1、Designation: D7093 13Standard Test Method forFormability of Thin Film Organic Coatings on Steel Over aBiaxially Stretched Dome1This standard is issued under the fixed designation D7093; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revisio
2、n, 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.1. Scope1.1 This test method covers the evaluation of the formabilityand adhesion of factory applied thin film orga
3、nic coatings onsteel with thicknesses of 2.5 to 10 microns (0.10 to 0.40 mils)typical of those used in the coil coating industry.1.2 The degree of oil removal prior to forming, the tech-niques of taping, and differences in adhesive strength of thetape can affect the adhesion rating.1.3 The values st
4、ated 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 standard to establish appro-priate safety
5、and health practices and determine the applica-bility of regulatory limitations prior to use. For a specifichazard statement, see Section 7.2. Referenced Documents2.1 ASTM Standards:2D3330/D3330M Test Method for PeelAdhesion of Pressure-Sensitive Tape2.2 Other Document:Pictorial Standards of Coating
6、 Defects33. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 dome height, nthe height of the dome formed in thetest.3.1.2 indenting ball diameter, nthe diameter of thespherical-ended penetrator (ball) used to deform the specimen.3.1.2.1 DiscussionThe 41 mm (158 in.) diameter ball
7、wasselected because it minimizes the variability in the localizedpeak strain. This size ball is commercially available and is aslarge as most testing machines can accommodate.3.1.3 percent strain, nthe percent elongation of scribedgage lengths after forming.3.1.3.1 DiscussionFor the draw height of 1
8、3 mm (0.512in.), using a 41 mm diameter ball, the localized peak strain isabout 19 % (see Fig. 1).4. Summary of Test Method4.1 A coated specimen is biaxially stretched a given dis-tance in an appropriate machine, adhesive tape is applied to thedeformed area (dome) and then pulled off, and the amount
9、 ofcoating removed is compared with a photographic standard todetermine the coating adhesion rating.5. Significance and Use5.1 The results of the combined deformation and tape testare related to the ability of the coated metal to withstandstamping in factory applications.5.2 This test can be used to
10、 control the manufacturingprocess or in development work to improve the product.5.3 It should be recognized that variability in the resultspersist due to the test conditions and forming machine varia-tions.6. Apparatus and Materials (see Fig. 2)6.1 Forming Machine, equipped with a spherical-endedpen
11、etrator to deform the specimen with appropriate dies, untilthe required height is obtained, and clamping arrangement tohold the specimen with a minimum pressure of 8.9 kN (2000lb).6.1.1 The speed of forming shall be between 4.8 and 25mm/min (0.2 and 1.0 in./min). The speed is usually slowed tomeasur
12、e more accurately the final height as shown on the dialindicator, but the final punch speed shall be controlled at 6 mm(0.24 in.) per min maximum.1This test method is under the jurisdiction of ASTM Committee D01 on Paintand Related Coatings, Materials, and Applications and is the direct responsibili
13、ty ofSubcommittee D01.53 on Coil Coated Metal.Current edition approved June 1, 2013. Published July 2013. Originally approvedin 2004. Last previous edition approved in 2004 as D7093 04 which waswithdrawn January 2013 and reinstated in June 2013. DOI: 10.1520/D7093-13.2For referenced ASTM standards,
14、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.3Copies of the pictorial photographic reference standard are contained in thepublication Pict
15、orial Standards of Coatings Defects and may be obtained from theFederation of Societies for Coatings Technology, 492 Norristown Rd., Blue Bell, PA19422. The silver halide gelatin photographs are intended to be the only primaryreference standards for this test method. The reproductions of them in thi
16、s testmethod are for the purpose of illustration only.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States16.2 Indenting Ball, with a diameter of 41 mm (158 in.), aRockwell hardness number not less than 61 on the Rockwell Cscale (HRC), and
17、 a smooth surface finish not exceeding 4 m(160 in.). The indenting ball shall not deform during the test.The ball and holder shall move through the centerline of the topand bottom dies. The ball shall be clean and free of oil, grease,oxide buildup, rust, dirt, nicks, or damage.6.3 Ball Holder, to ho
18、ld the ball in its seat during the test.Most ball holders are removable so that other ball punchdeformation tests can be done in the same machine.6.4 Upper and Lower Dies, with a hardness of 56 HRC orhigher. The upper die shall have an approach radius of 1.6 60.05 mm (0.0625 6 0.002 in.) for steel t
19、hicknesses less than1.50 mm (0.059 in.) and an approach radius of 4.8 6 0.15 mm(0.1875 6 0.006 in.) for steel thicknesses greater than 1.52 mm(0.060 in.). The diameter of the opening in the upper and lowerdie shall be 42 mm (1.64 in.). In most machines, these dies areremovable.6.5 Dial Indicator, ri
20、ding on the surface of the forming sheetto monitor the movement of the penetrator (ball) and graduatedso that the displacement, or ball height, can be measured atleast to 6 60 mm (0.0025 in.) but preferably to 6 25 mm(0.001 in.).6.6 Adhesive Tape, 25 mm (1 in.) wide, transparent, high-tack, pressure
