Bsi bs en 24499 1993 (1999) iso 4499 1978

This British Standard, having been prepared under the direction of the Iron and Steel Standards Policy Committee, was published under the authority of the Standards Board and comes

BRITISH STANDARD BS EN

24499:1993 ISO 4499:1978

Specification for

Hardmetals —

Metallographic

determination of

microstructure

The European Standard EN 24499:1993 has the status of a

British Standard

UDC 669.018.25:620.186

This British Standard, having

been prepared under the

direction of the Iron and Steel

Standards Policy Committee,

was published under the

authority of the Standards

Board and comes

into effect on

15 June 1993

© BSI 12-1999

The following BSI references

relate to the work on this

standard:

Committee reference ISM/65

Special announcement

BSI NewsJanuary 1993

ISBN 0 580 21922 4

Cooperating organizations

The European Committee for Standardization (CEN), under whose supervision this European Standard was prepared, comprises the national standards organizations of the following countries:

Austria Oesterreichisches Normungsinstitut Belgium Institut belge de normalisation Denmark Dansk Standardiseringsraad Finland Suomen Standardisoimisliito, r.y

France Association française de normalisation Germany Deutsches Institut für Normung e.V

Greece Hellenic Organization for Standardization Iceland Technological Institute of Iceland

Ireland National Standards Authority of Ireland Italy Ente Nazionale Italiano di Unificazione Luxembourg Inspection du Travail et des Mines Netherlands Nederlands Normalisatie-instituut Norway Norges Standardiseringsforbund Portugal Instituto Portuguès da Qualidade Spain Asociación Española de Normalización y Certificación Sweden Standardiseringskommissionen i Sverige

Switzerland Association suisse de normalisation United Kingdom British Standards Institution

Amendments issued since publication

Amd No Date Comments

BS EN 24499:1993

Contents

Page Cooperating organizations Inside front cover

4 Preparation of test piece section 3

National annex NA (informative) Committees responsible Inside back cover

ii © BSI 12-1999

National foreword

This British Standard has been prepared under the direction of the Iron and Steel Standards Policy Committee and is the English language version of

EN 24499:1993 Hardmetals — Metallographic determination of microstructure,

published by the European Committee for Standardization (CEN) It is identical with ISO 4499:1978, prepared by Technical Committee 119 “Powder metallurgy”,

of the International Organization for Standardization (ISO) with the active participation of the UK

This British Standard supersedes BS 5600-4.13:1980, which is withdrawn This edition makes no technical changes to the standard

A British Standard does not purport to include all the necessary provisions of a contract Users of British Standards are responsible for their correct application

Compliance with a British Standard does not of itself confer immunity from legal obligations.

Summary of pages

This document comprises a front cover, an inside front cover, pages i and ii, the EN title page, pages 2 to 6, an inside back cover and a back cover

This standard has been updated (see copyright date) and may have had amendments incorporated This will be indicated in the amendment table on the inside front cover

EUROPEAN STANDARD

NORME EUROPÉENNE

EUROPÄISCHE NORM

EN 24499 April 1993

UDC 669.018.25:620.186

Descriptors: Powder metallurgy, hard metals, metallography, microscopic analysis, microstructure, grain structure

English version

Hardmetals — Metallographic determination of

microstructure

(ISO 4499:1978)

Métaux-durs — Détermination

métallographique de la microstructure

(ISO 4499:1978)

Hartmetalle — Metallographische Bestimmung der Mikrostruktur

(ISO 4499:1978)

This European Standard was approved by CEN on 1993-04-02 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 without 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 made 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,

Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy,

Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and

United Kingdom

CEN

European Committee for Standardization Comité Européen de Normalisation Europäisches Komitee für Normung

