SIST EN ISO 683-7:2024

SLOVENSKI STANDARD
01-december-2024
Toplotno obdelana, legirana in avtomatna jekla -7. del: Svetli izdelki iz nelegiranih
in legiranih jekel (ISO 683-7:2023)
Heat-treatable steels, alloy steels and free-cutting steels - Part 7: Bright products of non-
alloy and alloy steels (ISO 683-7:2023)
Für eine Wärmebehandlung bestimmte Stähle, legierte Stähle und Automatenstähle -
Teil 7: Blankstahlerzeugnisse aus unlegierten und legierten Stählen (ISO 683-7:2023)
Aciers pour traitement thermique, aciers alliés et aciers pour décolletage - Partie 7:
Produits en aciers non alliés et alliés transformés à froid (ISO 683-7:2023)
Ta slovenski standard je istoveten z: EN ISO 683-7:2024
ICS:
77.140.10 Jekla za toplotno obdelavo Heat-treatable steels
77.140.20 Visokokakovostna jekla Stainless steels
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EN ISO 683-7
EUROPEAN STANDARD
NORME EUROPÉENNE
October 2024
EUROPÄISCHE NORM
ICS 77.140.10; 77.140.20; 77.140.45 Supersedes EN 10277:2018
English Version
Heat-treatable steels, alloy steels and free-cutting steels -
Part 7: Bright products of non-alloy and alloy steels (ISO
683-7:2023)
Aciers pour traitement thermique, aciers alliés et Für eine Wärmebehandlung bestimmte Stähle, legierte
aciers pour décolletage - Partie 7: Produits en aciers Stähle und Automatenstähle - Teil 7:
non alliés et alliés transformés à froid (ISO 683- Blankstahlerzeugnisse aus unlegierten und legierten
7:2023) Stählen (ISO 683-7:2023)
This European Standard was approved by CEN on 13 October 2024.

CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this
European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references
concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN
member.
This European Standard exists in three official versions (English, French, German). A version in any other language made by
translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management
Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2024 CEN All rights of exploitation in any form and by any means reserved Ref. No. EN ISO 683-7:2024 E
worldwide for CEN national Members.

Contents Page
European foreword . 3

European foreword
The text of ISO 683-7:2023 has been prepared by Technical Committee ISO/TC 17 "Steel" of the
International Organization for Standardization (ISO) and has been taken over as EN ISO 683-7:2024 by
Technical Committee CEN/TC 459/SC 5 “Steels for heat treatment, alloy steels, free-cutting steels and
stainless steels” the secretariat of which is held by DIN.
This European Standard shall be given the status of a national standard, either by publication of an
identical text or by endorsement, at the latest by April 2025, and conflicting national standards shall be
withdrawn at the latest by April 2025.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
This document supersedes EN 10277:2018.
The main changes compared to the previous edition EN 10277:2018 are listed below:
— this standard EN ISO 683-7 is the comparable ISO standard with nearly identical content;
— editorially revised.
Any feedback and questions on this document should be directed to the users’ national standards
body/national committee. A complete listing of these bodies can be found on the CEN website.
According to the CEN-CENELEC Internal Regulations, the national standards organizations of the
following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria,
Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland,
Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Republic of
North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and the
United Kingdom.
Endorsement notice
The text of ISO 683-7:2023 has been approved by CEN as EN ISO 683-7:2024 without any modification.
The European steel numbers to the steel grades are to be found in informative Annex E.
