ISO 5951:2013

INTERNATIONAL ISO
STANDARD 5951
Fifth edition
2013-06-01
Hot-rolled steel sheet of higher yield
strength with improved formability
Tôles en acier laminées à chaud à limite d’élasticité et aptitude au
formage accrues
Reference number
©
ISO 2013
© ISO 2013
All rights reserved. Unless otherwise specified, 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
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.org
Web www.iso.org
Published in Switzerland
ii © ISO 2013 – All rights reserved

Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Dimensions . 2
5 Conditions of manufacture . 2
5.1 Steelmaking . 2
5.2 Chemical composition . 2
5.3 Chemical analysis . 3
5.4 Weldability . 4
5.5 Application . 4
5.6 Mechanical properties . 4
5.7 Surface condition . 5
5.8 Oiling . 5
6 Dimensional and shape tolerances . 5
7 Sampling — Tensile test . 6
8 Mechanical property tests . 6
8.1 Tensile test . 6
8.2 Impact test . 6
9 Retests . 6
9.1 Machining and flaws. 6
9.2 Elongation . 6
9.3 Additional tests . 6
10 Resubmission . 6
11 Workmanship . 6
12 Inspection and acceptance . 7
13 Coil size
........................................................................................................................................................................................................................... 7
14 Marking . 7
15 Information to be supplied by the purchaser. 7
Bibliography . 9
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out
through ISO technical committees. Each member body interested in a subject for which a technical
committee has been established has the right to be represented on that committee. International
organizations, governmental and non-governmental, in liaison with ISO, also take part in the work.
ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of
electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International
Standards adopted by the technical committees are circulated to the member bodies for voting.
Publication as an International Standard requires approval by at least 75 % of the member bodies
casting a vote.
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.
ISO 5951 was prepared by Technical Committee ISO/TC 17, Steel, Subcommittee SC 12, Continuous mill
flat rolled products.
This fifth edition cancels and replaces the fourth edition (ISO 5951:2008), which has been technically revised.
iv © ISO 2013 – All rights reserved

INTERNATIONAL STANDARD ISO 5951:2013(E)
Hot-rolled steel sheet of higher yield strength with
improved formability
1 Scope
1.1 This International Standard applies to all grades of hot-rolled steel sheet of higher yield strength
with improved formability. The steel is killed, made according to a fine grain practice and has a suitable
chemical composition, including microalloying elements, to provide improved formability. The product
is intended for the fabrication of parts requiring better formability than is provided by normal high yield
strength steel sheet. It is generally used in the delivered condition.
1.2 Because of the combination of higher strength and improved formability, it is possible to obtain
savings in mass along with better weldability.
1.3 This International Standard does not cover steel intended for boilers or pressure vessels, steels
designated as commercial quality or drawing quality (covered in ISO 3573), steels designated as weathering
steels, having increased atmospheric corrosion resistance, or lower yield strength steels having less
formability compared with those in this International Standard (covered in ISO 4995 and ISO 4996).
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
ISO 148-1, Metallic materials — Charpy pendulum impact test — Part 1: Test method
ISO 6892-1, Metallic materials — Tensile testing — Part 1: Method of test at room temperature
ISO 16160, Hot-rolled steel sheet products — Dimensional and shape tolerances
ISO 20805, Hot-rolled steel sheet in coils of higher yield strength with improved formability and heavy
thickness for cold forming
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
microalloying element
element, such as niobium, vanadium, titanium, added singly or in combination to obtain higher strength
levels combined with better formability, weldability and toughness as compared with non-alloyed steel
produced to equivalent strength levels
3.2
hot-rolled steel sheet
product obtained by rolling heated steel through a continuous hot strip mill or other hot rolling processes
that produce a coiled product to the required sheet thickness and tolerances
Note 1 to entry: The product has a surface covered with oxide or scale resulting from the hot rolling operation.
3.3
hot-rolled descaled steel sheet
hot-rolled steel sheet from which oxide or scale has been removed, commonly by pickling in an acid solution
Note 1 to entry: Descaling may also be performed by mechanical means such as grit blasting. Some change in
properties can result from descaling.
3.4
mill edge
normal edge without any definite contour produced in hot rolling
Note 1 to entry: Mill edges may contain some irregularities such as cracked or torn edges or thin (feathered) edges.
3.5
sheared edge
normal edge obtained by shearing, slitting or trimming a mill edge product
Note 1 to entry: Normal processing does not necessarily provide a definite positioning of the slitting burr.
4 Dimensions
4.1 Hot-rolled sheet less than 600 mm wide may be slit from wide sheet and will be considered as sheet.
NOTE Hot-rolled sheet up to but not including 3 mm in thickness is commonly known as sheet. Hot-rolled
sheet 3 mm and over in thickness is commonly known as either “sheet” or “plate”.
4.2 This product is commonly prod
...