1、BRITISH STANDARDBS EN 843-4:2005Advanced technical ceramics Mechanical properties of monolithic ceramics at room temperature Part 4: Vickers, Knoop and Rockwell superficial hardnessThe European Standard EN 843-4:2005 has the status of a British StandardICS 81.060.30g49g50g3g38g50g51g60g44g49g42g3g58
2、g44g55g43g50g56g55g3g37g54g44g3g51g40g53g48g44g54g54g44g50g49g3g40g59g38g40g51g55g3g36g54g3g51g40g53g48g44g55g55g40g39g3g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g58BS EN 843-4:2005This British Standard was published under the authority of the Standards Policy and Strategy Committee on 31 January 2
3、007 BSI 2007ISBN 978 0 580 49928 9National forewordThis British Standard was published by BSI. It is the UK implementation of EN 843-4:2005. It supersedes DD ENV 843-4:1995 which is withdrawn.The UK participation in its preparation was entrusted to Technical Committee RPI/13, Advanced technical cera
4、mics.A list of organizations represented on RPI/13 can be obtained on request to its secretary.This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application.Compliance with a British Standard cannot confer immunity from leg
5、al obligations.Amendments issued since publicationAmd. No. Date CommentsEUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 843-4 June 2005 ICS 81.060.30 Supersedes ENV 843-4:1994 English version Advanced technical ceramics - Mechanical properties of monolithic ceramics at room temperature - Part 4
6、: Vickers, Knoop and Rockwell superficial hardness Cramiques techniques avances - Proprits mcaniques des cramiques monolithiques temprature ambiante- Partie 4: Essais de duret Vickers, Knoop et Rockwell surperficiel Hochleistungskeramik - Mechanische Eigenschaften monolithischer Keramik bei Raumtemp
7、eratur - Teil 4: Hrteprfung nach Vickers, Knoop und Rockwell This European Standard was approved by CEN on 29 April 2005. CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard witho
8、ut any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the Central Secretariat or to any CEN member. This European Standard exists in three official versions (English, French, German). A version in any other language ma
9、de by translation under the responsibility of a CEN member into its own language and notified to the Central Secretariat has the same status as the official versions. CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany
10、, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG Management
11、Centre: rue de Stassart, 36 B-1050 Brussels 2005 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 843-4:2005: EEN 843-4:2005 (E) 2 Contents Page Foreword 3 1 Scope. 4 2 Normative references. 4 3 Terms and definitions 5 4 Significanc
12、e and use 5 4.1 General points 5 4.2 Verification of test equipment . 5 4.3 Conversion of hardness numbers to other scales. 6 5 Test method: method A: Vickers test 6 5.1 Principle 6 5.2 Machine calibration 7 5.3 Test piece 7 5.4 Test procedure 8 5.5 Accuracy and uncertainties. 8 6 Test method: Metho
13、d B: Knoop test .9 6.1 Principle 9 6.2 Machine calibration 10 6.3 Test piece 10 6.4 Test procedure 10 6.5 Accuracy and uncertainties. 11 7 Test method: Method C: Rockwell tests. 11 7.1 Principle 11 7.2 Machine calibration 11 7.3 Test piece 12 7.4 Test procedure 12 7.5 Accuracy and uncertainties. 12
14、8 Interpretation 13 8.1 Microstructural factors. 13 8.2 Interpretation of results . 13 9 Test report. 13 Annex A (informative) Interlaboratory evaluation of hardness test methods . 19 Bibliography 21 EN 843-4:2005 (E) 3 Foreword This document (EN 843-4:2005) has been prepared by Technical Committee
15、CEN/TC 184 “Advanced technical ceramics”, the secretariat of which is held by BSI. This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by December 2005, and conflicting national standards shall be withdr
16、awn at the latest by December 2005. EN 843 Advanced technical ceramics Mechanical properties of monolithic ceramics at room temperature consists of six parts: Part 1: Determination of flexural strength Part 2: Determination of Youngs modulus, shear modulus and Poissons ratio Part 3: Determination of
17、 subcritical crack growth parameters from constant stressing rate flexural strength tests Part 4: Vickers, Knoop and Rockwell hardness tests Part 5: Statistical analysis Part 6: Guide for fractographic investigation This document supersedes ENV 843-4:1994. According to the CEN/CENELEC Internal Regul
18、ations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, No
