SIST EN ISO 642:2002
(Main)Steel - Hardenability test by end quenching (Jominy test) (ISO 642:1999)
Steel - Hardenability test by end quenching (Jominy test) (ISO 642:1999)
Method for determining the hardenability of steel by the end quench, (Jominy test), by using a test piece of 25 mm diameter and 100 mm long.
Stähle - Stirnabschreckversuch (Jominy-Versuch) (ISO 642:1999)
Diese Internationale Norm legt das Verfahren zur Ermittlung der Härtbarkeit von Stahl durch den Stirnabschreckversuch (Jominy-Versuch) an einer Probe mit 25 mm Durchmesser und 100 mm Länge fest. Anmerkung: Der in dieser Internationalen Norm beschriebene Versuch kann nach Vereinbarung und für einen bestimmten Anwendungsbereich durch die Berechnung der Jominy-Kurve nach einem anerkanntenmathematischen Verfahren (siehe Anhang C) ersetzt werden. In Schiedsfällen muß der Versuch durchgeführt werden.
Acier - Essai de trempabilité par trempe en bout (essai Jominy) (ISO 642:1999)
La présente Norme internationale spécifie la méthode de détermination de la trempabilité de l'acier par trempe en bout (essai Jominy), à l'aide d'une éprouvette de 25 mm de diamètre et 100 mm de longueur.NOTE Par accord et pour un domaine donné d'application, l'essai décrit dans la présente Norme internationale peut être remplacé par le calcul de la courbe Jominy conformément à un modèle mathématique accepté (voir annexe C). En cas de litige, l'essai doit être effectué.
Jeklo - Preskus kaljivosti jekla po Jominyju (ISO 642:1999)
General Information
Relations
Standards Content (Sample)
SLOVENSKI STANDARD
SIST EN ISO 642:2002
01-junij-2002
Jeklo - Preskus kaljivosti jekla po Jominyju (ISO 642:1999)
Steel - Hardenability test by end quenching (Jominy test) (ISO 642:1999)
Stähle - Stirnabschreckversuch (Jominy-Versuch) (ISO 642:1999)
Acier - Essai de trempabilité par trempe en bout (essai Jominy) (ISO 642:1999)
Ta slovenski standard je istoveten z: EN ISO 642:1999
ICS:
77.040.99 Druge metode za Other methods of testing of
preskušanje kovin metals
77.080.20 Jekla Steels
SIST EN ISO 642:2002 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
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SIST EN ISO 642:2002
INTERNATIONAL ISO
STANDARD 642
Second edition
1999-09-01
Steel — Hardenability test by end
quenching (Jominy test)
Acier — Essai de trempabilité par trempe en bout (essai Jominy)
A
Reference number
ISO 642:1999(E)
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SIST EN ISO 642:2002
ISO 642:1999(E)
Contents Page
1 Scope .1
2 Normative references .1
3 Principle.1
4 Symbols and designations .2
5 Form of test pieces and their preparation.2
6 Apparatus .3
7 Heating and quenching of test piece.6
8 Preparation for, and measurement of, hardness after quenching.6
9 Expression of results .7
10 Test report .8
Annex A (informative) Specification for the hardenability of a product .10
Annex B (informative) Additional information to clause 10 .13
Annex C (informative) Calculation of the hardenability.15
Bibliography.16
© ISO 1999
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic
or mechanical, including photocopying and microfilm, without permission in writing from the publisher.
International Organization for Standardization
Case postale 56 • CH-1211 Genève 20 • Switzerland
Internet iso@iso.ch
Printed in Switzerland
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© ISO
ISO 642:1999(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO
member bodies). The work of preparing International Standards is normally carried out through ISO technical
committees. Each member body interested in a subject for which a technical committee has been established has
the right to be represented on that committee. International organizations, governmental and non-governmental, in
liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical
Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 3.
Draft International Standards adopted by the technical committees are circulated to the member bodies for voting.
Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote.
International Standard ISO 642 was prepared by Technical Committee ISO /TC 17 Steel, Subcommittee SC 7,
Methods of testing (other than mechanical tests and chemical analysis).
This second edition cancels and replaces the first edition (ISO 642:1979) which has been technically revised.
Annexes A, B, and C of this International Standard are for information only.
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SIST EN ISO 642:2002
INTERNATIONAL STANDARD © ISO ISO 642:1999(E)
Steel — Hardenability test by end quenching (Jominy test)
1 Scope
This International Standard specifies a method for determining the hardenability of steel by end quenching (Jominy
test) by using a test piece 25 mm in diameter and 100 mm long.
NOTE By agreement and for a defined field of application, the test described in this International Standard may be replaced by
the calculation of the Jominy curve in accordance with an accepted mathematical model (see annex C). In case of dispute, the
test shall be carried out.
