1、Designation: B926 09 (Reapproved 2017)Standard Method forPinhole Determination in Aluminum and Aluminum AlloyPlain Foil by Means of a Light Table1This standard is issued under the fixed designation B926; the number immediately following the designation indicates the year oforiginal adoption or, in t
2、he case of revision, 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. Scope*1.1 This method covers the identification and counting ofpinholes, including roll holes,
3、 in plain foil using a light table,and inspector with normal 20/20 or corrected 20/20 vision, anda darkened inspection area.1.2 The values stated in inch-pound units are to be regardedas standard. The values given in parentheses are mathematicalconversions to SI units that are provided for informati
4、on onlyand are not considered standard.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 standard to establish appro-priate safety, health, and environmental practices and deter-mine the applicability
5、 of regulatory limitations prior to use.1.4 This international standard was developed in accor-dance with internationally recognized principles on standard-ization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recom-mendations issued by the World
6、 Trade Organization TechnicalBarriers to Trade (TBT) Committee.2. Referenced Documents2.1 ASTM Standards:2B881 Terminology Relating to Aluminum- and Magnesium-Alloy Products3. Terminology3.1 DefinitionsRefer to Terminology B881 for definitionsof product terms used in this specification.3.2 Definitio
7、ns of Terms Specific to This Standard:3.2.1 calibration, ndetermination of the values of thesignificant parameter(s) by comparison with a value(s) indi-cated by a reference instrument or by a set of referencestandards.3.2.2 pinhole, nany small void in the foil that will permitthe transmission of lig
8、ht. Classification criteria for pinholeslimits these voids to those that are too small in size to be clearlyvisible to the unaided eye (1 visual inspection).3.2.3 roll hole, nthe producers classification of a pinholecaused by an imperfection on any type of roll the foil contactsduring production. Th
9、e distinguishing feature of a roll hole(s)is the repeatability of this void on a regular interval. Thisinterval is directly proportional to the circumference of the rollcausing the void (this interval will also increase proportionallyto subsequent thickness reductions).4. Summary of Method4.1 This m
10、ethod contains guidelines for determining thenumber of pinholes present in the area with the highest pinholeconcentration in a sample of foil.4.2 A full width sample is placed on the light table, and thepinholes are counted in a sample of known area (five or moresquare feet).5. Significance and Use5
11、.1 Foil in thickness of about 0.002 in. (0.05 mm) andheavier is virtually free of pinholes. With decrease in thickness,the number of pinholes may increase.5.2 This method is provided to develop and maintainuniformity in the methods of evaluating pinholes in aluminumfoil. The pinhole data provides as
12、sessments of process capa-bility and quality levels of the foil as well.6. Apparatus6.1 A light table which provides illumination between 1500and 1800 lux light intensity with a smooth and uniforminspection surface on which the foil is examined. The lighttable must be in a black booth or in an area
13、where the lights areturned off to provide darkness of less than 50 lux. The lighttable should be able to accommodate the widest width of foilto be examined. The usual construction of the light table1This test method is under the jurisdiction of ASTM Committee B07 on LightMetals and Alloys and is the
14、 direct responsibility of Subcommittee B07.03 onAluminum Alloy Wrought Products.Current edition approved Dec. 1, 2017. Published December 2017. Originallyapproved in 2003. Last previous edition approved in 2009 as B926 09. DOI:10.1520/B0926-09R17.2For referenced ASTM standards, visit the ASTM websit
15、e, 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.*A Summary of Changes section appears at the end of this standardCopyright ASTM International, 100 Barr Harbor Dri
16、ve, PO Box C700, West Conshohocken, PA 19428-2959. United StatesThis international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for theDevelopment of International Standards, Guides and Recommendations is
17、sued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.1consists of a shallow box painted white on the inside with rowsof fluorescent lights and with a frosted or milk glass coveringto provide uniform light diffusion.6.2 One or more counting frames (grids) that have opening
18、sof one square foot (one square decimeter for SI counts).6.3 Sheet of foil to be tested.6.4 Calibration of the necessary light intensities can beaccomplished using a standard light meter.7. Procedure7.1 Test a full-width representative sample with a minimumof five square feet. Examine the full width
19、 of the sheet. The foilgage should be within tolerance.7.2 Place the foil sample on the light table carefully to avoidwrinkling/creasing with the long direction of the bulbs perpen-dicular to the rolling direction of the foil and turn the lights onin the light table and off in the booth or area. All
20、ow areasonable time for eyes to adjust to darkened conditions.7.3 If necessary, move the foil on the light table until theentire width has been examined. (Move the foil carefully andas little as possible because moving the sample may createvoids in the sample.)7.4 If a counting frame is used, place
21、it over the area andcount the holes. The person should be approximately 18 in.from the sample when counting.7.5 Record the count.8. Report8.1 The report shall include the following:8.1.1 Identification of the roll from which the sample wastaken,8.1.2 The average number of pinholes per square foot of
22、sample,8.1.3 Gage of the foil sample, and8.1.4 Sample lot identification.9. Precision and Bias9.1 PrecisionIt is not practicable to specify the precisionof the procedure in Method B926 for counting pinholesbecause as the gage decreases, their variability and numberincrease.9.2 BiasSince the vision o
23、f the inspector(s) are the mostsignificant aspect of bias in counting pinholes, it is recom-mended that samples of known counts be used routinely toverify if bias exists. Operating outside of the range of lightintensities stated will also cause biased counts.SUMMARY OF CHANGESCommittee B07 has ident
24、ified the location of selected changes to this standard since the last issue (B926 03)that may impact the use of this standard. (Approved Dec. 1, 2009.)(1) ASTM references B373, B479 and E252 are not referencedin this document and were removed from Section 2.(2) ASTM B881 was added to Section 2 and
25、referenced inSection 3.(3) Foil was removed from Section 3.2, because it is includedin ASTM B881.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 determi
26、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
27、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
28、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
29、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 Copyright Clearance Center, 222Rosewood Drive, Danvers, MA 01923, Tel: (978) 646-2600; http:/ 09 (2017)2
