1、 FORD LABORATORY TEST METHOD EU-BU 003-02 Date Action Revisions 2000 11 13 Revised Editorial no technical change A. Cockman 1994 02 28 Printed copies are uncontrolled Page 1 of 5 Copyright 2000, Ford Global Technologies, Inc. BLOCK SHEAR STRENGTH OF METAL TO METAL ADHESIVES Application This procedur
2、e is used to test the block shear strength of thermosetting adhesives used for bonding metal to metal. Apparatus Required Press An air driven press which will deliver a constant pressure to the test specimens during cure is required. The press is equipped with controlled electric heaters which heat
3、the test specimens to required temperature during cure under pressure (see Drawing 1). Mechanical Convection Oven Capable of mainta ining a temperature of 80 +/ - 2 C. Tensile Tester A tensile testing machine with a scale range of 0 - 100 KN and capable of a load at a uniform rate of 10 mm/minute is
4、 required. The tensile machine shall have an indicator for recording the shear strengt h of the adhesive in Newton at the moment of rupture. Shear Strength Fixture The fixture for holding the bonded test specimen during loading is shown in the attached Drawing 1. The fixture is equipped with an elec
5、trically controlled heater for determinin g shear strength at elevated temperatures. Abrasive Paper or Sand Blast (a) Abrasive Paper Type: KK 14; Size: 230 x 280 mm; Grit Size: 150 Used for polishing the mating surfaces of the test specimens or sand blast (depending on surface desired). Sourc e: V.S
6、.M Abrasive or Vereinigte Schmirgel and Maschinenfabriken AG Watford, England 3 Hannover Hainholz, Germany FORD LABORATORY TEST METHOD EU-BU 003-02 Page 2 of 5 Copyright 2000, Ford Global Technologies, Inc. (b) Sand Blast Sand or Grit Size Retained on 20 Sieve - 12 % maximum Retained on 50 Sieve - 1
7、 % maximum Operating Pressure 700 N/ m Exposure Time 50 seconds per 10 cm Nozzle Distance to Specimen 75 mm Nozzle Size 9.5 mm Test Specimens East test specimen assembly consists of one strip and one disc of BS 1474: 1969 HE 15 TB or DIN 1725 BL 1 AlCuMg 1F40 3.1325 aluminum. The strip is 28 mm by 1
8、11 mm by 6.0 mm and the disc is 28 mm in diameter by 6.0 mm thick, with a hole in the centre of the disc to give a firm fit over the pin in the press. Tetrachloroethylene To clean the test specimen. Paper Masking Tape Normal paint shop masking tape with dimensions 25 mm wide x 0.17 mm thick to build
9、 up the required layers. Spring Paper Clips “Bulldog“ type or similar. Jaw width approximately 63 mm to fix the test sample assembly. Surgical Scalpel To scribe marks at positioning points . Spatula To spread and level the applied adhesive. Conditioning and Test Conditions All test values indicated
10、herein are based on material conditioned in a controlled atmosphere of 23 +/ - 2 C and 50 +/ - 5 % relative humidity for not less than 24 h pr ior to testing and tested under the same conditions unless otherwise specified. Procedure 1. Prepare the mating surfaces of the aluminum strips and discs to
11、give a uniform finish, by using abrasive paper or sand blast. 2. Wipe clean with a cloth wetted with tetrachloroethylene. 3. Lay the required number of prepared aluminum strips on a flat surface. Ensure that the long edges are touching and parallel. FORD LABORATORY TEST METHOD EU-BU 003-02 Page 3 of
12、 5 Copyright 2000, Ford Global Technologies, Inc. 4. On the last panel at each end of the series make 2 light scribe marks a minimum of 28 mm apart and equidistant from the longitudinal mid point of the panel. 5. Using the scribe marks as positioning points, lay 3 layers of masking tape across the p
13、anels so as to leave a gap of approximately 28 mm across the centre of each panel. At one end leave an excess of about 80 mm of tape which can be doubled under to make a 40 mm tab with which to pull the tape away from the panels when required. See drawing No. 2. 6. Spread the adhesive evenly along t
14、he gap then level off with a spatula and remove excess. Note: The build - up of 3 layers of 0.17 mm tape will assist in leveling a 0.50 mm layer of wet adhesive across the centre of each specimen, which will produce approximately 0.17 mm dry film thickness when using a 40 % total solids adhesive. To
15、 obtain 0 .15 - 0.20 total dry film thickness with lower total solids material, additional thickness of tape will be required. For example, a 26 % solids adhesive would require a buildup of 4 layers of 0.17 mm tape. 7. Secure the aluminum test strips with spring c lips at either end so as to restric
16、t movement of the strips when the tape is removed. 8. Carefully remove the masking tape by pulling upwards from the end with the excess tape. See Drawing 2. 9. Air dry for 15 minutes. 10. Bake to give 20 minutes at 80 +/ - 2 C metal temperature. 11. Cool to 23 +/ - 2 C and remove clips. 12. Separate
17、 the specimens carefully by slitting through the adhesive with a surgical scalpel at each junction. 13. Bond an aluminum disc to each strip so that the prepared surface i s in contact with the adhesive. Use light finger pressure to ensure even contact. 14. Position the test assembly in the press, lo
18、cating the hole in the disc over the pin in the press, and apply the specified load at the specified time and temperature as required by the material specification. 15. Allow the bond test assemblies to cool, position each assembly in the test fixture for shear adhesion (see drawing) and apply a loa
19、d at 10 mm per minute to failure of the bond at the temperature specified in the material specification. Evaluation Report shear strength of the specimen, test temperature, type of adhesive, cure time and temperature. All specimens must meet the requirements of the relevant Material Specification. C
20、hemicals, materials, parts, and equipment referenced in this document must be used and handled properly. Each party is responsible for determining proper use and handling in its facilities. FORD LABORATORY TEST METHOD EU-BU 003-02 Page 4 of 5 Copyright 2000, Ford Global Technologies, Inc. BLOCK SHEAR STRENGTH OF METAL TO METAL ADHESIVES BLOCK SHEAR STRENGTH TEST FIXTURE ( EXPLODED VIEW ) FORD LABORATORY TEST METHOD EU-BU 003-02 Page 5 of 5 Copyright 2000, Ford Global Technologies, Inc.
