1、Designation: D 2557 98 (Reapproved 2004)Standard Test Method forTensile-Shear Strength of Adhesives in the SubzeroTemperature Range from 267.8 to 55C (450 to 67F)1This standard is issued under the fixed designation D 2557; the number immediately following the designation indicates the year oforigina
2、l adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the determination of the com-parative she
3、ar strength of adhesives for bonding metals whentested on a standard specimen and under specified conditions ofpreparation and testing at extreme subzero temperatures.1.2 This test method is applicable to the temperature rangefrom -267.8 to -55C (-450 to -67F).1.3 The values stated in SI units are t
4、o be regarded as thestandard. The values given in parentheses are for informationonly.1.4 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices a
5、nd determine the applica-bility of regulatory limitations prior to use. Specific precau-tions are given in 8.3.2. Referenced Documents2.1 ASTM Standards:2A 167 Specification for Stainless and Heat-ResistingChromium-Nickel Steel Plate, Sheet, and StripB 209 Specification for Aluminum and Aluminum-All
6、oySheet and PlateB 265 Specification for Titanium and Titanium Alloy Strip,Sheet, and PlateD 907 Terminology of AdhesivesD 1002 Test Method for Apparent Shear Strength of Single-Lap-Joint Adhesively Bonded Metal Specimens by Ten-sion Loading (Metal-to-Metal)D 4896 Guide for Use of Adhesive-Bonded Si
7、ngle Lap-Joint Specimen Test Results3. Terminology3.1 DefinitionsMany terms in this test method are definedin Terminology D 907.4. Significance and Use4.1 This test method may be used as an accelerated screen-ing test for assessing the strength properties of adhesives andadhesive joints at subzero t
8、emperatures. This test method mayalso be used to determine the effects of various surfacepreparations, substrates, or adhesive systems on the durabilityof the adhesive joints at subzero temperatures.4.2 Tensile shear strengths of various adhesives, surfacepreparations, and substrates may be compared
9、 by using this testmethod for uniform sets of conditions. To assess the overalltensile shear strength of a given adhesive, surface preparation,and substrate should be tested under a range of stress andtemperatures. For a specific end use, the needed strengthproperties using only one set of test cond
10、itions may beobtained.4.3 The misuse of strength values obtained from this testmethod as design-allowable stress values for structural jointscould lead to product failure, property damage, and humaninjury.4.3.1 The apparent shear strength of an adhesive obtainedfrom a given small single-lap specimen
11、 may differ from thatobtained from a joint made with different adherends or by adifferent bonding process. The normal variation of temperatureand moisture in the service environment causes the adherendsand the adhesive to swell or shrink. The adherends andadhesive are likely to have different therma
12、l and moisturecoefficients of expansion. Even in small specimens, short-termenvironment changes can induce internal stresses of chemicalchanges in the adhesive that permanently affect the apparentstrength and other properties of the adhesive.4.3.2 The problem of predicting joint behavior in a chang-
13、ing environment is even more difficult if a different type ofadherend is used in a larger structural joint than was used in thesmall specimen.4.3.3 The apparent shear strength measured with a single-lap specimen is not suitable for determining design-allowablestresses for designing structural joints
14、 that differ in any manner1This test method is under the jurisdiction of ASTM Committee D14 onAdhesives and is the direct responsibility of Subcommittee D14.80 on MetalBonding Adhesives.Current edition approved April 1, 2004. Published April 2004. Originallyapproved in 1966. Last previous edition ap
15、proved in 1998 as D 2557 98.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 10
16、0 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.from the joints tested without thorough analysis and under-standing of the joint and adhesive behaviors.4.3.4 Single-lap tests may be used for comparing andselecting adhesives or bonding processes for susceptibility to
17、fatigue and environmental changes, but such comparisons mustbe made with great caution since different adhesives mayrespond differently in different joints. See Guide D 4896 forfurther discussion of the concepts relative to interpretation ofadhesive-bonded single-lap-joints.5. Apparatus5.1 The testi
18、ng machine shall conform to the requirementsof Test Method D 1002 except that pin-type grips as shown inFig. 1 shall be used to hold the test specimen.5.2 The cooling equipment shall consist of a cold box or acryostat filled with a gaseous or liquid refrigerant in which thestandard specimen is immer
19、sed prior to and during the test. Atypical cryostat is shown in Fig. 2.6. Test Specimens6.1 Test specimens shall be cut from panels shown in Fig.3(A). These test specimens shall conform to the form anddimensions shown in Fig. 3(B). The specimens are in everyrespect similar to the tension lap shear s
20、pecimens described inTest Method D 1002 Fig. 1, except that doublers and pin gripsshall be used.6.2 The selection of materials shall be based on the testtemperature range. The following metals (Note 1) are recom-mended for use although other aluminum, titanium, andstainless steel alloys may be used.
