ISO 14590:2016

DRAFT INTERNATIONAL STANDARD
ISO/DIS 14590
ISO/TC 17/SC 12 Secretariat: ANSI
Voting begins on: Voting terminates on:
2015-08-10 2015-11-10
Cold-reduced steel sheet of high tensile strength and low
yield point with improved formability
Tôles en acier laminées à froid à haute résistance à la traction et faible limite d’élasticité, et aptitude au
formage accrue
ICS: 77.140.50
THIS DOCUMENT IS A DRAFT CIRCULATED
FOR COMMENT AND APPROVAL. IT IS
THEREFORE SUBJECT TO CHANGE AND MAY
NOT BE REFERRED TO AS AN INTERNATIONAL
STANDARD UNTIL PUBLISHED AS SUCH.
IN ADDITION TO THEIR EVALUATION AS
BEING ACCEPTABLE FOR INDUSTRIAL,
TECHNOLOGICAL, COMMERCIAL AND
USER PURPOSES, DRAFT INTERNATIONAL
STANDARDS MAY ON OCCASION HAVE TO
BE CONSIDERED IN THE LIGHT OF THEIR
POTENTIAL TO BECOME STANDARDS TO
WHICH REFERENCE MAY BE MADE IN
Reference number
NATIONAL REGULATIONS.
ISO/DIS 14590:2015(E)
RECIPIENTS OF THIS DRAFT ARE INVITED
TO SUBMIT, WITH THEIR COMMENTS,
NOTIFICATION OF ANY RELEVANT PATENT
RIGHTS OF WHICH THEY ARE AWARE AND TO
©
PROVIDE SUPPORTING DOCUMENTATION. ISO 2015

ISO/DIS 14590:2015(E)
© ISO 2015, Published in Switzerland
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
Ch. de Blandonnet 8 • CP 401
CH-1214 Vernier, Geneva, Switzerland
Tel. +41 22 749 01 11
Fax +41 22 749 09 47
copyright@iso.org
www.iso.org
ii © ISO 2015 – All rights reserved

Revision to ISO 14590:2005(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 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 14590 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 14590:2005), which has been technically
revised.
Draft International Standard Revision to ISO 14590:2005(E)

Cold-reduced steel sheet of high tensile strength and low yield
point with improved formability
1 Scope
This International Standard applies to killed cold-reduced steel sheet of two types that are commercially
available in the world. Type 1 represents steels that are produced to mechanical properties only and Type 2
represents steels that are produced to both chemical and mechanical properties. Bake hardening steels are
included in both types.
This International Standard does not cover steels designated as commercial quality or drawing qualities
(covered in ISO 3574), steels of structural quality (covered in ISO 4997) or steels of higher strength with
improved formability (covered in ISO 13887).
2 Normative references
The following referenced documents, in whole or in part, are normatively referenced in this document and 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 6892-1, Metallic materials — Tensile testing at ambient temperature
ISO 16162, Cold-rolled steel sheet products — Dimensional and shape tolerances
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
bake hardening steel
highly formable steel that, subsequent to cold working, has been subjected to a low-temperature heat treatment,
such as that used for paint baking (170 °C to 200 °C), in order to effect a significant increase in its yield strength,
primarily due to carbon ageing
3.2
cold-reduced steel sheet
product obtained from hot-rolled descaled steel sheet by cold-reducing to the required sheet thickness followed
by annealing to recrystallize the grain structure
3.3
dual-phase steel
steel whose thermal processing has resulted in a multi-phase structure that includes one or more low-
temperature transformation products, thus providing for improved formability at higher strength levels
3.4
restrictive squareness
steel sheet processed to approach a true 90 angle at the shear cut.
Note This product is sometimes referred as “resquared”

Revision to ISO 14590:2005(E)
3.5
skin pass
light cold-rolling of the product
NOTE 1 to entry  The purpose of the skin passing is one or more of the following: to minimize the appearance of coil
breaks, stretcher strains and fluting; to control the shape; to obtain the required surface finish.

NOTE 2 to entry   Some increase in hardness and some loss of ductility will result from skin passing.

3.6
ageing
change in steel properties with the passage of time
Note 1 to entry Ageing may result in a change in yield strength and a corresponding decrease in ductility during storage.
Ageing always has a negative effect on formability. The redevelopment of a definite yield point phenomenon as a result of
ageing can result in a renewed susceptibility to surface imperfections, such as stretcher strain marks (Lüder’s Lines) and
fluting when the steel is formed. To avoid these adverse outcomes, it is essential that the period between final processing
at the producing mill and fabrication be kept to a minimum. Rotation of stock, by using the oldest material first, is
important. Effective roller leveling immediately prior to fabrication can achieve reasonable freedom from stretcher strain
marks.
3.7
lot
50 t or less of steel sheet of the same grade rolled to the same thickness and condition.
3.8
Type 1
Cold-reduced steel sheet specified to mechanical properties only.
3.9
Type 2
Cold-reduced steel sheet specified to both mechanical properties and chemical composition.

