August 2018

DIN ISO 15787

D
ICS 01.100.20; 01.110; 25.200 Supersedes
DIN ISO 15787:2010­01

Technical product documentation –

Heat­treated ferrous parts –
Presentation and indications (ISO 15787:2016),
English translation of DIN ISO 15787:2018-08

Technische Produktdokumentation –
Wärmebehandelte Teile aus Eisenwerkstoffen –
Darstellung und Angaben (ISO 15787:2016),
Englische Übersetzung von DIN ISO 15787:2018-08
Documentation technique de produits –
Produits ferreux traités thermiquement –
Présentation et indications (ISO 15787:2016),
Traduction anglaise de DIN ISO 15787:2018-08
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Document comprises 40 pages

Translation by DIN-Sprachendienst.
In case of doubt, the German-language original shall be considered authoritative.

© No part of this translation may be reproduced without prior permission of English price group 16
DIN Deutsches Institut für Normung e. V., Berlin. Beuth Verlag GmbH, 10772 Berlin, Germany,
has the exclusive right of sale for German Standards (DIN-Normen).
www.din.de
www.beuth.de
!%zL)"
08.18 2874106
 DIN ISO 15787:2018-08

A comma is used as the decimal marker.

Contents
Page
National foreword ................................................................................................................................................................................................................... 4
National Annex NA (informative) Bibliography ............................................................................................................................................ 5
Foreword...........................................................................................................................................................................................................................................6
Introduction................................................................................................................................................................................................................................... 7
1 Scope.................................................................................................................................................................................................................................. 7
2 Normative references....................................................................................................................................................................................... 7
3 Terms, definitions.
............................................................................................................................................................................................... 7
4 Abbreviated terms............................................................................................................................................................................................... 8
5 Indications in drawings.................................................................................................................................................................................. 8
5.1 General............................................................................................................................................................................................................ 8
5.2 Material data........................................................................................................................................................................................... 10
5.3 Heat‐treatment condition............................................................................................................................................................ 10
5.4 Hardness data........................................................................................................................................................................................ 10
5.4.1 Surface hardness............................................................................................................................................................ 10
5.4.2 Core hardness................................................................................................................................................................... 10
5.4.3 Hardness value and limit deviations............................................................................................................ 10
5.5 Markings..................................................................................................................................................................................................... 11
5.5.1 Marking of test points............................................................................................................................................... 11
5.5.2 Marking of slip zones................................................................................................................................................. 12
5.6 Key for the allocation test point and nominal value............................................................................................. 12
5.7 Indication of local areas................................................................................................................................................................ 12
5.8 Hardness depth.................................................................................................................................................................................... 13
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5.9 Carburizing depth (CD)................................................................................................................................................................. 13

5.10 Compound layer thickness (CLT).......................................................................................................................................... 14
5.11 Oxide layer thickness (OLT). ..................................................................................................................................................... 14
5.12 Strength data.......................................................................................................................................................................................... 15
5.13 Microstructure...................................................................................................................................................................................... 15
5.14 Heat‐treatment order (HTO).................................................................................................................................................... 15
5.15 Heat‐treatment document (HTD)......................................................................................................................................... 15
6 Graphical representation.......................................................................................................................................................................... 16
6.1 General......................................................................................................................................................................................................... 16
6.2 Heat‐treatment of the entire part......................................................................................................................................... 16
6.2.1 Uniform condition........................................................................................................................................................ 16
6.2.2 Areas with different conditions........................................................................................................................ 16
6.3 Local heat‐treatment....................................................................................................................................................................... 16
6.3.1 General................................................................................................................................................................................... 16
6.3.2 Areas requiring heat‐treatment. ...................................................................................................................... 17
6.3.3 Areas that may be heat‐treated. ....................................................................................................................... 17
6.3.4 Areas that shall not be heat‐treated. ............................................................................................................ 17
6.4 Heat‐treatment sketch.................................................................................................................................................................... 18
7 Practical examples............................................................................................................................................................................................18
7.1 General......................................................................................................................................................................................................... 18
7.2 Quench‐hardening, quench‐hardening and tempering, austempering. .............................................. 18
7.2.1 Heat‐treatment of the entire part — Allover uniform requirements. ............................. 18
7.2.2 Heat‐treatment of the entire part — Areas with different hardnesses.......................... 20
7.2.3 Local heat‐treatment.................................................................................................................................................. 21

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7.3 Surface-hardening ............................................................................................................................................................................. 22

7.3.1 General................................................................................................................................................................................... 22
7.3.2 Specification of surface hardness ................................................................................................................... 22
7.3.3 Specification of surface‐hardening hardness depth (SHD) ...................................................... 22
7.3.4 Practical examples ....................................................................................................................................................... 22
 7.4 Case-hardening .................................................................................................................................................................................... 28
7.4.1 Specification of surface hardness ................................................................................................................... 28
7.4.2 Specification of case‐hardening hardness depth (CHD) ............................................................. 28
7.4.3 Specification of carburizing depth (CD).................................................................................................... 29
7.4.4 Practical examples........................................................................................................................................................ 29
7.5 Nitriding and nitrocarburizing. .............................................................................................................................................. 34
7.5.1 Specification of nitriding hardness depth (NHD). ............................................................................ 34
7.5.2 Specification of compound layer thickness (CLT)............................................................................. 34
7.5.3 Practical examples........................................................................................................................................................ 35
7.6 Boriding...................................................................................................................................................................................................... 37
7.7 Annealing................................................................................................................................................................................................... 37
Annex A (normative) Graphical symbols.......................................................................................................................................................38
Bibliography.............................................................................................................................................................................................................................. 40
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 DIN ISO 15787:2018-08

National foreword
This standard (ISO 15787:2016) has been prepared by Technical Committee ISO/TC 10 “Technical product
documentation”, Subcommittee SC 6 “Mechanical engineering documentation” (Secretariat: SAC, China).

The responsible German bodies involved in its preparation were DIN-Normenausschuss Werkstofftechnologie
(DIN Standards Committee Technology of Materials), Working Committee NA 145-02-02 AA “Heat treatment
processes/Heat treatment specifications” and DIN-Normenausschuss Technische Grundlagen (DIN Standards
Committee Technical Fundamentals), Working Committee NA 152-06-05 AA “Technical product
documentation”.

The DIN documents corresponding to the international documents referred to in this document are as follows:

ISO 128-20 DIN EN ISO 128-20

ISO 2639 DIN EN ISO 2639
ISO 4885 DIN EN ISO 4885
ISO 6506-1 DIN EN ISO 6506-1
ISO 6507-1 DIN EN ISO 6507-1
ISO 6508-1 DIN EN ISO 6508-1
ISO 81714-1 DIN EN ISO 81714-1
ISO/TS 8062-2 DIN CEN ISO/TS 8062-2 (DIN SPEC 91184)

NOTE ISO 2639 has been replaced by ISO 18203.

