Coil coated metals
BS EN 13523-6:2020 pdf free.Coil coated metals – Test methods Part 6: Adhesion after indentation (cupping test).
For the purposes of this document, the terms and definitions given in EN 13523-0 apply.
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The test specimen is cross-hatched with a cutting tool and is then deformed by pressing under specified conditions. After pressing, the test specimen can be artificially aged by immersion in boiling water.
5 Apparatus and materials
5.1 Cross-hatching device
A single-bladed knife, very sharp to avoid any burrs. For coatings less than 60 Itm in thickness, it is also possible to use a purpose-made cutting tool, capable of making a minimum of six parallel cuts.
5.2 Pressing device
Apparatus in accordance with EN ISO 1520, consisting essentially of:
a) a steel die, of inside diameter (27 ± 0,05) mm. its contact surface with the test specimen being flat and polished;
b) a retaining ring, having its flat and polished surface in contact with the test specimen;
c) an indenter consisting of a polished steel sphere, of diameter (20 ± 0,05) mm with a maximum of 0,1 mm displacement from the axis of the die;
d) a system, preferably hydraulic, allowing movement of the indenter at a speed of (12 ± 6) mm/mm.
5.3 Ageing device
The ageing device shall consist of:
a) a vessel, to contain boiling water, whose dimensions allow the complete immersion of the test specimen;
b) a heating system.
5.4 Pincers, the jaws of which shall be flat, blunt and having a width of at least 5 mm.
5.5 Magnifying glass x 10.
5.6 Transparent pressure-sensitive adhesive tape, 25 mm wide, with an adhesion strength of (10 ± 1) N per 25 mm width when tested in accordance with EN 60454-2.
Sampling shall be in accordance with EN 13523-0.
7 Test panels
Preparation and conditioning of test panels shall be in accordance with EN 13523-0.
8.1 Ambient conditions
Measure the coating adhesion at ambient temperature. For more accurate measurements, as required
for instance in case of dispute. the temperature shall be (23 ± 2) °C and the relative humidity (50 ± 5) %,
in accordance with EN 23270.
8.2 Cross-hatching (not used for evaluation of resistance to cracking)
8.2.1 For coatings greater than or equal to 60 pim thickness (see Figure 1)
Make two parallel cuts 5 mm apart, together with two additional similar cuts at right angles to form a
central 5 mm x 5 mm square.
Each cut shall just reach the metallic substrate, and each cut shall measure at least 50 mm in length. Each cut shall be at a distance of not less than 20 mm from the edge of the test panel.
8.2.2 For coatings less than 60 um thickness (see Figure 2)
Make at least six parallel cuts 1 mm apart, together with at least six additional similar cuts at right angles.
Each cut shall just reach the metallic substrate, and each cut shall measure at least 50 mm in length.
Each cut shall be at a distance of not less than 20 mm from the edge of the test panel.
NOTE At this stage, none of the squares formed exhibit adhesion failure from the metallic substrate.
Choose an indentation depth in millimetres, for example 80 % of the depth which ruptures the metallic substrate.
Clamp the test panel between the retaining ring and the die, the coating facing the die and the end of the indenter being in contact with the test panel. The measuring device shall be in position 0. Ensure that the cross-hatching shall be centred on the dome.
Move the spherical end of the indenter at constant speed of (12土6) mm/min to reach the chosen depth of indentation.
8.4 Ageing [optional and only for coatings greater than or equal to 60 um thickness)
Immerse the test panel in boiling water for a pre-agreed period of time.
Generally, ageing shall be carried out after the deformation but it may be performed before.
8.5.1 For coatings greater than or equal to 60 pm thickness
Make an attempt to pull the strips of the organic coating away from the metallic substrate in each of the four directions, starting from the central square. Lift the end of the strips with the knife (5Jj, then pull with the pincers (5A) until the rupture of the strip.
Observe the extent of the peeling and express in percentage of the distance between the top and the base of the dome.
If ageing is carried out, express the adhesion as a percentage of peeling for the ageing period.
8.5.2 For coatings less than 60 pm thickness
Remove two complete laps from a reel of the adhesive tape (5..f) and discard. Remove an additional length at a steady rate and cut a piece, approximately 75 mm long.
Place the centre of the tape over the lattice in a direction parallel to one set of the cuts and smooth the tape into place over the area of the lattice and for a distance of at least 20 mm beyond.
To ensure good contact with the coating, rub the tape firmly with a fingertip. The colour of the coating seen through the tape Is a useful indication of overall contact.
Within 1 mm of applying the tape, remove the tape by holding the free end and pulling it off steadily in 0,5 s to I s at an angle that is as close as possible to 600 (see also EN ISO 2409:2013, A.2) to the panel.
Assess the degree of adhesion after removal of the adhesive tape.Retain the tape for reference purposes, for example by attaching it to a sheet of transparent film.
8.6 Assessment of cracking (optional) Assess the degree of cracking on the dome of deformation with the x 10 magnifying glass (5).
If cracking is observed, the indentation depth shall be reduced and the test repeated until no cracking is observed.
9 Expression of results
9.1 For coatings greater than or equal to 60 pm thickness
Express the results as the percentage of the distance between the top and the base of the dome for peeling.
9.2 For coatings less than 60 lam thickness
Express the results as the percentage of cross-hatched squares removed after taping.
Express the results in millimetres at which no cracking is observed.
No precision data are currently available. BS EN 13523-6 pdf download.Coil coated metals