ISO 4996:1999
(Main)Hot-rolled steel sheet of high yield stress structural quality
Hot-rolled steel sheet of high yield stress structural quality
Tôles laminées à chaud en acier de construction à haute limite d'élasticité
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Standards Content (Sample)
INTERNATIONAL ISO
STANDARD 4996
Third edition
1999-09-15
Hot-rolled steel sheet of high yield stress
structural quality
Tôles laminées à chaud en acier de construction à haute limite d'élasticité
A
Reference number
ISO 4996:1999(E)
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ISO 4996:1999(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO
member bodies). The work of preparing International Standards is normally carried out through ISO technical
committees. Each member body interested in a subject for which a technical committee has been established has
the right to be represented on that committee. International organizations, governmental and non-governmental, in
liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical
Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 3.
Draft International Standards adopted by the technical committees are circulated to the member bodies for voting.
Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote.
International Standard ISO 4996 was prepared by Technical Committee ISO/TC 17, Steel, Subcommittee 12,
Continuous mill flat rolled products.
This third edition cancels and replaces the second edition (ISO 4996:1991) which has been technically revised.
© ISO 1999
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic
or mechanical, including photocopying and microfilm, without permission in writing from the publisher.
International Organization for Standardization
Case postale 56 • CH-1211 Genève 20 • Switzerland
Internet iso@iso.ch
Printed in Switzerland
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INTERNATIONAL STANDARD © ISO ISO 4996:1999(E)
Hot-rolled steel sheet of high yield stress structural quality
1 Scope
1.1 This International Standard applies to hot-rolled steel sheet of high yield stress structural quality in the grades
and classes listed in Tables 1 and 2, with the use of microalloying elements. The product is intended for structural
purposes where particular mechanical properties are required. It is generally used in the delivered condition and is
intended for bolted, riveted or welded structures.
Because of the combination of higher strength and microalloy composition, it is possible to obtain savings in mass
along with better formability and weldability as compared with steel sheet without microalloying elements. The
product is produced on a wide strip mill, not a plate mill.
1.2 This product is commonly produced in thicknesses from 1,6 mm to 6 mm and widths of 600 mm and over, in
coils and cut lengths.
1.3 Hot-rolled sheet less than 600 mm wide may be slit from wide sheet and 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”.
1.4 This International Standard does not cover steel intended for boilers or pressure vessels, steels designated as
commercial quality or drawing qualities (ISO 3573, Hot-rolled carbon steel sheet of commercial and drawing
qualities), steels to be rerolled to cold-reducing products, steels designated as weathering steels, having increased
atmospheric corrosion resistance or steels having improved formability properties compared with those in this
document.
2 Normative reference
The following normative document contains provisions which, through reference in this text, constitute provisions of
this International Standard. For dated references, subsequent amendments to, or revisions of, this publication do
not apply. However, parties to agreements based on this International Standard are encouraged to investigate the
possibility of applying the most recent edition of the normative document indicated below. For undated references,
the latest edition of the normative document referred to applies. Members of ISO and IEC maintain registers of
currently valid International Standards.
ISO 6892:1998, Metallic materials — Tensile testing at ambient temperature.
3 Terms and definitions
For the purposes of this International Standard, the following terms and definitions apply.
3.1
microalloying elements
elements, such as niobium, vanadium, titanium, etc., added singly or in combination to obtain higher strength levels
combined with better formability, weldability and toughness as compared to non-alloyed steel produced to
equivalent strength levels
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© ISO
ISO 4996:1999(E)
3.2
hot-rolled steel sheet
product obtained by rolling heated steel through a continuous-type or reversing-type wide strip mill to the required
sheet thickness the product having 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 Descaling may also be performed by mechanical means such as grit blasting. Some changes in properties may result
from descaling.
3.4
edges
3.4.1
mill edge
normal edge without any definite contour produced in hot rolling
NOTE Mill edges may contain some irregularities such as cracked or torn edges or thin (feathered) edges.
3.4.2
sheared edge
normal edge obtained by shearing, slitting or trimming a mill edge product
NOTE Normal processing does not necessarily provide a definite positioning of the slitting burr.
3.5
aluminum killed
steel which has been deoxidized with aluminum sufficient to prevent the evolution of gas during solidification
4 Conditions of manufacture
4.1 Steelmaking
Unless otherwise agreed by the interested parties, the processes used in making the steel and in manufacturing
hot-rolled sheet are left to the discretion of the manufacturer. On request, the purchaser shall be informed of the
steelmaking process being used.
4.2 Chemical composition
The chemical composition (heat analysis) shall conform to the requirements given in Table 1.
4.3 Chemical analysis
4.3.1 Heat analysis
An analysis of each heat of steel shall be made by the manufacturer in order to determine compliance with the
requirements given in Table 1. When requested, at the time of ordering, this analysis shall be reported to the
purchaser or to his representative.