Amendments

This standard differs from DIN ISO 15787:2010-01 as follows:

a) an indication of both states of the part has been added: 1) after the heat treatment (before final
machining) and 2) after the final machining (Figure 16 and Figure 30);
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b) examples representing the hardness values and their limiting deviations have been added (Table 1);

c) line types for the indication of local areas and their applications have been added (Table 2);

d) line type 07.2 (dotted wide line) has been added for carburized, carbonitrided, nitrided or
nitrocarburized workpieces to indicate areas where heat treatment is not allowed;

e) the representation of hardness values, hardness depths, layer thicknesses and limiting deviations has
been replaced by their values and limiting deviations (Tables 1, 3, 4 and 5);

f) marking of slip zones (5.5.2), key for the allocation test point and nominal value (5.6), indication of local
areas (5.7), oxide layer thickness (OLT) (5.11), heat-treatment order (HTO) (5.14), heat-treatment
document (HTD) (5.15) have been added;

g) the title “Drawings providing specific indication of heat treatment” has been replaced by “Heat-
treatment sketch” (6.4);

h) subclause 6.4 “Surface fusion hardening” has been deleted;

i) ini n Annex A, all tables have been deleted;

j) graphical symbols have been added (Annex A).

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Previous editions

DIN 6773: 1967-10, 2001-04

DIN 6773-2: 1977-05
DIN 6773-3: 1976-11
DIN 6773-4: 1977-05
DIN 6773-5: 1977-05
DIN ISO 15787: 2010-01

National Annex NA
(informative)

Bibliography

DIN 17023, Heat treatment of ferrous metals — (WBA) Forms — Heat-treatment order

DIN CEN ISO/TS 8062-2 (DIN SPEC 91184), Geometrical Product Specifications (GPS) — Dimensional and
geometrical tolerances for moulded parts — Part 2: Rules

DIN EN ISO 128-20, Technical drawings — General principles of presentation — Part 20: Basic conventions for
lines
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DIN EN ISO 2639, Steels — Determination and verification of the depth of carburized and hardened cases

DIN EN ISO 4885, Ferrous materials — Heat treatments — Vocabulary

DIN EN ISO 6506-1, Metallic materials — Brinell hardness test — Part 1: Test method

DIN EN ISO 6507-1, Metallic materials — Vickers hardness test — Part 1: Test method

DIN EN ISO 6508-1, Metallic materials — Rockwell hardness test — Part 1: Test method

DIN EN ISO 81714-1, Design of graphical symbols for use in the technical documentation of products — Part 1:
Basic rules

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 DIN ISO 15787:2018-08


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.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2. www.iso.org/directives
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received. www.iso.org/patents
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation on the meaning of ISO specific terms and expressions related to conformity assessment,
as well as information about ISO’s adherence to the World Trade Organization (WTO) principles in the
Technical Barriers to Trade (TBT), see the following URL: www.iso.org/iso/foreword.html.
The committee responsible for this document is Technical Committee ISO/TC 10 Technical product
documentation, Subcommittee SC 6, Mechanical engineering documentation.
This second edition of ISO 15787 cancels and replaces the first edition (ISO 15787:2001), which has
been technically revised.
In addition to a number of editorial revisions, the following main changes have been made with respect
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to the previous edition:

— addition of an indication of both states of the part: 1) after the heat treatment (before final
machining); and 2) after the final machining (Figure 16 and Figure 30);
— addition of examples representing the hardness values and their limiting deviations (Table 1);
— addition of line types for the indication of local areas and their applications (Table 2);
— addition of line type 07.2 (dotted wide line) for carburized, carbonitrided, nitrided or nitrocarburized
workpieces to indicate areas where heat treatment is not allowed;
— replacement of the representation of hardness values, hardness depths, layer thicknesses and
limiting deviations by their values and limiting deviations (Tables 1, 3, 4 and 5);
— addition of marking of slip zones (5.5.2), key for the allocation test point and nominal value (5.6),
indication of local areas (5.7), oxide layer thickness (OLT) (5.11), heat‐treatment order (HTO)(5.14),
heat‐treatment document (HTD)(5.15);
— replacement of the title of “Drawings providing specific indication of heat treatment” by “Heat‐
treatment sketch” (6.4);
— deletion of the former 6.4 surface fusion hardening in the 2001 edition;
— deletion of the Annex A tables present in the 2001 edition;
— addition of graphical symbols (Annex A).

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Introduction
Technical drawings of workpieces are the most important documents
— for construction, development and production,
— for the assembling, and
— for the use of the final products.
Generally, a drawing provides information about the workpiece, its shape and design, the material used,
the dimensions, surface behaviour, permitted abbreviations, inspection data, and more.
Workpieces made from steel and iron often have to withstand severe conditions to resist wear and
corrosion.
To attain the required properties, the workpieces are heat‐treated in most applications. A drawing is a
very important document as it also informs the heat‐treater about the parameters to be aware of for a
successful heat‐treatment. For that, he should know the material used, the required heat‐treatment, the
required hardness and hardness depth, the expected or permitted microstructure, the required testing
method and the test points for testing the heat‐treated workpiece.
In this time of global production, it is essential to dispose of an International Standard for technical
product documentation, especially for the presentation and indication of heat‐treated parts. Therefore,
ISO 15787:2001 was revised to help to improve the quality of heat‐treated workpieces.
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1 Scope
This document specifies the manner of presenting and indicating the final condition of heat‐treated
ferrous parts in technical drawings N1).

2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements 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.
ISO 128‐24:2014, Technical drawings — General principles of presentation — Part 24: Lines on mechanical
engineering drawings
ISO 4885, Ferrous products — Heat‐treatments — Vocabulary
ISO 6506‐1, Metallic materials — Brinell hardness test — Part 1: Test method
ISO 6507‐1, Metallic materials — Vickers hardness test — Part 1: Test method
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/TS 8062‐2, Geometrical product specifications (GPS) — Dimensional and geometrical tolerances for
moulded parts — Part 2: Rules
ISO 81714‐1, Design of graphical symbols for use in the technical documentation of products — Part 1:
Basic rules

3 Terms, definitions
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For the purposes of this document, the terms and definitions given in ISO 4885 apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— IEC Electropedia: available at http://www.electropedia.org/
— ISO Online browsing platform: available at http://www.iso.org/obp

N1) National footnote: In this context see 5.1.

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4 Abbreviated terms
For the purposes of this document, the following abbreviated terms apply.

CHD Case-hardening hardness depth

CD Carburizing depth

CLT Compound layer thickness

NHD Nitriding hardness depth

SHD Surface‐hardening hardness depth

HTO Heat‐treatment order

HTD Heat‐treatment document

IOD Internal oxidation depth

OLT Oxide layer thickness

5 Indications in drawings

5.1 General
Indications in drawings concerning the heat‐treatment condition can relate to the assembly or final
condition as well as to the condition directly after heat‐treatment. This difference has to be observed
implicitly, as heat‐treated parts are often subsequently machined (e.g. by grinding). By this, the
hardness depth is reduced, especially with case‐hardened, surface‐hardened and nitrided parts, as is
the compound layer thickness of nitrided and nitrocarburized parts. The machining allowance shall
therefore be taken into account appropriately during heat‐treatment. If no separate drawing is made
for the condition of the heat‐treated part before the subsequent machining or finishing, it is necessary
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to give information about the machining allowance. For this, indications should be made for both states
of the part: 1) after the heat‐treatment (before final machining); and 2) after the final machining.
NOTE This can be done, for example, by indicating the heat‐treated state and the finished state in accordance
with ISO/TS 8062‐2, by an additional representation, or by adding the words “before grinding” or “after grinding”
(see Figures 16 and 30).

