ISO 4997:2015

Cold-reduced carbon steel sheet of structural quality

ISO 4997:2015 applies to cold-reduced carbon steel sheet of structural quality in grades CR220, CR250, CR320, and CH550, usually without the use of microalloying elements. The product is intended for structures that include bolting, riveting, and welding. It is generally used in the delivered condition for fabricating purposes, such as bending, forming, and welding. ISO 4997:2015 does not cover steels designated as commercial quality or drawing qualities (covered in ISO 3574), cold-reduced carbon steel sheet according to hardness requirements (covered in ISO 5954), cold-reduced steel sheet of higher strength with improved formability (covered in ISO 13887), or cold-reduced steel sheet of high tensile strength and low yield point with improved formability (covered in ISO 14590).

Tôles en acier au carbone laminées à froid, de qualité destinée à la construction

General Information

• Status: Published
• Publication Date: 18-Jan-2015
• 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: 9599 - Withdrawal of International Standard
• Start Date: 01-Apr-2025
• Completion Date: 13-Dec-2025

Relations

• Consolidated By: ISO 22081:2021 - Geometrical product specifications (GPS) - Geometrical tolerancing - General geometrical specifications and general size specifications
• Effective Date: 06-Jun-2022
• Revised: ISO 4997:2025 - Cold-reduced carbon steel sheet of structural quality
• Effective Date: 18-Mar-2023
• Revises: ISO 4997:2007 - Cold-reduced carbon steel sheet of structural quality
• Effective Date: 27-Jul-2013

Overview

ISO 4997:2015 specifies requirements for cold‑reduced carbon steel sheet of structural quality - commonly supplied in grades CR220, CR250, CR320, and CH550. The standard covers chemical composition, manufacture, mechanical properties, surface quality, dimensional tolerances and testing for sheets and coils intended for structural fabrication (bolting, riveting, bending, forming and - where appropriate - welding). Typical dimensions are thicknesses from about 0.36 mm to 3 mm and widths from 600 mm upwards, supplied in coils or cut lengths.

Key topics and requirements

• Grades and metallurgy: Limits on carbon, manganese, phosphorus and sulphur (e.g., C max 0.15% for CR220; C up to 0.25% for other grades). Limits on minor elements (Cu, Ni, Cr, Mo, Nb, V, Ti) and rules for their sums are included.
• Manufacture and condition: Cold reduction followed by annealing and usually a light skin‑pass (except CH550 which is not annealed after reduction). Manufacturer’s processes are generally at their discretion but heat analysis can be supplied on request.
• Mechanical properties: Specified yield, tensile strength and elongation values for CR220, CR250 and CR320 (for example CR320: Re ≈ 320 MPa, Rm ≈ 400 MPa). CH550 is a high‑strength grade with yield approaching tensile strength and is tested using 0.5% proof strength per ISO 6892‑1.
• Weldability: Product is normally weldable under suitable parameters; however, welding becomes harder as carbon exceeds 0.15% and CH550 is generally not recommended for welding because welding heat can reduce its strength.
• Surface quality and finish: Two grades - Surface A (unexposed) allows minor defects that do not affect formability or coatings; Surface B (exposed) requires one face to be free of imperfections affecting coating appearance.
• Testing and conformity: Heat and product chemical analyses, tensile testing (per ISO 6892‑1), dimensional/shape tolerances (per ISO 16162), retest and inspection rules are specified.

Applications and users

• Useful for structural fabricators, steel producers, procurement/specification engineers, quality and inspection teams, and designers of bolted, riveted or formed steel components.
• Typical applications: structural panels, chassis, frames and fabricated assemblies where forming, bending and mechanical fastening are required.
• Specification helps ensure predictable formability, strength and surface condition for downstream painting or coating processes.

Related standards

• ISO 6892‑1 (tensile testing)
• ISO 16162 (dimensional and shape tolerances)
• Exclusions referenced in ISO 4997: ISO 3574, ISO 5954, ISO 13887, ISO 14590 (other cold‑reduced qualities and special formability/hardness/strength classes).

