ISO/TR 21555:2019

TECHNICAL ISO/TR
REPORT 21555
First edition
2019-08
Paints and varnishes - Overview of
test methods on hardness and wear
resistance of coatings
Reference number
©
ISO 2019
© ISO 2019
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ii © ISO 2019 – All rights reserved

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Hardness tests . 2
4.1 Indentation tests with resting indenter . 2
4.1.1 Indentation test with Buchholz indenter. 2
4.1.2 Indentation test with Knoop indenter . 5
4.1.3 Indentation test with Pfund indenter . 6
4.1.4 Indentation test with Vickers indenter . 8
4.2 Indentation tests with oscillating indenter .10
4.2.1 Oscillation damping test with König pendulum .10
4.2.2 Oscillation damping test with Persoz pendulum .11
4.2.3 Oscillation damping test with rocker .13
5 Wear resistance tests .14
5.1 Single-scratch tests .14
5.1.1 Scratch test with pencils .14
5.1.2 Scratch test with ball stylus 1 .17
5.1.3 Scratch test with ball stylus 2 .20
5.1.4 Scratch test with conical stylus 3 .22
5.1.5 Scratch test with conical stylus 4 .25
5.1.6 Scratch test with conical stylus 5 .28
5.1.7 Scratch test with conical stylus 6 .31
5.1.8 Scratch test with disc-shaped stylus .33
5.1.9 Scratch test with U-shaped stylus .37
5.2 Multiple scratch tests .39
5.2.1 Multiple scratch test with locked abrasive wheel .39
5.2.2 Multiple scratch test with abrasive cylinder .40
5.2.3 Multiple scratch test with rotating abrasive wheels .42
5.2.4 Multiple scratch test with rotating brush .43
5.3 Dry abrasion tests .45
5.3.1 Abrasion test with locked abrasive wheel .45
5.3.2 Abrasion test with rotating abrasive wheels 1 .47
5.3.3 Abrasion test with abrasive wheels 2 .48
5.3.4 Abrasion test with rotating abrasive wheels 3 .50
5.3.5 Abrasion test with rotating abrasive wheels 4 .51
5.4 Wet abrasion tests .53
5.4.1 Scrub test with brush .53
5.4.2 Scrub test with non-woven web 1 .55
5.4.3 Scrub test with non-woven web 2 .57
5.5 Falling-sand tests .60
5.5.1 Falling-sand test with corundum granulate .60
5.5.2 Falling-sand test with quartz sand .62
Annex A (informative) Overview on test methods on hardness and wear resistance of coatings .64
Bibliography .69
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 of 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 www .iso
.org/iso/foreword .html.
This document was prepared by Technical Committee ISO/TC 35, Paints and varnishes, Subcommittee
SC 9, General test methods for paints and varnishes.
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

