1、Designation: B648 10 (Reapproved 2015)1Standard Test Method forIndentation Hardness of Aluminum Alloys by Means of aBarcol Impressor1This standard is issued under the fixed designation B648; the number immediately following the designation indicates the year oforiginal adoption or, in the case of re
2、vision, 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.1NOTEAppendix X1 was moved to appear one page in October 2015.1. Scope1.1 This test method covers the determin
3、ation of indentationhardness of aluminum alloys using a Barcol Impressor, ModelNo. 934-1.1.2 The values stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.2.1 ExceptionThe values given in parentheses are forinformation only.NOTE 1Another mo
4、del, No. 935, is for use on plastics but is notincluded in this test method and should not be used for aluminum alloys.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-pri
5、ate safety and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2E6 Terminology Relating to Methods of Mechanical TestingE10 Test Method for Brinell Hardness of Metallic MaterialsE18 Test Methods for Rockwell Hardness
6、of Metallic Ma-terialsE177 Practice for Use of the Terms Precision and Bias inASTM Test MethodsE691 Practice for Conducting an Interlaboratory Study toDetermine the Precision of a Test Method3. Terminology3.1 DefinitionsThe definitions of terms relating to hard-ness testing appearing in Terminology
7、E6 shall be consideredas applying to the terms used in this test method.4. Significance and Use4.1 The Barcol Impressor is portable and therefore usefulfor in situ determination of the hardness of fabricated parts andindividual test specimens for production control purposes.4.2 This test method shou
8、ld be used only as cited inapplicable material specifications.5. Apparatus5.1 Barcol Impressor, Model 934-1 See Fig. 1 and Fig. 2.5.2 IndentorThe indentor shall consist of a hardened steeltruncated cone having an angle of 26 with a flat tip 0.157 mm(0.0062 in.) in diameter. It shall fit into a hollo
9、w spindle and beheld down by a spring-loaded plunger. See Fig. 2.5.3 Indicating DeviceThe indicating dial shall have 100divisions, each representing a depth of 0.0076 mm (0.00030in.) penetration. The higher the reading, the harder the material.6. Test Parts or Specimen6.1 The testing area shall be s
10、mooth, clean, and free ofmechanical damage. The surface may be lightly polished toeliminate scratches or die lines. It shall be such that it can beessentially perpendicular to the indentor during the test.NOTE 2The effect of curvature of the test specimen on the BarcolImpressor readings is presented
11、 in Appendix X1, Fig. X1.1.6.2 DimensionsTest parts or specimens shall be at least1.5 mm (116 in.) thick and large enough to ensure a minimumdistance of 3 mm (18 in.) in any direction from the indentorpoint to the edge.7. Calibration7.1 With the plunger upper guide backed out until it justengages th
12、e spring, place the impressor on a glass surface andpress down until the penetrator point is forced all the way backinto the lower plunger guide. The indicator should then read100 6 1. If it does not, loosen the locknut and turn the lowerplunger guide in or out to obtain a reading of 100.1This test
13、method is under the jurisdiction of ASTM Committee B07 on LightMetals and Alloys and is the direct responsibility of Subcommittee B07.05 onTesting.Current edition approved Oct. 1, 2015. Published October 2015. Originallyapproved in 1978. Last previous edition approved in 2010 as B648 10. DOI:10.1520
14、/B0648-10R15E01.2For 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 standards Document Summary page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor
15、 Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States17.2 Read the hardness of a “hard” aluminum alloy referencedisk supplied by the manufacturer of the impressor and, ifnecessary, adjust so that the reading is within the range markedon the disk.7.3 Repeat the process with a “soft” re
16、ference disk.7.4 If the reference readings cannot be obtained, subsequentmeasurements are not valid.8. Procedure8.1 Support the test parts or specimens on a hard, firmsurface if they are likely to bend or deform under the pressureof the indentor (Note 3). The indentor must be perpendicular tothe sur
17、face being tested.NOTE 3Curved surfaces may be more difficult to support. When theload is applied, bending and spring action in the part or specimen shouldbe avoided.8.2 Grasp the impressor firmly between leg and point sleeveand set both on the surface to be tested. For irregular parts orsmall speci
18、mens this may require the impressor leg to beshimmed so that the indentor will be perpendicular to the testsurface.8.3 Quickly apply by hand sufficient pressure (4 to 7 kg, or10 to 15 lb) on the housing to ensure firm contact with the testspecimen and record the highest dial reading to the nearest 0
19、.5division (Note 4). Take care to avoid sliding or scraping whilethe indentor is in contact with the surface being tested.NOTE 4For relatively soft materials, the dial may indicate some drifttoward lower numbers with time after the initial pressure. For this reasonit is recommended that readings be
