A Preface
ISO (International Organization for Standardization) is a global alliance of national standards bodies (ISO member bodies). The development of international standards is usually carried out through ISO technical committees. Each member institution interested in a subject on which a technical committee has been established has the right to be represented in the committee. Government and non-governmental international organizations that liaize with standardization organizations are also involved in this work. ISO works closely with the International Electrotechnical Commission (IEC) on all matters of electrical standardization.

The procedures used to develop this document as well as those used for further maintenance are described in Part 1 of the ISO/IEC Directive. In particular, attention should be paid to the different approval criteria required for different types of ISO documents. This document has been drafted in accordance with the editorial rules of Part 2 of the ISO/IEC Directive (see iso.org/directives).

ISO 17872-2019 – Primer Guide for Marking with Paints and varnishes on Sheet Metal Coatings for corrosion Testing

Please note that certain contents of this document may be subject to patent rights. ISO is not 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 in the ISO list of patent claims received (see iso.org/patents).

Any trade names used in this document are provided as information for the convenience of the user and do not constitute an endorsement.

Voluntary, related standards and conformity assessment related ISO specific terminology and express the meaning of and the ISO in the technical barriers to trade (TBT) adhere to the principle of the world trade organization (WTO) information, please see the iso.org/iso/foreword.html.

This document is prepared by Technical Committee ISO/TC 35, Paints and varnishes, Subcommittee SC 9, General Test methods for paints and varnishes.

The second edition cancels and replaces the technically revised first edition (ISO 17872:2007). Compared with the previous edition, the main changes are as follows:

– Article 2 “Normative reference” and Article 3 “Terms and definitions” have been added;

– Added L-shaped and diagonal scribe graphics;

ISO 17872-2019 – Primer Guide for Marking with Paints and varnishes on Sheet Metal Coatings for corrosion Testing

— A second variant of the cross-section shape marked with a U-dot is added to Figure 2;

– V-shaped replaceable inserts, disc milling cutters, engravers and ceramic cutters have been added to the list of possible cutting tools;

– The cross section picture has been added to the corresponding cutting tool;

– Examples of cutting tools in Table A.1 have been grouped into knife or insert tools, pencil tools, and milling machines;

— The original Appendix B has been replaced by a new annex that presents examples of the different results that may occur in a corrosion test when different marking tools are used.

Any feedback or questions regarding this document should be directed to the user’s national standards body. A full list of these agencies can be found at iso.org/members.html.

ISO 17872-2019 – Primer Guide for Marking with Paints and varnishes on Sheet Metal Coatings for corrosion Testing

Introduction
Many international standards deal with corrosion tests in which scribe marks are introduced through coatings on metal substrates. However, the methods introduced by the underline mark (underline patterns, tools, etc.) are not standardized in these standards.

The main purposes of deliberately causing damage to the coating prior to corrosion testing are as follows:

1) Simulate and study how to ensure the adhesion of coating caused by damage after exposure;

b) Obtain an accelerated response during corrosion testing, such as quality control in the production process;

c) Study the general durability of the coating by observing the corrosion rate as damage spreads after exposure.

Preliminary investigations indicated the use of several scribing tools in terms of shape and size. These differences occur both between and within countries. The effect of using different tools is to produce streaking marks with different cross-section shapes, depths and bare metal areas. These differences will greatly affect the test results obtained during the corrosion test, as the purpose of introducing the marking into the coating system is to enable the oxygen and electrolytes present during the exposure test to enter the well-defined and active metal surface.

The actual method used to introduce scribble marks depends on the coating type and thickness. However, in all cases, the recommendation is that the cross section be as smooth as possible, the metal substrate be evenly exposed, and there is no coating residue on the exposed substrate.

ISO 17872-2019 – Primer Guide for Marking with Paints and varnishes on Sheet Metal Coatings for corrosion Testing

1 Scope
This document describes a method for performing corrosion tests on scrip-coated steel or specimens, where the coating system is applied at a dry film thickness of less than 500 μm. It is only used as a guide, based on the results of cooperative tests, and no subsequent corrosion tests are conducted to determine whether the introduced scribe marks are suitable for such tests.

This document covers the marking of metal panels or test pieces (chemically or non-chemically treated) made of:

– Steel;

– galvanized steel;

– aluminum alloy;

— Magnesium alloy.

It does not include the streaking of electroplated metal or composite aluminum plates.

2 Normative references
The following documents are referenced in the text in such a way that some or all of their contents constitute the requirements of this document. For dated references, only the cited version applies. For undated references, the new version of the reference (including any revisions) applies.

ISO 4618, Paints and varnishes — Terms and definitions

ISO 17872-2019 – Primer Guide for Marking with Paints and varnishes on Sheet Metal Coatings for corrosion Testing

3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 4618 apply.

ISO and IEC maintain terminology databases for standardization at the following addresses:

– ISO online browsing platform: available at iso.org/obp

– IEC Electronic Encyclopedia: available at electropedia.org/

Only the standard information component is publicly available. To see the full content, you’ll need to purchase the standards through formal channels.