19、rway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. EN 843-4:2005 (E) 4 1 Scope This part of EN 843 defines conditions for conducting, and provides guidelines concerning the value that may be ascribed to the results of, standard hardness tests when applied to a
20、dvanced monolithic technical ceramics. It is assumed that the calibration and test procedures employed are exactly those for metallic materials. This European Standard refers to Rockwell A, Rockwell N-scale, Vickers, and Knoop hardness testing, as described in existing international standards. 2 Nor
21、mative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. EN ISO 6507-1, Metallic materia
22、ls Vickers hardness test Part 1: Test method (ISO 6507-1:1997) EN ISO 6507-2, Metallic materials Vickers hardness test Part 2: Verification of testing machines (ISO 6507-2:1997) EN ISO 6507-3, Metallic materials Vickers hardness test Part 3: Calibration of reference blocks (ISO 6507-3:1997) EN ISO 6
23、508-1, Metallic materials Rockwell hardness test Part 1: Test method (scales A, B, C, D, E, F, G, H, K, N, T) (ISO 6508-1:1999) EN ISO 6508-2, Metallic materials Rockwell hardness test Part 2: Verification and calibration of testing machines (scales A, B, C, D, E, F, G, H, K, N, T) (ISO 6508-2:1999)
24、 EN ISO 6508-3, Metallic materials Rockwell hardness test Part 3: Calibration of reference blocks (scales A, B, C, D, E, F, G, H, K, N, T) (ISO 6508-3:1999) EN ISO/IEC 17025, General requirements for the competence of testing and calibration laboratories (ISO/IEC 17025:1999) EN ISO 23878, Hardmetals
25、 Vickers hardness test (ISO 3878:1983) ISO 4545, Metallic materials Hardness testing Knoop test ISO 4546, Metallic materials Hardness test Verification of Knoop hardness testing machines ISO 9385, Glass and glass-ceramics Knoop hardness test ISO 14705, Fine ceramics (advanced ceramics, advanced tech
26、nical ceramics) Test method for hardness of monolithic ceramics at room temperature OIML-36, Verification of indenters for hardness testing machines.1)1This international recommendation is available from the International Organization of Legal Metrology (OIML), 11, rue Tugot, 75009, Paris, France).
27、EN 843-4:2005 (E) 5 3 Terms and definitions For the purposes of this European Standard, the following terms and definitions apply. 3.1 hardness resistance displayed by a material to penetration by a hard indenter of defined geometry and forced into the test surface in a prescribed manner 3.2 hardnes
28、s number hardness calculated in a specified hardness test, usually without units specified, derived from the depth of penetration of the indenter or lateral dimension of the indentation, and the applied force 3.3 hardness indenter hard device of defined geometry, and for the purposes of testing cera
29、mics usually fabricated from single-crystal diamond NOTE Types of hardness test are defined in clause 5, 6, and 7 for Vickers, Knoop and Rockwell tests respectively. 4 Significance and use 4.1 General points The three types of test defined in clauses 5, 6 and 7 have been standardised for metallic ma
30、terials, and are widely used as a guide to the state of thermal treatment or work-hardening. In advanced technical ceramics they are also widely used, especially to describe materials for applications in a wear environment. Whereas in a metal a hardness test is a measure of the yield stress, in a br
31、ittle material the deformation tends not to be homogeneous. In addition to plastic flow, there is usually some cracking and fragmentation occurring, the extent of which has a marked effect on the apparent hardness and the ability to perform meaningful measurements. A hardness test on a range of wide
32、ly differing ceramics will enable them to be ranked in order of resistance to localised penetration, which may be correlated with other behavioural characteristics of similar type, e.g. abrasive wear or erosion resistance. Such an interpretation may not be possible if materials show similar characte
33、ristics because the discrimination shown by hardness tests may be inadequate. Uses beyond this application should be viewed with caution. It is, for example, recommended that hardness tests are not used as a pass/fail criterion in a specification. The potential differences between observers and/or t
34、est machines, as explained below, are too great for high levels of confidence in the test results, leading to possible dispute between parties to the specification. 4.2 Verification of test equipment Hardness standard test blocks are usually supplied with the test machine. It is imperative that they