Keywords: ISO 4997, cold‑reduced carbon steel sheet, structural quality, CR220, CR250, CR320, CH550, weldability, surface quality, mechanical properties, chemical composition.

Standards Content (Sample)

INTERNATIONAL ISO
STANDARD 4997
Fifth edition
2015-02-01
Cold-reduced carbon steel sheet of
structural quality
Tôles en acier au carbone laminées à froid, de qualité destinée à la
construction
Reference number
©
ISO 2015
© ISO 2015
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form
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the requester.
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ii © ISO 2015 – 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
5.3.1 Heat analysis . . 3
5.3.2 Product analysis . 3
5.4 Weldability . 3
5.5 Application . 4
5.6 Mechanical properties . 4
5.7 Surface quality . 4
5.7.1 General. 4
5.7.2 Surface quality A (unexposed) . 4
5.7.3 Surface quality B (exposed) . 4
5.8 Surface finish . 5
5.9 Suitability for surface coating . 5
5.10 Oiling . 5
6 Dimensional and shape tolerances . 5
7 Tensile-test sampling . 5
8 Tensile test . 5
9 Retests . 5
9.1 Machining and flaws. 5
9.2 Elongation . 5
9.3 Additional tests . 6
10 Resubmission . 6
11 Workmanship . 6
12 Inspection and acceptance . 6
13 Coil size . 6
14 Marking . 6
15 Information to be provided by the purchaser. 7
Bibliography . 8
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
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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. 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. 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 meaning of ISO specific terms and expressions related to conformity
assessment, as well as information about ISO’s adherence to the WTO principles in the Technical Barriers
to Trade (TBT), see the following URL: Foreword — Supplementary information.
The committee responsible for this document is ISO/TC 17, TC Steel, Subcommittee SC 12, Continuous
mill flat rolled products.
This fifth edition cancels and replaces the fourth edition (ISO 4997:2007), which has been technically revised.
iv © ISO 2015 – All rights reserved

INTERNATIONAL STANDARD ISO 4997:2015(E)
Cold-reduced carbon steel sheet of structural quality
1 Scope
This International Standard applies to cold-reduced carbon steel sheet of structural quality in grades
CR220, CR250, CR320, and CH550, usually without the use of microalloying elements. The product is
intended for structures that include bolting, riveting, and welding. It is generally used in the delivered
condition for fabricating purposes, such as bending, forming, and welding.
This International Standard does not cover steels designated as commercial quality or drawing
qualities (covered in ISO 3574), cold-reduced carbon steel sheet according to hardness requirements
(covered in ISO 5954), cold-reduced steel sheet of higher strength with improved formability (covered
in ISO 13887), or cold-reduced steel sheet of high tensile strength and low yield point with improved
formability (covered in ISO 14590).
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable to its application. For dated references, only the edition cited applies. For undated
references, the latest edition of the reference documents (including any amendments) applies.
ISO 6892-1, Metallic materials — Tensile testing — Part 1: Method of test at room 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
microalloying element
niobium, vanadium, titanium, etc. added singly or in combination to obtain higher strength levels
combined with better formability, weldability, and toughness compared to non-alloyed steels produced
to equivalent strength levels
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
Note 1 to entry: The annealed product is normally supplied skin-passed (see 3.3) but may be supplied annealed-
last (i.e. without a skin pass), if specified by the purchaser on his order.
Note 2 to entry: CH 550 is a product which has not been annealed after reduction to the specified thickness.
3.3
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:
a)  to minimize the appearance of coil breaks, stretcher strains, and fluting;
b)  to control the shape;
c)  to obtain the required surface finish.
Note 2 to entry: Some increase in hardness and some loss in ductility will result from skin passing.
3.4
lot
50 t or less of sheet of the same grade rolled to the same thickness and condition
4 Dimensions
4.1 The product is commonly produced in thicknesses from 0,36 mm up to 3 mm and in widths of
600 mm and over, in coils and cut lengths.
4.2 Cold-reduced sheet less than 600 mm wide can be slit from wide sheet and will be considered as 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 cold-reduced sheet are left to the discretion of the manufacturer. On request, the
purchaser shall be informed of the steelmaking process being use
...