The words indicating the heat‐treated condition, the hardness and the hardness depth data shall be
placed near the title block of the drawing.
For some applications, it might be necessary to keep special data on the heat‐treatment process to make
sure that the required properties after the heat treatment are attained.
— In this case, a heat‐treatment order (HTO) should be used. If an HTO exists, in the drawing, a
reference shall be given by the wording “see HTO number …”. Examples are given in Figures 11, 12,
25, 29 and 42.
— To document the heat‐treatment process carried‐out in the heat-treatment workshop, a heat‐
treatment document (HTD) should be used.

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5.2 Material data

Regardless of the heat‐treatment method, generally the drawing shall identify the material used for the
heat‐treated part (name of the material, reference to the bill of materials, etc.).

5.3 Heat‐treatment condition

The heat‐treated condition shall be specified in words, such as “quench‐hardened”, “quench‐hardened
and tempered”, “case‐hardened”, “surface‐hardened”, “nitrided”, etc.
If more than one heat‐treatment is required, these treatments shall each be identified in words in the
sequence of their execution, for example, “quench-hardened and tempered”. Indications by wording
shall be chosen in accordance with ISO 4885. See Clause 7 for practical examples.
The heat‐treatment condition can be achieved in different ways. As a result, the performance
characteristics can differ. Particulars of the technical process shall be specified in supplementary
documents (e.g. HTO, HTD) where this is of importance for the heat‐treated condition.

5.4 Hardness data

5.4.1 Surface hardness

The surface hardness shall be indicated

— as Rockwell hardness in accordance with ISO 6508‐1,
— as Vickers hardness in accordance with ISO 6507‐1, or
— as Brinell hardness in accordance with ISO 6506‐1.
Additional hardness values shall be given in instances where the parts in the heat‐treated condition
have areas with different hardnesses (see Clause 6).
For case‐hardened, surface‐hardened, nitrided or nitrocarburized parts, the hardness decreases
downwards from the surface to the core. A test of the hardness in a cross section of a part from the
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surface until the core yields a hardness profileN2); this profile can be used, for instance, in accordance with
ISO 2639N3) to specify the hardness depth. The surface hardness value depends on the hardness profile,
the hardness depth and the test load. Therefore, if the surface hardness is indicated for case‐hardened
or surface‐hardened parts, the test load shall be adjusted according to the hardness depth and the
expected surface hardness.

5.4.2 Core hardness

The core hardness shall be indicated in the drawing where a specification is given that it is to be tested.
The core hardness shall be given
— as Rockwell hardness in accordance with ISO 6508‐1,
— as Vickers hardness in accordance with ISO 6507‐1, or
— as Brinell hardness in accordance with ISO 6506‐1.

5.4.3 Hardness value and limit deviations

All hardness values shall be toleranced. They can be written as shown in the examples in Table 1.

N2) National footnote: In Germany, the terms “Härteverlauf”, “Härteverlaufskurve” or “Härtetiefenverlauf” are also
commonly used.
N3) National footnote: ISO 2639 has been replaced by ISO 18203.

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Table 1 — Examples of how to represent hardness values and their limiting deviations
Written mode Lower and upper limit
(62 ±2) HRC
(64  0/-4) HRC
(60 +4/0) HRC
60 HRC up to 64 HRC
(60 ) HRC
+4
0

(61 +3/-1) HRC

(750 ±75) HV10
(825 0/-150) HV10
(675 +150/0) HV10
675 HV10 up to 825 HV10
(700 +125/-25) HV10

(700 +125
−25 ) HV10
Tolerances should be as large as functionality permits.

5.5 Markings

5.5.1 Marking of test points

If it is necessary to mark the test point in the drawing, the symbol for the test point shall be indicated
according to Figure 1. The graphical symbol for the test point shall be drawn in accordance with A.2.

Figure 1 — Symbol for the test point

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The precise position of the symbol shall be placed according to Figure 2.

Figure 2 — General dimensioning of a test point

If there is more than one test point, the symbol shall be directly combined with an identification number
for each test point according to Figure 3. The graphical symbol for the test point with its identification
number shall be drawn in accordance with A.3.

Figure 3 — Identification number for each test point

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If a section of the heat‐treated part is cut off in order to test the heat‐treated state, marking shall be
as shown in Figure 4. If there is a section of a piece that should be cut off after the heat‐treatment, this
section should be marked by a long‐dashed double‐dotted narrow line of type 05.1 in accordance with
ISO 128‐24 (see Figure 4).

Figure 4 — Marking of a section where the heat-treated part is cut off

5.5.2 Marking of slip zones

A slip zone is a zone of a surface‐hardened workpiece N4), where the surrounding surface‐hardening
operation has to be stopped to avoid the reheating the area where the surface‐hardening operation began.
It should be decided where the slip zone can be placed without affecting the functional properties of the
workpiece. If it is necessary to mark the slip zone in the drawing, the symbol for the slip zone shall be
indicated according to Figure 24. The graphical symbol for the slip zone shall be drawn in accordance
with A.4. The length of the slip zone and its position shall be dimensioned as shown in Figure 25.

5.6 Key for the allocation test point and nominal value
If more than one test point N5) is allocated, the number of the measuring point should be written together
with the nominal values of the hardness or of the hardness depth. See the example in Figure 12.

5.7 Indication of local areas

In some cases, it is necessary to indicate local areas of a part which have the following special conditions:
a) surface‐hardened areas of surface‐hardened parts;
b) areas of a part where heat‐treating may be allowed;
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c) not heat‐treated areas of a quench-hardened, carburized, carbonitrided, nitrided or

nitrocarburized part;
d) indication of expected or wished spread of a hardened area.
Parts which will have the mentioned special conditions in 5.7 a), b) and c) shall be marked in accordance
with Table 2.

N4) National footnote: For example on a larger cam or cam disc, where the re-heating of a hardened area may cause
cracks. The slip zone is then not hardened.
N5) National footnote: In the German version of this standard, this term has been translated as “Prüfstelle”. In the
original ISO document, the term “measuring point” has been used in error. Correct is “test point”.

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Table 2 — Line types for the indication of local areas and their applications
Line according to ISO 128‐24 Application
No. Description and representation
04.2 Long-dashed dotted wide line For surface‐hardened or case‐hardened workpieces:
to indicate the areas that should be surface‐hardened or case‐
hardened
Dashed wide line For surface‐hardened or case‐hardened workpieces:
02.2 to indicate the areas that may be surface‐hardened or case‐
hardened
Dotted wide line For carburized, carbonitrided, nitrided or nitrocarburized
07.2N6) workpieces:
to indicate the areas where the heat‐treatment is not allowed
Long-dashed dotted narrow line For surface‐hardened workpieces:
04.1 to indicate the expected or wished spread of the surface‐hard-
ened areas

5.8 Hardness depth

The hardness depth shall be given as surface‐hardening hardness depth (SHD), case‐hardening
hardness depth (CHD) or nitriding hardness depth (NHD) according to the heat‐treatment method.
Hardness depth values shall be toleranced and should be written as shown in the examples in Table 3.
The tolerance should be as large as functionality permits.

Table 3 — Examples of how to represent hardness depths and their limiting deviations
Written mode Lower and upper limit
1,0 ±0,3
1,3 0/-0,6
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0,7 +0,6/0
0,7 mm up to 1,3 mm
+0,6
0, 7 0

0,9 +0,4/-0,2

5.9 Carburizing depth (CD)

The CD is determined from the carbon content profile with the carbon content, expressed as percentage
by mass as a limiting characteristic (see ISO 4885). The carbon content limit shall then be added as a
suffix (subscript) to the symbol.
EXAMPLE A carbon content limit of 0,35 of carbon percentage by mass is indicated by “CD0,35”.