2 Normative references
The following normative documents contain provisions which, through reference in this text, constitute provisions of
this International Standard. For dated references, subsequent amendments to, or revisions of, any of these
publications do not apply. However, parties to agreements based on this International Standard are encouraged to
investigate the possibility of applying the most recent editions of the normative documents indicated below. For
undated references, the latest edition of the normative document referred to applies. Members of ISO and IEC
maintain registers of currently valid International Standards.
Metallic materials — Vickers hardness test — Part 1: Test method.
ISO 6507-1,
ISO 6508-1, Metallic materials — Rockwell hardness test — Part 1: Test method (scales A, B, C, D, E, F, G, H, K,
N, T)
.
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 6508-3, Metallic materials — Rockwell hardness test — Part 3: Calibration of reference blocks (scales A, B, C,
D, E, F, G, H, K, N, T).
3 Principle
The test consists of:
a) heating a cylindrical test piece to a specified temperature in the austenitic range for a specified period of time;
b) quenching it by spraying water on one of its ends under specified conditions;
c) measuring the hardness at certain given points, on longitudinal flats made on the test piece, in order to
determine the hardenability of the steel by variations of this hardness.
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4 Symbols and designations
Symbol Designation Value
Total length of test piece
L
(100 ± 0,5) mm
D Diameter of test piece +05,
25 mm
()
0
Time during which test piece is maintained at heating temperature +5
t
30 min
()
0
t Maximum time lag between removal of test piece from furnace and start 5 s
m
of quenching
Temperature of cooling water
T
(20 ± 5) °C
a Internal diameter of vertical water supply pipe
(12,5 0,5) mm
±
h Height of water jet without test piece in position
(65 ± 10) mm
Distance from end of water supply pipe to lower end of test piece
l
(12,5 ± 0,5) mm
e Depth of flats for measurement of hardness (0,4 to 0,5) mm
d Distance, in millimetres, from quenched end to points where hardness is measured
Jxx-d Jominy hardenability index at distance d, in Rockwell HRC-mm
JHVxx-d Jominy hardenability index at distance d, in Vickers HV 30-mm
5 Form of test pieces and their preparation
5.1 Sampling
In the absence of specific requirements in the product standard, and unless otherwise agreed on the order and
regardless of the thickness (or diameter) of the product, the sampling of test piece from the product can be made:
either by hot rolling or forging of test piece with 30 mm to 32 mm diameter;
+ 05, + 5
or by machining of test piece with diameter 25 mm whose axis shall be at least at 20 mm from the
() ()
0 0
surface product (see Figure 1).
In case of products from continuous casting, a minimum reduction ratio 8:1 is recommended before sampling.
In all the forming processes preceding the machining of the test piece, the deformation of the product from all sides
should be as uniform as possible.
In the case of a separately cast reference test piece, the original cross section before deformation must be at least
three times that corresponding to the required diameter of 30 mm to 32 mm.
By special agreement, the test piece can be obtained by a suitable casting process and tested in the as-cast
condition.
The flats of the test piece shall have their axes at approximately the same distance from the product surface (see
Figure 1). For this purpose, the test piece shall be marked so that its position in the round bar can be clearly
recognized.
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5.2 Dimensions
The test piece shall consist of a round bar machined to a diameter of 25 mm and a length of 100 mm.
5.2.1
5.2.2 The end of the test piece which will not be quenched shall be 30 mm to 32 mm or 25 mm in diameter,
depending upon the form of that end. Two examples, test pieces with a flange or an undercut (to permit rapid
centring and fitting in position for the quenching operation by means of an appropriate support) are shown in
Figure 2.
5.2.3 The test piece shall, if necessary, be marked (on the end opposite to the end to be quenched) to enable its
position to be identified in relation to the original product.
5.3 Heat treatment
Unless otherwise agreed, the test piece shall be normalized before machining and quenching. The normalizing
process shall be carried out at the average temperature within the range specified in the material standard. If the
material standard does not specify a temperature for normalizing, the normalizing temperature shall be subject to
special agreement or duly selected by the testing department. The holding time at normalizing temperature shall be
+5
30 min .
()
0
The heat treatment shall be carried out in each case in such a way that the finish-machined test piece shows
absolutely no traces of decarburization.
5.4 Machining
The cylindrical surface of the test piece shall be machined by fine turning; the surface of the test piece end to be
quenched shall have a reasonably fine finish, preferably obtained by fine grinding, and should be free from burrs
(see Figure 2).
6 Apparatus
The apparatus consists of a device for quenching the test piece.