The references to following European standards are given for information:
EN 10025-2, Hot rolled products of structural steels - Part 2: Technical delivery conditions for non-alloy
structural steels
EN 10027-1, Designation systems for steels - Part 1: Steel name
EN 10027-2, Designation systems for steels - Part 2: Numerical system
EN 10079, Definition of steel products
EN 10204, Metallic products - Types of inspection documents
EN 10247, Micrographic examination of the non-metallic inclusion content of steels using standard
pictures
INTERNATIONAL ISO
STANDARD 683-7
First edition
2023-11
Heat-treatable steels, alloy steels and
free-cutting steels —
Part 7:
Bright products of non-alloy and alloy
steels
Aciers pour traitement thermique, aciers alliés et aciers pour
décolletage —
Partie 7: Produits en aciers non alliés et alliés transformés à froid
Reference number
ISO 683-7:2023(E)
ISO 683-7:2023(E)
© ISO 2023
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on
the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below
or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: +41 22 749 01 11
Email: copyright@iso.org
Website: www.iso.org
Published in Switzerland
ii
ISO 683-7:2023(E)
Contents Page
Foreword .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 2
4 Classification and designation . 3
4.1 Classification . 3
4.2 Designation . 3
5 Information to be supplied by the purchaser . 3
5.1 Mandatory information . 3
5.2 Options/Supplementary or special requirements . 4
5.3 Ordering example. 4
6 Manufacturing process . 5
6.1 General . 5
6.2 Treatment and surface condition at delivery . 5
6.2.1 Treatment condition . 5
6.2.2 Surface conditions . 5
6.3 Traceability of the cast . 5
7 Requirements . 5
7.1 General . 5
7.2 Chemical composition . 5
7.3 Mechanical properties . 6
7.4 Hardenability . 6
7.5 Machinability . 6
7.6 Grain size . 7
7.7 Non-metallic inclusions . 7
7.7.1 Microscopic inclusions . 7
7.7.2 Macroscopic inclusions . 7
7.8 Internal soundness . 7
7.9 Decarburization . . 7
7.10 Shape, dimensions and tolerances . 7
7.11 Surface quality . 8
8 Inspection . 8
8.1 Testing procedures and types of documents. 8
8.2 Frequency of testing . 9
8.3 Specific inspection and testing . 10
8.3.1 Verification of the hardenability, hardness and mechanical properties . 10
8.3.2 Visual and dimensional inspection . 11
9 Test methods .11
9.1 Chemical analysis . 11
9.2 Mechanical tests . 11
9.2.1 Tensile test . 11
9.2.2 Impact test . 11
9.3 Hardness and hardenability tests . 11
9.3.1 Hardness in treatment conditions +A and +FP . 11
9.3.2 Verification of hardenability .12
9.4 Verification of dimensions .12
9.5 Retests . 12
10 Marking . .12
Annex A (informative) Steel grades and chemical composition according to ISO 630-2,
ISO 683-1, ISO 683-2, ISO 683-3 and ISO 683-4 .39
iii
ISO 683-7:2023(E)
Annex B (normative) Determination of the diameter of the equivalent ruling section for
mechanical properties.45
Annex C (normative) Supplementary or special requirements .48
Annex D (normative) Methods for evaluating straightness .50
Annex E (informative) Designation of steels given in this document and of comparable
grades covered in various designation systems .51
Bibliography .55
iv
ISO 683-7:2023(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.
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 document should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).
ISO draws attention to the possibility that the implementation of this document may involve the use
of (a) patent(s). ISO takes no position concerning the evidence, validity or applicability of any claimed
patent rights in respect thereof. As of the date of publication of this document, ISO had not received
notice of (a) patent(s) which may be required to implement this document. However, implementers are
cautioned that this may not represent the latest information, which may be obtained from the patent
database available at www.iso.org/patents. ISO shall not be held responsible for identifying any or all
such patent rights.
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, 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
www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 17, Steel, Subcommittee SC 4, Heat
treatable and alloy steels.
This first edition of ISO 683-7, together with ISO 16143-4, cancels and replaces ISO 683-18:2014, which
has been technically revised.
The main changes are as follows:
— ISO 683-18 was split into ISO 683-7 for non-alloy and alloy steels and into ISO 16143-4 for stainless
steels;
— definition for out-of-round was modified with two new definitions on ovality and out-of-shape;
— editorial revision.
