1、Designation: D 6905 03Standard Test Method forImpact Flexibility of Organic Coatings1This standard is issued under the fixed designation D 6905; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last revision. A number in
2、 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 a procedure for determining theability of a coating film and its substrate to resist shattering,cracking, or chipping w
3、hen the film and substrate are distendedbeyond their original form by impact.1.2 This test method does not measure impact resistance butuses rapid impact to improve Test Methods D 522, another testmethod for flexibility. Since the impact of the coating is almostinstantaneous, all of the problems ass
4、ociated with time vari-ables in the mandrel tests are eliminated.1.3 This test method is similar in content but not technicallyequivalent to Test Method D 2794.1.4 The values stated in SI units are to be regarded as thestandard. The values given in parentheses are for informationonly.1.5 This standa
5、rd 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 and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 AST
6、M Standards:D 522 Test Methods for Mandrel Bend Test of AttachedOrganic Coatings2D 609 Practice for Preparation of Cold-Rolled Steel Panelsfor Testing Paint, Varnish, Conversion Coatings, Lacquer,and Related Coating Products2D 823 Practices for Producing Films of Uniform Thicknessof Paint, Varnish,
7、and Related Products on Test Panels2D 1186 Test Methods for Nondestructive Measurement ofDry Film Thickness of Nonmagnetic Coatings Applied toa Ferrous Base2D 1400 Test Method for Nondestructive Measurement ofDry Film Thickness of Nonconductive Coatings Applied toa Nonferrous Metal Base2D 2240 Test
8、Method for Rubber PropertyDurometerHardness3D 2794 Test Method for Resistance of Organic Coatings tothe Effects of Rapid Deformation (Impact)23. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 impact flexibilityof a coating, the percent areaincrease required to produce cracking i
9、n the deformed coating.4. Summary of Test Method4.1 The organic coating under test is applied to suitable thinmetal panels. After the coating has cured, a standard weight/indenter is dropped from a measured distance so as to strike thesubstrate which deforms the coating and the substrate. Thepercent
10、 elongation is the highest area of distensibility in whichthere is no film breaks that the film can stand.5. Significance and Use5.1 Coatings attached to substrates are subjected to damag-ing impacts during the manufacture of articles and their use inservice. This impact resistance test method has b
11、een found tobe useful in predicting the performance of organic coatings fortheir ability to resist cracking caused by impacts.6. Apparatus6.1 Impact Flexibility Tester4, assembly illustrated in Figs.1 and 2. The instrument contains a 1.63 kg (3.6 lb) weight/indenter, a rubber pad and an aluminum pad
12、, Fig. 3. The roundrod weight/indenters two spherical ends (Marked “A” and“B”) are shown in Figs. 4 and 5. The dimensions for theSpherical weight/indenter are shown in Table 1. The rod slidesin a vertical, slotted guide and serves as a falling weight toimpact a test panel with the “embossed” end. Wh
13、en positioned1This test method is under the jurisdiction of ASTM Committee D01 on Paintand Related Coatings, Materials, and Applications and is the direct responsibility ofSubcommittee D01.23 on Physical Properties of Applied Paint Films.Current edition approved May 10, 2003. Published July 2003.2An
14、nual Book of ASTM Standards, Vol 06.01.3Annual Book of ASTM Standards, Vol 09.01.4The sole source of supply of the apparatus known to the committee at this timeis the IM-172-GE Impact Tester, available from the Paul N. Gardner Company, Inc.,316 N.E. First Street, Pompano Beach, FL 33060. If you are
15、aware of alternativesuppliers, please provide this information to ASTM International Headquarters.Your comments will receive careful consideration at a meeting of the responsibletechnical committee1, which you may attend.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshoh
16、ocken, PA 19428-2959, United States.properly, the lifting knob on the weight/indenter coincides withthe bottom of the guide tube.7. Test Specimens7.1 Apply uniform coatings of the material to be tested tometal panels treated as specified. Prepare a minimum of fourcoated panels for the material.NOTE
