ASTM D3170 D3170M-2014 Standard Test Method for Chipping Resistance of Coatings《覆层耐切割性的标准试验方法》.pdf

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1、Designation: D3170/D3170M 14Standard Test Method forChipping Resistance of Coatings1This standard is issued under the fixed designation D3170/D3170M; the number immediately following the designation indicates theyear of original adoption or, in the case of revision, the year of last revision. A numb

2、er in parentheses indicates the year of lastreapproval. A superscript epsilon () indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the U.S. Department of Defense.1. Scope1.1 This test method covers the determination of the resi

3、s-tance of coatings to chipping damage by stones or other flyingobjects.NOTE 1This test method is similar to SAE J-400.1.2 All dimensions are nominal unless otherwise specified.1.3 The values stated in either SI units or inch-pound unitsare to be regarded separately as standard. The values stated in

4、each system may not be exact equivalents; therefore, eachsystem shall be used independently of the other. Combiningvalues from the two systems may result in non-conformancewith the standard.1.4 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It i

5、s 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 ASTM Standards:2D609 Practice for Preparation of Cold-Rolled Steel Panelsfor Testing Paint, Varnis

6、h, Conversion Coatings, andRelated Coating ProductsD823 Practices for Producing Films of Uniform Thicknessof Paint, Varnish, and Related Products on Test PanelsD1005 Test Method for Measurement of Dry-Film Thick-ness of Organic Coatings Using MicrometersD1186 Test Methods for Nondestructive Measurem

7、ent ofDry Film Thickness of Nonmagnetic Coatings Applied toa Ferrous Base (Withdrawn 2006)3D1400 Test Method for Nondestructive Measurement of DryFilm Thickness of Nonconductive Coatings Applied to aNonferrous Metal Base (Withdrawn 2006)3D1733 Method for Preparation of Aluminum Alloy Panelsfor Testi

8、ng Paint, Varnish, Lacquer, and Related Products(Withdrawn 1979)3D2201 Practice for Preparation of Zinc-Coated and Zinc-Alloy-Coated Steel Panels for Testing Paint and RelatedCoating Products2.2 Other Documents:Test for Chip Resistance of Surface Coatings (J-400)43. Summary of Test Method3.1 Standar

9、dized road gravel is projected by means of acontrolled air blast at the coated specimens. All testing isconducted under controlled temperature conditions, generallyeither at ambient (room) temperature or at -29 6 3C -20 65F. After the gravel impact, tape is applied to remove anyloose coating chips a

10、nd the degree of chipping is determined.4. Significance and Use4.1 Owners consider chipping of coatings, particularly onthe leading faces and edges of automobile surfaces, unaccept-able. In formulating a coating or coating system to meet servicerequirements, the resistance to chipping damage by flyi

11、ngobjects such as gravel is one of the properties of importancesince it can vary considerably as other properties are adjusted.Since resistance to chipping decreases at lower temperaturespartly as the result of decreased flexibility, the test may bemore directly related to service conditions by perf

12、orming it at1This test method is under the jurisdiction of ASTM Committee D01 on Paintand Related Coatings, Materials, and Applications and is the direct responsibility ofSubcommittee D01.55 on Factory Applied Coatings on Preformed Products.Current edition approved June 15, 2014. Published July 2014

13、. Originallyapproved in 1973. Last previous edition approved in 2012 as D3170 12. DOI:10.1520/D3170_D3170M-14.2For 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 st

14、andards Document Summary page onthe ASTM website.3The last approved version of this historical standard is referenced onwww.astm.org.4Available from Society of Automotive Engineers (SAE), 400 CommonwealthDr., Warrendale, PA 15096-0001, http:/www.sae.org.Copyright ASTM International, 100 Barr Harbor

15、Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1a low temperature. This test method is designed to produce acontrolled amount of impact by the media on the coated panelin order to enhance reproducibility.5. Apparatus5.1 Gravel-Projecting Machine (Gravelometer), con-structed accor

16、ding to the design specifications shown in Fig.1.5,6There are two types of Gravelometers: the old cabinetstyle and the newer, modular style with an electronic feedmechanism.NOTE 2It is recommended that the operation/maintenance checklistshown in Appendix X1 should be completed at least once per mont

17、h forgravelometers that are operated on a weekly basis, and once every 6months for gravelometers that are operated less frequently. Note thatvalues in the checklist are specific to the standard gravel testing protocol.Different specifications may be necessary for other media types.5.2 GravelWater-er

18、oded alluvial road gravel7,6passingthrough a 16-mm 58-in. space screen but retained on a9.5-mm 38-in. space screen. Note that mesh screen is not asubstitute for a space screen. It is important to remove thesmall pieces of gravel before reusing the gravel. Other mediamay be used as agreed by contract

