1、Designation: B647 10Standard Test Method forIndentation Hardness of Aluminum Alloys by Means of aWebster Hardness Gage1This standard is issued under the fixed designation B647; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the ye
2、ar 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. Scope1.1 This test method covers the determination of indentationhardness of aluminum alloys with a Webster hardness gage
3、Model B.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 1Two other models,Aand B-75, are in use, but are not coveredin this test method. Model A do
4、es not provide numerical values ofhardness and Model B-75 covers only a part of the range of interest foraluminum 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-p
5、riate 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 Hardnes
6、s 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 Terminolog
7、y E6 shall be consideredas applying to the terms used in this test method.4. Significance and Use4.1 The Webster hardness gage is portable and thereforeuseful for in situ determination of the hardness of fabricatedparts and individual test specimens for production controlpurposes. It is not as sensi
8、tive as Rockwell or Brinell hardnessmachines; see 10.2.4.2 This test method should be used only as cited inapplicable material specifications.5. Apparatus ( Fig. 1)5.1 The Webster hardness gage, Model B, consists of threemain parts: the frame, operating handle, and penetrator housingassembly. The pe
9、netrator housing assembly includes the prin-cipal working parts, including the penetrator, loading spring,adjusting nut, penetrator housing, housing key, return spring,and dial indicator.5.2 The indentor is a hardened steel truncated cone.5.3 The dial indicator is graduated from 1 to 20, and isactua
10、ted by the penetrator so that the higher the reading, thehigher is the hardness of the test material.5.4 The configuration of the Webster hardness gage is suchthat it is operated like a pair of pliers.5.5 The clearance between the penetrator and the anvil isabout 6 mm (14 in.), limiting the thicknes
11、s of sample that canbe tested.6. Test Parts or Specimens6.1 Any part or piece of material greater than 1 mm (0.04in.) in thickness and equal to or less than 6 mm (14 in.) inthickness and with a clear flat area at an edge approximately 25by 25 mm (1 by 1 in.) in size is suitable for test.6.2 The surf
12、aces shall be essentially parallel, smooth, clean,and free of mechanical damage. The test surface may be lightlypolished to eliminate scratches or die lines.1This test method is under the jurisdiction of ASTM Committee B07 on LightMetals and Alloys and is the direct responsibility of Subcommittee B0
13、7.05 onTesting.Current edition approved Dec. 1, 2010. Published January 2011. Originallyapproved in 1984. Last previous edition approved in 2006 as B647 84 (2006).DOI: 10.1520/B0647-10.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceast
14、m.org. For Annual Book of ASTMStandards 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.6.3 The clear, flat area shall be such that there will be a c
15、leardistance of at least 3 mm (18 in.) from the edge of the part orspecimen.6.4 Parts or specimens with a slight taper or curvature mayalso be tested if a round anvil is used, as described in 8.1.1 andFig. 2.7. Calibration7.1 Zero Adjustment:7.1.1 Operate the instrument against the bare anvil and no
16、tewhether or not the indicator gives the zero (full-scale) reading.7.1.2 A correction in zero reading is normally not neededexcept for one of the reasons listed below:7.1.2.1 A new penetrator has been installed,7.1.2.2 The dial indicator is changed from one instrument toanother, or7.1.2.3 Excessive
17、wear has taken place.7.1.3 If an adjustment in zero is needed, turn the zeroadjustment screw below the indicator dial slowly (Fig. 3),while operating the tester against the bare anvil and maintain-ing handle pressure, until the hand of the dial indicator rests onthe zero line (which is located at th
18、e full-scale reading of 20).7.1.4 The zero adjustment should never be used to make theindicator read correctly on a standard sample.7.2 Load Spring Adjustment:7.2.1 Measure the hardness of a standard sample of mediumto low hardness, either one furnished with the tester or onedeveloped from reference
19、 stock; the dial should show thereading indicated for the standard within 60.5.7.2.2 If the readings on the standard or the bare anvil, orboth, do not indicate the proper values, adjust the load springwith the special wrench provided until agreement is reached(Fig. 4).8. Procedure8.1 Place the test
20、part or specimen between the penetratorand the anvil, and apply pressure to the handle.FIG. 1 Webster Hardness Gage, Model BFIG. 2 Making the TestFIG. 3 Zero Adjustment Screw, A (indicated by arrow)B647 1028.1.1 If the test part or specimen has a slight taper orcurvature, use a round anvil and apply
21、 the gage in such a waythat the penetrator is applied normal to the test surface and theanvil bears along a line that is parallel to the surface in contactwith the penetrator, as illustrated in Fig. 2.8.2 Apply sufficient pressure to cause the flat face of thepenetrator housing to come in contact wi
