ASTM E448 - 82(2008) Standard Practice for Scleroscope Hardness Testing of Metallic Materials (Withdrawn 2017).pdf

《ASTM E448 - 82(2008) Standard Practice for Scleroscope Hardness Testing of Metallic Materials (Withdrawn 2017).pdf》由会员分享，可在线阅读，更多相关《ASTM E448 - 82(2008) Standard Practice for Scleroscope Hardness Testing of Metallic Materials (Withdrawn 2017).pdf（5页珍藏版）》请在麦多课文档分享上搜索。

1、Designation: E448 82 (Reapproved 2008)Standard Practice forScleroscope Hardness Testing of Metallic Materials1This standard is issued under the fixed designation E448; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of las

2、t 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 practice covers the determination of the Sclero-scope2hardness of metallic materials (Part A), the verificationof Sc

3、leroscope hardness instruments (Part B), and the calibra-tion of standardized hardness test blocks (Part C).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 information onlyand are n

4、ot considered standard.1.3 This standard does not purport to address all of thesafety problems, 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

5、 to use.2. Referenced Documents2.1 ASTM Standards:3A427 Specification for Wrought Alloy Steel Rolls for Coldand Hot ReductionE140 Hardness Conversion Tables for Metals RelationshipAmong Brinell Hardness, Vickers Hardness, RockwellHardness, Superficial Hardness, Knoop Hardness, Sclero-scope Hardness,

6、 and Leeb Hardness3. Terminology3.1 Definitions:3.1.1 calibrationdetermination of the values of the sig-nificant parameters by comparison with values indicated by areference instrument or by a set of reference standards.3.1.2 forged roll Scleroscope hardness number (HFRSc orHFRSd)4a number related t

7、o the height of rebound of adiamond-tipped hammer dropped on a forged steel roll. It ismeasured on a scale determined by dividing into 100 units theaverage rebound of a hammer from a forged steel roll ofaccepted maximum hardness.NOTE 1The flat striking surface of the hammer in the forged rollScleros

8、cope is slightly larger than the corresponding surface in theScleroscope described in 3.1.3 (see Fig. 1). Hence the forged rollScleroscope yields correspondingly higher hardness numbers.3.1.3 Scleroscope hardness number (HSc or HSd)a num-ber related to the height of rebound of a diamond-tippedhammer

9、 dropped on the material being tested. It is measured ona scale determined by dividing into 100 units the averagerebound of the hammer from a quenched (to maximumhardness) and untempered high carbon water-hardening toolsteel test block of AISI W-5.3.1.4 Scleroscope hardness testa dynamic indentation

10、hardness test using a calibrated instrument that drops adiamond-tipped hammer (Note 2) from a fixed height onto thesurface of the material under test. The height of rebound of thehammer is a measure of the hardness of the material.NOTE 2An all-steel “Magnifier Hammer” that yielded a greater spreadin

11、 hardness readings on soft nonferrous metals has been available. Thishammer has become obsolete and, hence, is not considered in thispractice.3.1.5 verificationconfirmation by examination and provi-sion of evidence that an instrument, material, reference orstandard is in conformance with a specifica

12、tion.1This practice is under the jurisdiction of ASTM Committee E28 on MechanicalTesting and is the direct responsibility of E28.06 on Indentation Hardness Testing.Current edition approved Sept. 1, 2008. Published January 2009. Originallyapproved in 1972. Last previous edition approved in 2002 as E4

13、48 82 (2002)1.2Registered trademark of the Shore Instrument & Mfg. Co., Inc. DOI: 10.1520/E0448-82R08.3For 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

14、Document Summary page onthe ASTM website.4The conversion from Forged Roll “C” Scleroscope hardness to Vickershardness contained in Specification A427 and to Rockwell C hardness contained inStandard E140 are presently the only Scleroscope hardness conversions in ASTMstandards.Copyright ASTM Internati

15、onal, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United StatesNOTICE: This standard has either been superseded and replaced by a new version or withdrawn.Contact ASTM International (www.astm.org) for the latest information1GENERAL DESCRIPTION OF INSTRUMENTS AND TEST PROCED

16、URE FOR SCLEROSCOPEHARDNESS TEST4. Apparatus4.1 The instrument used for determining Scleroscope hard-ness numbers is supplied in two models designated Model Cand Model D.54.2 Scleroscope Model CThis model consists of a verti-cally disposed barrel containing a precision bore glass tube. Ascale, gradu

17、ated from 0 to 140, is set behind and is visiblethrough the glass tube. A pneumatic actuating head, affixed tothe top of the barrel, is manually operated by a rubber bulb andtube. A hammer drops from a specified height and reboundswithin the glass tube.4.3 Scleroscope Model DThis model is known as t

18、he DialRecording Scleroscope. It consists of a vertically disposedbarrel containing a clutch to arrest the hammer at maximumheight of rebound. This is made possible by using a hammerwhich is longer and heavier than the hammer in the Model CScleroscope, and which develops the same striking energy ind

19、ropping through a shorter distance. A number of supportingdevices are available with this instrument and it is recom-mended that one of these be used (see section 4.5).4.4 Diamond-Tipped Hammers:4.4.1 There are two sizes of diamond-tipped hammerscommonly used in the Scleroscope hardness instruments.