35、 be used for checking the machine behaviour and, in the case of Vickers and Knoop tests, also the visual criteria being employed by the operator for measurement. The test block should also be used to ensure that the indenter is free from chips or cracks which might easily develop when used on very h
36、ard materials. Very high hardness calibration blocks are recommended when testing ceramics. The test force for hardness measurements on ceramics may not be the normal one for which the test machine has previously been calibrated. If this situation occurs, it is desirable to carry out checks that the
37、 intended force is actually being applied to the test surface for the required period of time. EN 843-4:2005 (E) 6 Direct verification of test equipment is described in EN ISO 6507-2 (for Vickers tests), ISO 4546 (for Knoop tests) and in EN ISO 6508-2 (for Rockwell N-scale tests). The procedure invo
38、lves calibration of force and of the reading system. This document does not deal directly with such issues. Indirect verification of test equipment ensures that the equipment is reading correctly at the time of use, by providing a check on the quality of indentations, particularly whether there is d
39、amage to the indenter and whether the indenter is correctly aligned. It can also provide a check on the reading criterion being used by the operator. Indirect verification is normally conducted using certified reference blocks, and by ensuring that the indenter being used has previously been certifi
40、ed as being geometrically within the tolerances defined in the above standards. Calibration of standard reference blocks is described in EN ISO 6507-3 (for Vickers tests), and in EN ISO 6508-3 (for Rockwell N-scale tests). There are currently no CEN or ISO standards for Knoop test block verification
41、 and calibration. Verification of the geometry of indenters is dealt with in OIML-36. 4.3 Conversion of hardness numbers to other scales Whereas for metallic materials there are conversion tables to convert between various hardness numbers on particular alloy types, there is no equivalent for cerami
42、c materials. Since ceramics tend to show a strong force dependence of hardness characteristics, it is highly unlikely that there could be a unique relationship between hardness values determined using different forces or different types of indenter. NOTE Attempts to convert hardness numbers from one
43、 scale to another are strongly discouraged. 5 Test method: method A: Vickers test 5.1 Principle A hardness test in which a square-based sharp pyramidal diamond indenter having specified face angles is forced into the test-piece surface under a defined force, held for a defined duration and removed.
44、The indentation diagonal lengths are measured, the mean result calculated, and this value then employed to calculate a hardness number which is equivalent to the mean force per actual unit area of indenter surface contacting the test surface (no units are given, but kgf/mm2are implied): HV F = 1,854
45、4 F/d 2(1) where HV F is the Vickers hardness number at applied force F (expressed as the mass in kg from which F is derived), and where d is the mean length of the diagonals of the indentation (expressed as mm). The Vickers test for metallic materials is described in detail in EN ISO 6507-1 for app
46、lied forces derived from masses of 0,2 - 100 kg, in EN ISO 23878 for hardmetals, and in ISO 14705 for advanced technical ceramics. NOTE 1 Other references to the Vickers test method, including microhardness tests may be found in references 1 and 2 of the Bibliography. In accordance with ISO 14705 an
47、d for the purposes of this document the use of SI units is preferred. In the use of equation (1), when F is expressed in newtons ( = mass in kg 9,807) and d is expressed in mm, the hardness HV is then computed in MPa. The results shall be expressed as, for example: 15,0 GPa HV 1,0 for a test under a
48、 force of 9,807 N derived from a mass of 1 kg. EN 843-4:2005 (E) 7 Unless otherwise agreed between parties, for the purposes of testing advanced monolithic technical ceramics, the applied force shall be that derived from a mass of 1,0 kg (i.e. 9,807 N), i.e. test type HV1,0. NOTE 2 If this force res
49、ults in excessive cracking, or indentations which are not readable (see 5.4), then a lower force is permitted. A higher force is permitted if there is minimal cracking associated (see 5.4). 5.2 Machine calibration 5.2.1 Direct verification Ensure that the test machine is constructed and has been directly verified in conformity with EN ISO 6507-2. Using a metallic reference block certified in accordance with EN ISO 6507-3, make at least three indentations at a test force of HV 1,0. Ensure that the correct cross-hair p