Introduction
The determination of the hardness and of the wear resistance is one of the most important preconditions
for evaluating the resistance of coatings to mechanical stress.
The procedures and numerical data given in this document provide a rough overview; detailed
information is found in the applicable standards.
For all of the methods for the evaluation of the hardness and of the wear resistance the visco-elastic
properties have a wide influence on the test result. Consequently, the time between testing and
evaluation are agreed and observed.
Mechanical properties of coatings depend on, among others, temperature and moisture content.
Consequently, the tests should be carried out immediately after the conditioning phase.
The tests are preferably carried out in the climatic chamber.
Each method has its specific application. An unsuitable method may lead to false conclusions. All of the
test methods require a certain expertise of the test person. For most of the test methods the test results
depend on, among others, the film thickness of the coating to be tested.
TECHNICAL REPORT ISO/TR 21555:2019(E)
Paints and varnishes - Overview of test methods on
hardness and wear resistance of coatings
1 Scope
This document provides an overview for selecting the most suitable test method regarding the
evaluation of the hardness and the wear resistance of coatings.
Annex A gives a summarized list of test methods for the evaluation of the hardness and of the wear
resistance of coatings for different stresses.
Methods for testing cross-linking (wear test in connection with solvents) and abrasion tests with
multiple impacts are not covered by this document.
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 4618, Paints and varnishes — Terms and definitions
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 4618 and the following 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
hardness
ability of a dry film or coat to resist indentation or penetration by a solid object
[SOURCE: ISO 4618:2014, 2.136]
3.2
wear
irreversible change of a coating which is caused by the mechanical impact of moved objects
3.3
stylus
scratching tool with specified geometry
[SOURCE: ISO 22557:2019, 3.1]
3.4
scratch
line-shaped damage of a coating which is caused by the impact of a loaded object being moved over
the coating
3.5
mar
blemish on the surface of a coating, extending over a particular area of the coating and visible due to
the difference in the light-reflection properties of the area affected compared with the light-reflection
properties of adjacent areas
[SOURCE: ISO 4618:2014, 1.152]
3.6
abrasion
wear (3.2) which is caused by removal of coating material on a surface
3.7
repeatability conditions
conditions where independent test results are obtained with the same method on identical test items
in the same laboratory by the same operator using the same equipment within short intervals of time
[SOURCE: ISO 5725-1:1994, 3.14]
3.8
repeatability limit
r
the value less than or equal to which the absolute difference between two test results obtained under
repeatability conditions (3.7) may be expected to be with a probability of 95 %
[SOURCE: ISO 5725-1:1994, 3.16]
3.9
reproducibility conditions
conditions where test results are obtained with the same method on identical test items in different
laboratories with different operators using different equipment
[SOURCE: ISO 5725-1:1994, 3.18]
3.10
reproducibility limit
R
the value less than or equal to which the absolute difference between two test results obtained under
reproducibility conditions (3.8) may be expected to be with a probability of 95 %
[SOURCE: ISO 5725-1:1994, 3.20]
4 Hardness tests
4.1 Indentation tests with resting indenter
4.1.1 Indentation test with Buchholz indenter
— Description
An indenter made of hardened steel, the shape and dimensions of which are specified in accordance
with Buchholz, impacts the coating under a load (500 g, corresponding to 4,96 N) for 30 s and
produces an indentation. After a resting time of 35 s the indentation length (mm) is determined
under specified lighting conditions using a measuring microscope (×20 magnification).
Figure 1 shows the test device and Figure 2 shows the Buchholz indenter. Figure 3 illustrates the
microscopic measurement of the indentation.
2 © ISO 2019 – All rights reserved

Key
1 steel block
2 indenter
3 tip
Figure 1 — Indentation tester in accordance with Buchholz
Dimensions in millimetres
Key
1 indentation edge
2 indenter
3 coating
4 substrate
Figure 2 — Buchholz indenter
a) Arrangement of the light source and of the microscope
b) Image of the Buchholz indentation
Key
1 light source
2 microscope
3 indentation
4 coating
5 substrate
l indentation length
Figure 3 — Measuring the Buchholz indentation
— Application
The indentation test with Buchholz indenter is generally applicable.
— Calibration
A calibration method is not specified.
— Procedure
— Condition test panel (23 °C / 50 % relative humidity / ≥ 16 h)
— First, lower the tips of the test device onto the coating, and then carefully lower the indenter.
— Leave the loaded indenter on the coating for 30 s and remove in reverse order.
— 35 s after removal of the load determine the indentation length (mm) using a measuring
microscope (see Figure 3).
— Evaluation
Test result is the indentation length (mm), as mean value of five determinations.
— Precision
The repeatability limit r is 0,23 mm.
The reproducibility limit R is 0,45 mm.
4 © ISO 2019 – All rights reserved