4 Dimensions
Cold-reduced steel of high tensile strength and low yield point with improved formability is produced in
thicknesses from 0,25mm to 3,2mm and in widths of 600 mm and over in coils and cut lengths. Product less
than 600 mm wide, slit from wide sheet, will be considered as sheet.
5 Conditions of manufacture
5.1 Steelmaking
Unless otherwise agreed upon by the interested party, the processes used in making the steel and in
manufacturing cold-reduced steel sheet are left to the discretion of the manufacturer. On request, the
purchaser shall be informed of the steelmaking process being used.
5.2 Chemical composition
The chemical composition (heat analysis) shall conform to the requirements given in Tables 1 and 2.
Table 1 - Chemical composition for Type 2 (heat analysis)
Mass fractions in percent
1a)
Grade C Si Mn P S
max. max. max. max. max.
SS220 0,10 0,50 1,00 0,100 0,030
Revision to ISO 14590:2005(E)
SS260 0,10 0,50 1,50 0,120 0,030
SS300 0,15 0,50 1,50 0,140 0,030
DP250 0,10 0,70 2,00 0,030 0,030
DP280 0,14 1,40 2,50 0,030 0,030
DP300 0,12 0.70 2,00 0,080 0,030
DP350 0,14 1,40 2,50 0,100 0,030
DP400 0,18 1,40 2,50 0,030 0,030
DP600 0,20 1,40 3,00 0,030 0,030
BH180 0,04 0,50 0,70 0,060 0,030
BH220 0,08 0,50 0,70 0,080 0,030
BH260 0,08 0,50 0,70 0,100 0,030
BH300 0,10 0,50 0,70 0,120 0,030
a)
SS = structural steel
DP = dual phase
BH = bake hardening
NOTE 1 Micro-alloying elements can be added.

Table 2— Limits on additional chemical elements
Mass fractions in percent
a a ab ab c cd c
Cu Ni Cr Mo Nb V Ti
Element
max. max. max. max. max. max. max.
Heat analysis 0,20 0,20 0,15 0,06 0,008 0,008 0,008
Product analysis 0,23 0,23 0,19 0,07 0,018 0,018 0,018
NOTE Each of the elements listed in this table shall be included in the report of the heat analysis. When the amount of copper,
nickel, chromium or molybdenum present is less than 0,02 %, the analysis may be reported as  0,02 %.
a
The sum of copper, nickel, chromium and molybdenum shall not exceed 0,50 % on heat analysis. When one or more of these
elements are specified, the sum does not apply, in which case, only the individual limits on the remaining elements apply.
b
The sum of chromium and molybdenum shall not exceed 0,16 % on heat analysis. When one or more of these elements are
specified, the sum does not apply, in which case, only the individual limits on the remaining elements apply.
c
For interstitial free steels only, the value of 0,15 % titanium, and 0,10 % maximum for niobium and vanadium are acceptable to
ensure that the carbon and nitrogen are fully stabilized.
d
Heat analysis greater than 0,008 % may be supplied after agreement between the producer and purchaser.

5.3 Chemical analysis
5.3.1 Heat analysis
An analysis of each heat of steel shall be made by the manufacturer to determine compliance with the
requirements of Table 1 and Table 2. On request, a report of the heat analysis shall be made available to the
purchaser or the purchaser’s representative. Each of the elements listed in Tables 1 and 2 shall be included in
the report of the heat analysis. When the amount of copper, nickel, chromium or molybdenum present is less
than 0,02%, the analysis may be reported as “<0,02%”.
5.3.2  Product Analysis
Revision to ISO 14590:2005(E)
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. The product analysis tolerances shall be in
accordance with Tables 2 and 3.
Table 3 — Product analysis tolerances
Mass fractions in percent
Element Range/maximum of specified element Tolerance
≤ 0,15 0,03
C
 0,15 to ≤ 0,40 0,04
 0,60 to ≤ 1,15 0,04
Mn  1,15 to ≤ 1,70 0,05
 1,70 Subject to negotiation
≤ 0,04 0,01
P
 0,04 Not applicable
S ≤ 0,06 0,01
 0,30 to ≤ 0,60 0,05
Si
 0,60 0,06
NOTE 1 This table applies to Type 2 Grades SS, DP and BH.
NOTE 2 The above maximum tolerance is the allowable excess over the specified requirement and not the heat analysis.
For example: For Grade DP350, the following product analysis values are within these tolerances: C 0,17; Mn 1,04; P not applicable;
S 0,04 and Si 0,55.
5.4 Mechanical properties
Type 1 and Type 2 steels shall satisfy the mechanical properties shown respectively, in Tables 4 and 5 when
they are determined in accordance with the requirements of Clause 6 and 7. On request, a report of the
mechanical properties shall be made to the purchaser.
NOTE Prolonged storage of the sheet can result in ageing, leading to an adverse effect on formability.

Table 4 — Mechanical properties for Type 1
5)
1) 2) 3) 4)
Grade R O R A min, %
eL BH m
2 2 2
N/mm , min. N/mm , min. N/mm , min.
L =50mm L =80mm
o o
175YL 175 — 340 31 29
205YL 205 — 370 29 27
235YL 235 — 390 27 25
265YL 265 — 440 23 21
295YL 295 — 490 21 19
325YL 325 — 540 18 17
355YL 355 — 590 15 14
225YY 225 — 490 22 20
245YY 245 — 540 19 18
265YY 265 — 590 16 15
Revision to ISO 14590:2005(E)
365YY 365 — 780 12 11
490YY 490 — 980 5 4
185YH 185 30 340 31 29
1)
YL = forming/drawing use
YY = dual phase
YH = bake hardening
2)
R = lower yield strength
eL
3)
O = see A.2.3
BH
4)
R = tensile strength
m
5)
A = percentage elongation after fracture
NOTE 1 MPa = N/mm
Revision to ISO 14590:2005(E)
Table 5— Mechanical properties for Type 2
1) 2) 3) 4) 5)
Grade R O R A min, %
eL BH m
MPa, min. MPa, min. MPa, min. L = 80 mm
o
SS220 220 — 320 30
SS260 260 — 360 28
SS300
...