22、th the surface of thetest part or specimen.NOTE 2Excess pressure on the handle is not harmful and does notaffect the reading, but neither is it necessary, as the hardness reading isdetermined solely by the spring deflection.8.3 Read the hardness from the dial indicator. Report thereading to the near
23、est 0.5.NOTE 3For relatively soft materials, the dial may indicate some drifttoward lower numbers with time, after the initial pressure. It is recom-mended that readings be made quickly and that the highest observed valuebe used.9. Report9.1 The report shall include the following:9.1.1 Identificatio
24、n of material tested,9.1.2 Model and serial number of hardness gage,9.1.3 Number of readings taken,9.1.4 Average of hardness values, rounded to the nearesthalf division, and9.1.5 Date of test.10. Precision and Bias10.1 The Webster hardness gage, Model B, is useful forhardness measurements of materia
25、l in the range from 3003-0 to7075-T6 representing a range in Rockwell hardness from about5 HRE to 110 HRE.10.2 The application of portable impressors, such as theWebster, will produce greater variation in hardness readingsthan standard fixed frame procedures, such as Test MethodsE10 and E18. Further
26、 since the scale of the Webster hardnessgage, Model B, has 20 divisions compared to 110 for theRockwell E scale, it is also less sensitive than the Rockwellscale.10.3 The variation in readings that results from the applica-tion of the Webster hardness impressor has not yet beenestablished.10.4 The
27、precision of this test method is based on aninterlaboratory study of B647, conducted in 2008. Each of fivelaboratories tested a total of four alloys. Every “test result”represents the average of three individual determinations.Three test results (9 total test readings) from every laboratorywere anal
28、yzed in order to determine the precision statisticslisted below. Practice E691 was followed for the design andanalysis of the data; the details are given in ASTM ResearchReport No. B07-1001.310.4.1 Repeatability limit (r)Two test results obtainedwithin one laboratory shall be judged not equivalent i
29、f theydiffer by more than the “r” value for that material; “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.10.4.1.1 Repeatability limits are listed in Ta
30、ble 1 below.10.4.2 Reproducibility limit (R)Two test results shall 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 differen
31、t equipment indifferent laboratories.10.4.2.1 Reproducibility limits are listed in Table 1 below.10.4.3 The above terms (repeatability limit and reproduc-ibility limit) are used as specified in Practice E177.10.4.4 Any judgment in accordance with 10.4.1 and 10.4.2would normally have an approximate 9
32、5 % probability of beingcorrect, however the precision statistics obtained in this ILSmust not be treated as exact mathematical quantities which are3Supporting data have been filed at ASTM International Headquarters and maybe obtained by requesting Research Report RR:B07-1001.FIG. 4 Adjusting Load o
33、n Load SpringTABLE 1 Summary Statistics for Webster Hardness (Webster Scale Units) From Tests On Several MaterialsMaterial AverageARepeatabilityStandard DeviationReproducibilityStandard DeviationRepeatabilityLimitReproducibilityLimitXSrSRrR3003-02 4.639 0.078 1.128 0.218 3.1575052-H32 10.356 0.546 1
34、665 1.529 4.6636061-T6 16.172 0.286 0.380 0.801 1.0637075-T6 19.028 0.096 0.096 0.269 0.269AThe average of the laboratories calculated averages.B647 103applicable to all circumstances and uses. The limited numberof materials tested and laboratories reporting results guaranteesthat there will be tim
35、es when differences greater than predictedby the ILS results will arise, sometimes with considerablygreater or smaller frequency than the 95 % probability limitwould imply. Consider the repeatability limit and the repro-ducibility limit as general guides, and the associated probabil-ity of 95 % as o
36、nly a rough indicator of what can be expected.10.5 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.10.6 The precision statement was determined through sta-tistical examination of
37、 60 results, from five laboratories, onfour alloys, described below:3003-02 - Alcoa Rolled Plate 0.250” x 12” x 12” from 48”wide production5052-H32- Alcoa Rolled Plate 0.250” x 12” x 12” from 48”wide production6061-T6 - Kaiser Rolled Plate 0.250” x 12” x 12” from 48”wide production7075-T6 - Kaiser R
38、olled Plate 0.250” x 12” x 12” from 48”wide productionASTM 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 r
39、ights, 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 withdrawn. Your comments are invited either f
40、or 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 your comments have not received a fair heari
41、ng 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 (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/).B647 104
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