— Reference
The indentation test with Buchholz indenter is specified in ISO 2815.
4.1.2 Indentation test with Knoop indenter
— Description
A diamond indenter, the shape and dimensions of which are specified in accordance with Knoop,
impacts the coating under a load (25 g, corresponding to 0,245 N) for 18 s and produces an
indentation. Immediately after removal of the load the length (mm) of the long diagonal of the
indentation is determined using a measuring microscope. From this, the “Knoop Hardness Number”
KHN (kg/mm ) is calculated.
Figure 4 shows the dimensions of the Knoop indenter. Figure 5 shows the top view of the Knoop
indentation.
Key
α angle of the longitudinal edge (172,5°)
β angle of the transverse edge (130°)
Figure 4 — Dimensions of the Knoop indenter
Key
l indentation length
Figure 5 — Top view of the Knoop indentation
— Application
The indentation test with Knoop indenter is generally applicable.
— Calibration
On a reference block the KHN value is determined and compared to the nominal value.
— Procedure
— Condition test panel (23 °C / 50 % relative humidity / ≥ 24 h).
— Lower the test device onto the coating in a plane area.
— Lower the indenter and apply the specified test load.
— Leave the loaded indenter on the coating for 18 s.
— Immediately after the removal of the load, determine the indentation length l (mm) using a
measuring microscope (see Figure 5).
— Evaluation
Calculate the KHN value using the measured length l: KHN = 0,356 / l . (Factor 0,356 results from
the test load and the shape factor of the indenter.)
Test result is the KHN value (kg/mm), as mean value of n determinations. (The number n is agreed.)
NOTE In accordance with ISO 4545-1, the Knoop hardness is expressed in HK, which is different from
the KHN used here.
— Precision
The repeatability (in accordance with ASTM D1474/D1474M) is 9 %.
The reproducibility (in accordance with ASTM D1474/D1474M) is 24 %.
— Reference
The indentation test with Knoop indenter is specified in ASTM D1474/D1474M-13, Method A: Knoop
Indentation Hardness.
A general method for the determination of the Knoop hardness HK is specified in ISO 4545-1.
For testing automobile coatings, the method is also described in References [47] and [56].
4.1.3 Indentation test with Pfund indenter
— Description
A transparent quartz or sapphire indenter (hemisphere Ø 0,318 mm), the shape and dimensions of
which are specified in accordance with Pfund, impacts the coating under load (1 kg, corresponding
to 9,8 N) for 60 s and produces an indentation. Immediately after that the diameter (mm) of the
indentation under load by the transparent indenter is determined using a measuring microscope.
From this, the “Pfund Hardness Number” PHN (kg/mm ) is calculated.
Figure 6 shows the principle of the indentation test with Pfund indenter.
6 © ISO 2019 – All rights reserved

Key
1 test panel
2 stop
3 load arm
4 transparent indenter
5 pivot
6 tare weight
7 load weight
8 light source
9 semi-transparent mirror
10 measuring microscope
11 microscopic image (Pfund indentation and scale)
Figure 6 — Principle of the indentation test
— Application
The indentation test with Pfund indenter is generally applicable.
— Calibration
On a reference block the PHN value is determined and compared to the nominal value.
— Procedure
— Condition test panel (23 °C / 50 % relative humidity / ≥ 24 h).
— Lower the test device onto the coating in a plane area.
— Lower the indenter and apply the specified test load.
— Leave the loaded indenter on the coating for 60 s.
— After that, still loaded, determine diameter d (mm) of the indentation through the transparent
indenter using a measuring microscope.
— Evaluation
Calculate the PHN value using the measured diameter d: PHN = 1,27 / d . (Factor 1,27 results from
the test load and the shape factor of the indenter.)
Test result is the PHN value (kg/mm ), as mean value of at least 5 determinations.
— Precision
The repeatability (in accordance with ASTM D1474/D1474M) is 18 %.
The reproducibility (in accordance with ASTM D1474/D1474M) is 36 %.
— Reference
An indentation test with Pfund indenter is specified in ASTM D1474/D1474M-13, Method B: Pfund
Indentation Hardness.
4.1.4 Indentation test with Vickers indenter
— Description
A diamond indenter, the shape and dimensions of which are specified in accordance with Vickers, is
pressed into the coating under increasing, controlled load. The Martens hardness HM (N/mm ) in
dependence of the indentation depth is calculated from the measured indentation depth (µm) and the
respective test load (N).
Figure 7 shows the dimensions of the indenter and Figure 8 shows the test principle.
Key
α pyramid angle (136°)
Figure 7 — Schematic diagram of the Vickers indenter
8 © ISO 2019 – All rights reserved

Key
1 substrate
2 coating
3 distance measuring device for the indentation depth
4 indenter with Vickers geometry
h indentation depth
F test load
Figure 8 — Principle of the indentation test with Vickers indenter
— Application
The indentation test with Vickers indenter is generally applicable.
— Calibration
On a certified calibration panel (e.g. glass of the BK 7 type) an indentation test with a specified load
is carried out. From the load-indentation curve the HM value is determined and compared to the
certified value.
— Procedure
— Agree the test parameters:
— The number and the values of the test load levels (N) [the test load levels are normally
1/2
selected proportionally (test load) ].
— Position the test panel in the test device and set the agreed test parameters.
— Start the test procedure and record the indentation depth h (µm) in dependence of test load F (N).
— Evaluation
2 2
Calculate the values for the Martens hardness HM = F/26,43 h (N/mm ) from the h-values and the
corresponding F-values. (Factor 26,43 results from the shape factor of the indenter.)
Test result is the Martens hardness HM (N/mm ) for an agreed indentation depth h (µm) and/or
the hardness profile (HM as a function of h).
— Precision
No precision data are currently available.
— Reference
An indentation test with Vickers indenter is specified in ISO 14577-1 and ISO 14577-4.
For testing automobile coatings slightly deviating procedures are described in
References [42] and [45].
4.2 Indentation tests with oscillating indenter
4.2.1 Oscillation damping test with König pendulum
— Description
A pendulum, the shape, mass and dimensions of which are specified in accordance with König,
together with its two integrated tungsten-carbide balls (Ø 5 mm) is lowered on the coating,
displaced by 6°, and released. The damping duration (s) of the pendulum swing until reaching the
specified final displacement (3°) is determined.
Figure 9 shows the test principle.
Key
1 angle scale
2 König pendulum
3 tungsten-carbide ball
4 test panel
5 adjusting weight
Figure 9 — Principle of the test with König pendulum
10 © ISO 2019 – All rights reserved