4.3.2 Product analysis
A product analysis may be made by the purchaser in order to verify the specified analysis of the product and shall
take into consideration any normal heterogeneity. Non-killed steels (such as rimmed or capped) are not
technologically suited to product analysis. For aluminum killed steels, the sampling method and deviation limits shall
be agreed upon between the interested parties at the time of ordering.
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© ISO
ISO 4996:1999(E)
Table 1 — Chemical Composition (heat analysis) %
a
Grade Class Method of C Mn Si P S
b
deoxidation
max. max. max. max. max.
HS355 C NE 0,20 1,60 0,50 0,040 0,040
D CS 0,20 1,60 0,50 0,035 0,035
HS390 C NE 0,20 1,60 0,50 0,040 0,040
D CS 0,20 1,60 0,50 0,035 0,035
HS420 C NE 0,20 1,70 0,50 0,040 0,040
D CS 0,20 1,70 0,50 0,035 0,035
HS460 C NE 0,20 1,70 0,50 0,040 0,040
D CS 0,20 1,70 0,50 0,035 0,035
HS490 C NE 0,22 1,70 0,50 0,040 0,040
D CS 0,22 1,70 0,50 0,035 0,035
NOTE 1 Nitrogen content is controlled; normally it should not exceed 0,009 % for NE steel or 0,015 % for
CS steel.
NOTE 2 Each grade includes at least one microalloying element such as vanadium, titanium, niobium, etc.
a
Class C steels are to be used in cases where, owing to conditions and the general design of the
structure, some resistance to brittle fracture is necessary. Class D steels are to be used in cases where,
owing to loading conditions and the general design of the structure, a high resistance to brittle fracture is
necessary.
b
NE = non-rimming; CS = aluminum killed.
4.4 Weldability
The product is suitable for welding if appropriate welding conditions are selected. For undescaled steel it may be
necessary to remove the scale or oxide depending upon the welding method. As the carbon content increases
above 0,15 %, spot welding becomes increasingly difficult.
4.5 Application
It is desirable that the specified product be identified for fabrication by the name of the part or by the intended
application, which shall be compatible with the grade and class specified. Proper identification of the part may
include visual examination, prints or description, or a combination of these.
4.6 Mechanical properties
At the time that the steel is made available for shipment, the mechanical properties shall be as stated in Table 2, if
they are determined on test pieces obtained in accordance with the requirements of clause 7.
4.7 Surface condition
Oxide or scale on hot-rolled steel sheet is subject to variations in thickness, adherence and colour. Removal of the
oxide or scale by pickling or blast cleaning may disclose surface imperfections not readily visible prior to this
operation.
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© ISO
ISO 4996:1999(E)
4.8 Oiling
As a deterrent to rusting, a coating of oil is usually applied to hot-rolled descaled steel sheet but sheet may be
furnished not oiled, if required. The oil is not intended as a drawing or forming lubricant and should be easily
removable with degreasing chemicals. On request, the manufacturer shall advise the purchaser which type of oil
has been used. Hot rolled descaled steel sheet may be ordered unoiled, if required, in which case, the supplier has
limited responsibility if oxidation occurs.
Table 2 — Mechanical Properties
a b
Grade R min. R min. A min.
e
m
(information
only)
2 2
N/mm N/mm %
e , 3 mm 3 < e < 6 mm
L 5 50 mm L 5 80 mm L 5 5,65 S L 5 50 mm
o o o o
o
HS355 355 430 18 16 22 21
HS390 390 460 16 14 20 19
HS420 420 490 14 12 19 18
HS460 460 530 12 10 17 16
HS490 490 570 10 8 15 14
NOTE R yield stress – may be either R or R but not both;
e eL eH
R upper yield stress;
eH
R lower yield stress;
eL
R tensile strength;
m
A percentage elongation after fracture;
L initial gauge length on test piece;
o
S original cross-sectional area of gauge length;
o
e thickness of steel sheet, in millimetres.
2
1 N/mm 5 1 MPa
a
The yield stress values can be measured by 0,5 % elongation proof stress (proof stress under load) or by
0,2 % offset when a definite yield phenomenon is not present.
b
For thicknesses up to 3 mm, use either L 5 50 mm or L 5 80 mm. For thicknesses from 3 mm to 6 mm,
o
o
use either L 2 5.65 S or L 5 50 mm. In case of dispute, however, only the results obtained on a
o o
o
proportional test piece will be valid for material 3 mm and over in thickness.
5 Dimensional tolerances
5.1 Dimensional tolerances applicable to hot-rolled steel sheet of high yield stress structural quality shall be as
given in Tables 3 to 11 inclusive.
5.2 Restricted thickness tolerances are given in Table 4.
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© ISO
ISO 4996:1999(E)
Table 3 — Normal thickness tolerances for hot-rolled sheet stee
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