21、-sensitive tape with an adhesive strength to steelof 50 g/mm (45 oz/in.) of width when tested in accordance withTest Method D3330/D3330M, and a tensile strength of 500g/mm (28 lb/in.) of width.6.7 Photographic Standard4Steps in rating from 10(good, no removal) to 0 (poor, complete removal) to ratevi
22、sually the adhesion of the coating after forming and taperemoval by comparison with the adhesive-backed tape.7. Hazards7.1 There are possible hazards to personnel when perform-ing tests on any hydraulic equipment. Stand free when machineis operating.8. Sampling and Test Specimens8.1 SamplingThe coat
23、ed steel coil is cut, usually at thehead or tail of the coil, into a sheet sample, which can be easilyhandled.8.2 Specimen SizeThe specimens may be square or rect-angular but not narrower than 90 mm (3.5 in.) in eitherdimension. Strips of full width of the coil can be tested ifprecautions are taken
24、not to nick or damage the adjacent domein the machine.8.3 Test specimens shall be free of oil, grease, lubricants,rust, and burrs that may affect the holding pressures or domeheight.8.3.1 Typically a light spindle oil is applied to reducecorrosion on the uncoated side of the coil.8.3.2 Remove oil, g
25、rease, and lubricants.9. Procedure9.1 Condition the specimens for at least 24 h at 23 6 2C(73.5 6 3.5F) and 50 6 5 % relative humidity beforeconducting the test, unless otherwise agreed.4The photographic reference standards that are part of this test method and areprovided in the Pictorial Standards
26、 of Coating Defects Handbook3are representativeof the adhesion ratings. The photograph shown in Fig. 3 is for illustration proposesonly and should not be used for evaluation.Draw distance = 0.512 in. (13 mm)Ball diameter = 158 in. (41 mm)FIG. 1 Survey of Strain Over Biaxially Stretched DomeKeyDimens
27、ionsInch-Pound Metric1 Test specimen 2 Spherical-ended penetra-tor (ball)158 in. 41 mm3 Ball holder 4 Clamp force (minimum) 2000 lbf 8.9 kN5 Upper die; bore diameter 1.64 in. 42 mm6 Lower die; bore diameter 1.64 in. 42 mm7 Dome height 0.512 in. 13 mm8 Upper die corner radius 0.0625 in. 1.6 mmFIG. 2
28、Tooling for Forming TestD7093 1329.2 Place the specimen in the machine so that the coating tobe tested will be on the convex side of the dome away from thepunch.9.3 With the ball touching the uncoated side of the specimenand the dial gage indicating zero penetration at the start of thetest, indent t
29、he specimen with the ball to a distance of 0. 10 mm(0.30 in.), ensuring that the hold-down pressure does notdecrease during forming of the dome and that there is noevidence of slippage of the specimen under the hold-down diesduring the test. The speed of forming the domes is done inaccordance with 6
30、.1.1.9.4 Return the ball to the original position, remove thespecimen from the machine, and lay it on a flat surface.9.5 Apply the tape over the peak of the dome, press firmly,and then pull the tape from the dome at a fast, steady rate. The25-mm (1-in.) wide tape will not fully cover the dome and wi
31、llwrinkle at the edges.9.6 Place the tape on a piece of white paper, compare theamount of coating on the tape with the photographic standard,and estimate coating adhesion to the nearest whole number. InFig. 3, areas of darkness are coating removal so that a taperating of No. 10 is perfect adhesion a
32、nd No. 0 is completeremoval of the coating. Wrinkles in the tape can be seen in thephotographic standards as light areas.9.7 Typically, a full-width specimen is cut from each coatedcoil and tested at three areas along the strip. Usually, domes aremade at both edges and the center of the coated full
33、width strip.10. Report10.1 Report the following information:10.1.1 Identification of the material such as coil number andlocation of the specimen within the coil,10.1.2 Specimen thickness,10.1.3 Number of tests or domes evaluated, and10.1.4 Adhesion rating including mean, range, or standarddeviation
34、, if applicable.11. Precision and Bias11.1 On the basis of an interlaboratory study of this testmethod, in which one operator in each of three laboratoriestested five separate panels cut from the same coated steel, thewithin-laboratory standard deviation was 0.61 units with 12 dfand the between-labo
35、ratory standard deviation was 0.35 with 2df. Based on these standard deviations, the following criteriashould be used for judging the acceptability of results at the95 % confidence level:11.1.1 RepeatabilityTwo results obtained by the sameoperator should be considered suspect if they differ by moret
36、han 2 rating numbers.11.1.2 ReproducibilityTwo results, each the mean of twodeterminations, obtained by operators in different laboratoriesshould be considered suspect if they differ by more than 2.9rating numbers.12. Keywords12.1 chromate complex; coil coating; conductive thin film;organic coatings
37、; zinc-rich primerFIG. 3 Photographic Standard Adhesion Rating on Tape After DeformationD7093 133ASTM 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 determi
38、nation 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 revised, either reapproved or wi
39、thdrawn. 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 may attend. If you feel that y
40、our 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 (si
41、ngle 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/).D7093 134
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