— Application
The oscillation damping test with König pendulum is generally applicable.
— Calibration
On a polished, plane glass panel the duration of a pendulum swing and the damping duration are
determined and compared to the corresponding nominal values.
— Procedure
— Condition test panel (23 °C / 50 % relative humidity / ≥ 16 h).
— Position the test panel in the test device.
— Lower the pendulum with the integrated hard-metal balls onto the coating so that the tip of the
pendulum is aligned with the zero point of the scale.
— Displace pendulum by 6° and release.
— Determine the damping duration (s) until reaching the final displacement (3°) by using a
stop watch.
— Evaluation
Test result is the damping duration (s), as mean value of three determinations.
— Precision
The repeatability limit r is 7 s, corresponding to 5 swings.
The reproducibility limit R is 14 s, corresponding to 10 swings.
— Reference
The oscillation damping test with König pendulum is specified in ISO 1522 and ASTM D4366.
For testing automobile coatings a slightly deviating method is described in Reference [61].
4.2.2 Oscillation damping test with Persoz pendulum
— Description
A pendulum, the shape, mass and dimensions of which are specified in accordance with Persoz,
together with its two integrated tungsten-carbide balls (Ø 8 mm) is lowered on the coating,
displaced by 12°, and released. The damping duration (s) of the pendulum swing until reaching the
specified final displacement (4°) is determined.
Figure 10 shows the principle.
Key
1 angle scale
2 Persoz pendulum
3 tungsten-carbide ball
4 test panel
Figure 10 — Principle of the test with Persoz pendulum
— Application
The oscillation damping test with Persoz pendulum is generally applicable.
— Calibration
On a polished, plane glass panel the duration of a pendulum swing and the damping duration are
determined and compared to the corresponding nominal values.
— Procedure
— Condition test panel (23 °C / 50 % relative humidity / ≥ 16 h).
— Position the test panel in the test device.
— Lower the pendulum with the integrated hard-metal balls onto the coating so that the tip of the
pendulum is aligned with the zero point of the scale.
— Displace pendulum by 12° and release.
— Determine the damping duration (s) until reaching the final displacement (4°) by using a
stop watch.
— Evaluation
Test result is the damping duration (s), as mean value of three determinations.
12 © ISO 2019 – All rights reserved

— Precision
The repeatability limit r is 3 %.
The reproducibility limit R is 8 %.
— Reference
The oscillation damping test with Persoz pendulum is specified in ISO 1522 and ASTM D4366.
4.2.3 Oscillation damping test with rocker
— Description
A rocker, the shape, mass and dimensions of which are specified in accordance with Sward, together
with its two races is lowered on the coating, displaced by 22° and released. The number of swings
until reaching the specified final displacement (16°) is determined.
Figure 11 shows the test arrangement.
Key
1 race
2 level for final displacement
3 level for initial displacement
4 adjustment apparatus
5 levelling level
6 adjustable foot
7 test panel
8 clamp mask
9 glass panel
Figure 11 — Arrangement of the oscillation damping test with rocker
— Application
The oscillation damping test with rocker is generally applicable.
— Calibration
On a glass panel the number of swings within a time period of 60 s is determined and compared to
the nominal value.
— Procedure
— Condition test panel (23 °C / 50 % relative humidity / ≥ 24 h).
— Secure the test panel with the clamp mask on the levelled glass plate (see Figure 11).
— Lower the rocker with the two races onto the coating, displace by 22° and release.
— Determine the number of swings until reaching the final displacement (16°).
— Evaluation
Test result is the number of swings, multiplied by two, within the specified angle range, as mean
value of four determinations.
— Precision
No precision data are currently available.
— Reference
The oscillation damping test with rocker is specified in ASTM D2134.
5 Wear resistance tests
5.1 Single-scratch tests
5.1.1 Scratch test with pencils
— Description
A pencil lead with specified geometry is pushed over the coating at an angle of 45° and a test load
of 7,5 N. The hardness degree is gradually increased in the range of 9B to 9H until a damage of the
coating is visible. The highest hardness degree is determined for which no damage is detected.
Figure 12 shows the set-up of the device. Figure 13 shows the shape of the pencil lead after using a
special sharpener.
14 © ISO 2019 – All rights reserved