The carburizing depth shall be toleranced and should be written as shown in the examples in Table 4.
Tolerances should be as large as functionality permits.

N6) National footnote: Line type 07.2 is included in ISO 128-20.

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Table 4 — Examples of how to represent carburizing depths and their limiting deviations
Written mode Lower and upper limit
2,0 ±0,5
2,5  0/-1,0
1,5 +1,0/0
1,5 mm up to 2,5 mm
+1,0
1, 5 0

1,8 +0,7/-0,3

In the case of carburizing or case-hardening, it might be necessary to indicate the internal oxidation
in accordance with its depth. For the depth of internal oxidation, the abbreviation IOD should be used.
This depth shall be toleranced and should be written like the examples in Table 5, with the dimension
micrometre.

5.10 Compound layer thickness (CLT)

The CLT is the thickness of the outer area of the nitrided layer (see also ISO 4885). It is usually
determined by light‐microscopy. The abbreviation of compound layer thickness is CLT.
NOTE Destruction of, or damage to, a workpiece is inevitable when testing. If necessary, testing can be
carried out on a reference sample heat‐treated together with the workpieces for this purpose.

The compound layer thickness shall be toleranced and should be written like the examples in Table 5.
The tolerances should be as large as functionality permits.

Table 5 — Examples for representation the CLT and their limiting deviations
Written mode Lower and upper limit
(15 ±5) µm
(20  0/-10) µm
(10 +10/0) µm
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10 µm up to 20 µm
(10 ) µm
+10
0

(12 +8/-2) µm

The wording “compound layer” can also be used for the boride layer of borided workpieces.

5.11 Oxide layer thickness (OLT)

The OLT is the thickness of the oxide layer after nitrocarburizing to optimize the corrosion resistance.
It is usually determined by light microscopy. The abbreviation of oxide layer thickness is OLT.
The oxide layer thickness shall be toleranced and can be written as shown in the examples in Table 5.
The tolerances should be as large as functionality permits.

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5.12 Strength data

Strength values are only indicated
a) if it is necessary and
b) if the shape and dimensions of the part are such that the heat‐treated probe N7) can be used to test the
strength.
If necessary, the place and its location from which the cut section is to be taken shall be indicated.
Indication of the core hardness is unnecessary in such instances.
The strength values are to be toleranced and can be written in the same manner like hardness values or
hardness depths. The tolerances should be as large as functionality permits.

5.13 Microstructure
If necessary, the information on the hardness and hardness depth may be supplemented by information
on the microstructure of the heat‐treated parts. For example, this information might include the
maximum amount of retained austenite, the quantity, size or layout of carbides, the length of the
martensite needles or other important criterions.
NOTE For investigation of the microstructure, destruction of, or (at least) damage to, the workpiece is
inevitable. It can be sufficient, however, to carry out investigation on a reference sample heat‐treated together
with the workpieces for this purpose.

5.14 Heat‐treatment order (HTO) N8)

An HTO is a document which accompanies the drawing of a heat-treated part. It contains details of the
required heat‐treatment process which could not be tested on the heat‐treated part. The HTO provides
the heat‐treatment workshop with instructions about the heat‐treatment process in order to make sure
that the indicated hardness, hardness depth, etc. will be reached.

5.15 Heat‐treatment document (HTD) N9)

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An HTD is a document about the heat‐treatment process which contains the specific data such as
the furnace used, the adjusted furnace temperature, the carbon level, the carburizing medium, the
quenching oil, etc. With the HTD, the user can follow how the heat‐treatment process was applied.

N7) National footnote: In the original ISO document, the term “probe” (German term “Sonde”) has been used in error .
This term has been translated as “Probe”.
N8) National footnote: In the German language, the HTO (heat-treatment order) is referred to as
“Wärmebehandlungsanweisung” (WBA), see DIN 17023.
N9) National footnote: In the German language, the terms “Prozessvorschrift” or “Wärmebehandlungsplan” are also used.

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6 Graphical representation

6.1 General

6.1.1 The heat‐treated condition shall be indicated by:

a) textual information (e.g. “surface-hardened”), as described in 5.3;

b) measurable dimensions and test points for the following material conditions:
1) hardness;
2) hardness depth;
3) carburizing depth;
4) compound layer thickness;
5) local heat‐treatment.

6.1.2 The graphical representation of a heat‐treatment condition can be supplemented by:

a) marking of test points;

b) heat‐treatment sketch;
c) strength data;
d) information on structural condition.

6.1.3 Graphical representations of heat‐treatment requirements shall be as shown in Figures 7 to 44.

6.2 Heat‐treatment of the entire part

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6.2.1 Uniform condition

The heat‐treated condition shall be specified in words indicating the heat‐treatment. Examples are
shown in Figures 7 to 11, 27 to 29, 38, 39, 41, 42 and 44.

6.2.2 Areas with different conditions

If a workpiece is to have different values in different areas, this shall be represented as follows:
a) the respective areas shall each be given a specific identity to indicate the heat‐treated condition
and the extent of its area;
b) characteristic numbers shall be repeated below the information, in words according to 5.3, together
with the required values (see Figures 12, 20, 22, 26, 32 and 34);
c) if appropriate, specified test points shall be marked according to 5.5.

6.3 Local heat‐treatment

6.3.1 General

It should be considered in each instance whether it is practical to locally limit the heat‐treatment, as
this can mean additional expenditure compared with the treatment of the entire part. Otherwise,
transitions with a lower hardness/strength would be created and breaks could be promoted.

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The size of the transition between heat‐treated and non‐heat‐treated areas depends on the method of
heat‐treatment, and the material and shape of the part to be heat‐treated. It is therefore appropriate
to specify the dimensions and tolerances for the size and position of the areas to be heat‐treated in
agreement with the hardening workshop.
If a workpiece is to have different values in different areas, this shall be represented by characteristic
numbers that shall be repeated below the information in words and according to 5.3 together with the
required values (see Figures 20, 22, 23, 26, 32 and 34).

6.3.2 Areas requiring heat‐treatment

Those areas of a part that are to be heat‐treated shall be marked in the graphical representation by a
type 04.2 long‐dashed dotted wide line, in accordance with Table 2, outside the body outlines of the
part. For parts with rotational symmetry, it shall be sufficient to indicate one relevant surface line (the
“generatrix”), if this is not misleading, for the purposes of simplification (e.g. Figure 15). If necessary,
the size and position of these areas shall be specified by dimensions and tolerances.
The transition between heat‐treated and non‐heat‐treated areas lies, in principle, outside the nominal
size for the length of the heat‐treated area.

6.3.3 Areas that may be heat‐treated

Apart from those areas that shall be heat‐treated, information should also be given on areas which may
be heat‐treated, as this can facilitate the execution of local heat‐treatment and reduce distortion.
Areas which may be heat‐treated shall be marked by a type 02.2 dashed wide line, in accordance with
Table 2, outside the body outlines and, if necessary, shall be dimensioned. Indications of tolerance are
generally not required for these areas (see Figures 5 and 14).
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Key
a heat‐treated area
b length of the area that may be heat‐treated
c distance between the left end of the axle and the beginning of zone “a”
Area a shall be dimensioned.

Figure 5 — Marking of areas that may be heat‐treated

6.3.4 Areas that shall not be heat‐treated

Areas where no heat‐treatment is allowed shall be marked by a dotted wide line of type 07.2, in
accordance with Table 2 (see Figure 6).