A list of all parts in the ISO 683 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.
v
INTERNATIONAL STANDARD ISO 683-7:2023(E)
Heat-treatable steels, alloy steels and free-cutting steels —
Part 7:
Bright products of non-alloy and alloy steels
1 Scope
This document specifies the technical delivery requirements for bright steel products in the drawn,
peeled/turned or additional ground condition and they are intended for mechanical purposes, for
example for machine parts. The bright steel products are subdivided into the following steel types:
a) non-alloy general engineering steels;
b) non-alloy free-cutting steels;
c) non-alloy and alloy case-hardening steels;
d) non-alloy and alloy steels for quenching and tempering.
Bright products of stainless steels are not part of this document, they are covered by ISO 16143-4.
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 148-1, Metallic materials — Charpy pendulum impact test — Part 1: Test method
ISO 286-2, Geometrical product specifications (GPS) — ISO code system for tolerances on linear sizes —
Part 2: Tables of standard tolerance classes and limit deviations for holes and shafts
ISO 377, Steel and steel products — Location and preparation of samples and test pieces for mechanical
testing
ISO 404, Steel and steel products — General technical delivery requirements
ISO 643, Steels — Micrographic determination of the apparent grain size
ISO 630-2, Structural steels — Part 2: Technical delivery conditions for structural steels for general
purposes
ISO 683-1, Heat-treatable steels, alloy steels and free-cutting steels — Part 1: Non-alloy steels for quenching
and tempering·
ISO 683-2, Heat-treatable steels, alloy steels and free-cutting steels — Part 2: Alloy steels for quenching and
tempering
ISO 683-3, Heat-treatable steels, alloy steels and free-cutting steels — Part 3: Case-hardening steels
ISO 683-4, Heat-treatable steels, alloy steels and free-cutting steels — Part 4: Free-cutting steels
ISO 3887, Steels — Determination of the depth of decarburization
ISO 4885, Ferrous materials — Heat treatments — Vocabulary
ISO 683-7:2023(E)
ISO 4948-1, Steels — Classification — Part 1: Classification of steels into unalloyed and alloy steels based
on chemical composition
ISO 4948-2, Steels — Classification — Part 2: Classification of unalloyed and alloy steels according to main
quality classes and main property or application characteristics
ISO 4967, Steel — Determination of content of non-metallic inclusions — Micrographic method using
standard diagrams
ISO 6506-1, Metallic materials — Brinell hardness test — Part 1: Test method
ISO 6892-1, Metallic materials — Tensile testing — Part 1: Method of test at room temperature
ISO 6929, Steel products — Vocabulary
ISO 10474, Steel and steel products — Inspection documents
ISO 14284, Steel and iron — Sampling and preparation of samples for the determination of chemical
composition
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 377, ISO 4885, ISO 4948-1,
ISO 4948-2, ISO 6929, ISO 14284 and the following apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
bright product
drawn or peeled/turned product with smoother surface quality and better dimensional accuracy in
comparison to hot-rolled product
3.2
drawn product
product of various cross-sectional shapes obtained, after descaling, by cold drawing of hot-rolled
product, on a drawing bench (cold formation without removing material)
Note 1 to entry: This operation gives the product special features with respect to shape, dimensional accuracy
and surface finish. In addition, the process causes cold working of the product, which can be eliminated by
subsequent heat treatment. Products in lengths are delivered straightened, products of small cross-section may
also be supplied in coils.
3.3
peeled/turned product
round bar produced by peeling or turning where the product can be further processed by straightening
and polishing
Note 1 to entry: This operation gives the bar special features with respect to shape, dimensional accuracy and
surface finish. The removal of metal is carried out in such a way that the bright product is generally free from
rolling defects and surface decarburization.