17、1The coatings should be applied in accordance with PracticesD 823, or as agreed upon between the producer and the user.7.2 Cure the coated panels under conditions of humidity andtemperature agreed upon between the producer and the user.NOTE 2The thickness of the dry coatings should be measured inacc
18、ordance with Test Methods D 1186, Test Method D 1400 or any othertest method as agreed upon between the producer and the user.8. Conditioning8.1 Unless otherwise agreed upon between the producer andthe user, condition the coated test panels for at least 24 h at 236 2C (73.5 6 3.5F) and 50 6 5 % rela
19、tive humidity.Conduct the test in the same environment or immediately onremoval therefrom.9. Procedure9.1 Install the weight/indenter having the specific heads intothe slotted guide tube. Install the aluminum plate with the toprubber anvil head in place on the base. This rubber anvil has aShore A ha
20、rdness of 60 6 5. Determine hardness in accordwith Test Method D 2240. Replace rubber anvil if outsidehardness specifications or if worn or damaged.9.2 With an uncoated panel in place on the rubber anvil,determine the height of drop for each end of the weight/indenter to show on the panel slight eve
21、nly spaced segmentmarks of the weight/indenter circumference. The heights sodetermined will always be used.9.3 Place the coated panel to be tested face down against therubber anvil and drop the weight/indenter from the determinedheight onto the panel so that the impression of the entire rim ofthe we
22、ight/indenter is made on the panel surface.9.4 Remove the panel from the tester after the first bounce.9.5 Replace the coated panel to be tested face down againstthe rubber anvil, reverse the weight/indenter and drop theweight/indenter from the above determined height.9.6 Remove the panel from the t
23、ester after the first impact.9.7 Using the naked eye or magnification, as agreed uponbetween the producer and the user, visually inspect the impactcoating area to detect fine surface cracking and record themaximum percent elongation, that is, the area increase accom-modated by the coating without cr
24、acking or other failure, usingvalues in Table 1.10. Report10.1 Report the following for each coating tested:10.1.1 The maximum percent elongation or flexibilitywhich the film will stand,10.1.2 Height the weight/indenter was raised from the panelsurface,10.1.3 Thickness of coating,10.1.4 Substrate th
25、ickness and type of metal,10.1.5 Method of panel preparation, and10.1.6 Atmospheric conditions under which the coated pan-els were conditioned and tested.11. Precision and Bias11.1 PrecisionThe precision of the procedure in TestMethod D 6905 for measuring flexibility is being determined.FIG. 1 Full
26、View Impact Flexibility TesterFIG. 2 Base View Impact Flexibility TesterD690503211.2 BiasSince there is no accepted reference materialsuitable for determining the bias for the procedure in this testmethod, bias cannot be determined.12. Keywords12.1 cracking failure; extrusion indentation; impact fai
27、lure;intrusion indentationASTM 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 expressly advised that determination of the validity of any such patent rights, and the riskof infrin
28、gement 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 revised, either reapproved or withdrawn. Your comments are invited either for revision of this standard
29、 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 may attend. If you feel that your comments have not received a fair hearing you shouldmake your views
30、 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
31、 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).FIG. 3 Intregal Indenter, Rubber Pad, Aluminum BaseFIG. 4 Indenter End “A”FIG. 5 Indenter EndTABLE 1 Table of Percent Area IncreaseSphericalSegmentEndBaseD
32、iameter,mm (in.)SegmentRadius,mm (in.)SegmentElevation,mm (in.)%AreaIncrease1 A 9.5 (0.375) 4.85 (0.194) 3.65 (0.146) 602 A 9.5 (0.375) 5.20 (0.208) 2.98 (0.119) 403 A 9.5 (0.375) 6.30 (0.252) 2.10 (0.084) 204 A 9.5 (0.375) 8.15 (0.326) 1.48 (0.059) 105 B 9.5 (0.375) 11.0 (0.440) 1.05 (0.042) 56 B 9.5 (0.375) 16.9 (0.676) 0.68 (0.027) 27 B 9.5 (0.375) 23.7 (0.947) 0.48 (0.019) 18 B 9.5 (0.375) 33.3 (1.332) 0.32 (0.013) 0.5D6905033
