ISO/TR 16203:2023

TECHNICAL ISO/TR
REPORT 16203
Second edition
2023-08
Overview of methods available for
particle-free erosion corrosion testing
in flowing liquids
Reference number
© ISO 2023
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ii
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principles . 1
4.1 Particle-free erosion corrosion . 1
4.2 Particle-free erosion corrosion test. 1
4.3 Material loss and observation of surface damage . 2
5 Test methods . 2
5.1 Tests for uniform corrosion . 2
5.1.1 Rotating cylinder test . 2
5.1.2 Test in a pipe or channel . 3
5.2 Tests for nonuniform corrosion . 3
5.2.1 Rotating disc test . 3
5.2.2 Test in a pipe or channel with changes in flow cross section . 4
5.2.3 Jet impingement test . 5
5.3 Application method of electrochemical measurement . 6
6 Test condition .9
6.1 General . 9
6.1.1 Selection of test method . 9
6.1.2 The effect of flow velocity and test duration in the respective tests . 9
6.1.3 Wall shear stress . 10
6.1.4 Selection of damage measuring methods . 11
6.1.5 Insulation of test specimen . 11
6.1.6 Use of multiple specimens . 11
6.1.7 Unit of metal loss . 11
6.2 Applications and limitations of tests . 11
Bibliography .14
iii
Foreword
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This document was prepared by Technical Committee ISO/TC 156, Corrosion of metals and alloys.
This second edition cancels and replaces the first edition (ISO/TR 16203:2016), which has been
technically revised.
The main changes are as follows:
— In addition to “erosion corrosion”, the description on the “corrosion” under flowing water was
added.
— Description on application method of electrochemical measurement was added.
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
Introduction
Particle-free erosion corrosion is a major problem in metallic materials in industries handling liquids
flowing rapidly which are corrosive. Specifically, the metallic materials include copper, copper alloys
and steels, and the liquids are various types of liquids such as seawater, tap water, industrial water,
chemical water (e.g. acid and alkali aqueous solution), waste water, etc. Particle-free erosion corrosion
usually leads to rapid metal loss with possibly catastrophic consequences. In order to prevent, mitigate
and/or control the problems, it is important to select methods for particle-free erosion corrosion
testing. This document provides an overview of the methods available for particle-free erosion
corrosion testing in flowing liquids.
v
TECHNICAL REPORT ISO/TR 16203:2023(E)
Overview of methods available for particle-free erosion
corrosion testing in flowing liquids
1 Scope
This document provides an overview of the erosion corrosion tests of materials in single-phase flowing
liquids and the test methods available.
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 8044, Corrosion of metals and alloys — Vocabulary
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 8044 and the following apply.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
3.1
erosion
progressive loss of original material from a solid surface due to mechanical interaction between that
surface and a fluid, a multicomponent fluid, or impinging liquid or solid particles
[1]
[SOURCE: ASTM G40-22 ]
3.2
particle-free erosion corrosion
erosion corrosion of metallic materials in single phase flowing liquids free of solid particles and gas
bubbles
4 Principles
4.1 Particle-free erosion corrosion
Particle-free erosion corrosion describes the synergistic metal dissolution and mechanical removal
of corrosion products formed on a metal surface leading to enhanced corrosion due to distributed or
turbulent flow. The details of the predominant phenomena between the dissolution and the mechanical
removal are ambiguous.
4.2 Particle-free erosion corrosion test
The conditions in which particle-free erosion corrosion occurs are sensitive to the application, but there
are a range of laboratory test methods that have been developed to simulate typical service applications.
These test methods can provide a basis for assessing the relative susceptibility of materials to damage
development. Particle-free erosion corrosion tests are conducted either by setting up a uniform flow
velocity distribution or turbulent flow mixing. In the former, corrosion damage increases due to the
increase in mass transfer in laminar boundary layers as the flow velocity of liquid increases, while in
the latter, the corrosion damage increases depending on the strength of turbulent mixing.
4.3 Material loss and observation of surface damage
Material loss by corrosion is detected by measuring mass loss or depth loss of a metal surface. The
mass of the sample after the testing or after the stripping the residual corrosion products, compared
to its initial mass can provide an indication of the importance of the phenomenon. The depth loss of the
sample surface can be also taken into account after the same procedures. The accuracy of corrosion
loss is guaranteed by appropriate test specimen size in the mass loss measurement and normalised
level of no-corrosion area in the depth measurement. The observations of the corroded surface or
the corrosion products are also useful for deducing the corrosion mechanism. Particle-free erosion
corrosion behaviour can be observed by electrochemical measurement using a potentiometer, a current
meter and a potentiostat. These measurements and observations are taken appropriately according to
the purpose of the test.
NOTE The thickness distribution of the corrosion products possibly occurs as same as the damage depth
distribution, in the case of nonuniform corrosion. The thickness and property of the corrosion products are
probably informative for the mechanisms of corrosion or particle-free erosion corrosion.
5 Test methods
5.1 Tests for uniform corrosion
5.1.1 Rotating cylinder test
A cylindrical specimen electrically insulated at the top and bottom end is used in this test. Figure 1 is a
schematic drawing of principle, as for example, Reference [2]. The cylindrical surface is the test surface.
It is attached with a shaft at the top end which rotates it around the longitudinal axis in the test solution.
The radius of the cylinder is chosen freely, but needs to be constant along the longitudinal distance,
so that a uniform distribution of circumferential flow velocity over the entire surface of specimen is
achieved. Either rounded insulator or squared-off one at the bottom can be used. This test is widely
used for elucidating the effect of flow velocity on the uniform corrosion.
Key
1 insulator
2 specimen
Figure 1 — Schematic drawing of principle of the rotating cylinder test
5.1.2 Test in a pipe or channel
The pipe specimen installed in the pipeline and the test specimens embedded in the wall of the duct,
schematically shown in Figure 2 (a) and (b), as for example, Reference [3] are also used for investigating
the effect of flow velocity on uniform corrosion. The specimen surfaces are installed parallel to the flow
direction. The upstream flow is possibly rectified or uniform in a pipe. It is not appropriate to put an
elbow joint and valve in
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