Central Secretariat: rue de Stassart 36, B-1050 Brussels

© 1993 Copyright reserved to CEN members

Ref No EN 24499:1993 E

© BSI 12-1999

2

Foreword

In 1992, ISO 4499:1978 Hardmetals —

Metallographic determination of microstructure was

submitted to the CEN Primary Questionnaire

procedure

Following the positive result of the CEN/CS

Proposal ISO 4499:1978 was submitted to the

Formal Vote The result of the Formal Vote was

positive

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

October 1993, and conflicting national standards

shall be withdrawn at the latest by October 1993

According to the Internal Regulations of

CEN/CENELEC, the following countries are bound

to implement this European Standard: Austria,

Belgium, Denmark, Finland, France, Germany,

Greece, Iceland, Ireland, Italy, Luxembourg,

Netherlands, Norway, Portugal, Spain, Sweden,

Switzerland and United Kingdom

EN 24499:1993

1 Scope and field of application

This International Standard specifies methods of

metallographic determination of the microstructure

of hardmetals

2 Symbols and designations

Table 1

3 Apparatus

3.1 Metallographic microscope, permitting

observations at magnifications up to 1 500 ×

3.2 Equipment for preparation of test-piece sections

4 Preparation of test-piece section

The test-piece section shall be prepared as for

metallographic examination and the surface to be

examined shall be free from grinding and polishing

marks Care shall be taken to avoid tearing out of

particles, which may lead to a wrong evaluation of

microstructure

NOTE There are several methods for preparation of hardmetal

surfaces for metallographic examination Firstly, careful coarse

grinding is carried out to remove sufficient material to ensure

that the true structure is revealed After grinding with fine

diamond grit wheels, polishing is effected by using diamond paste

or diamond powders of progressively finer grain size down

to 1 4m on rigidly supported laps of, for example, thin plastic,

thin felt or paper.

5 Procedure

The microstructure is examined by the gradual

development of phases by etching There are several

methods for etching hardmetal surfaces for

metallographic examination Examples of suitable

etching techniques are given in Table 2 Care shall

be taken to ensure that the true microstructure is

revealed

5.1 The existence of ½-type phases is determined after lightly etching the section, for example by technique 1 (see Table 2) Phases of ½-type are coloured orange to brown, while other phases are unetched Etching by technique 1 does not prevent subsequent etching by techniques 2 and 3

The whole surface is examined at a low magnification and, if necessary, at magnifications

up to 1 500 × The existence and distribution

of ½-type phases is noted and recorded

5.2 The existence of ¾-type phases is determined after etching the surface, for example by

technique 2 (see Table 2) This phase is coloured light yellowish-brown and has a typically rounded shape (see Figure 1) The etched section is examined and the existence of ¾-phase is noted and recorded Its size is estimated and recorded according

to Figure 1 as ¾-fine, ¾-medium or ¾-coarse

5.3 The existence of µ-phase is determined after etching the surface, for example by technique 3 or,

in the case of the presence of ¾-phase, by technique 2 (see Table 2) The µ-phase appears grey and often has an angular shape The etched section is examined and the existence of µ-phase is noted and recorded Its size is estimated and recorded

according to Figure 2 as µ-fine, µ-medium

or µ-coarse

5.4 The ¶-phase is identified after etching the surface, for example by technique 2 or 3 (see Table 2) This phase remains white

6 Test report

The test report shall include the following information:

a) reference to this International Standard; b) all details necessary for identification of the test sample;

c) the result obtained;

d) all operations not specified by this International Standard, or regarded as optional; e) details of any occurrence which may have affected the result

Symbol Designation

µ-phase Tungsten carbide

¶-phase Binder phase (for example based on

Co, Ni, Fe)

¾-phase Carbide having a cubic lattice (for

example TiC, TaC) which may contain

other carbides (for example WC) in

solid solution

½-type

phases Multiple carbides of tungsten and at least one metal of the binder phase

4 © BSI 12-1999

Table 2

Etching

technique Composition of etchants Conditions of etching Application of etching

1 A Freshly prepared mixture

of equal quantities of 10

to 20 % (m/m) aqueous

solutions of potassium hexacyanoferrate(III) (potassium ferricyanide) and potassium or sodium hydroxide

Etch in mixture A at approximately 20 °C for 1 to 20 s Flush the test-piece section with water immediately, without removing the oxide layer Dry the surface carefully with acetone or alcohol without wiping

Identification

of ½-phases

2 A See technique 1 Etch at approximately 20 °C in mixture A

for 3 to 4 min Then wash in water and etch in mixture B for approximately 10 s

Next wash in water, then in alcohol, and dry the test-piece section Finally, etch in mixture A for approximately 20 s

Identification

of ¾-phase

B A mixture of equal volumes

of concentrated hydrochloric acid and water

3 A See technique 1 Etch in mixture A at approximately 20 °C

for 3 to 6 min Identification of µ-phase

NOTE The separate solutions of potassium hexacyanoferrate(III) and potassium or sodium hydroxide may be stored for a long time, but must be freshly mixed each day when used.

EN 24499:1993

Figure 1 — ¾-phase × 1 500

6 © BSI 12-1999

Figure 2 — µ-phase × 1 500

BS EN 24499:1993

© BSI 12-1999

National annex NA (informative)

Committees responsible

The United Kingdom participation in the preparation of this European Standard was entrusted by the Iron and Steel Standards Policy Committee (ISM/-) to Technical Committee ISM/65 upon which the following bodies were represented:

British Hardmetal Association

Federation of British Engineers (Test Manufacturers)

Society of Motor Manufacturers and Traders Limited

Coopted member

389 Chiswick High Road

London

W4 4AL

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