3.4
product in the ground condition
ground product
drawn or peeled/turned round bar given an improved surface quality and dimensional accuracy by
grinding or by grinding and polishing
ISO 683-7:2023(E)
3.5
thickness
nominal dimension of the product
Note 1 to entry: That means:
a) the diameter in the case of rounds;
b) the lateral length in the case of squares;
c) the width over flats in the case of hexagons;
d) the shorter lateral length in the case of flats (rectangular bars) and wide-flats.
For special sections, 'thickness' shall be defined at the time of enquiry and order.
3.6
ovality
difference between the smallest and largest dimension measured across the pairs of opposing points at
a common cross-section
3.7
out of shape
deviation from the nominal section profile
EXAMPLE Parallelism, perpendicularity and twist.
3.8
ruling section
section for which the specified mechanical properties apply
Note 1 to entry: Independent of the actual shape and dimensions of the cross-section of the product, the size of its
ruling section is always given by a diameter. This corresponds to the diameter of an “equivalent round bar”. That
is a round bar which will show the same cooling rate as the actual ruling section of the product concerned at its
position for taking the test pieces, when being cooled from austenitizing temperature.
4 Classification and designation
4.1 Classification
The classification of the relevant steel grades is allocated in accordance with ISO 4948-1 and ISO 4948-2.
The general engineering and the free cutting steels are quality steels. The steels for case hardening and
for quenching and tempering are special steels.
4.2 Designation
For the steel grades covered by this document, the steel names given in the relevant tables are allocated
in accordance with ISO/TS 4949.
NOTE Designation of steels covered by this document and of comparable grades covered in various other
designation systems are given in Annex E.
5 Information to be supplied by the purchaser
5.1 Mandatory information
The manufacturer shall obtain the following information from the purchaser at the time of enquiry and
order:
a) quantity (mass, number of bars) to be delivered;
ISO 683-7:2023(E)
b) shape of the product (e. g. round, hexagon, square, flat);
c) the dimensions and tolerances of the product, see 7.10, Table 3 and Tables 12 to 14;
d) a reference to this document, i.e. ISO 683-7:2023;
e) the designation of the steel grade and the delivery condition (see Tables 5 to 11);
f) standard designation for a test report 2.2 or, if required, any other type of inspection document in
accordance with ISO 10474.
5.2 Options/Supplementary or special requirements
A number of options are specified in this document and listed below.
a) reference testing for products used in the quenched and tempered condition (for steels for
quenching and tempering only (see Table 2, footnote d and C.2);
b) any fine grain requirement and verification of fine grain size (see 7.6 and C.3);
c) non-destructive testing (see 7.8 and C.4);
d) the disposition of tolerances in accordance with 7.10 and C.5;
e) bar end conditions may be specified at the time of enquiry and order in accordance with C.6;
f) product analysis (see 7.2, Table 1 and C.7);
g) for a minimum reduction ratio or minimum thickness deformation (see 6.1 and C.8);
h) temporary corrosion protection (see 6.2.1 and C.9);
i) any requirement to special marking (see Clauses 10 and C.10);
j) any additionally requirement concerning the surface condition, i.e. ground surface +G or polished
surface +PL for round bars (see 6.2.2 and Table 3);
k) surface quality class if another than the standard class is requested (see 7.11 and Table 4);
l) verification of the straightness (see 7.10, Table 15, Table 16 and Annex D);
m) any requirement to the hardenability (+H, +HH, +HL), for special steels only (see 7.4);
n) any requirement for non-metallic inclusions (see 7.7);
o) any requirement regarding the permissible depth of decarburization (see 7.9);
p) impact test at a temperature lower than room temperature (see 9.2.2).
5.3 Ordering example
2 t round bars with nominal diameter 20 mm, tolerance h9, stock length 6 000 mm made of steel grade
C45 according to this document in delivery condition +C, surface quality class 1 and a test report 2.2 as
specified in ISO 10474.