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Figure 6 — Marking of areas that shall not be heat-treated

6.4 Heat‐treatment sketch

If the representation of a part would become unclear by adding an instruction on heat‐treatment or if
confusion with other methods of treatment would be possible, a heat‐treatment sketch shall be included.
In this sketch (which may be a detail drawing), drafting details not required for heat‐treatment shall
be omitted. It shall be designated “heat‐treatment sketch” and contain all the necessary instructions
indicating the heat‐treatment condition (see Figure 23).
A true‐to‐scale representation is not necessary. The heat‐treatment sketch shall be placed near the title
block of the drawing.

7 Practical examples
7.1 General
The figures and the associated instructions in this clause are practical examples. The suitability of the
instruction to be given shall be determined on the basis of the technical details of the heat‐treatment
process.
Unless otherwise specified, all dimensions are in millimetres.

7.2 Quench‐hardening, quench‐hardening and tempering, austempering

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7.2.1 Heat‐treatment of the entire part — Allover uniform requirements

The quench‐hardened condition of the part illustrated by Figure 7 shall be designated by the wording
“quench‐hardened”, by indicating the hardness value with its permissible deviation, and by marking
the test point. The symbol for the test point without any indication of a precise position allows the
hardness test at an optional point of the indicated geometric element.

quench‐hardened
(62 ±2) HRC

Figure 7 — Marking of a part with quench-hardened condition N10)

If tempering is carried out after hardening, “quench‐hardened” is not sufficient to designate the
quench‐hardened and tempered condition unambiguously. In such instances, the full wording “quench‐
hardened and tempered” shall be given in accordance with 5.3 (see Figure 8).

N10) National footnote: The symbol for the test point does not apply in practice, if no such test point or test point area
requires marking (see 5.5).

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Dimensions in millimetres

quench‐hardened and tempered

(61 ±2) HRC

Figure 8 — Marking of a part in quench-hardened and tempered condition

The part shown in Figure 9 is to be quench‐hardened and tempered. The designation shall read “quench‐
hardened and tempered”.N11)No test point is indicated; therefore, the hardness can be tested at any point.

quench‐hardened and tempered

(375 ±25) HBW2,5/187,5
(quench-hardened: (62 ±2) HRC)

Figure 9 — Marking of a part in quench-hardened and tempered condition

For quench‐hardened and tempered parts, where the tempering is done at a higher temperature to
achieve high toughness, it is necessary to control the hardness before tempering would be started. This
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avoids a too low quenching rate and a too slow tempering temperature. Therefore, the hardness should
be tested after quench‐hardening and before tempering (see Figure 9).
If a section of the heat‐treated part is cut off in order to test the quench‐hardened and tempered state
by a tensile test, marking shall be as shown in Figure 10. It is recommended to use a section with the
same diameter as the workpiece to be tested.

quench‐hardened and tempered

Rm = (1 150 ±50) N/mm2
Rp0,2 ≥ 900 N/mm2
A≥9%

Figure 10 — Marking of a heat-treated part where a section is cut off for testing

The part shown in Figure 11 is austempered. The designation shall read “austempered”. If the heat‐
treatment is to be carried out in accordance with a heat‐treatment order (HTO), a reference shall be
made to the HTO, see Figure 11.

N11) National footnote: The English term “quench-hardened and tempered” has been translated into German as “vergütet”
instead of “gehärtet und angelassen”, since the examples (see Figure 9 and Figure 10) represent a specific form of
hardening and tempering, i.e. tempering at higher temperatures. In the English language, there is no term for “vergüten”.

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austempered, see HTO….

(60 ±1) HRC

Figure 11 — Marking of an austempered part

7.2.2 Heat‐treatment of the entire part — Areas with different hardnesses

If a part is to have different hardness values for individual areas and heat‐treatment is to be carried out
in accordance with a heat‐treatment order (HTO), the areas of different hardnesses shall be marked
and, if necessary, dimensioned. In addition, reference shall be made to the HTO (see Figure 12).
Dimensions in millimetres

quench‐hardened and tempered, see HTO…

1: (60 ±2) HRC
2: (43 ±2) HRC

Figure 12 — Marking of a part with different hardness values

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7.2.3 Local heat‐treatment

The part shown in Figure 13 is to be locally heat‐treated. The heat‐treated area shall be marked by
a type 04.2 long‐dashed dotted wide line, in accordance with Table 2, and with dimensional data
according to 6.3. The test point shall be marked in accordance with 5.5.
Dimensions in millimetres

quench‐hardened and entire part tempered

(61 ±1) HRC

Figure 13 — Marking of a part which is locally heat-treated

When heat‐treating a workpiece, for reasons of processing, it may be more convenient to harden a larger
area than required. If this is done, the additionally quench-hardened area shall be marked by a type
02.2 dashed wide line, in accordance with Table 2, and with dimensional data indicating the position of
the heat‐treated area (see Figure 14).
Dimensions in millimetres

quench‐hardened and entire part tempered

(61 ±1) HRC
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Figure 14 — Marking of a part with an additionally quench-hardened area

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7.3 Surface‐hardening

7.3.1 General

Surface‐hardening is normally locally limited. Consequently, the requirements given in 6.3 shall be
applied.

7.3.2 Specification of surface hardness

When specifying the test method for the determination of the surface hardness of surface‐hardened
parts, a careful adaptation of the test load to SHD shall be observed N12).

7.3.3 Specification of surface‐hardening hardness depth (SHD)

The abbreviation of the surface-hardening hardness depth is SHD. It shall be appended the numerical
value for the limiting hardness, normally tested as Vickers hardness HV1. The limiting hardness in
normal case is 80 % of the minimum surface hardness.
The hardness depth is given as a nominal dimension in millimetres and the value shall be toleranced
and can be written as shown in Table 3. The tolerance should be as large as functionality permits.

7.3.4 Practical examples

7.3.4.1 Generally applicable examples

In the simplest instance, a type 04.2 long‐dashed dotted wide line, in accordance with Table 2, shall
be used for marking the surface‐hardened area (see Figure 15) and keyed with the wording “surface‐
hardened”. The surface hardness and the surface‐hardening hardness depth are characteristic for the
surface‐hardened state.
The transition between the surface‐hardened and non‐surface‐hardened area lies, in principle, outside
the nominal dimension for the length of the surface‐hardened area. The transition width depends on
the depth of hardening, the surface‐hardening method, and the material and shape of the workpiece.
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Dimensions in millimetres

surface‐hardened and entire part tempered

(700 ±80) HV30
SHD 500 = 1,2 ±0,4

Figure 15 — Marking of a part which is surface-hardened

In most cases, surface‐hardened parts have to be finished by grinding. Thereby, the surface hardness
and the surface‐hardening hardness depth will be reduced. If it is necessary to present both states in a
drawing, this shall be indicated
— by adding the words “before grinding” and “after grinding”[see the left caption “a)” of Figure 16], or
— by adding symbols in accordance with ISO/TS 8062‐2 and adding the data that have to be tested [see
the right caption “b)” of Figure 16]. The written mode on the right is explained in ISO 10135.

N12) National footnote: See 7.4.1 “eggshell effect”.

