1、Designation: B 648 78 (Reapproved 2006)Standard Test Method forIndentation Hardness of Aluminum Alloys by Means of aBarcol Impressor1This standard is issued under the fixed designation B 648; the number immediately following the designation indicates the year oforiginal adoption or, in the case of r
2、evision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.1. Scope1.1 This test method covers the determination of indentationhardness of aluminum alloys using a Barc
3、ol Impressor, ModelNo. 934-1.1.2 The values stated in SI units are to be regarded as thestandard. The values given in parentheses are for informationonly.NOTE 1Another model, 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 st
4、andard 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 and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1
5、 ASTM Standards:2E6 Terminology Relating to Methods of Mechanical Test-ingE10 Test Method for Brinell Hardness of Metallic Materi-alsE18 Test Methods for Rockwell Hardness and RockwellSuperficial Hardness of Metallic Materials3. Terminology3.1 DefinitionsThe definitions of terms relating to hard-nes
6、s testing appearing in Terminology E6shall 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
7、purposes.4.2 This test method should 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 d
8、iameter. It shall fit into a hollow 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 Speci
9、men6.1 The testing area shall be smooth, 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 Bar
10、colImpressor readings is presented 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.1This test method is under the jurisdiction of
11、ASTM Committee B07 on LightMetals and Alloys and is the direct responsibility of Subcommittee B07.05 onTesting.Current edition approved Sept. 1, 2006. Published September 2006. Originallyapproved in 1978. Last previous edition approved in 2000 as B 648 78 (2000).2For referenced ASTM standards, visit
12、 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.FIG. 1 Barcol Impressor, Model 934-11Copyright ASTM International, 100 Barr Harbor Drive, PO Box C
13、700, West Conshohocken, PA 19428-2959, United States.7. Calibration7.1 With the plunger upper guide backed out until it justengages the 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
14、 then read100 6 1. If it does not, loosen the locknut and turn the lowerplunger guide in or out to obtain a reading of 100.7.2 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 mar
15、kedon the disk.7.3 Repeat the process with a “soft” reference 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
16、(Note 3). The indentor must be perpendicular tothe surface 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 s
17、urface to be tested. For irregular parts orsmall specimens 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 testspecime
18、n and record the highest dial reading to the nearest 0.5division (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 pressu
19、re. For this reasonit is recommended that readings be 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
20、 material tested,9.1.2 Model and serial number of impressor,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 Bias; Number of Readings10.1 Application of portable impressors such as the Barcolwill produc
21、e greater variation in hardness readings than stan-dard fixed-frame procedures such as Test Methods E 10 andE18. On homogeneous materials, three readings are needed tomaintain a variance-of-average of 0.28 at an 80 Barcol reading;for the same variance-of-average at 50 Barcol, six readings areneeded.
22、 Table 1 shows the recommended sample sizes to obtaincomparable variance at other hardness levels.NOTE 5These findings were obtained with a round robin conducted ina workshop with all participants present. Eight plastic materials ofdifferent hardness were evaluated with six different Barcol (934-1)I
23、mpressors. The report is filed with ASTM Headquarters.33Round-robin data have been filed at ASTM Headquarters as RR: D20-1087.FIG. 2 Diagram of Barcol ImpressorB 648 78 (2006)2APPENDIX(Nonmandatory Information)X1. EFFECT OF CURVATURE OF TEST SPECIMEN ON BARCOL IMPRESSOR READINGSX1.1 The effect of cu
24、rvature on the results of BarcolImpressor tests on sheet is illustrated in Fig. X1.1.TABLE 1 Recommended Sample Sizes to Equalize theVariance of the AverageHardness,M-934-1ScaleReadingVarianceCoefficientof Variation,%Variance ofAverageMinimumNo. ofReadings50 1.66 1.1 0.28 660 1.39 0.9 0.28 570 1.12
25、0.8 0.28 480 0.85 0.7 0.28 3B 648 78 (2006)3ASTM 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
26、 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 withdrawn. Your comments are invited either for revisio
27、n 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 your comments have not received a fair hearing you sho
28、uldmake 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 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).FIG. X1.1 Effect of Curvature of Sheet on Barcol Impressor ReadingsModel 934-1, 0.064-in. thick 2024-T3B 648 78 (2006)4