6.1 The quenching device consists essentially of a means of suddenly inducing the water jet to impinge on the end
of the test piece to be quenched. This can be realized e.g., by a quick action tap and a system to adjust the flow
rate of the water or a disc allowing the water jet to be released and cut off rapidly (see Figure 3). In the case of a
quick action tap the length of the water supply pipe behind the tap shall be at least 50 mm in order to ensure non-
turbulent water flow.
6.2 The relative positions of the end of the water supply pipe and the test piece support shall be such that the
distance between the end of the water supply pipe and the test piece end to be quenched is (12,5 ± 0,5) mm (see
Figure 3).
6.3 The test piece support shall allow precise centring of the test piece above the end of the water supply pipe and
the holding of it in position during spraying. It shall be dry while the test piece is being placed in position; the test
piece shall be protected from water splashes while it is being placed in position as well as before and during the
actual end quenching operation.
6.4 The height of the water jet above the end of the water supply pipe without the test piece in position shall be
(65 ± 10) mm (see Figure 4).
The water temperature in the pipe shall be (20 ± 5) °C.
In the case of comparative tests, tests shall be carried out with the same water temperature.
6.5 The test piece shall be protected from draughts throughout the heating and quenching.
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Dimensions in millimetres
Key
1 Test flats.
Figure 1 — Sampling by machining of the test piece
Dimensions in millimetres
a) test piece with flange b) test piece with undercut
Figure 2 — Dimensions of test piece
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Dimensions in millimetres
Key
1 Device for fixing and centring the test piece. 4 End of water supply pipe.
2 Test piece in position. 5 Quick-action tap.
3 Disc. 6 Water supply pipe.
Figure 3 — Diagram of quenching device
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Dimensions in millimetres
Key
1 Height of free water jet.
2 Diameter of end of water supply pipe.
Figure 4 — End of water supply pipe
7 Heating and quenching of test piece
7.1 Heating
7.1.1 The test piece shall be heated uniformly to the temperature specified in the relevant product standard or fixed
+5
by special agreement for at least 20 min and then maintained for 30 min at the agreed-upon temperature. For
()
0
particular types of furnace, this period can be determined as a result of previous experience establishing the
minimum time necessary for the centre of the test piece to reach the desired temperature (this temperature can be
verified by means of, e.g., a thermocouple placed in a hole drilled along the axis of the test piece at the head end).
7.1.2 Precautions shall be taken to minimize decarburization or carburization of the test piece, and to avoid any
marked oxidation with formation of scale.
7.2 Quenching
The time between removal of the test piece from the furnace and the commencement of spraying shall not
7.2.1
exceed 5 s.
During its removal from the furnace and positioning in the holder, the test piece shall only be held with the tongs at
the end which is not to be quenched either on the flange side or the undercut side.
7.2.2 The time of spraying shall be at least 10 min. After this time, the cooling of the test piece can be completed
by immersing it in cold water.
8 Preparation for, and measurement of, hardness after quenching
8.1 Two flats for measuring the hardness shall be ground on the surface 180° apart and parallel to the axis of the
test piece. In the case of test pieces prepared by machining, the two flats shall be at the same distance from the
product surface (see Figure 1). They shall be from 0,4 mm to 0,5 mm deep. These flats shall be machined using an
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abundant supply of coolant with fine grinding wheel to avoid any heating which is likely to modify the microstructure
of the test piece.
8.2 It should be ascertained, as follows, that no softening has been caused by grinding: immerse the test piece in a
5 % (V/V) nitric acid solution in water until it is completely blackened. The colour obtained shall be uniform.
If there are any stains, indicating the presence of soft spots, two new flats shall be made at 90° and etched as
stated above to make sure that these were acceptable. In this case, the hardness measurement shall be carried out
on the second set of flats and this fact shall be recorded in the test report.
8.3 Precautions shall be taken to ensure that the test piece is well supported and is rigidly held during the
hardness measurements.
The device for moving the test piece on the hardness testing machine shall allow accurate centring of the flat and
spacing of the indentations to within ± 0,1 mm. The latter are made along the axis of the flat, in accordance with
ISO 6508-1, ISO 6508-2 and ISO 6508-3.
8.3.1 By special agreement, the Rockwell C hardness measurements may be replaced by measurements of
Vickers hardness HV 30 in accordance with ISO 6507-1.
8.3.2 It is necessary to ensure that any raised edges of hardness indentations on the first flat do not influence the
measurements on the second flat.
8.4 The positions of the measurement points shall be such that one or the other of the following two determinations
can be made:
a) drawing of a curve representing variations in hardness (see 8.4.1);
b) determination of hardness at one or more specified points (see 8.4.2).
8.4.1 Drawing of a curve representing variations in hardness
8.4.1.1 In the general case, the distances, expressed in millimetres, of the first eight points taken from the
quenched end are a
...
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