EN ISO 20567-2:2017 pdf free
EN ISO 20567-2:2017 pdf free.Paints and varnishes一Determination of stone-chip resistance of coatings
The stone-chip resistance of the coating under test is checked by projecting a defined impact body onto it. The impact body used in the test has a wedge-shaped cutting edge to obtain a damage pattern equivalent to that produced in a multi-impact test. The wedge-shaped impact body is pushed onto the coating under test by the transmission of a pulse of energy from a steel ball accelerated using compressed air.
Loose fragments of coating material are removed.
The stone-chip resistance is evaluated by measuring the total width of the delaminated coating,including the mark left by the wedge.
Figure 1 shows the upper part of the test apparatus.
Figure 2 shows the shape of the impact body and its dimensions. The impact body shall be made of hardened steel (hardness 60 HRC to 66 HRC).
The test panel is inserted on the tester with the wedge-shaped end of the impact body touching the coated test panel and the spring exerting a slight pressure on the body. A steel ball of mass inferior to that of the impact body is accelerated by a compressed-air blast (p = 300 kPa) and transmits part of its energy to the impact body, which then strikes the test panel.
NOTE 100kPa= 1bar.
The impact body shall be checked, and replaced if necessary, after a maximum of 500 test runs (i.e. after 500 impacts) or at the end of the series of tests during which the impact body passes the point at which it has been used for a total of 500 test runs.
Place the test panel on the test apparatus with the coated side facing towards the impact body (see Figure 1), place a counterweight (of mass exceeding 1 kg) on it and turn on the compressed air to accelerate the steel ball and activate the impact body.
When several impacts are to be delivered to one test panel, turn off the compressed air after each impact, move the panel by about 20 mm, replace the counterweight and then repeat the impact. Remove any loose paint from the test area. Examples of suitable methods are given in Annex A. The method for removing the loose paint shall be agreed between the interested parties and shall be stated in the test report.EN ISO 20567-2 pdf free.
