1、ICS 71.060.10Prfung von Kohlenstoffmaterialien Hrteprfung nachRockwell Verfahren mit Kugel; FeststoffeIn keeping with current practice in standards published by the International Organization for Standardization(ISO), a comma has been used throughout as the decimal marker.Ref. No. DIN 51917 : 2002-1
2、2English price group 07 Sales No. 010707.03DEUTSCHE NORM December 200251917 No part of this translation may be reproduced without the prior permission ofDIN Deutsches Institut fr Normung e.V., Berlin. Beuth Verlag GmbH, 10772 Berlin, Germany,has the exclusive right of sale for German Standards (DIN-
3、Normen).Translation by DIN-Sprachendienst.In case of doubt, the German-language original should be consulted as the authoritative text.Rockwell hardness testing of carbonaceousmaterials by the steel ball indentation methodContinued on pages 2 to 5.ForewordThe December 1997 edition of this standard h
4、as been revised by Technical Committee Prfverfahren frKohlenstoff und Graphit of the Normenausschuss Materialprfung (Materials Testing Standards Committee)taking into account DIN EN ISO 6508-1 (which has superseded DIN EN 10109-1) on which it was based.AmendmentsThis standard differs from the Decemb
5、er 1997 edition in that the steel ball has been replaced by a hard-metalball, details relating to the test pieces have been changed, the text has been editorially revised and refer-ences have been updated.Previous editionsDIN 51917: 1987-10, 1997-12.1 ScopeThis standard specifies a method of determi
6、ning the Rockwell hardness of carbon/graphite materials, whichcan also be used to determine the hardness of metal/graphite materials such as those of carbon brushesfor use in electrical machinery.NOTE: In this standard, the ball indentation method specified in DIN EN ISO 6508-1 has been modified tob
7、e suitable for carbonaceous materials.2 Normative referencesThis standard incorporates, by dated or undated reference, provisions from other publications. Thesenormative references are cited at the appropriate place in the text and the titles of the publications are listedbelow. For dated references
8、, subsequent amendments to or revisions of any of these publications apply tothis standard only when incorporated into it by amendment or revision. For undated references, the latestedition of the publication referred to applies.DIN 1333 Presentation of numerical dataDIN 51200 Design and application
9、 of test piece holding devices in hardness testing machinesSupersedesDecember1997 edition.Page 2DIN 51917 : 2002-12DIN EN ISO 6506-2 Metallic materials Brinell hardness Part 2: Verification and calibration of testingmachines (ISO 6506-2 : 1999)DIN EN ISO 6508-1 Metallic materials Rockwell hardness t
10、est Part 1: Test method (scales A, B, C, D, E,F, G, H, K, N, T) (ISO 6508-1 : 1999)DIN EN ISO 6508-2 Metallic materials Rockwell hardness test Part 2: Verification and calibration of testingmachines (scales A, B, C, D, E, F, G, H, K, N, T) (ISO 6508-2 : 1999)IEC 413 Test procedures for determining t
11、he physical properties of brush materials for electricalmachinesISO 5725-1 : 1994 Accuracy (trueness and precision) of measurement methods and results Part 1: Generalprinciples and definitionsISO 5725-2 : 1994 Accuracy (trueness and precision) of measurement methods and results Part 2: Basicmethod f
12、or the determination of repeatability and reproducibility of a standard measure-ment method3 PrincipleA hard-metal ball indenter is forced into a test piece in two stages under the conditions specified in clause 9,and the permanent depth of the indentation, h, produced by the initial test force is m
13、easured after removingthe additional test force. The Rockwell hardness number, HR, is then determined using the following equation(cf. table 1):hRockwell hardness, HR = N S4 Quantities, symbols and unitsSee tables 1 and 2 and figure 1.Table 1: Quantities, symbols and unitsSymbol Quantity UnitF0Initi
14、al test force NF1Additional test force NF Total test force NS Scale unit mmN Hardness number specific to the scale hPermanent indentation depth at F0mmafter removing additional test forceePermanent indentation depth, expressed inmultiples of S, i.e. 0,002 mm or 0,001 mm.HR 10/20, HR 5/20HR 10/40, HR
15、 5/40 hHR 10/60, HR 5/60 Rockwell hardness HR = 130 HR 10/100, HR 5/100 0,002HR 10/150, HR 5/150hHR 5/7, HR 2,5/7 Rockwell hardness HR = 100 0,001Page 3DIN 51917 : 2002-12Table 2: Test forces5 DesignationDesignation of a Rockwell hardness test1) (HR) in accordance with this standard, determined with
