1、Designation: G14 04 (Reapproved 2010)1Standard Test Method forImpact Resistance of Pipeline Coatings (Falling WeightTest)1This standard is issued under the fixed designation G14; the number immediately following the designation indicates the year of originaladoption or, in the case of revision, the
2、year of last revision. A number in parentheses indicates the year of last reapproval. A superscriptepsilon () indicates an editorial change since the last revision or reapproval.1NOTEEquation in Table X2.1 was corrected editorially in November 2012.1. Scope1.1 This test method covers the determinati
3、on of the energyrequired to rupture coatings applied to pipe under specifiedconditions 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 n
4、ot 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 ASTM Standar
5、ds:2G12 Test Method for Nondestructive Measurement of FilmThickness of Pipeline Coatings 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
6、surface, tup, which is restrainedvertically and dropped from varying heights to produce 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
7、 film.4. Significance and Use4.1 The ability of a pipe coating to resist mechanicaldamage 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 te
8、st method can be successfully used with impactapparatus conforming to the following specifications:5.1.1 TupThe tup shall be made up from a tup body and atup nose having a combined, fixed weight of 1.361 kg (3.00 lb)and shall be used over a drop range of 0.61 to 1.22 m (2 to 4ft). With most coatings
9、, a 1.361-kg (3.00-lb) tup droppedthrough a distance of 914 mm (3 ft) yields suitable results. 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
10、 retaining an impact toughness of at least 15 ftlb (20.34 J). Ballbearings conforming to 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, a
11、luminum, or any other suitably rigidmaterial and internally sized to provide a minimum 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
12、 and holding the pipespecimen on line with the axis of the vertical drop tube.NOTE 2An 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
13、.5.1.4 Apparatus SupportBoth the apparatus and sampleshall be firmly supported and secured to a rigid base tooptimize energy transfer from the tup to the specimen.1This test method is under the jurisdiction of ASTM Committee D01 on Paintand Related Coatings, Materials, and Applications and is the di
14、rect responsibility ofSubcommittee D01.48 on Durability of Pipeline Coating and Linings.Current edition approved Dec. 1, 2010. Published December 2010. Originallyapproved in 1969. Last previous edition approved in 2004 as G14 04. DOI:10.1520/G0014-04R10E01.2For referenced ASTM standards, visit the A
15、STM 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.3Available from SAE International (SAE), 400 Commonwealth Dr., Warrendale,PA 15096-0001, http:/www.sae.o
16、rg.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States15.2 A design for the test apparatus appears in Figs. X1.1-X1.3 of Appendix X1.5.3 Thickness GageMeasurements of coating thicknesswill be required for this test, and shall be done in a
17、ccordancewith Test Method G12.5.4 Holiday DetectorA suitable detector as specified inTest Methods G62 shall be 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 prepa
18、red with its surface preparation and coatingprocedures equivalent to that of production coated pipe.6.2 Seven 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. Preli
19、minary Measurements8.1 Measure the applied coating thickness of each specimenin accordance with Test Method G12.8.2 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 zero
20、mark of the scale.8.3 Make a preliminary set of impact readings to determinethe approximate starting point for 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 suitabl
21、e Holiday Detector as specified inTest Methods G62.8.3.1 Reduce the height by 50 % and make a secondexploratory 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 locati
22、ons at the specimen surface in a randommanner and keep at least a 76.2 mm (3 in.) distance between adjacentpoints 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
23、the height immediately precedingthe occurrence of the nonfailure to determine if an approximatelevel for the mean impact strength has been bracketed. Twosuccessive reversals of coating performance between failureand nonfailure will give sufficient indication that the point hasbeen reached.9. Procedu
24、re9.1 Perform the test at a room temperature of 21 to 25C (70to 77F).9.2 Begin testing from the approximate height 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 s
25、pecified in Test Method G62,to determine penetration or lack thereof of the coating aftereach individual impact.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 higher
26、increment.9.5 In a similar manner, determine the height of fall by theperformance of the coating on each preceding 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
27、the mean value of impact strength, m,ing/cm (or in./lb) as follows:m 5Fh01dSAN612DG3W (1)where:h0= minimum height 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 increm
28、ents above the h0value for each observation in the N total,N = total number of the less frequent event (coating failuresor 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 i
29、t isbased on the nonfailures.10.2 Calculate the sample standard deviation, s, in gram-centimetres (or inch-pounds) as follows:S 5 1.620 dWSNB 2 A2!N21CD(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 ea
30、ch heightincrement times the square of the number of incrementsabove the h0value for each observation in the N total.NOTE 5Adequate definition of coating impact strength will result onlyif the height increment, d, has been properly chosen. When testingpolymeric films in the range from 0.254 to 1.016
31、 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 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 devi
32、ation (d/s)is less than 0.20, the test should be repeated using a larger value for theincrement d. This procedure 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 calc
33、ulation is described by Dixon, W.J. and Mood, A. M., “A Method for Obtaining and Analyzing Sensitivity Data,”Journal Am. Statistical Assn., JSTNA, Vol 43, March, 1948, p. 109.G14 04 (2010)1211. Report11.1 The report shall include the following:11.1.1 Complete identification of the specimen including
34、: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-runnumber,11.1.1.4 Minimum, maximum, and average coatingthickness,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
35、 in./lb),11.1.3 Sample standard deviation in g/cm (or in./lb).12. Precision and Bias12.1 The reproducibility of 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, repeatabilit
36、y on the same sampleshould not differ more than 6 15 %. Bias cannot be determinedsince there is no acceptable standard material available for thistest.13. Keywords13.1 falling weight test; impact resistance; pipeline coatingsAPPENDIXES(Nonmandatory Information)X1. SUGGESTED DESIGN FOR TEST APPARATUS
37、X1.1 A design for the impact test apparatus is shown inFigs. X1.1-X1.3.G14 04 (2010)13FIG. X1.1 Test Apparatus AssemblyG14 04 (2010)14FIG. X1.2 Detailed Design of Test ApparatusFIG. X1.3 Detailed Design of Test ApparatusG14 04 (2010)15X2. SAMPLE CALCULATIONSX2.1 Test results for 20 drops with a 1.36
38、1 kg (3 lb) tup aregiven in Table X2.1.ASTM 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
39、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 withdrawn. Your comments are invited either for revision of
40、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 your comments have not received a fair hearing you shouldma
41、ke 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 (single or multiple copies) of this standard may be obtained
42、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/).TABLE X2.1 Test ResultsTestNo
43、.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 yes 20 13.8 yesHeight increment = 0.3 in.Failures
44、 = 11Nonfailures = 9Nonfailures at 13.2 in. (h0) = 1; at 13.5 in. = 3; at 13.8 in. = 3; at 14.1 in. = 2A =(01)+(13)+(23)+(32)=15B = (0)2 1) + (1)2 3) + (2)2 3) + (3)22)=33m 5F13.210.3S159112DG3.05 41.55 in.lbmean impact resistance = 41.55 in.lbS 5 1.62030.333.0 FS9 3332 s15d2s9d2 D G10.0295 1.338 in.lbs.Sample standard deviation = 1.338 in.lbG14 04 (2010)16