Key
1 rubber O-ring
2 pencil
3 substrate
4 levelling device
5 clamping device
6 test direction (“pushing”)
7 pencil lead
8 coating
9 metal block
Figure 12 — Device for scratch test with pencils
Key
l lead length (5 mm to 6 mm)
Figure 13 — Pencil after sharpening
— Application
The scratch test with pencils is generally applicable.
— Calibration
A calibration method is not specified.
— Procedure
— Condition test panel (23 °C / 50 % relative humidity / ≥ 16 h).
— Prepare the pencils in accordance with Figure 13 and sand the tips of the leads plane.
— Secure a pencil of a “medium” hardness degree in the horizontally aligned device in accordance
with Figure 12 and lower the device onto the coating.
— Push the loaded pencil lead over the coating with constant speed in the direction of arrow 6 in
Figure 12.
— After 30 s visually inspect the coating (if agreed, using a magnifier, magnification ×6 to ×10) for
damages and, if applicable, determine the type of damage.
— Carry out further scratch tests with varied pencil hardness degrees until a damage of at least
3 mm length is detectable on the coating.
— Based on this, carry out scratch tests with decreasing pencil hardness degrees until the coating
is not damaged any more.
— Evaluation
Test result is the highest pencil hardness degree for which no damage, i.e. any visual deviation from
the undamaged area, is detected on the coating.
— Precision
No precision data are currently available.
Figure 14 graphically shows the results of scratch tests with pencils which have been carried out
by different persons, on different coatings, and with different types of pencils:
Key
X identifications of coatings
Y hardness degrees of the leads
Figure 14 — Results of scratch tests with pencils
The results of the measurements in accordance with Figure 14 suggest that the scratch test with
pencils is not meaningful for the comparison of different coatings. It is more meaningful to carry
out relative assessments within a range of test panels which show significant differences during
the scratch test with pencils.
— Reference
A scratch test with pencils is specified in ISO 15184.
For testing coil coatings a slightly deviating method is described in EN 13523-4.
Further methods with higher test load are described in References [53] and [57].
16 © ISO 2019 – All rights reserved

5.1.2 Scratch test with ball stylus 1
— Description
A tungsten-carbide ball stylus (diameter 0,50 mm, 0,75 mm, or 1,00 mm) loaded with a test load in
the range of 0,5 N to 20 N is manually moved over the surface of a coating. A produced damage is
visually inspected and assessed. The lowest test load for mars (classification test) is determined, or
if the coating is marred using the agreed test load (“pass/fail” test).
Figure 15 shows the set-up and the function of the device.
Key
1 metal sleeve
2 slot
3 scale (test load)
4 slider
5 locking screw
6 pressure spring
7 head piece
8 ball stylus with (9)
9 spherical hard-metal tip
Figure 15 — Hardness pen for the scratch test with ball stylus 1
18 © ISO 2019 – All rights reserved