20、These are the small hammer used in the Model C instrumentand the larger hammer used in the Model D instrument.4.4.2 The following dimensions are applicable to thediamond-tipped hammers:Model CDiameter 0.234 in. (5.94 mm)Mass 2.300 0.500 gOver-all length 0.815 to 0.840 in. (20.7 to 21.3 mm)Distance h

21、ammerfalls9.890 + 0.005, 0.015 in. (251.2 + 0.1,0.4 mm)Model DDiameter 0.3125 in. (7.94 mm)Mass 36.0 2.0 gOver-all length 3.990 to 4.010 in. (101.33 to 104.10 mm)Distance hammerfalls0.704 + 0.017, 0.021 in. (17.9 + 0.4, 0.5mm)4.4.3 The geometry of the diamond tip is of significanceonly at its ultima

22、te extremity because of the limited penetrationof the diamond into the material being tested. Such penetrationis about 0.001 in. (0.025 mm) on mild steel and about 0.0005in. (0.013 mm) on hardened tool steel. Further, the variation inhardness of commercially available industrial diamonds has asignif

23、icant effect on the readings of a rebound-type hardnessinstrument. Consequently, the geometry of the diamond mustbe shaped to produce a correct reading on reference bars ofknown hardness. In the forged roll Scleroscope the diamond tipis specifically dimensioned to produce a correct reading on a5The

24、sole source of supply of the Model C and D Scleroscopes known to thecommittee at this time is the Shore Instrument and Manufacturing Co., Inc.,Jamaica, NY. If you are aware of alternative suppliers, please provide thisinformation to ASTM International Headquarters. Your comments will receivecareful

25、consideration at a meeting of the responsible technical committee,2whichyou may attend.FIG. 1 Profile of Scleroscope Diamond Showing Range of Diam-etersofFlatTipE448 82 (2008)2forged-steel roll of known hardness. In profile, the diamond isconvex, having an approximate radius terminated by a flatstri

26、king surface, as shown in Fig. 1. The flat striking surface isapproximately circular and from 0.004 to 0.016 in. (0.1 to 0.4mm) in diameter, depending on the type of instrument and thehardness and other physical characteristics of the diamond.4.5 Supporting DevicesThe three supporting devices usedmo

27、st frequently with the Scleroscope are (a) the clampingstand, (b) the swing arm and post, and (c) the roll-testing stand.5. Test Specimens5.1 FormSpecimens used in Scleroscope testing varygreatly with respect to size and shape. Smaller specimens maybe tested in the clamping stand which has a jaw cap

28、acity of 3in. (76 mm) high by 212 in. (64 mm) deep. Large specimens,beyond the jaw capacity of the clamping stand, may be testedwith the instrument mounted on the swing arm and post or theroll-testing stand. The swing arm and post has a height andreach capacity of 9 in. (230 mm) and 14 in. (360 mm),

29、respectively. The roll-testing stand may be used for mountingthe instrument on cylindrical specimens with a diameter of 212in. (64 mm) and upward without limit. The roll-testing standmay also be used for mounting the instrument on flat, horizon-tal surfaces with a minimum perimetric dimension of 3 b

30、y 5 in.(76 by 130 mm). The Model C Scleroscope may be used freehand for testing specimens with a minimum mass of 5 lb (2.3kg). It is not recommended that the Model D Scleroscope beused free hand.5.2 ThicknessThin strips or sheets may be tested, withsome limitations, but only when the Scleroscope is

31、mounted inthe clamping stand. Ideally, the sheet should be flat and withoutundulation. If the sheet material is bowed, the concave sideshould be up to preclude any possibility of erroneous readingsdue to spring effect. The minimum thicknesses of sheet invarious categories that may be tested are as f

32、ollows:MaterialThicknessin. mmHard steel 0.005 to 0.006 (0.13 to 0.15)Half-hard brass strip 0.010 (0.25)Cold-rolled steel 0.010 (0.25)Annealed-brass sheet 0.015 (0.38)5.3 FinishThe degree of test-surface finish is important.An excessively coarse finish will yield low and erratic read-ings. Hence, wh

33、en necessary, the surface shall be filed,machined, ground, or polished to permit accurate, consistentreadings to be obtained. Care should be taken to avoidoverheating or excessively cold working the surface. Thesurface finish required to obtain reproducible results varieswith the hardness of the tes

34、t specimen. In proceeding from softmetals to hardened steel the required surface finish ranged froma minimum finish as produced by a No. 2 file to a finely groundor polished finish. For intermediate hardness metals a No. 125machined surface, minimum, finish is required.6. Verification of Apparatus6.