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Dimensions in millimetres

surface‐hardened and surface‐hardened and

tempered tempered

before grinding: (700 ±80) HV30 (700 ±80) HV30

SHD 500 = 1,2 ±0,4 SHD 500 = 1,2 ±0,4

after grinding: (680 ±80) HV30 (680 ±80) HV30

SHD 475 = 1,1 ±0,4 SHD 475 = 1,1 ±0,4

a) b)

Figure 16 — Marking of a surface-hardened part with two states: before and after grinding

If a part is surface‐hardened, for processing reasons, it may be more convenient to harden a larger area
than required. If this is done, the additionally hardened area shall be marked by a type 02.2 dashed
wide line, in accordance with Table 2, together with dimensional data indicating the position of the
surface‐hardened area (see Figure 17).
Dimensions in millimetres

surface‐hardened and entire part tempered

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(575 ±60) HV10

SHD 425 = 0,6 ±0,2

Figure 17 — Marking of a part which is surface-hardened with a larger area than required

If for surface hardening of a part it is not necessary that the hardened surface layer extends to the
edge (of considerable value in reducing the danger of spalling at the edges), this shall be specified by
appropriate dimensioning. See Figure 18.

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The workpiece should not be tempered after surface hardening. Therefore, the word “tempering” is not
used. In order to reduce the danger of cracks at the edges, it is practicable to dimension the chamfers
as large as needed and to have an adequate distance of the surface‐hardened area to the edges. The
distances have to be adjusted to the possibilities of the heat‐treatment process. The surface‐hardened
area is marked by a type 04.2 long‐dashed dotted wide line in accordance with Table 2.
Dimensions in millimetres

surface‐hardened
(700 ±80) HV50
SHD 500 = 1,2 ±0,4

Figure 18 — Marking of a part which is surface-hardened and where the hardened surface layer
should not extend to the edges

Where the surface-hardened layer extends to the edge, the configuration of the zone shall be indicated
by a type 04.1 long‐dashed dotted narrow line, in accordance with Table 2, within the workpiece outlines
(as it is for the right‐hand cam of the part shown in Figure 19). On the left cam, only the cylindrical area
is surface hardened. So in the chamfer area is a lower SHD allowed in accordance to the long dashed
dotted narrow line. Where the hardened surface layer extends to the edge, it is permissible to have a
lower SHD value directly adjacent to the edge (end of the hardened zone); this shall also be indicated by
the long‐dashed dotted narrow line (see the left‐hand cam in Figure 19).
NOTE In both instances, the edges are provided with a chamfer in order to reduce the danger of cracking.
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surface‐hardened and tempered

(60 ±2) HRC
SHD 600 = 1,2 ±0,4

Figure 19 — Marking of a part which is surface-hardened and where the surface-hardened layer
should extend to the edge

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7.3.4.2 Heat‐treatment pictures for gears

7.3.4.2.1 General

Where the configuration and the position of the hardened surface layer is of importance for the
performance characteristics (e.g. surface‐hardening of the tooth flanks including the tooth bottom in
respect of gears), this shall be indicated by a type 04.1 long‐dashed dotted narrow line, in accordance
with Table 2, within the workpiece outlines (see Figures 20, 21 and 22).

7.3.4.2.2 Full tooth hardening

A type 04.2 long‐dashed dotted wide line, in accordance with Table 2, at the periphery of the gear and
a type 04.1 long‐dashed dotted narrow line, in accordance with Table 2, shall be used to show that the
teeth are fully hardened (see Figure 20).
NOTE Depending on the nature of the process, different hardness values will occur over the tooth height.
Test of the hardness depth makes no sense in this example.

surface‐hardened and entire part tempered

1: (59 ±3) HRC
2: (53 ±3) HRC
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3: ≤30 HRC

Figure 20 — Marking of a gear where the teeth are fully surface-hardened

7.3.4.2.3 Tooth flank surface‐hardening

A type 04.2 long‐dashed dotted wide line, in accordance with Table 2, outside the body outlines shall
be used to mark the surface‐hardened area. A type 04.1 long‐dashed dotted narrow line, in accordance
with Table 2, shall be used to set off its position and configuration (see Figure 21). Because of the
required configuration of the hardened layer, measuring points N13) for the surface-hardening hardness
depth shall be defined.

N13) National footnote: In the German version of this standard, this term has been translated as “Prüfstelle”. In the
original ISO document, the term “measuring point” has been used in error. Correct is “test point”.

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 DIN ISO 15787:2018-08


surface‐hardened and entire part tempered

(58 ±3) HRC
SHD 75 N14) = 1,5 ±0,5

Figure 21 — Marking of a part with a surface-hardened tooth flank

7.3.4.2.4 Tooth bottom surface‐hardening

A type 04.2 long‐dashed dotted wide line, in accordance with Table 2, outside the body edges shall be
used to mark the surface‐hardened area, and a type 04.1 long‐dashed dotted narrow line, in accordance
with Table 2, shall be used to mark its position and configuration. Because of the configuration of the
hardened surface layer, test points for the hardness depth shall be defined (see Figure 22).

surface‐hardened and entire part tempered

1: SHD 425 = 2,2 ±0,6
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2: SHD 425 = 1,5 ±0,5

Figure 22 — Marking of a part where the ground between the teeth is surface-hardened

7.3.4.3 Differing surface‐hardening hardness depths

In the individual areas of the part, shown in Figure 23, differing values are required for the hardness
depths. In addition, dimensioning of the hardened zones is necessary. These additional indications may
make the representation of the part unclear. For this reason, a heat‐treatment sketch has been included
at the top of Figure 23 for details Y and Z. A type 04.1 long‐dashed dotted narrow line, in accordance
with Table 2, shall be used to indicate the configuration of the hardened surface layer. The size and
position shall be specified by dimensioning.

N14) National footnote: According to the German working committee, this should read “SHD 475”. The clarification
at ISO level will be carried out in the next revision of the ISO standard.

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Dimensions in millimetres

surface‐hardened surface‐hardened
1: (600 ±50) HV 30 3: (600 ±50) HV 30
2: SHD 450 = 0,9 ±0,3 SHD 450 = 1,5 ±0,5

Figure 23 — Marking of a part with different surface-hardening hardness depths

7.3.4.4 Surface‐hardening treatment with slip zone

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In the case of surface‐hardening treatment by surrounding a workpiece, it might be more efficient to

leave a small area untreated, depending of the heat‐treatment process and the required properties of
the piece. In this area, called a “slip zone”, the hardness would be as low as before the heat treatment.
It is necessary to define, where a permitted slip zone may be located and how long it is. Additional data
shall be given in an HTO to which reference shall be made.
The symbol to be used for a slip zone is shown in Figure 24. The length of the slip zone shall be
dimensioned as shown in Figure 25. The graphical symbol for the slip zone shall be drawn in accordance
with A.4.

Figure 24 — Symbol for a slip zone

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Dimensions in millimetres

surface‐hardened, see HTO…

(60 ±2) HRC
SHD 400 = 1,8 ±0,5
Figure 25 — Marking of a surface-hardened part with a slip zone

7.3.4.5 Example with more than one test point

The surface‐hardened part (see Figure 26) shall have the given values in areas marked by type 04.2
long‐dashed dotted wide lines, in accordance with Table 2, and by dimensioning (the process can be
achieved by, for example, additional local tempering).
Dimensions in millimetres

surface‐hardened and tempered

1: (520 ±50) HV 30
       SHD 375 = 1,5 ±0,5
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2: (750 ±50) HV 30
       SHD 575 = 1,5 ±0,5
Figure 26 — Marking of a part with more than one measuring point N15)

7.4 Case‐hardening
7.4.1 Specification of surface hardness

When specifying the surface hardness of case‐hardened parts, a careful adaptation of the test load
determining the CHD shall be observed to avoid the eggshell effect N16).
7.4.2 Specification of case‐hardening hardness depth (CHD)

The abbreviation of the case-hardening hardness depth is CHD. The limiting hardness to define the CHD
is normally 550 HV1 in accordance with ISO 2639 N17) .
The case‐hardening hardness depth is given as a nominal dimension in millimetres. The value shall be
toleranced and should be written as shown in the examples in Table 3. The tolerance should be as large
as functionally possible.

