1、Designation: D2557 98 (Reapproved 2010)1Standard 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 D2557; the number immediately following the designation indicates the year oforiginal
2、 adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.1NOTESection 8.6.4 was editorially corrected in October 2010.1. Scope1.1 This t
3、est method covers the determination of the com-parative shear 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
4、-55C (-450 to -67F).1.3 The values stated in SI units are to 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 stand
5、ard to establish appro-priate safety and health practices and determine the applica-bility of regulatory limitations prior to use. Specific precau-tions are given in 8.3.2. Referenced Documents2.1 ASTM Standards:2A167 Specification for Stainless and Heat-ResistingChromium-Nickel Steel Plate, Sheet,
6、and StripB209 Specification for Aluminum and Aluminum-AlloySheet and PlateB265 Specification for Titanium and Titanium Alloy Strip,Sheet, and PlateD907 Terminology of AdhesivesD1002 Test Method for Apparent Shear Strength of Single-Lap-Joint Adhesively Bonded Metal Specimens by Ten-sion Loading (Met
7、al-to-Metal)D4896 Guide for Use ofAdhesive-Bonded Single Lap-JointSpecimen Test Results3. Terminology3.1 DefinitionsMany terms in this test method are definedin Terminology D907.4. Significance and Use4.1 This test method may be used as an accelerated screen-ing test for assessing the strength prope
8、rties of adhesives andadhesive joints at subzero temperatures. 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, s
9、urfacepreparations, and substrates may be compared 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
10、strengthproperties using only one set of test conditions 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 adhes
11、ive obtainedfrom a given small single-lap specimen 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 adheren
12、ds andadhesive are likely to have different thermal and moisture1This 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 Oct. 1, 2010. Published October 2010. Originallyapp
13、roved in 1966. Last previous edition approved in 2004 as D2557 98 (2004).DOI: 10.1520/D2557-98R10E01.2For 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 D
14、ocument Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.coefficients of expansion. Even in small specimens, short-termenvironment changes can induce internal stresses of chemicalchanges in the adhesive
15、 that permanently affect the apparentstrength and other properties of the adhesive.4.3.2 The problem of predicting joint behavior in a chang-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 apparen
16、t shear strength measured with a single-lap specimen is not suitable for determining design-allowablestresses for designing structural joints that differ in any mannerfrom the joints tested without thorough analysis and under-standing of the joint and adhesive behaviors.4.3.4 Single-lap tests may be
17、 used for comparing andselecting adhesives or bonding processes for susceptibility tofatigue and environmental changes, but such comparisons mustbe made with great caution since different adhesives mayrespond differently in different joints. See Guide D4896 forfurther discussion of the concepts rela
18、tive to interpretation ofadhesive-bonded single-lap-joints.5. Apparatus5.1 The testing machine shall conform to the requirementsof Test Method D1002 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
19、 filled with a gaseous or liquid refrigerant in which thestandard specimen is immersed 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
20、 in Fig. 3(B). The specimens are in everyrespect similar to the tension lap shear specimens described inTest Method D1002 Fig. 1, except that doublers and pin gripsshall be used.NOTE 1“A” dimension varies with specimen thickness.FIG. 1 Clevis for Holding “Pin-Type” Lap Shear CouponsNOTE 1Cold box co
21、nfigurations are commercially available whichcan be used from room temperature to 185C. These utilize chilledgaseous nitrogen or gaseous carbon dioxide.FIG. 2 Diagrammatic View of Cryostat and AccessoriesD2557 98 (2010)126.2 The selection of materials shall be based on the testtemperature range. The
22、 following metals (Note 1) are recom-mended for use although other aluminum, titanium, andstainless steel alloys may be used.NOTE 1Other alloys can be used as adherends, but caution should beused in choice since many alloys become brittle at extreme subzerotemperatures.MetalAASTM DesignationSteel, c
23、orrosion-resistant sheet, 301 FH A167Aluminum alloy, sheet, 2024-T3 B209Titanium alloy, sheet, 5A1-2.5 Sn B265AThe above sheets 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 Spec
24、imens7.1 Cut test specimens to dimensions from the test panel, asshown in Fig. 3(B). Measure the width of the specimen and 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 b
25、y bonding individualstrips as shown in Fig. 3(B). Machine unbonded individualstrips to size. They shall be free of burrs or other irregularities.8. 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
26、 grips of the testingmachine so that the long axis of the test specimen coincideswith 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
27、cryogen, extreme caution should beexercised to avoid explosive conditions. Liquid 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 dum
28、my test specimen having two thermo-couples positioned in the geometric center of 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
29、.8.6 Test the specimen as follows:8.6.1 Permit no slack in the test fixture just 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 whenus
30、ing a gaseous coolant. This is not required when utilizing aconstant boiling liquid.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 9.7MPa (1200 to 1400 psi)/min (approximately 0.05 in./mincross-head separation speed).9. Calculation9.1 Th
31、e load at fracture and the nature and amount of thisfracture (cohesion in adhesive 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.
32、1 Report the following:10.1.1 Complete identification of the adhesive tested, in-cluding type, source, manufacturers code numbers, form, etc.,NOTE 1t shall be as specified in 4.2.FIG. 3 Form and Dimension of Bonded Panel and Test SpecimensD2557 98 (2010)1310.1.2 Complete identification of the metal
33、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 used, and bondline thickness,10.1.5 Conditioning procedure used for specimens prior totesting,10.1.6 Test te
34、mperature 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 fracture, including the averageestimated percentages of fracture in the cohesion of theadhesive, contact fr
35、acture, 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 layer shall be describedincluding procedure, location of measurements, and range ofmeasurements.11. Precisio
36、n and Bias11.1 Precision and bias information does not exist for thistest method 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 t
37、est cooling medium. Precision shall bereported in terms of standard deviation of 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
38、 connection with any item mentionedin this standard. Users of this standard are expressly 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 re
39、sponsible technical committee and must be reviewed every five years andif not revised, 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 care
40、ful consideration at a meeting of theresponsible technical committee, which you may 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 Internationa
41、l, 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). Permission rights to photocopy the standard may also be secured from the ASTM website (www.astm.org/COPYRIGHT/).D2557 98 (2010)14