2 t round bars 20 h9 × stock 6 000
steel grade ISO 683-7 - C45+C
Inspection document ISO 10474 - 2.2
ISO 683-7:2023(E)
6 Manufacturing process
6.1 General
The manufacturing process of the steel and of the products is with the restrictions given by the
requirements in 6.2 and 6.3 left to the discretion of the manufacturer.
For minimum reduction ratio or minimum thickness deformation ratio of rolled and forged products,
see C.8.
6.2 Treatment and surface condition at delivery
6.2.1 Treatment condition
The treatment and heat-treatment condition (if any) at the time of delivery shall conform with the
condition agreed in the order and shall be one of the conditions indicated in Table 2.
Bright steel products in cold drawn or peeled/turned condition are coated with a light film of grease
from processing, for bright steel products in a finally heat-treated condition, the manufacturer chooses
the rust protection after heat treatment.
The usual light application of ordinary grease or oil does not afford positive protection against rusting,
particularly in the presence of condensation water. The use of a selected rust inhibitor or a special type
of packing shall, if required, be agreed at the time of enquiry and order, see C.9.
6.2.2 Surface conditions
The surface condition and the tolerance classes on bright steel products shall conform with Table 3.
One of the classes written in brackets can be agreed at the time of enquiry and order if requested by the
purchaser.
6.3 Traceability of the cast
Each product shall be traceable to the cast, see Clause 10.
7 Requirements
7.1 General
Combination of usual treatment conditions at the time of delivery and requirements concerning
chemical composition and mechanical properties are shown in Table 2.
In addition to this document, the general technical delivery requirements of ISO 404 shall apply.
This document lists the mechanical characteristics for products up to 100 mm in thickness. For
dimensions greater 100 mm thickness, mechanical properties shall be agreed between manufacturer
and purchaser at the time of enquiry and order.
7.2 Chemical composition
The chemical composition of the steels determined by the cast analysis shall conform with ISO 630-2,
ISO 683-1, ISO 683-2, ISO 683-3 and ISO 683-4. The grades and the chemical composition of the steels
are also listed for information in this document, see Annex A.
Permissible deviations between the limiting values for cast analysis and the values for product analysis
are given in the corresponding tables of ISO 630-2, ISO 683-1, ISO 683-2, ISO 683-3 and ISO 683-4. The
product analysis shall be carried out when specified at the time of enquiry and order (see C.7).
ISO 683-7:2023(E)
If steels for case hardening or for quenching and tempering are ordered with hardenability
requirements in accordance with ISO 683-1, ISO 683-2 and ISO 683-3, such hardenability requirements
shall be considered as the governing criteria for acceptance. In such cases, the cast analysis may deviate
by the values given in ISO 683-1, ISO 683-2 and ISO 683-3.
WARNING — Due to hazardous effects to health and environmental problems of Pb, it is
recommended to use instead steels only with sulfur and other innocuous free-cutting element
additions.
7.3 Mechanical properties
For steels ordered in one of the treatment conditions in Table 2, the requirements for mechanical
properties specified in Tables 5 to 11 shall apply. The mechanical property values given in Tables 5 to 11
shall apply to test pieces that have been taken and prepared in accordance with Figure 1. By agreement,
alternative mechanical properties may be agreed. For bright products in heat treated condition +N,
+A, +FP after cold drawing and in the condition +N+SH the requirements of the relevant International
Standard, i.e. ISO 630-2, ISO 683-1, ISO 683-2 or ISO 683-3, shall apply.
In this case, the normal and narrowed hardenability values given in ISO 683-1, ISO 683-2 for special
steels and the narrowed hardenability values in ISO 683-3 for alloy special steels are for guidance
purposes only.
An impact test shall be performed if mentioned in the tables of mechanical properties for the condition
+QT+SH/+C+QT. For cold drawn bars (+C, +C+G, +C+PL), an impact test shall not be performed, since
there are no reference values unless impact test and Charpy values are agreed at the time of enquiry
and order. Additional requirements concerning the impact energy and the verification at temperatures
other than room temperature (0 °C, –20 °C and –40 °C) can be agreed at the time of enquiry and order.