N15) National footnote: In the German version of this standard, this term has been translated as “Prüfstelle”. In the
original ISO document, the term “measuring point” has been used in error. Correct is “test point”.
N16) National footnote: It means that, due to an excessive test load with a too small depth of hardening, a (too low)
mixed value will be determined as result of the hardness test.
N17) National footnote: ISO 2639 has been replaced by ISO 18203.

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7.4.3 Specification of carburizing depth (CD)

Specification of carburizing depth is required in instances where the workpiece has to be tested after
carburizing and before a quench‐hardening treatment. The abbreviation CD, used for the carburizing
depth, shall be appended a suffix designating the limiting characteristic specified for the determination
of the carburizing depth (see Figures 36 and 37).
It is a general rule to use a carbon percentage by mass of 0,35 as a limiting characteristic. However, it is
also permissible to specify other, differing values.
The carburization depth is given as a nominal dimension in millimetres. The value shall be toleranced
and can be written as shown in Table 4. The tolerance should be as large as functionally possible.

7.4.4 Practical examples

7.4.4.1 Allover case‐hardening

Allover case‐hardening shall be indicated by the wording “case‐hardened” (see Figures 27 to 31).
In the simplest instance, marking shall be as shown in the example in Figure 27, indicating the heat‐
treatment condition, the surface hardness and the case‐hardening hardness depth, and, in each case,
the permissible deviation (see Figure 27).

case‐hardened and tempered

(62 ±2) HRC
CHD = 1 ±0,2

Figure 27 — Marking of an allover case-hardened part

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If a limiting hardness or test load, or both, other than that or those specified in the regular instance (see
ISO 2639) is to be applied when testing the case‐hardening hardness depth, this shall be indicated by
specifying the CHD (see Figure 28).

case‐hardened and tempered

(750 ±50) HV 30
CHD 600 HV 3 = 0,6 ±0,1

Figure 28 — Marking of an allover case-hardened part with a hardness N18) and a test load other
than those specified in the regular instance (see ISO 2639)

N18) National footnote: The English term “hardness limit” has been translated as “Grenzhärte”. In ISO 15787, the term
“limit” is missing.

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If specific provisions need to be observed during heat‐treatment (e.g. regarding the data of the
time/temperature curve), these provisions shall be taken from the heat‐treatment order (HTO) or
the heat‐treatment document (HTD). A reference shall be made to that document in the drawing (see
Figure 29).

case‐hardened and tempered, see HTO …

(750 ±50) HV 30
CHD 600 HV 3 = 0,6 ±0,1

Figure 29 — Marking of an allover case-hardened part where specific provisions are to be

observed in the heat-treatment process

In most cases, case‐hardened parts have to be finished by grinding. Thereby, the surface hardness and
the surface‐hardening hardness depth N19) will be reduced. If it is necessary to present both states in a
drawing, this shall be indicated
— by adding the words “before grinding” and “after grinding”[see the left caption “a)” of Figure 30], or
— by adding symbols in accordance with ISO/TS 8062‐2 and adding the data that have to be tested [see
the right caption “b)” of Figure 30]. The written mode on the right is explained in ISO 10135.

case‐hardened and tempered case‐hardened and tempered

before grinding: (750 ±50) HV30 (750 ±50) HV30

CHD = 0,6 ±0,1 CHD = 0,6 ±0,1
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after grinding: (750 ±50) HV30 (750 ±50) HV30

CHD = 0,5 ±0,1 CHD = 0,5 ±0,1

a) b)

Figure 30 — Marking of an allover case-hardened part with two states: before and after
grinding

7.4.4.2 Allover case‐hardening with differing surface hardness or hardness depth

7.4.4.2.1 General

Allover case‐hardened parts with areas in which the values for the surface hardness or the hardness
depth, or both, differ from the rest of the area shall be marked as shown in Figures 31 and 32.

N19) National footnote: Has been translated as “Einsatzhärtungs-Härtetiefe”. In the original ISO document, the term
“surface-hardening hardness depth” has been used in error. Correct is “case-hardening hardness depth”.

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7.4.4.2.2 Differing surface hardness

The part shown in Figure 31 shall have the given hardness values in the area identified as the test
points 1 and 2. The entire part is tempered, but the area for which a hardness value ≤ 550 HV10 is given
is tempered at a higher temperature to achieve the lower hardness value than in the area identified as
the test point 1.
Dimensions in millimetres

case‐hardened and tempered

1: (750 ±50) HV 10
      CHD = 0,4 ±0,1
2: ≤550 HV 10

Figure 31 — Marking of a part with different surface hardness

7.4.4.2.3 Differing case‐hardening hardness depth

The gear shown in Figure 32 is allover case‐hardened and tempered. In the area of test points, the
values specified for surface hardness and for the case‐hardening hardness depth shall be present.
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case‐hardened and tempered

1, 3: (62 ±2) HRC
          CHD = 1 ±0,2
2:      (750 ±50) HV 10
N20)

Figure 32 — Marking of a case-hardened and tempered part with different hardnesses and
hardness depths

N20) National footnote: According to the German working committee, a case-hardening hardness depth (CHD) is to be
given at this point, e.g. “CHD = 0,6 ± 0,2”. The clarification at ISO level will be carried out in the next revision of the
ISO standard.

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7.4.4.3 Local case‐hardening

7.4.4.3.1 General

The marking of case‐hardened and non‐case‐hardened areas shall be in accordance with 6.3.
The transition between case‐hardened and non‐case‐hardened areas lies, in principle, outside the
nominal dimension for the length of the case‐hardened area. The transition width depends on the
carburizing depth after carburizing, the method of case hardening, the material, the shape of the
workpiece and the way in which local case hardening is carried out.

7.4.4.3.2 Case‐hardening with not carburized areas

The area on a case‐hardened part that shall not be carburized should be marked by a type 07.2 dotted
wide line in accordance with Table 2. The wording “not carburized” behind the dotted wide line should
be added (see Figures 33 and 34). The entire part is quench‐hardened after carburizing.
Dimensions in millimetres

case‐hardened and tempered

(750 ±70) HV 30
CHD = 0,8 ±0,3
not carburized

Figure 33 — Marking of a case-hardened part with a “not carburized” area

Dimensions in millimetres
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case‐hardened and tempered

1: (32 ±8) HRC
2: (60 ±2) HRC
CHD = 1,5 ±0,3
not carburized

Figure 34 — Marking of a case-hardened part with a “not carburized” area

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7.4.4.3.3 Local case‐hardening, entire part carburized

The case‐hardened area on an entire carburized part should be marked by a type 04.2 long‐dashed
dotted wide line, in accordance with Table 2. The wording “entire part carburized” should be added to
make clear the advance of the heat‐treatment (see Figure 35).

