1、Designation: G 14 04Standard Test Method forImpact Resistance of Pipeline Coatings (Falling WeightTest)1This standard is issued under the fixed designation G 14; the number immediately following the designation indicates the year of originaladoption or, in the case of revision, the year of last revi
2、sion. A number in parentheses indicates the year of last reapproval. A superscriptepsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the determination of the energyrequired to rupture coatings applied to pipe under specifiedconditions
3、of impact from a falling weight.1.2 The values stated in SI units to three significant deci-mals are to be regarded as the standard. The values given inparentheses are for information only.1.3 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is
4、 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:2G12 Test Method for Nondestructive Measurement of FilmThickness of Pipeline Coating
5、s on SteelG62 Test Methods for Holiday Detection in Pipeline Coat-ings2.2 SAE Standard:Grade 52100 Steel33. Summary of Test Method3.1 This test method uses a falling fixed weight having aspecified diameter impact surface, tup, which is restrainedvertically and dropped from varying heights to produce
6、 impactenergies over the required range. Electrical inspection is usedto detect resultant breaks in the coating. Impact resistance isdetermined as the amount of energy required to cause penetra-tion of the coating film.4. Significance and Use4.1 The ability of a pipe coating to resist mechanicaldama
7、ge during shipping, handling, and installation will dependupon its impact resistance. This test method provides asystematic means for screening coating materials with regardto this property.5. Apparatus5.1 This test method can be successfully used with impactapparatus conforming to the following spe
8、cifications:5.1.1 TupThe tup shall be made up from a tup body anda tup nose having a combined, fixed weight of 1.361 kg (3.00lb) and shall be used over a drop range of 0.61 to 1.22 m (2 to4 ft). With most coatings, a 1.361-kg (3.00-lb) tup droppedthrough a distance of 914 mm (3 ft) yields suitable r
9、esults. Thetup nose shall have a 15.875-mm (58-in.) hemispherical head.NOTE 1Frequent replacement of the tup nose can be avoided if it iscut from steel capable of being hardened to a hardness of Rockwell C/45while retaining an impact toughness of at least 15 ftlb (20.34 J). Ballbearings conforming t
10、o SAE Grade 52100 have also been found suitablefor this purpose.5.1.2 Drop TubeA tube 1.52 m (5 ft) long shall be used tocontain the tup and guide it during free fall. The drop tube shallbe constructed of steel, aluminum, or any other suitably rigidmaterial and internally sized to provide a minimum
11、of frictionto the falling tup. A scale shall be attached for measuring theheight of drop to the nearest 2.54 mm (0.10 in.).5.1.3 Specimen HolderThe base plate of the apparatusshall include a device for positioning and holding the pipespecimen on line with the axis of the vertical drop tube.NOTE 2An
12、arrangement using a V-notch vise made of metal withspring clamp is recommended for this purpose. Glancing blows, caused byan out-of-plumb condition between drop tube and pipe sample, will causeerratic test results.5.1.4 Apparatus SupportBoth the apparatus and sampleshall be firmly supported and secu
13、red to a rigid base tooptimize energy transfer from the tup to the specimen.5.2 A design for the test apparatus appears in Figs. X1.1-X1.3 of Appendix X1.1This test method is under the jurisdiction of ASTM Committee D01 on Paintand Related Coatings, Materials, and Applications and is the direct resp
14、onsibility ofSubcommittee D01.48 on Durability of Pipeline Coating and Linings.Current edition approved Nov. 1, 2004. Published November 2004. Originallyapproved in 1969. Last previous edition approved in 1996 as G 14 88 (1996)e1.2For referenced ASTM standards, visit the ASTM website, www.astm.org,
15、orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.3Available from Society of Automotive Engineers (SAE), 400 CommonwealthDr., Warrendale, PA 15096-0001.1Copyright ASTM International
16、, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.5.3 Thickness GageMeasurements of coating thicknesswill be required for this test, and shall be done in accordancewith Test Method G12.5.4 Holiday DetectorA suitable detector as specified inTest Methods G62shall be
17、 used to locate breaks in the coatingfilm.6. Test Specimen6.1 The test specimen shall be a 406.4 mm (16 in.) longpiece of Schedule 40, 60.325 mm (2.375 in.) outside diametercoated pipe prepared with its surface preparation and coatingprocedures equivalent to that of production coated pipe.6.2 Seven
18、specimens shall be required for the test.7. Conditioning7.1 The specimen shall be exposed to a room temperature of21 to 25C (70 to 77F) for a period of 24 h before beginningthe test.8. Preliminary Measurements8.1 Measure the applied coating thickness of each specimenin accordance with Test Method G1
19、2.8.2 Place test specimen in sample holder and lightly placetup on surface of the coating. Adjust either the drop tube or theattached scale so that the wing bolt (lifting pin) is at the zeromark of the scale.8.3 Make a preliminary set of impact readings to determinethe approximate starting point for
20、 the test. This shall be doneby striking the first specimen from a height sufficient to causefailure of the coating film. Consider any penetration a failure ifit is detectable with a suitable Holiday Detector as specified inTest Methods G62.8.3.1 Reduce the height by 50 % and make a secondexplorator
21、y drop at a fresh area on the pipe surface. Continuetesting in this manner, with the corresponding reduction inheight between drops, until the coating fails to break.NOTE 3Choose test locations at the specimen surface in a randommanner and keep at least a 76.2 mm (3 in.) distance between adjacentpoi