16、 an indenterof diameter (10 t 0,005) mm (10) and a total test force of 60 daN (60):Test DIN 51917 HR 10/606 Apparatus6.1 Testing machine, capable of applying the test forces specified in table 2 and conforming toDIN EN ISO 6508-2.6.2 Hard-metal ball indenter, having a diameter of (10 t 0,005) mm, (5
17、 t 0,004) mm or (2,5 t 0,003) mm andmeeting the requirements specified in DIN EN ISO 6506-2.6.3 Depth-measuring device, conforming to DIN EN ISO 6508-2.7 SamplingSampling shall be subject to agreement.8 Test piecesTest pieces of any size may be used, provided that they meet the following requirement
18、s.a) The thickness is such that no deformation is visible on the back of the test piece after testing. (Theminimum thickness will depend on the material of the test piece and may need to be determined by experi-ment.b) The surfaces of test pieces are flat and the arithmetical mean deviation of the p
19、rofile, Ra, is no greaterthan 5 m.1) Cf. section 303.2 of IEC 413.HardnesssymbolDiameterof ballindenter,in mmHardnessnumber,NScale unit,S,in mmInitial testforce,F0,in NAdditional testforce,F1,in NTotal test force,F,in NPage 4DIN 51917 : 2002-129 ProcedureTesting shall be carried out at an ambient te
20、mperature of between 10 C and 35 C.Place the test piece on a supporting surface or in a holder so that the surface to be indented is normal to thedirection of the indenting force.Since any permanent change in the position of the test piece caused by the applied test force affects themeasured indenta
21、tion depth, the contact surfaces of the test piece and support or holder shall be free of foreignmatter, such as grease or dust. If its shape allows, the test piece shall be clamped in the machine (cf. DIN 51200).Press the test piece against the steel ball indenter until the initial force, F0, is re
22、ached and then set the datumposition of the measuring device at the hardness number, N.Avoiding shock and vibration as far as possible, slowly apply the additional force, F1, for five to eight secondsuntil the total force, F, is reached. Maintain this force until the reading is steady (which normall
23、y takes ten totwenty seconds).Now remove the additional force, avoiding shock and vibration as far as possible. The Rockwell hardness canusually be read directly from the measuring device, but if necessary, determine it from the permanent inden-tation depth, h (see figure 1).1 Initial test force2 Su
24、rface of test piece3 Datum linea Indentation depth due to initial test force, F0b Indentation depth due to additional test force, F1c Recovery after removal of additional test forced Permanent indentation depth, hFigure 1: Principle of Rockwell hardness testThe distance between the centres of two ad
25、jacent indentations and that from the centre of each indentation tothe edge of the test piece shall be at least equal to the ball diameter or 2,5 times the diameter of the indentation,unless otherwise agreed.If the mean value obtained is greater than 110 or less than 30, repeat the measurement after
26、 selecting a moresuitable indenter diameter and test forces from table 2.10 EvaluationMost testing machines give a direct reading of the Rockwell hardness; where this is not the case, calculate theRockwell hardness, HR / (ball diameter/total test force), using the following equations:he =SHR / = N e
27、Rounding of results shall be in accordance with DIN 1333.11 Test reportThe test report shall refer to this standard and include the following information:a) type, position, orientation and identification of test pieces;b) number of test pieces;c) ball diameter and total test force;abdcPage 5DIN 5191
28、7 : 2002-12d) Rockwell hardness obtained and the mean of all results, both rounded to the nearest integer;e) any agreed deviations from this standard;f) date of testing.12 Precision(cf. ISO 5725-1 and ISO 5725-2)The following characteristics shall be used to assess the reliability of results.Repeata
29、bility limit(same observer, same equipment)If two results are obtained under repeatability conditions, both results shall be considered acceptable and inconformity with this standard if they differ by no more than the value shown in table 3.Reproducibility limit(different observers, different equipm
30、ent)If two laboratories each obtain a result under reproducibility conditions, both results shall be consideredacceptable and in conformity with this standard if they differ by no more than the value shown in table 3.Table 3: Repeatability and reproducibilityCarbon/graphite materials Metal/graphite materialsHR 10/40 HR 5/40 HR 10/40 HR 5/40Repeatability limit 3 5 4 7Reproducibility limit 4 8 6 9Other relevant standardASTM C 748-83 Test method for Rockwell hardness of fine-grained graphite materials (1993 revision)2)2) Obtainable from Beuth Verlag GmbH, 10772 Berlin, Germany.