— Application
The scratch test with ball stylus 1 is generally applicable.
— Calibration
A calibration method is not specified.
— Procedure
— Agree test variation:
— Classification test (varied test load);
— “Pass/fail” test (fixed, specified test load).
— Agree test tool:
— Ball stylus A1 (tip diameter 0,50 mm);
— Ball stylus A2 (tip diameter 0,75 mm);
— Ball stylus A3 (tip diameter 1,00 mm).
— Condition the test paneltest panel (23 °C / 50 % relative humidity / ≥ 16 h), if not agreed
otherwise.
— Insert the agreed ball stylus into the hardness pen and adjust the intended or agreed test load.
— Secure the test panel onto a support, vertically press down the hardness pen onto the surface
and move over the coating uniformly (speed about 10 mm/s / test distance ≥ 10 mm).
— Visually inspect the test distance and determine whether the coating has been marred.
— When carrying out the test as classification test determine the minimum test load (N) for
marring by carrying out further scratch tests.
— Carry out all scratch tests in duplicate on the same test panel.
— Evaluation
Test result is
— for carrying out the test as classification test: minimum test load (N) for marring, and
— for carrying out the test as “pass/fail” test: the information if the coating is marred under the
agreed test conditions (“fail”) or not (“pass”).
Additionally, the type of damage is indicated.
— Precision
No precision data are currently available.
— Reference
The scratch test with ball stylus 1 is specified in ISO 22557, Method A: Test with ball stylus.
For testing automobile coatings slightly deviating methods are described in References [50], [55]
and [58].
For testing furniture surfaces slightly deviating methods are described in References [51] and [52].
5.1.3 Scratch test with ball stylus 2
— Description
By means of a diamond stylus (tip radius 0,09 mm) radially displaced scratch tests with test loads
-1
in accordance with a specified loading scheme are carried out on the rotating (5 min ) test panel.
The scratch resistance (N) is determined as lowest test load for a continuous scratch mark as well
as the characteristic value “stress group” (6-step classification) which is derived from it.
Figure 16 shows the set-up of the test device. Figure 17 shows the dimensions of the test stylus.
Key
1 scale for adjusting the test load
2 moveable load weight
3 stylus with inserted diamond
4 motor-driven turntable
5 load arm
6 clamping device
Figure 16 — Set-up of the device for the scratch test with conical stylus 2
20 © ISO 2019 – All rights reserved

Key
1 stylus shaft
2 diamond insert with spherical tip
R radius of the spherical tip: R = (0,090 ± 0,003) mm
α cone angle: α = (90 ± 1)°
Figure 17 — Dimensions of the tip of the conical stylus 2
— Application
The stress test with conical stylus 2 is preferably carried out on coated furniture surfaces.
— Calibration
A calibration method is not specified.
— Procedure
— Condition test panel (23 °C / 50 % relative humidity / 7 d).
— For the pre-test position the test panel on the turntable of the test device.
— Load the conical stylus with 5 N and carry out a scratch test over the entire circumference
(1 rotation).
— By means of further scratch tests with roughly varied test load approximately determine the
lowest test load for which a continuous scratch mark is visible.
— Position the test panel for the main test on the turntable of the test device.
— Increase the final test load determined in the pre-test by 1 N, load the conical stylus with it, and
carry out a scratch test.
— By means of further scratch tests with finely decreased test loads determine the highest test
load for which no continuous scratch mark is visible.
— Evaluation
Visually evaluate the damage pattern of the main test in a specified light cabin and by means of an
inspection template in accordance with Figure 18. Determine the lowest test load (N) which results
in a continuous scratch mark, which is then considered scratch resistance.
Test result is
— the scratch resistance (N), as mean value of three determinations, with indication of the single
values, and
— the characteristic value “stress group” (6-step classification: 4 A to 4 F) derived from the scratch
resistance by means of numerical criteria.
Dimensions in millimetres
Key
1 inspection slot with visible scratch marks
Figure 18 — Test panel with attached inspection template
— Precision
No precision data are currently available.
— Reference
The scratch test with ball stylus 2 is specified in DIN 68861-4.
5.1.4 Scratch test with conical stylus 3
— Description
By means of a diamond stylus (tip radius 0,09 mm) radially displaced scratch tests with four
-1
specified test loads in the range of 1 N to 6 N are carried out on the rotating (5 min ) test panel. A
characteristic value (degree 1 to degree 5) is determined by comparison of the damage pattern to
reference images.
Figure 19 shows the set-up of the test device. Figure 20 shows the dimensions of the test stylus.
22 © ISO 2019 – All rights reserved