20、made quickly and that the highestobserved value be used.8.4 Impressions should not be made within 3 mm (18 in.) ofthe edge of the part or specimen or of other impressions.9. Report9.1 The report shall include the following:9.1.1 Identification of material tested,9.1.2 Model and serial number of impr
21、essor,9.1.3 Number of readings taken,9.1.4 Average of hardness values rounded to the nearestwhole scale reading, and9.1.5 Date of test.10. Precision and Bias10.1 The precision of this test method is based on aninterlaboratory study of B648, conducted in 2008. Each of fivelaboratories tested a total
22、of four alloys. Every test resultrepresents the average of three individual determinations.Three test results (9 total test readings) from every laboratorywere analyzed in order to determine the precision statisticslisted below. Except for the limited number of replicatesavailable from some laborato
23、ries, Practice E691 was followedfor the design and analysis of the data; the details are given inASTM Research Report No. B07-1002.310.1.1 Repeatability limit (r)Two test results obtainedwithin one laboratory shall be judged not equivalent if theydiffer by more than the “r” value for that material;
24、“r” is theinterval representing the critical difference between two testresults for the same material, obtained by the same operatorusing the same equipment on the same day in the samelaboratory.10.1.1.1 Repeatability limits are listed in Table 2.10.1.2 Reproducibility limit (R)Two test results shal
25、l bejudged not equivalent if they differ by more than the “R” valuefor that material; “R” is the interval representing the criticaldifference between two test results for the same material,obtained by different operators using different equipment indifferent laboratories.10.1.2.1 Reproducibility lim
26、its are listed in Table 2.10.1.3 The above terms (repeatability limit and reproduc-ibility limit) are used as specified in Practice E177.10.1.4 Any judgment in accordance with 10.1.1 and 10.1.2would normally have an approximate 95 % probability of beingcorrect, however the precision statistics obtai
27、ned in this ILSmust not be treated as exact mathematical quantities which areapplicable to all circumstances and uses. The limited numberof materials tested, and laboratories reporting replicate results,guarantees that there will be times when differences greaterthan predicted by the ILS results wil
28、l arise, sometimes withconsiderably greater or smaller frequency than the 95 %probability limit would imply. The repeatability limit and thereproducibility limit should be considered as general guides,and the associated probability of 95 % as only a rough indicatorof what can be expected.3Supporting
29、 data have been filed at ASTM International Headquarters and maybe obtained by requesting Research Report RR:B07-1002.FIG. 1 Barcol Impressor, Model 934-1TABLE 1 Recommended Sample Sizes to Equalize theVariance of the AverageHardness,M-934-1ScaleReadingVarianceCoefficientof Variation,%Variance ofAve
30、rageMinimumNo. ofReadings50 1.66 1.1 0.28 660 1.39 0.9 0.28 570 1.12 0.8 0.28 480 0.85 0.7 0.28 3B648 10 (2015)1210.2 BiasAt the time of the study, there was no acceptedreference material suitable for determining the bias for this testmethod, therefore no statement on bias is being made.10.3 The pre
31、cision statement was determined through sta-tistical examination of 60 results, from five laboratories, on thefour alloys described below.3003-02 - Alcoa Rolled Plate 0.250” x 12” x12” from 48”wide production5052-H32- Alcoa Rolled Plate 0.250” x 12” x12” from 48”wide production6061-T6 - Kaiser Rolle
32、d Plate 0.250” x 12” x12”from 48”wide production7075-T6 - Kaiser Rolled Plate 0.250” x 12” x12”from 48”wide productionFIG. 2 Diagram of Barcol ImpressorTABLE 2 Hardness (Instrument Scale Units)Material AverageARepeatabilityStandard DeviationReproducibilityStandard DeviationRepeatabilityLimitReproduc
33、ibilityLimitXSrSRrR3003-02 60.282 0.597 1.314 1.671 3.6785052-H32 73.784 0.427 0.562 1.197 1.5746061-T6 83.347 0.671 1.379 1.879 3.8627075-T6 92.211 0.522 0.741 1.461 2.075AThe average of the laboratories calculated averages.B648 10 (2015)13APPENDIX(Nonmandatory Information)X1. EFFECT OF CURVATURE O
34、F TEST SPECIMEN ON BARCOL IMPRESSOR READINGSX1.1 The effect of curvature on the results of BarcolImpressor tests on sheet is illustrated in Fig. X1.1.ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. User
35、s 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 responsible technical committee and must be reviewed every
36、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 consideration at a meeting of theresponsible technica
37、l 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 Barr Harbor Drive, PO Box C700, West Conshohocken,
38、 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 Copyright Clearance Center, 222Rosewood Drive, Danvers, MA 01923, Tel: (978) 646-2600; http:/ X1.1 Effect of Curvature of Sheet on Barcol Impressor ReadingsModel 934-1, 0.064-in. thick 2024-T3B648 10 (2015)14