35、1 Verification MethodThe instrument shall be verified asspecified in Part B.7. Procedure7.1 Test MethodTo perform a test with either the Model Cor Model D Scleroscope, hold or set the instrument in a verticalposition with the bottom of the barrel in firm contact with thetest specimen. Bring the hamm

36、er to the elevated position andthen allow it to fall and strike the test surface and measure theheight of rebound. When using the Model C Scleroscope bringthe hammer to the elevated position by squeezing and releasingthe rubber bulb. Release the hammer by again squeezing therubber bulb. The height t

37、o which the hammer rebounds on thefirst bounce indicates the hardness of the material. When usingthe Model D Scleroscope bring the hammer to the elevatedposition by turning the knurled control knob clockwise until adefinite stop is reached. Release this control knob to allow thehammer to strike the

38、specimen and observe the readingrecorded on the dial. The dial hand comes to rest at a value thatindicates the hardness of the material. Although the dial handreturns momentarily to zero in the course of each test cycle, itdoes not normally remain at zero.7.2 AlignmentTo prevent errors resulting fro

39、m misalign-ment the instrument must be set or held in a vertical position,using the plumb bob or spirit level on the instrument todetermine verticality. The most accurate readings of the Scl-eroscope are obtained with the instrument mounted in theclamping stand, which is essentially a C clamp with a

40、 tripodmounting to facilitate levelling of the anvil and to ensureverticality of the barrel. The opposite sides of the specimenstested in the clamping stand must be parallel. Lateral vibrationsmust be avoided since they tend to cause the free fall of thehammer to be impeded and, hence, cause the ins

41、trument to readlow.7.3 Spacing of IndentationsAn error may result if theindentations are spaced too closely together. Space indenta-tions at least 0.020 in. (0.51 mm) apart and make only once atthe same spot. Flat specimens with parallel surfaces may betested within14 in. (6 mm) of the edge when pro

42、perly clamped.7.4 MagnetizationDo not make tests on magnetized ma-terials. Any magnetization of specimen or hammer will resultin low readings.7.5 Reading the ScleroscopeExperience is necessary toread the Model C Scleroscope accurately. Thin materials orthose weighing less than 5 lb (2.3 kg) must be

43、clamped toacquire the inertia of the support. The sound of the impact is anindication of the effectiveness of the clamp: a dull thudindicates that the sample has been clamped solid, whereas ahollow ringing sound indicates that the sample is not tightlyclamped or is warped and not properly supported.

44、 Fivehardness determinations should be made and their averagetaken as representative of the hardness of a particular sample.8. Accuracy8.1 The accuracy of the Scleroscope Hardness Method isrelated to (1) the accuracy of the mass and geometry of thehammer, (2) the distance the hammer falls during a t

45、est, (3) thecondition of the test and support surfaces, and (4) the supportof the test piece during the test. Under optimum conditions, theaccuracy that can be expected is 63 Scleroscope points fromE448 82 (2008)3the mean of the spread in Scleroscope hardness numbersmarked on the standardized refere

46、nce hardness test blocks (seeSection 13). Under less than ideal conditions, any reduction inaccuracy can be established empirically by employing statisti-cal methods.9. Report9.1 The report shall include the following information:9.1.1 The Scleroscope hardness number, and9.1.2 The test conditions (m

47、ethod of support) and the typeof Scleroscope instrument used.10. Precision10.1 The precision of this method has not been establisheddue to the wide variety of materials tested by this method andthe possible variations in test specimens. The accepted practiceis to utilize the information in 8.1 when

48、establishing hardnesstolerances for specific applications. The precision of thismethod, whether involving a single operator, multiple opera-tors or multiple laboratories, can be established by employingstatistical methods.B. VERIFICATION OF SCLEROSCOPE HARDNESS INSTRUMENTS11. Scope11.1 Part B covers

49、 the procedure for the verification ofScleroscope hardness instruments by a standardized test blockmethod.12. General Requirements12.1 Before a Scleroscope hardness instrument is verified,the instrument shall be examined to ensure that:12.1.1 The instrument has been properly set up and leveledin a clamping stand resting on a vibration-free support.Hardness verifications shall only be made on test blocks withthe Scleroscope mounted in a clamping stand. Under nocircumstances shall hardness verifications be made on testblocks with the Scl