Key
1 scale for adjusting the test load
2 moveable load weight
3 stylus with inserted diamond
4 motor-driven turntable
5 load arm
6 clamping device
Figure 19 — Set-up of the device for the scratch test with conical stylus 3
Key
1 stylus shaft
2 diamond insert with spherical tip
R radius of the spherical tip: R = (0,090 ± 0,003) mm
α cone angle: α = (90 ± 1)°
Figure 20 — Dimensions of the tip of the conical stylus 3
— Application
The scratch test with conical stylus 3 is preferably carried out on HP(D)L [High-pressure
(decorative) laminate] films.
— Calibration
A calibration method is not specified.
— Procedure
— Condition test panel (23 °C / 50 % relative humidity / 72 h).
— Secure the test panel on the turntable of the test device.
— Load the conical stylus with 1 N and carry out two scratch tests, with only a slight distance in
between, over the entire circumference (1 rotation).
— Repeat this process with the test loads 2 N, 4 N, and 6 N in sufficient distance in each case.
— Treat the stressed surface using a contrast agent (graphite, talcum, or ethanolic colouring
solution, depending on the lightness / colour of the test panel).
— Evaluation
Visually evaluate the damage pattern in a specified light cabin and classify in 5 steps (degree 1 to
degree 5) by means of reference images (see Figure 21).
Test result is the determined characteristic value (degree).
24 © ISO 2019 – All rights reserved

Figure 21 — Reference images for degree 1 to degree 5
— Precision
No precision data are currently available.
— Reference
The scratch test with conical stylus 3 is specified in EN 438-2:2016, Clause 25, and in
ISO 4586-2:2018, Clause 14.
5.1.5 Scratch test with conical stylus 4
— Description
A conical stylus (Ø 0,5 mm / 1,0 mm) loaded with a test load in the range of 1 N to 20 N is pulled
over the surface (test distance ≥40 mm) with constant speed (35 mm/s). The lowest test load for
the penetration of the conical stylus down to a specified film (classification test) is determined or
whether the penetration down to the specified film occurs for an agreed test load (“pass/fail” test).
Figures 22 and 23 show two variations of the test device.
Key
1 attached weight
2 stylus
3 load arm
4 pivot for load arm
5 tare weight
6 lowering apparatus (ramp and guide bolt)
7 test panel
8 specimen holder (is motorically moved in the direction of the arrow)
9 base plate
Figure 22 — Device for the scratch test with conical stylus 4 (variation with attached weight)
Key
1 stylus
2 load arm with scale
3 slide weight
4 pivot for load arm
5 tare weight
6 lowering apparatus (ramp and guide bolt)
7 test panel
8 specimen holder (is motorically moved in the direction of the arrow)
9 base plate
Figure 23 — Device for the scratch test with conical stylus 4 (variation with slide weight)
26 © ISO 2019 – All rights reserved

— Application
The scratch test with conical stylus 4 is generally applicable.
— Calibration
A calibration method is not specified.
— Procedure
— Agree test specification:
— Scratch down to the substrate;
— Scratch down to an agreed film.
— Agree test variation:
— Classification test (varied test load);
— “Pass/fail” test (fixed, specified test load).
— Agree test tool:
— Stylus A (tip radius 0,50 mm / tungsten carbide);
— Stylus B (tip radius 0,25 mm / tungsten carbide);
— Stylus C (tip radius 0,50 mm / ruby);
— Stylus D (tip radius 0,25 mm / ruby).
— Condition test panel (23 °C / 50 % relative humidity / ≥ 16 h).
— Secure the test panel on the specimen holder of the test device.
— Mount the agreed stylus into the horizontal load arm and tare the load arm.
— Load the stylus, carry out a scratch test, and evaluate the result using a magnifier (≥×4).
— When carrying out the test as classification test carry out further scratch tests with varied test
load (0,5-N steps) until the coating is penetrated in the specified way.
— When carrying out the test as “pass/fail” test determine whether the coating is penetrated or
not in the specified way when carrying out the scratch test with the agreed test load.
— Evaluation
Test result is
— for carrying out the test as classification test the lowest test load (N) from three determinations
for which the coating was penetrated in the specified way, and
— for carrying out the test as “pass/fail” test the conclusion, whether the coating was penetrated
(“fail”) or not (“pass”) in the agreed way in at least one of six scratch tests with the agreed
test load.
— Precision
For the repeatability limit r no data are currently available.
The reproducibility limit R is 30 %.
— Reference
The scratch test with conical stylus 4 is specified in ISO 1518-1.
For testing coil coatings a slightly deviating method is described in EN 13523-12.
For testing automobile coatings a slightly deviating method is described in Reference [54].
For testing automobile coatings similar methods are described in References [43], [49] and [50].
5.1.6 Scratch test with conical stylus 5
— Description
A loaded conical stylus (Ø 0,06 mm) is pulled over the coating (test distance 100 mm) with constant
speed (10 mm/s). During this, the test load is i
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