EN ISO 8503-2-2012 pdf free download.Preparation of steel substrates before application of paints and related products – Surface roughness characteristics of blast- cleaned steel substrates – Part 2: Method for the grading of surface profile of abrasive blast-cleaned steel – Comparator procedure (ISO 8503-2:2012). The surface profile of the test surface is compared by visual or tactile means with the profile of each of the segments of a calibrated ISO surface profile comparator to identify the two segments between the profiles of which the test surface lies. The results are converted to the appropriate grading: “fine”, medium or coarse. 5 Apparatus 5.1 ISO surface profile comparator, calibrated, conforming to the requirements of ISO 8503-1 or other comparator design and configuration with four segments that conform to the profiles specified in ISO 8503-1. NOTE In ISO 8503-1, two comparators are specified: one with surface profiles corresponding to surfaces which have been blast-cleaned using grit abrasives (reference comparator G) and one with surface profiles corresponding to surfaces which have been blast-cleaned using metalhc shot abrasives (reference comparator S). The nominal values for these profiles, which identify the limits of the three grades ‘fine”, ‘medium” and “coars&, are given in ISO 8503-1. If a mixture of shot and grit abrasives is used to blast-clean a substrate, the grit-abrasive reference comparator G should preferably be used. Some abrasives (for example cast steel and cut wire) change their shape during use so that the “new” abrasive gives an angular profile, but a “working mix” gives a rounded profile. Hence, the relevant comparator should be selected for these abrasives (described in ISO 8504-2). 5.2 Hand lens, with magnification not exceeding x7, 6 Maintenance and re-calibration of comparators Comparators require careful handling. If any wear is detected, the comparator shall be discarded or. if appropriate, re-calibrated (see ISO 8503-1:2012. Clause 7). Comparators in frequent use should be checked against an unused comparator at three-monthly intervals or whenever the surface appears worn or damaged. If a segment of a used comparator. when compared with the equivalent segment of an unused comparator, yields a different grading assessment (see this part of ISO 8503) of a surface profile, the used comparator should be discarded or re-calibrated. 7 Procedure 7.1 Remove all loose dust and debris from the test surface. Sharp edges due to mechanical or flame cutting. boring. etc.. are not considered part of the primary profile and should be...
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