19、ual parties.5.3 Tape, 51 to 102 mm 2.0 to 4.0 in. wide.8,6Other tapemay be used as agreed upon by the contractual parties.5.4 Temperature-Conditioning Equipment (alternatives):5.4.1 A cold room or freezer of sufficient size in which thegravel-projecting machine and test specimens can be main-tained

20、at the specified temperature of testing.5.4.2 A freezer or cooler in which the test panels can becooled 5C 10F below the specified test temperature.5The sole source of a suitable apparatus meeting these specifications known tothe committee at this time is Q-Panel Co., 26200 First St., Westlake, OH 4

21、4135.6If you are aware of alternative suppliers, please provide this information toASTM International Headquarters. Your comments will receive careful consider-ation at a meeting of the responsible technical committee,1which you may attend.7The sole source of supply of gravel meeting these specifica

22、tions known to thecommittee at this time is Q-Panel Co., 26200 First St., Westlake, OH 44135.8The sole source of supply of No. 898 filament strapping tape known to thecommittee at this time is the 3M Co., St. Paul MN 55101.FIG. 1 Gravel Projecting MachineD3170/D3170M 1425.4.3 AmbientRoom maintained

23、at a temperature between20C 68F and 30C 86F.5.5 Transparent GridA chip counting aid constructed oftransparent plastic approximately 3.2 mm thick by 127 mmsquare 18 by 5 by 5 in., on which a 102 by 102 mm 4 by 4in. grid of 25.4 mm 1 in. squares has been etched or scribed.5.6 Chipping Rating Standards

24、A photographictransparency9,6depicting size and number of chips in eachcategory. See Fig. 2 for an example of the transparencies.These standards depict various degrees of chipping severityand are arranged sequentially from best to worst according tochipping frequency.6. Test Specimens6.1 The composi

25、tion, surface preparation, and size of speci-mens shall be agreed upon between the purchaser and theseller. Test panels of 102 by 305 mm 4 by 12 in. arecommonly used.NOTE 3It is recommended that three replicates of each test specimenbe exposed in the gravelometer. More replicates will improve theacc

26、uracy.6.2 The number, type, method of application, and aging ofcoatings shall be agreed upon between the purchaser and theseller.9The sole source of supply of Chipping Rating Standards, Part #AE-400, knownto the committee at this time is the Society of Automotive Engineers, 400Commonwealth Dr., Warr

27、endale, PA 15096.NOTE 1Reprinted with permission from SAE EA-400 (c) 1985, Society of Automotive Engineers, Inc.FIG. 2 Representation of Chipping RatingsD3170/D3170M 143NOTE 4Application, metal preparation, and film thickness measure-ment methods are given in the following ASTM Practices: D609, D823

28、and D2201, and Test Methods D1005, D1186, D1400, and D1733.7. Procedure7.1 Condition the specimens for a minimum of1hatthespecified test temperature in the equipment specified in 5.4.Make certain the test specimens are separated and have freeaccess to the conditioning environment so that optimum hea

29、ttransfer occurs.7.2 Adjust the air pressure on the gravel apparatus to 480 620 kPa 70 6 3 psi with the air valve open.NOTE 5For cabinet type gravelometers, keep the lid to the gravelchamber closed during this operation as a safety precaution. Other airpressures can be used as agreed upon by the con

30、tractual parties.7.3 Cabinet Style Gravelometer:7.3.1 After adjusting the air pressure, shut off the air valve,open the lid to the gravel chamber and collect 473 mL(1.00 USLiquid Pint) of graded gravel (approximately 250 to 300stones) in a suitable container. Collect the gravel by scrapingacross the

31、 screen to allow fines to fall through.7.3.2 Place one test specimen at the desired test temperaturein the panel holder with the coated side facing the front of theapparatus and close the lid to the panel chamber.7.3.3 Open the gravel feed door and pour gravel from theone pint container obtained fro

32、m 7.3.1 into the top of the gravelhopper. Do not allow gravel to fall into the nozzle entrance.7.3.4 Open the air valve to allow the air to project the gravelat the specimen.NOTE 6The gravel hopper must empty in 7 to 10 s. If gravel remainsin the hopper after 10 s, stop the test and investigate the

33、cause. Theoperator should not touch the gravel during the test or otherwisephysically help the gravel into the funnel.NOTE 7It is important to know that the vibrator may become frozenwhen the chamber is installed in a cold room or freezer. If the vibrator isfrozen, discontinue the test until the vib