entire part carburized

case‐hardened and tempered
(62 ±2) HRC
CHD = 1 ±0,2

Figure 35 — Marking of an entire carburized and local case-hardened part

7.4.4.4 Examples for carburized parts

7.4.4.4.1 Allover carburization

Allover carburization shall be indicated by the wording “carburized” (see Figure 36).
In the simplest case, the carburized condition shall be marked with the wording “carburized” and by
indicating the carburizing depth with the permissible deviation (see Figure 36).
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carburized
CD0,35 = 1,4 ±0,2

Figure 36 — Marking of an allover carburized part

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7.4.4.4.2 Local carburizing

The marking of the carburized and non‐carburized areas shall be in accordance with 6.3.
The transition between carburized and non‐carburized areas lies, in principle, outside the nominal
dimension for the length of the carburized area. The transition width depends on the carburizing
depth, the carburizing method, the material and shape of the workpiece, and the way in which local
carburizing is carried out.
The carburized area is marked by a long‐dashed dotted wide line, type 04.2 in accordance with Table 2.
The carburized condition shall be designated by the word “carburized”. If testing the carburizing depth
before the quench‐hardening, the depth and abbreviation should be indicated (see Figure 37).
Dimensions in millimetres

carburized
CD0,35 = 1 ±0,3

Figure 37 — Marking of a local carburized part

7.5 Nitriding and nitrocarburizing

7.5.1 Specification of nitriding hardness depth (NHD)

For the nitriding hardness depth, the abbreviation NHD shall be used. The limiting hardness is by
default actual core hardness plus 50 HV.
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The nitriding hardness depth is given as a nominal dimension in millimetres. The value shall be
toleranced. Examples of the written mode are given in Table 3. The tolerance should be as large as
functionally possible.

7.5.2 Specification of compound layer thickness (CLT)

For the thickness of the compound layer, the abbreviation CLT should be used. The CLT and its tolerance
are given in micrometres. The value shall be toleranced. Examples of the written mode are given in
Table 4. The tolerance should be as large as functionally possible.

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7.5.3 Practical examples

7.5.3.1 Allover nitriding

In its simplest instance, the nitrided condition shall be designated by the word “nitrided” and by
indicating the nitriding hardness depth with the permissible deviation (see Figure 38).
If the nitriding is to be carried out in “gas”, the word “gas” shall appear before the word “nitrided” in
accordance with ISO 4885. Likewise, if the nitriding is to be carried out in “plasma”, the word “plasma”
shall appear before the word “nitrided”. An example of the “plasma” case is shown in Figure 38.

plasma nitrided
NHD = 0,30 ±0,05 N21)
≥950 HV 10

Figure 38 — Marking of an allover plasma-nitrided part

When testing of the nitriding hardness depth is carried out with a test load other than HV0,5 for
instance, this shall be indicated when specifying NHD, as shown in the key of example of Figure 39.

nitrided
NHD HV 0,3 = 0,12 ±0,02
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≥800 HV 3

Figure 39 — Marking of an allover nitrided part, where the hardness profile is tested with a test
load of HV0,3

7.5.3.2 Local nitriding

A line of type 07.2 in accordance with Table 2 shall be used to mark the non‐nitrided areas. The words
“not nitrided” should be added behind the dotted wide line (see Figure 40).
The transition between nitrided and non‐nitrided areas lies, in principle, outside the nominal dimension
for the length of the nitrided area. The transition width depends on the nitriding depth N22) and the
nitriding process, the material and shape of the workpiece, and the way in which local nitriding is
carried out.

N21) National footnote: In comparison with the figures in 7.4, the sequence surface hardness - depth of hardening in
Figure 38 and Figure 39 is inversed. This other sequence is intended and is due to the fact that the nitriding
hardness depth NHD is the actual target value during nitriding, while the surface hardness is subordinated. Being
based on the steel composition and the nitriding process, the surface hardness cannot be specified at will.
N22) National footnote: Has been translated as “Nitrierhärtetiefe”. According to the German working committee, the
term “nitriding depth” has been used in error in the original ISO document. Correct is “nitriding hardness depth”.
The clarification at ISO level will be carried out in the next revision of the ISO standard.

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Dimensions in millimetres

nitrided
NHD400 = 0,4 ±0,1
≥900 HV 10
not nitrided

Figure 40 — Marking of a local limited nitrided part

7.5.3.3 Allover nitrocarburizing

In its simplest instance, the nitrocarburized condition shall be indicated by the word “nitrocarburized”
and by indicating the compound layer thickness (CLT) with its tolerance in micrometres (see Figure 41).
The value shall be toleranced and can be written as shown in Table 4. The tolerance should be as large
as functionally possible.

nitrocarburized
CLT = (15 ±5) µm
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Figure 41 — Marking of an allover nitrocarburized part

If nitrocarburizing is carried out in a specific medium, the wording of the indication of the process
shall be supplemented accordingly (see ISO 4885). If necessary, reference shall be made to additional
information (see Figure 42).

salt-bath nitrocarburized, see HTO …

CLT = (25 ±4) µm

Figure 42 — Marking of an allover nitrocarburized part, where the nitrocarburizing is carried

out in a salt bath as specified in an HTO

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7.5.3.4 Local nitrocarburizing

A dotted wide line of type 07.2 in accordance with Table 2 shall be used marking the non‐ nitrocarburized
area (see Figure 43).
The transition between the nitrocarburized and non‐nitrocarburized areas lies, in principle, outside
the nominal dimension for the length of the nitrocarburized area. The transition width depends on the
thickness of the compound layer, the nitrocarburizing method, the material and shape of the workpiece,
and the way in which local nitrocarburizing is carried out.

nitrocarburized
CLT = (20 ±5) µm
not nitrocarburized

Figure 43 — Marking of a local nitrocarburized part

7.6 Boriding
In its simplest instance, the borided condition shall be indicated by the word “borided” and by indicating
the compound layer thickness (CLT) with its tolerance in micrometres (see Figure 44). The value shall
be toleranced and can be written as shown in Table 4. The tolerance should be as large as functionally
possible.
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borided
CLT = (30 ±10) µm

Figure 44 — Marking of a borided part

7.7 Annealing
The annealed‐state condition shall be indicated by the word “annealed”, with an additional designation
specifying the annealing method more precisely (see ISO 4885), such as
— “stress relieved”,
— “soft annealed”,
— “spheroidized”,
— “recrystallized”, or
— “normalized”.
In addition, hardness data or further data on the structural condition shall be given as necessary.

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Annex A
(normative)

Graphical symbols

A.1 General
In order to harmonize the sizes of the graphical symbols specified in this document with those of the
other inscriptions on the drawing (dimensions, tolerances, etc.), apply the rules given in ISO 81714‐1.
The height of the identification number in Figure A.2 shall be larger than the normal lettering on the
technical drawing by a factor of √2.

A.2 Test point

See Figure A.1.
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Figure A.1 — Graphical symbol for test point

A.3 Test point with identification number

See Figure A.2.

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Figure A.2 — Graphical symbol for measuring point N23) with identification number

For double‐digit numbers, the circle for the identification number can be enlarged if needed.

A.4 Slip zone

See Figure A.3.
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Figure A.3 — Graphical symbol for slip zone

N23) National footnote: In the German version of this standard, this term has been translated as “Prüfstelle”. In the
original ISO document, the term “measuring point” has been used in error. Correct is “test point”.

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Bibliography

[1] ISO 2639, Steels — Determination and verification of the depth of carburized and hardened cases
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