NOTE In Tables 5 to 11, grades alloyed with further elements for better machinability are not explicitly
mentioned, but the mechanical properties are also valid for them (see Tables A.1 to A.4).
7.4 Hardenability
Unless otherwise agreed for alloy case-hardening steels, the normal hardenability requirements given
in ISO 683-3 shall apply. If agreed at the time of enquiry and order, alloy case-hardening steels with
restricted hardenability scatterbands given in ISO 683-3 shall be supplied and these values shall apply
in addition to Table 2, columns 6 and 7. By agreement, alternative hardenability may be agreed.
If special steels for quenching and tempering are ordered by using the designations to normal or to
narrowed hardenability scatterbands, the values of hardenability given in ISO 683-1 or ISO 683-2 shall
apply in addition to Table 2, columns 8 and 9.
NOTE In Tables 9 to 11, grades alloyed with further elements for better machinability are not explicitly
mentioned, but the mechanical properties are also valid for them (see Tables A.3 and A.4).
7.5 Machinability
Depending on the steel grade, machinability is possible in the condition cold drawn (+C), treated to
ferrite/pearlite structure (+FP), normalized (+N) or soft annealed (+A). After machining, small changes
in the shape may occur. Stress relieving' (+SR) will reduce these effects.
If improved machinability is required, grades with defined ranges of alloying elements, which support
the machinability and/or with a specific treatment to improve machinability should be ordered (see
also footnote b in Tables A.1, A.3 and A.4).
Free-cutting steels with low carbon content have their best machinability in the cold drawn condition.
NOTE Non-leaded steels with comparable chemical composition generally have identical mechanical
properties but often lower machinability than leaded steels.
ISO 683-7:2023(E)
7.6 Grain size
Unless otherwise agreed at the time of enquiry and order the grain size of the general engineering,
free-cutting steels and the non-alloy steels for quenching and tempering shall be left to the discretion of
the manufacturer. If a fine grain structure is required for non-alloy steels for quenching and tempering
or for case-hardening or quenched and tempered free-cutting steels, Annex C, the requirement in C.3
shall be ordered.
If direct hardening treatment is used for free-cutting case-hardening steels, a fine grain structure
should be ordered.
The case-hardening and the alloy steels for quenching and tempering shall have a fine grain structure
with an austenite grain size of 5 or finer when tested in accordance with ISO 643. See C.3 for verification
only.
7.7 Non-metallic inclusions
7.7.1 Microscopic inclusions
The special steels shall have a certain degree of cleanliness, however, verification of the non-metallic
inclusion content requires a special agreement. If there is such an agreement at the time of enquiry and
order, the microscopically non-metallic inclusion content shall be determined to an agreed procedure
and within agreed limits according to ISO 4967 or another regional standard, e.g. EN 10247 or JIS G
0555.
For grades with specified minimum sulfur content, the agreement should only concern the oxides.
7.7.2 Macroscopic inclusions
Freedom of macroscopic inclusions cannot be ensured in any steel. This requirement is applicable for
the verification of the macroscopic inclusions in special steels. If verification is agreed, then the method
and acceptance limits shall be agreed at the time of enquiry and order.
7.8 Internal soundness
Requirements relating to the internal soundness of the products may be agreed at the time of enquiry
and order, see C.4.
7.9 Decarburization
For steels for quenching and tempering, requirements relating to the permissible depth of
decarburization may be agreed at the time of enquiry and order.
The depth of decarburization shall be determined in accordance with the micrographic method
specified in ISO 3887.
7.10 Shape, dimensions and tolerances
The tolerance class on thickness (and width for flats) shall conform with the requirements agreed at
the time of enquiry and order and shall be in accordance with Table 3. If there is no agreement on the
tolerance class, the bright products are delivered with the standard tolerance class given in Table 3.