22、nts of impact and within 38 mm (112 in.) from the ends. Choosing testpoints in any regular pattern will bias the experiment and introduce errorinto the test results.8.3.2 Repeat the test at the height immediately precedingthe occurrence of the nonfailure to determine if an approximatelevel for the m
23、ean impact strength has been bracketed. Twosuccessive reversals of coating performance between failureand nonfailure will give sufficient indication that the point hasbeen reached.9. Procedure9.1 Perform the test at a room temperature of 21 to 25C (70to 77F).9.2 Begin testing from the approximate he
24、ight determinedin 8.2 and corresponding to the point at which the firstnonfailure was registered. Maintain a fixed increment betweenadjacent testing heights.9.3 Use a suitable detector, as specified in Test Method G 6,to determine penetration or lack thereof of the coating aftereach individual impac
25、t.9.4 If the coating film is penetrated on the initial drop, makethe next test at the next lower height increment. If the firstspecimen does not fail, make the second test at the next higherincrement.9.5 In a similar manner, determine the height of fall by theperformance of the coating on each prece
26、ding drop. Maintain aconstant height increment between readings. Continue to applythis “up-and-down” method4until 20 successive impact read-ings have been made.10. Calculation10.1 Calculate the mean value of impact strength, m,ing/cm (or in./lb) as follows:m 5Fh01 dSAN612DG3 W (1)where:h0= minimum h
27、eight at which the less frequent eventoccurs, cm (or in.),d = increment in height of drop, cm (or in.),A = sum of the frequency of occurrence at each heightincrement times the number of increments above theh0value for each observation in the N total,N = total number of the less frequent event (coati
28、ngfailures or nonfailures), andW = tup weight, g (or lb).NOTE 4The minus sign is used when the calculation of the mean isbased on the total number of coating failures and the plus sign when it isbased on the nonfailures.10.2 Calculate the sample standard deviation, s, in gram-centimetres (or inch-po
29、unds) as follows:S 5 1.620 dWSNB 2 A2!N21 CD(2)where:C = 0.737 when d is in cm, or 0.029 when d is in in., d, N,A, and W are as defined in 10.1, andB = sum of the frequency of occurrence at each heightincrement times the square of the number of incre-ments above the h0value for each observation in t
30、he Ntotal.NOTE 5Adequate definition of coating impact strength will resultonly if the height increment, d, has been properly chosen. When testingpolymeric films in the range from 0.254 to 1.016 mm (0.010 to 0.040 in.),height increments of from 5.1 to 12.7 mm (0.2 to 0.5 in.) have been foundsuitable
31、with the 1.361 kg (3.0 lb) tup. Larger increments may benecessary for thicker materials. If after making the calculations of 10.1and 10.2, the ratio of the height increment to the standard deviation (d/s)is less than 0.20, the test should be repeated using a larger value for theincrement d. This pro
32、cedure will result in an improved estimate of thecoating impact strength.10.3 An illustration of the use of these equations appears inAppendix X2.4This system of testing, nomenclature, and calculation is described by Dixon, W.J. and Mood, A. M., “A Method for Obtaining and Analyzing Sensitivity Data
33、,”Journal Am. Statistical Assn., JSTNA, Vol 43, March, 1948, p. 109.G1404211. Report11.1 The report shall include the following:11.1.1 Complete identification of the specimen including:11.1.1.1 Name and code number of the coating,11.1.1.2 Size of pipe,11.1.1.3 Source, production date, and production
34、-run num-ber,11.1.1.4 Minimum, maximum, and average coating thick-ness,11.1.1.5 Date of test, and11.1.1.6 Other information that may be pertinent,11.1.2 Average impact strength in g/cm (or in./lb),11.1.3 Sample standard deviation in g/cm (or in./lb).12. Precision and Bias12.1 The reproducibility of
35、the impact resistance deter-mined by this method should not differ between one laboratoryand another by more than 6 15 %. When the same instrumentis used by the same operator, repeatability on the same sampleshould not differ more than 6 15 %. Bias cannot be determinedsince there is no acceptable st
36、andard material available for thistest.13. Keywords13.1 falling weight test; impact resistance; pipeline coatingsAPPENDIXES(Nonmandatory Information)X1. SUGGESTED DESIGN FOR TEST APPARATUSX1.1 A design for the impact test apparatus is shown inFigs. X1.1-X1.3.G14043FIG. X1.1 Test Apparatus AssemblyG1
37、4044FIG. X1.2 Detailed Design of Test ApparatusFIG. X1.3 Detailed Design of Test ApparatusG14045X2. SAMPLE CALCULATIONSX2.1 Test results for 20 drops with a 1.361 kg (3 lb) tup aregiven in Table X2.1.ASTM International takes no position respecting the validity of any patent rights asserted in connec
38、tion 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 responsib
39、le 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 careful con
40、sideration 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 International, 100
41、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 web
42、site(www.astm.org).TABLE X2.1 Test ResultsTestNo.Heightof Drop,in.FailedTestNo.Heightof Drop,in.Failed1 14.1 yes 11 13.5 no2 13.8 no 12 13.8 no3 14.1 no 13 14.1 yes4 14.4 yes 14 13.8 yes5 14.1 yes 15 13.5 no6 13.8 no 16 13.8 yes7 14.1 no 17 13.5 yes8 14.4 yes 18 13.2 no9 14.1 yes 19 13.5 no10 13.8 y
43、es 20 13.8 yesHeight increment = 0.3 in.Failures = 11Nonfailures = 9Nonfailures at 13.2 in. (h0) = 1; at 13.5 in. = 3; at 13.8 in. = 3; at 14.1 in. = 2A =(03 1) + (1 3 3) + (2 3 3) + (3 3 2) = 15B = (0)23 1) + (1)23 3) + (2)23 3) + (3)23 2) = 33m 5F13.2 1 0.3S159112DG3.0 5 41.55 in. lbmean impact resistance = 41.55 in.lbS 5 1.620 3 0.29 3 3.0S9 3 33 2 15!29!2 D5 1.338 in.lbs.Sample standard deviation = 1.383 in.lbG14046
