ISO 4960:2019

Steel strip, cold-reduced with a mass fraction of carbon over 0,25 %

This document specifies the minimum requirements for steel strip of carbon over 0,25 %, in coils and cut lengths. The product is applicable to highly stressed parts of many different types and is characterized by close dimensional tolerances and controlled surface finishes. The steel strip is produced in a number of types and surface finishes to be compatible with differing applications requirements. This document does not apply to alloy steels or stainless steels.

Feuillards en acier au carbone laminés à froid à teneur en carbone supérieure à 0,25 %

General Information

• Status: Published
• Publication Date: 22-Jul-2019
• ICS: 77.140.50 - Flat steel products and semi-products
• Technical Committee: ISO/TC 17/SC 12 - Continuous mill flat rolled products
• Drafting Committee: ISO/TC 17/SC 12 - Continuous mill flat rolled products
• Current Stage: 9093 - International Standard confirmed
• Start Date: 17-Mar-2025
• Completion Date: 13-Dec-2025

Relations

• Revises: ISO 4960:2007 - Cold-reduced carbon steel strip with a mass fraction of carbon over 0,25 %
• Effective Date: 25-Feb-2017

Overview

ISO 4960:2019 specifies minimum requirements for cold‑reduced carbon steel strip with a mass fraction of carbon over 0.25%, supplied in coils or cut lengths. The standard targets products used for highly stressed parts where close dimensional tolerances and controlled surface finishes are critical. It covers grades (CS30–CS95), chemical composition and limits, production and ordering conditions, surface finishes, tests, inspection and marking. The document excludes alloy steels and stainless steels.

Key topics and requirements

• Grades and chemistry: Defines grades CS30 through CS95 with carbon ranges (approximately 0.28% up to 1.03%) and specified limits for Mn, P, S, Si and additional elements (Cu, Ni, Cr, Mo, Nb, V, Ti). Sum limits (e.g., Cu+Ni+Cr+Mo ≤ 0.50% on heat analysis) are included unless otherwise agreed.
• Dimensions and form: Typical thicknesses are 6 mm and under, widths up to 600 mm, available as coils or cut lengths. Wider widths may be agreed between purchaser and producer.
• Surface finishes and roughness: Standardizes finishes - matte, regular bright, plating bright, and best bright - with typical Ra ranges (matte ~0.5–2.0 µm; regular bright ~0.5 µm; plating bright ≤0.25 µm; best bright ≤0.10 µm).
• Manufacture and ordering conditions: Allows for manufacturer discretion in steelmaking unless specified; ordering options include full‑hard, spheroidized annealed, and other conditions (e.g., quenched as specified).
• Mechanical requirements & testing: Specifies hardness (HRBW) and tensile testing requirements, with referenced test methods (Vickers, Rockwell, tensile at room temperature).
• Quality control: Includes heat analysis, optional purchaser product analysis, sampling, decarburization limits, retests, inspection and acceptance criteria, coil size, oiling and marking.

Applications and users

ISO 4960:2019 is intended for:

• Steel producers and strip mills manufacturing cold‑reduced carbon strip
• Purchasing and specification engineers who select materials for highly stressed components
• Quality and metallurgical inspectors performing heat/product analysis, hardness and tensile testing
• Converters, stampers and finishers requiring controlled surface finish for painting, plating or subsequent forming

Typical practical uses include precision parts where tight thickness tolerances, controlled surface roughness and defined mechanical properties are required.

Related standards

Normative references cited in ISO 4960:2019 include:

• ISO 6507-1 (Vickers hardness test)
• ISO 6508-1 (Rockwell hardness test)
• ISO 6892-1 (Tensile testing at room temperature)

For procurement, design and quality control, reference ISO 4960:2019 when specifying cold‑reduced steel strip (carbon >0.25%) to ensure consistent chemistry, surface finish and mechanical performance.

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 4960
Fourth edition
2019-07
Steel strip, cold-reduced with a mass
fraction of carbon over 0,25 %
Feuillards en acier au carbone laminés à froid à teneur en carbone
supérieure à 0,25 %
Reference number
©
ISO 2019
© ISO 2019
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: [phone]
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Website: www.iso.org
Published in Switzerland
ii © ISO 2019 – 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 . 3
5.3 Chemical analysis . 3
5.3.1 Heat analysis . . 3
5.3.2 Product analysis . 3
5.4 Ordering conditions . 4
5.5 Mechanical properties . 5
5.5.1 Hardness . 5
5.5.2 Tensile properties . 5
5.6 Application . 5
5.7 Weldability . 5
5.8 Surface finish condition . 5
5.9 Oiling . 5
5.10 Dimensional tolerances . 7
6 Sampling . 8
7 Test methods . 8
7.1 Hardness test . 8
7.2 Tensile test . 8
8 Decarburization . 8
9 Retests . 8
9.1 Machining and flaws. 8
9.2 Additional tests . 8
10 Resubmission .11
11 Workmanship .11
12 Inspection and acceptance .11
13 Coil size .11
14 Marking .11
15 Information to be supplied by the purchaser.12
Bibliography .13
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 documents 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).
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. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www .iso .org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation on 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 the following
URL: www .iso .org/iso/foreword .html.
This document was prepared by Technical Committee ISO/TC 17, Steel, Subcommittee SC 12, Continuous
mill flat rolled products.
This fourth edition cancels and replaces the third edition (ISO 4960:2007), which has been technically
revised. The main changes compared to the previous edition are as follows:
— added definitions for surface finishes and "lot";
— revised scope;
— added Clause 4 for “Dimensions”;
— “Specified qualities appropriate to the particular grade” changed to “Ordering conditions”,
renumbered as 5.3;
— 5.5.1 changed from HRB to HRBW;
— previous 5.5 changed to 5.8 using revised surface finish terminology, addition of surface roughness
requirements;
— revised Table 5.
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.
iv © ISO 2019 – All rights reserved