The tolerance class and the corresponding tolerances are given in Table 12 for rounds, squares and
hexagons and in Table 13 for drawn flats. Where specified by the purchaser at the time of enquiry and
order, the disposition tolerances specified in Table 12 shall be in accordance with C.5.
Unless otherwise agreed at the time of enquiry and order, the length and the tolerance on length shall
be as specified in Table 14.
ISO 683-7:2023(E)
Maximum deviation from 'ovality’ shall be not more than half the specified tolerance range and in any
case never above the upper limit of the tolerance. Any requirements concerning out of shape may be
agreed at the time of enquiry and order together with the measurement method.
For the evaluation of straightness, automatic methods can be used at the discretion of the manufacturer.
Where specified at the time of enquiry and order and in cases of dispute, an agreed number of bars
shall be evaluated for straightness in accordance with one of the methods specified in Annex D. The
tolerances specified in Tables 15 and 16 shall apply.
Non-round bars (i.e. square, hexagon and flat) in widths ≤150 mm may have an undefined profile within
a distance of 0,2 mm of the hypothetical edge, flats in widths >150 mm within a distance of 0,5 mm of
the hypothetical edge, unless otherwise agreed. For widths >150 mm sharp corners can specifically be
ordered.
7.11 Surface quality
Bright products shall have a smooth, scale free surface. Bright products in the final heat-treated
condition shall be free from loose surface scale; their surface might be discoloured or darker. For
hexagons, squares, flats and profiles with special cross-sections, one cannot achieve – for manufacturing
reasons – the same quality of surface finish as for round cross-sections.
Since surface discontinuities (cracks, overlapping, scale, isolated pores, pits, grooves, etc.) cannot
be completely avoided during manufacturing (hot and cold forming, heat treatments, handling and
storage) and since they are retained when drawing, agreements shall be made regarding surface
quality. The surface quality of the products shall be one of the classes in accordance with Table 4. Cold
drawn bars are normally delivered in class 1, while peeled/turned bars as well as ground/polished
bars are delivered in class 3. Different classes may be agreed at the time of enquiry and order.
For flats, squares in sizes greater than 20 mm and hexagons in sizes greater than 50 mm, the maximum
possible depth of surface discontinuities shall be agreed at the time of enquiry and order.
NOTE Where automatic testing of the surface is applied, 50 mm of each end of the bar is not normally
covered.
Surface defects cannot be eliminated without removal of material. Products in the 'technically crack
free by manufacture' condition are only available in the peeled/turned and/or ground conditions.
8 Inspection
8.1 Testing procedures and types of documents
8.1.1 Products conforming with this document shall be ordered and delivered with one of the
inspection documents specified in ISO 10474. The type of document shall be agreed upon at the time of
enquiry and order. If the order does not contain any specification of this type, a test report 2.2 shall be
issued.
8.1.2 If, in accordance with the agreements made at the time of enquiry and order, a test report 2.2
must be provided, this shall cover the following information:
a) confirmation that the material conforms with the requirements of the order;
b) results of the cast analysis for all elements specified for the steel type concerned.
8.1.3 If, in accordance with the agreements made at the time of enquiry and order, an inspection
certificate 3.1 or 3.2 in accordance with ISO 10474 must be provided, the specific inspections and tests
ISO 683-7:2023(E)
described in 8.3 and Clause 9 shall be carried out and the results shall be confirmed in the inspection
certificate.
In addition, the inspection certificate shall cover:
a) confirmation that the material conforms with the requirements of the order;
b) results of the cast analysis for all elements specified for the steel type concerned;
c) the result of all inspections and tests ordered by supplementary requirements (see Annex C);
d) the symbol letters or numbers relating the inspection certificate, test pieces and products to each
other.
8.2 Frequency of testing
The amount of testing, the sampling conditi
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