21、NOTE 1Other alloys can be used as adherends, but caution should beused in choice since many alloys become brittle at extreme subzerotemperatures.MetalAASTM DesignationSteel, corrosion-resistant sheet, 301 FH A 167Aluminum alloy, sheet, 2024-T3 B 209Titanium alloy, sheet, 5A1-2.5 Sn B 265AThe above s
22、heets shall have a thickness of 1.270 mm (0.050 in.) except in thecase of the aluminum alloy sheet which shall have a thickness of 1.630 mm (0.064in.).7. Preparation of Test Specimens7.1 Cut test specimens to dimensions from the test panel, asshown in Fig. 3(B). Measure the width of the specimen and
23、 thelength of the overlap to the nearest 0.25 mm (0.01 in.).7.2 Specimens are to have bonded, spot welded, or me-chanically attached doublers.7.3 Test specimens may be prepared by bonding individualstrips as shown in Fig. 3(B). Machine unbonded individualstrips to size. They shall be free of burrs o
24、r other irregularities.NOTE 1“A” dimension varies with specimen thickness.FIG. 1 Clevis for Holding “Pin-Type” Lap Shear CouponsNOTE 1Cold box configurations are commercially available whichcan be used from room temperature to 185C. These utilize chilledgaseous nitrogen or gaseous carbon dioxide.FIG
25、. 2 Diagrammatic View of Cryostat and AccessoriesD 2557 98 (2004)28. Procedure8.1 Test the specimens, prepared in accordance with Section7 in shear by tension loading after conditioning.8.2 Place specimens in the pin-type grips of the testingmachine so that the long axis of the test specimen coincid
26、eswith the direction of the applied pull through the center line ofthe grip assembly.8.3 Cool specimens by completely surrounding them with alow-temperature fluid (liquid or gas). (WarningWhen usingliquid hydrogen as the cryogen, extreme caution should beexercised to avoid explosive conditions. Liqu
27、id helium has aboiling point of 269C (452F). Liquid hydrogen has aboiling point of 252C (423F). Liquid nitrogen has aboiling point of 195C (320F).)8.4 Obtain the time required to reach the desired testtemperature on a dummy test specimen having two thermo-couples positioned in the geometric center o
28、f the bond. Imbedone thermocouple in the center of the bond and superimposeand bond or spot weld the other to the outer surface.8.5 Immerse test specimens in fluid for 5 min more than thetime required to reach equilibrium.8.6 Test the specimen as follows:8.6.1 Permit no slack in the test fixture jus
29、t prior to applyingload; a preload, if used, shall not exceed 345 kPa (50 psi) atambient temperature.8.6.2 Control the temperature by a thermocouple mountedon the outer surface of the test specimen in the bond area whenusing a gaseous coolant. This is not required when utilizing aconstant boiling li
30、quid.8.6.3 The test temperature tolerance shall be 61%.8.6.4 Load the test specimen to failure at a rate of 8.3 to 7MPa (1200 to 1400 psi)/min (approximately 0.05 in./mincross-head separation speed).9. Calculation9.1 The load at fracture and the nature and amount of thisfracture (cohesion in adhesiv
31、e or metal, or adhesion) shall berecorded for each specimen. All loads at fracture shall beexpressed in megapascals (or pounds per square inch) and ifpossible shall be reported to three significant figures.10. Report10.1 Report the following:10.1.1 Complete identification of the adhesive tested, in-
32、cluding type, source, manufacturers code numbers, form, etc.,10.1.2 Complete identification of the metal used, its thick-ness, and the method of cleaning and preparing its surfacesprior to bonding,10.1.3 Application and bonding conditions used in prepar-ing the specimens,10.1.4 Length of overlap use
33、d, and bondline thickness,10.1.5 Conditioning procedure used for specimens prior totesting,10.1.6 Test temperature and cooling medium,10.1.7 Number of specimens tested,10.1.8 Number of joints represented,10.1.9 Maximum, minimum, and average values for theload at fracture,10.1.10 The nature of the fr
34、acture, including the averageestimated percentages of fracture in the cohesion of theadhesive, contact fracture, and adhesion to the metal, and10.1.11 Average thickness of adhesive layer after formationof the joint, within 0.02 mm (0.001 in.). The method ofobtaining the thickness of the adhesive lay
35、er shall be describedincluding procedure, location of measurements, and range ofmeasurements.NOTE 1t shall be as specified in 4.2.FIG. 3 Form and Dimension of Bonded Panel and Test SpecimensD 2557 98 (2004)311. Precision and Bias11.1 Precision and bias information does not exist for thistest method
36、because resources necessary for round-robin test-ing have not been forthcoming.11.2 The precision and bias of this test method are afunction of the adhesive system, surface preparation, substrate,test temperature, and test cooling medium. Precision shall bereported in terms of standard deviation of
37、the data and thestandard error of the mean.12. Keywords12.1 adhesive; metals; subzero temperature range; tensileshear strengthASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are e
38、xpressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not rev
39、ised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you m
40、ay attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).D 2557 98 (2004)4
