. C., “A Wedge Test for Evaluating
7.2 It is desirable to prevent plastic deformation (yielding)
Adhesive Bonded Surface Durability,” 21st SAMPE Symposium, Vol 21, April 6–8,
of the test specimen adherends when inserting the wedge into
1976.
3
Scardino, W. M., Marceau J. A., “Comparative Stressed Durability of Adhesive
the bondline. However, some plastic deformation is permis-
Bonded Aluminum Alloy Joints” Symposium on Durability of Adhesive Bonded
sible providing it is not excessive. (Fig. 2 illustrates data in
S
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