INTERNATIONAL STANDARD ISO 4960:2019(E)
Steel strip, cold-reduced with a mass fraction of carbon
over 0,25 %
1 Scope
This document specifies the minimum requirements for steel strip of carbon over 0,25 %, in coils and
cut lengths.
The product is applicable to highly stressed parts of many different types and is characterized by close
dimensional tolerances and controlled surface finishes.
The steel strip is produced in a number of types and surface finishes to be compatible with differing
applications requirements.
This document does not apply to alloy steels or stainless steels.
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 6507-1, Metallic materials — Vickers hardness test — Part 1: Test method
ISO 6508-1, Metallic materials — Rockwell hardness test — Part 1: Test method
ISO 6892-1, Metallic materials — Tensile testing — Part 1: Method of test at room temperature
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https: //www .iso .org/obp
— IEC Electropedia: available at http: //www .electropedia .org/
3.1
cold-reduced carbon steel strip
product produced from a hot-rolled pickled coil which has been given substantial cold reduction
Note 1 to entry: The product is characterized by an improved surface, greater uniformity in thickness and
improved mechanical properties compared to hot-rolled strip. A cold-reduced strip is also characterized by
tighter thickness tolerances than a cold-reduced sheet, as well as by specified edges.
3.2
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; and to obtain the required surface finish.
Note 2 to entry: Some increase in hardness and some loss in ductility will result from skin passing.
3.3
mill edge
normal side 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.
3.4
sheared edge
material with a burr developed where the material was cut
3.5
matte finish
dull finish
rougher finish obtained by temper passing cold-reduced strip using rolls roughened by mechanical or
chemical means
Note 1 to entry: Surface roughness of the strip is typically Ra 0,5 μm to 2,0 μm, which is beneficial in obtaining
better paint adhesion, and in aiding drawing by reducing surface friction due to better oil adhesion.
3.6
regular bright finish
moderately bright reflective lustre finish obtained by temper passing cold-reduced strip using rolls
with a ground finish
Note 1 to entry: Surface roughness of the strip is typically Ra 0,5 μm, which is suitable for many applications but
not necessarily for bright plating applications.
3.7
plating bright finish
smooth bright finish where a high lustre is not necessary obtained by temper passing cold-reduced
strip using rolls with a fine ground finish
Note 1 to entry: Surface roughness of the strip is typically Ra 0,25 μm max.
3.8
best bright finish
mirror bright finish obtained by temper passing cold-reduced strip using rolls with a polished finish
Note 1 to entry: Surface roughness is of the strip is typically Ra 0,10 μm max., which is suitable for bright plating.
3.9
lot
up to a specified quantity of material of the same designation rolled to the same thickness and surface
condition
4 Dimensions
Cold-reduced steel strip is commonly produced in thicknesses of 6 mm and under, and in widths up to
600 mm, in coils and cut lengths. Strip products may be available in widths greater than 600 mm by
agreement between producer and purchaser; however, such products are typically classified as cold-
rolled sheet.
5 Conditions of manufacture
5.1 Steelmaking
Unless otherwise agreed by the interested parties, the processes used in making the steel and in
manufacturing steel strips are left to the discretion of the manufacturer. On request, the purchaser
shall be informed of the steelmaking process being used.
2 © ISO 2019 – All rights reserved

5.2 Chemical composition
The chemical composition (heat analysis) shall conform to the requirements given in Tables 1 and 2.
5.3 Chemical analysis
5.3.1 Heat analysis
An analysis of each heat shall be made by the manufacturer in order to determine conformity with
the requirements given in Tables 1 and 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
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 shall be in accordance
with Tables 2 and 3.
Table 1 — Chemical composition (heat analysis)
Mass fractions in percent
a b b c
Grade C Mn P S Si
max. max. max.
CS30 0,28 to 0,34 0,60 to 0,90 0,035 0,03 0,35
CS35 0,32 to 0,38 0,60 to 0,90 0,035 0,03 0,35
CS40 0,37 to 0,44 0,60 to 0,90 0,035 0,03 0,35
CS45 0,43 to 0,50 0,60 to 0,90 0,035 0,03 0,35
CS50 0,48 to 055 0,60 to 0,90 0,035 0,03 0,35
CS55 0,50 to 0,60 0,60 to 0,90 0,035 0,03 0,35
CS60 0,55 to 0,65 0,60 to 0,90 0,035 0,03 0,35
CS65 0,60 to 0,70 0,60 to 0,90 0,035 0,03 0,35
CS70 0,65 to 0,75 0,60 to 0,90 0,035 0,03 0,35
CS75 0,70 to 0,80 0,40 to 0,70 0,035 0,03 0,35
CS85 0,80 to 0,93 0,70 to 1,00 0,035 0,03 0,35
CS95 0,90 to 1,03 0,30 to 0,50 0,035 0,03 0,35
a
Other manganese values can be specified upon agreement at the time of ordering, provided a range of 0,30 % is
maintained.
b
When specified, phosphorus and sulfur may be ordered to 0,020 % maximum by heat analysis.
c
Silicon can be specified as a restricted range upon agreement at the time of ordering.
Table 2 — Limits on additional chemical elements
Mass fractions in percent
Grade
...