ISO 5951:2001
(Main)Hot-rolled steel sheet of higher yield strength with improved formability
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
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INTERNATIONAL ISO
STANDARD 5951
Third edition
2001-10-15
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 5951:2001(E)
©
ISO 2001
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ISO 5951:2001(E)
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ii © ISO 2001 – All rights reserved
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ISO 5951:2001(E)
Contents Page
Foreword.iv
1 Scope.1
2 Normative references.1
3 Terms and definitions .2
4 Conditions of manufacture.2
5 Dimensional tolerances.4
6 Sampling — Tensile test .4
7 Mechanical property tests .4
8 Retests.5
9 Resubmission.5
10 Workmanship.5
11 Inspection and acceptance.5
12 Coil size.6
13 Marking.6
14 Information to be supplied by the purchaser .6
Bibliography.13
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ISO 5951:2001(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.
Attention is drawn to the possibility that some of the elements of this International Standard may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights.
International Standard ISO 5951 was prepared by Technical Committee ISO/TC 17, Steel, Subcommittee SC 12,
Continuous mill flat rolled products.
This third edition cancels and replaces the second edition (ISO 5951:1993), which has been technically revised.
iv © ISO 2001 – All rights reserved
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INTERNATIONAL STANDARD ISO 5951:2001(E)
Hot-rolled steel sheet of higher yield strength with improved
formability
1 Scope
1.1 This International Standard applies to continuously hot-rolled steel sheet of higher yield strength with
improved formability in the grades listed in Table 1. The steel is killed, made according to a fine grain practice and
has a suitable chemical composition, which may include microalloying elements, to provide improved formability.
The product is intended for applications where parts are to be fabricated requiring better formability than is provided
by normal high yield strength steel sheet. It is generally used in the delivered condition.
Because of the combination of higher strength and improved formability, it is possible to obtain savings in mass
along with better weldability.
1.2 This product is commonly produced in the range of thicknesses of 1,6 mm and over 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 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”.
1.4 This International Standard does not cover steel intended for boilers or pressure vessels, or steels
designated as commercial quality or drawing qualities (covered in ISO 3573), or steels designated as weathering
steels, having increased atmospheric corrosion resistance, or lower yield strength steels having less formability
properties (covered in ISO 4995 and ISO 4996) compared with those included in this International Standard.
2 Normative references
The following normative documents contain provisions which, through reference in this text, constitute provisions of
this International Standard. For dated references, subsequent amendments to, or revisions of, any of these
publications do not apply. However, parties to agreements based on this International Standard are encouraged to
investigate the possibility of applying the most recent editions of the normative documents indicated below. For
undated references, the latest edition of the normative document referred to applies. Members of ISO and IEC
maintain registers of currently valid International Standards.
ISO 148:1983, Steel-Charpy impact test (V-notch)
ISO 6892:1998, Metallic materials — Tensile testing at ambient temperature
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ISO 5951:2001(E)
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, 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-type or reversing-type wide strip hot-rolling mill to the
required sheet thickness
NOTE 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 Descaling may also be performed by mechanical means such as grit blasting. Some change in properties may result
from descaling.
3.4
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.
3.5
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.
3.6
Resquared
Steel sheet that may have received an additional shearing operation after being cut to length in an attempt to
approach a true 90∞ angle at the shear cut
NOTE “Resquared” is referred to as “restricted” in some areas of the world.
4 Conditions of manufacture
4.1 Steelmaking
Unless otherwise agreed upon 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
4.2.1 The steel covered by this International Standard may contain microalloying elements.The chemical
composition may be agreed between the interested parties at the time of enquiry and ordering.
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ISO 5951:2001(E)
4.2.2 At the time of choice of grade or chemical composition to be used, attention shall be brought to the welding
process to be used (see 4.4).
4.3 Chemical analysis
4.3.1 Heat analysis
A heat analysis of each cast of steel shall be made by the manufacturer to determine the percentage of carbon,
manganese, phosphorus and sulfur, and the contents of other elements giving the specified mechanical strength
and formability.On request, this analysis shall be reported to the purchaser or 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 semi-finished or
finished steel and shall take into consideration any normal heterogeneity.The sampling method and deviation limits
shall be agreed upon between the interested parties at the time of enquiry and ordering.
4.4 Weldability
This product is normally 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 hot-rolled steel sheet be identified for fabrication by name of the part or by the intended
application. 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 1,
when they are determined on test pieces in accordance with the requirements of clause 7. Any additional property
requirements specified or required are subject to agreement between the interested parties at the time of enquiry
and ordering. Such additional requirements may include characterization or prescribed values for properties such
as impact for sheet over 6 mm in thickness (see 7.2).
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.
The steel shall be supplied as-rolled or pickled and oiled as requested by the purchaser at the time of enquiry and
ordering.
4.8 Oiling
As a deterrent to rusting, a coating of oil is usually applied to hot-rolled descaled steel sheet. The oil is not intended
as a drawing or forming lubricant and should be easily removable with degreasing chemicals. The product may be
ordered not oiled, if required, in which case, the supplier has limited responsibility if oxidation occurs.
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ISO 5951:2001(E)
Table 1 — Mechanical properties
a b, c
Grade R min R min A min
e m
(information only)
2 2
N/mm N/mm e < 3 mm 3 u e u 6 mm
L = 50 mm L = 80 mm L = 5,65 S L = 50 mm
o o oo o
HSF 275 275 350 25 23 28 27
HSF 355 355 420 21 19 24 23
HSF 420 420 480 18 16 21 20
HSF 490 490 540 15 13 18 17
HSF 560 560 610 12 10 15 14
R = yied strength
e
R = tensile strength
m
A = percentage elongation after fracture
L = gauge length on test piece
o
S = original cross sectional area of gauge length
o
e = thickness of steel sheet, in millimetres
2
1N/mm = 1 MPa
a
The yield strength can be measured either by 0,5 % elongation proof stress R (proof stress under load) or by 0,2 % offset R when
t0,5 p0,2
a definite yield phenomenon is not present.
b
For thicknesses up to 3 mm, use either L = 50 mm or L = 80 mm. For t
...
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