34、rator has thawed and is operatingcorrectly.7.3.5 Shut the air valve, open the lid to the specimenchamber and remove the specimen.7.4 Modular Style Gravelometer:7.4.1 After adjusting the air pressure, shut off the air valve,open the lid to the gravel hopper and pour 473 mL (1.00 USLiquid Pint) of gra

35、ded gravel (approximately 250 to 300stones) into the top of the gravel hopper.7.4.2 Pull back on the specimen mounting clamp to open thespecimen holder on the holder assembly. Place one testspecimen at the desired test temperature in the panel holderwith the coated side facing the front of the appar

36、atus. Clamp toclose the specimen holder.7.4.3 Set the test timer.NOTE 8There are two ways to operate a test on the Modular stylegravelometer. A timed test is a test that shuts off the machine after a presetamount of time has passed. A manual test requires the operator to shut offthe machine after th

37、e desired amount of time has passed.7.4.3.1 Timed Test:(1) Make sure that the control switch is set to stop.(2) Set the test timer to the desired test time. A typical testtime is 10 s.(3) Turn the main power switch on.(4) Turn the control switch to Timed Start.7.4.3.2 Manual Test:(1) Make sure that

38、the control switch is set to stop.(2) Turn the main power switch on.(3) Turn the control switch to Manual.(4) After the desired amount of time has passed turn thecontrol switch to Off.NOTE 9Manual mode requires the operator to manually stop the test.Once started, the test will not stop by itself.7.4

39、.4 When the test has been completed, remove the testpanel from the specimen holder by pulling back on theSpecimen Mounting Clamp and removing the test specimen.7.4.5 Remove the gravel from the return receptacle andscreen before reuse.7.5 Allow the test specimens to return to room temperatureand dry

40、with a soft cloth to remove any condensation.7.6 Use the tape referenced in 5.3 to remove all loose ordamaged paint.7.6.1 Cover the entire test area of the specimen with astrip(s) of tape.(1) For 51 to 56 mm 2.0 to 2.2 in. wide tape, apply thestrips side by side over the evaluation area.(2) For 56 t

41、o 102 mm 2.2 to 4.0 in. wide tape, strip(s)may be applied consecutively with the first strip covering onlypart of the test area. The second strip, if needed, is applied afterremoval of the first strip and covers the remaining test area aswell as overlapping part of the test area covered by the first

42、strip.7.6.2 Apply uniform pressure to ensure that the tape(s) isfirmly adhered to the specimen. There should not be any airbubbles trapped beneath the tape.NOTE 10Uniform pressure can be applied by using a pencil eraser ortongue depressor. Methods such as plastic squeegee and rubber roller mayalso b

43、e acceptable for applying uniform pressure, but should be agreedupon by contractual parties before use.7.6.3 Remove the tape(s) by pulling straight up.7.6.4 Apply new strips of tape as specified in 7.6.1 and7.6.2, but in the opposite direction.7.6.5 Remove the tape by pulling straight up in the oppo

44、sitedirection to 7.6.3.7.6.6 Continue this procedure using new strips of tape untilall loose or damaged paint is removed.NOTE 11Other tapes or loose paint removal methods may be used asagreed upon by contractual parties.8. Chip Rating Systems8.1 There are two generally accepted methods for determin-

45、ing the degree of chipping on the test panel. In the first method,the exact number of chips in each size range is tabulated for thetest area. The second method utilizes a visual comparison ofthe test panel to the Chipping Rating Standards.9An exampleof the chipping standards is shown in Fig. 2.NOTE

46、12The first method, while the most time consuming, is the mostprecise and should be used where definitive accuracy is required or as thereferee method in case differences arise between laboratories. The secondmethod, while more of an approximation than the first method, can beD3170/D3170M 144used fo

47、r many routine laboratory evaluations where the accuracy of thefirst method is not required. The second method also lends itself to fieldsurvey work where the chipped areas can be rated by direct comparisonwith the Chipping Rating Standards.NOTE 13Other rating methods may be employed as agreed upon

48、bycontractual parties. The evaluation may also be carried out using digitaloptical imaging which offers further possibilities of evaluation andreproducibility. A guide for use of digital optical imaging is beingprepared by ASTM Subcommittee D01.25.8.2 The chipped area to be evaluated on the test spe

49、cimenshould be the 102 by 102 mm 4 by 4 in. square that is thecenter of the chipped area.8.3 The chip rating system consists of one or more number-letter combinations in which the numbers indicate the numberof chips and the letters designate the size of the correspondingchips. A point of failure notation may also be included in therating if a more descriptive statement is desired.8.3.1 Number of ChipsA number, as shown in Table 1,from 100 that is used to indicate the number size in the 102by 102 mm 4 by 4 in. test a