1、Designation: G10 10Standard Test Method forSpecific Bendability of Pipeline Coatings1This standard is issued under the fixed designation G10; the number immediately following the designation indicates the year of originaladoption or, in the case of revision, the year of last revision. A number in pa
2、rentheses indicates the year of last reapproval. A superscriptepsilon () indicates an editorial change since the last revision or reapproval.1. Scope1.1 This method covers the specific determination of theeffect of short-radius bends on coatings applied to 33.4-mm(1-in. nominal) diameter pipe.1.2 Th
3、e 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 theresponsibility of the user of this
4、 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:2G6 Test Method for Abrasion Resistance of Pipeline Coat-ingsG12 Test Method for Nondestructive Measurement of FilmThickne
5、ss of Pipeline Coatings on Steel3. Summary of Method3.1 The method consists of bending a 33.4-mm (1-in.nominal) diameter specimen of coated pipe around a mandrelto produce a range of short-radius bends. Coating failure in theform of cracking or loss of adhesion is detected through visualand electric
6、al inspection of the bent specimen.4. Significance and Use4.1 This test will provide information on the ability ofcoatings applied to pipe to resist cracking, disbonding, or othermechanical damage as a result of bending. Because the test isapplied to coated pipe from commercial production, the resul
7、tscan be directly used in the selection of similar materials forservice. The test also has application as a quality controlmethod when variations in coating application or materialformulation will affect bending performance.5. Apparatus5.1 The bending apparatus shall be essentially as shown inFigs.
8、1-3 and shall include the following:5.1.1 Variable-Radius Mandrel, constructed from four19-mm (0.75-in.) thick pieces of plywood, bolted together andconforming to the geometric shape shown in Fig. 1. Thegeometric construction is accomplished by laying out along theouter edge of the mandrel a series
9、of seven consecutive arcs atdecreasing radii of 610, 530, 460, 380, 300, and 230 mm (24,21, 18, 15, 12, and 9 in.). The first five arcs shall be carriedthrough a 45-deg angle to the next point of tangency. A 45-degV-notch shall be cut into the edge of the mandrel for seating thepipe specimen. Holes
10、shall be drilled at appropriate locations inthe mandrel face for positioning the lever arm and fasteningpipe clamps.5.1.2 Lever Arm-Roller AssemblyA 1.83-m (72-in.) leverarm with nylon roller supplies the mechanical advantagenecessary to bend the pipe specimen. The lever arm shallcontain a series of
11、 holes which are used to maintain properclearance between the roller and pipe sample during thebending operation.5.2 Thickness GageMeasurements of coating thicknesswill be required for this test. This shall be done in accordancewith Test Method G12.5.3 Holiday DetectorA low-voltage d-c holiday detec
12、torof the wet-sponge type, specified in Test Method G6, shall beused to locate breaks in the coating film.6. Test Specimens6.1 The test specimen should be 2.5 m (100 in.) in length. Itshould be representative of production-coated pipe and be freeof obvious coating flaws or defects. Coating specimens
13、 shall beapplied to 33.4-mm (1-in. nominal) diameter pipe.1This test method is under the jurisdiction of ASTM Committee D01 on Paintand Related Coatings, Materials, and Applications and is the direct responsibility ofSubcommittee D01.48 on Durability of Pipeline Coating and Linings.Current edition a
14、pproved Dec. 1, 2010. Published December 2010. Originallyapproved in 1969. Last previous edition approved in 2002 as G10 83 (2002). DOI:10.1520/G0010-10.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMSt
15、andards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.7. Conditioning7.1 The specimen shall be exposed to room temperature fora sufficient time to
16、ensure thermal equilibrium in the pipe andcoating. A temperature in the range from 20 to 30C (68 to85F) shall be considered room temperature.8. Procedure8.1 Perform the test at a room temperature of 21 to 25C (70to 77F).8.2 Measure the applied coating thickness of each specimenin accordance with Tes
17、t Method G12.8.3 The time to execute the test at a uniform velocity shouldbe agreed upon by the producer and the user.8.4 Place the conditioned test specimen into the V-notch.Secure the pipe in place with clamp No. 1 and tighten thethumb screw. Remove the threaded handle from clamp No. 1 toallow for
18、 clearance of the lever arm. With the steel pivot pin athole A of the lever arm (see Fig. 3), insert the pin into thesocket on the bed of the bending jig. Place the nylon roller atposition C on the lever arm. Apply the roller to the pipespecimen, and with a constant, even force with the leverhandle,
19、 bend the pipe around the mandrel until the 460-mm(18-in.) radius bend has been made. Insert and secure pipeclamp No. 2. Continue bending the pipe until the 300-mm(12-in.) radius has been reached. Insert and secure pipe clampNo. 3. Reposition the lever arm by moving the pivot pin to the25-mm (1-in.)
20、 diameter hole in the mandrel surface. Move thenylon roller to position B on the lever arm. Apply the roller tothe pipe and complete the bending operation by forming thespecimen through the 230-mm (9-in.) radius.FIG. 1 Variable-Radius MandrelFIG. 2 Details of Mandrel Assembly and Support BracketsG10
21、1028.5 Examine the bent specimen with a wet-sponge holidaydetector to determine at what point, if any, cracking of thecoating film occurred. Note the number, size, location, and typeof cracks present. Examine the pipe specimen for any loss ofcoating bond caused by the bending operation.NOTE 1The pos
22、sibility of some coatings developing stress-inducedcracks in the period following the bending operation should not beoverlooked. If this is a consideration, the bent specimen should be retainedfor a 24-h post-bent inspection.9. Report9.1 The initial test report shall include the following:9.1.1 Comp
23、lete identification of the coated pipe tested,including: name and type of coating, average coating thickness,minimum coating thickness, maximum coating thickness,manufacturers lot number, and date of manufacture.9.1.2 Temperature of the pipe specimen as tested,9.1.3 Radius at which cracking first oc
24、curred,9.1.4 Description of the type of cracking,9.1.5 Location and extent of any loss in pipe-to-coatingbond,9.1.6 Number of specimens tested,9.1.7 Any peculiar characteristics of the specimen notedduring the test or after immediate removal from the testapparatus, and9.1.8 Post-bend retention time.
25、9.2 As this test method serves as a coating performanceguide to investigators wishing to compare the relative merits ofpipe-coating materials, no precision and bias statement isrequired.10. Keywords10.1 bendability; flexability; pipeline coatingsASTM International takes no position respecting the va
26、lidity 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 infringement of such rights, are entirely their own responsibility.This standard is su
27、bject 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 or for additional standardsand should be addressed to ASTM International Headqu
28、arters. 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 known to the ASTM Committee on Standards, at the address shown below.This stand
29、ard 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 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/).FIG. 3 Details of Lever Arm and Pipe ClampsG10103
