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1、 Reference number ISO 21227-3:2007(E) ISO 2007 INTERNATIONAL STANDARD ISO 21227-3 First edition 2007-04-01 Paints and varnishes Evaluation of defects on coated surfaces using optical imaging Part 3: Evaluation of delamination and corrosion around a scribe Peintures et vernis valuation par imagerie o
2、ptique des dfauts des surfaces revtues Partie 3: valuation du dcollement et de la corrosion autour dune rayure Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=IHS Employees/1111111001, User=Wing, Bernie Not for Resale, 05/08/2007 08:17:59 MDTN
3、o reproduction or networking permitted without license from IHS -,-,- ISO 21227-3:2007(E) PDF disclaimer This PDF file may contain embedded typefaces. In accordance with Adobes licensing policy, this file may be printed or viewed but shall not be edited unless the typefaces which are embedded are li
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6、g to it is found, please inform the Central Secretariat at the address given below. ISO 2007 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without
7、 permission in writing from either ISO at the address below or ISOs member body in the country of the requester. ISO copyright office Case postale 56 CH-1211 Geneva 20 Tel. + 41 22 749 01 11 Fax + 41 22 749 09 47 E-mail copyrightiso.org Web www.iso.org Published in Switzerland ii ISO 2007 All rights
8、 reserved Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=IHS Employees/1111111001, User=Wing, Bernie Not for Resale, 05/08/2007 08:17:59 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 21227-3:2007(E) ISO 2007 Al
9、l rights reserved iii Contents Page Foreword iv Introduction v 1 Scope . 1 2 Normative references. 1 3 Terms and definitions. 1 4 Principle. 1 5 Requirements 2 6 Calibration . 2 7 Procedure 2 8 Evaluation 3 9 Precision 4 10 Test report . 5 Annex A (normative) Ratings in accordance with ISO 4628-8 to
10、 be used to evaluate the delamination and corrosion around a scribe. 6 Annex B (informative) Extended evaluation 8 Bibliography. 9 Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=IHS Employees/1111111001, User=Wing, Bernie Not for Resale, 05/0
11、8/2007 08:17:59 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 21227-3:2007(E) iv ISO 2007 All rights reserved Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of prep
12、aring 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
13、liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task
14、of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. Attention
15、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. ISO 21227-3 was prepared by Technical Committee ISO/TC 35, Paints and varnishes, Subcommittee SC 9, General tes
16、t methods for paints and varnishes. ISO 21227 consists of the following parts, under the general title Paints and varnishes Evaluation of defects on coated surfaces using optical imaging: Part 1: General guidance Part 2: Evaluation procedure for multi-impact stone-chipping test Part 3: Evaluation of
17、 delamination and corrosion around a scribe Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=IHS Employees/1111111001, User=Wing, Bernie Not for Resale, 05/08/2007 08:17:59 MDTNo reproduction or networking permitted without license from IHS -,-
18、,- ISO 21227-3:2007(E) ISO 2007 All rights reserved v Introduction The conventional ISO test methods for evaluating surface defects and changes in appearance often utilize pictorial standards which depict particular types of surface deterioration and require human visual evaluation. The technology a
19、nd procedures described in this part of ISO 21227 can yield more objective, accurate, quantitative and reproducible results when compared to the human visual evaluation techniques. Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=IHS Employees/
20、1111111001, User=Wing, Bernie Not for Resale, 05/08/2007 08:17:59 MDTNo reproduction or networking permitted without license from IHS -,-,- Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=IHS Employees/1111111001, User=Wing, Bernie Not for Res
21、ale, 05/08/2007 08:17:59 MDTNo reproduction or networking permitted without license from IHS -,-,- INTERNATIONAL STANDARD ISO 21227-3:2007(E) ISO 2007 All rights reserved 1 Paints and varnishes Evaluation of defects on coated surfaces using optical imaging Part 3: Evaluation of delamination and corr
22、osion around a scribe 1 Scope This part of ISO 21227 specifies a method for evaluating delamination and corrosion around a scribe by means of digital optical imaging. The damaged surface can be produced in accordance with ISO 9227, ISO 11997-1 or ISO 11997-2. 2 Normative references The following ref
23、erenced documents are indispensable for the application 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 4628-8, Paints and varnishes Evaluation of degradation of coat
24、ings Designation of quantity and size of defects, and of intensity of uniform changes in appearance Part 8: Assessment of degree of delamination and corrosion around a scribe ISO 21227-1, Paints and varnishes Evaluation of defects on coated surfaces using optical imaging Part 1: General guidance 3 T
25、erms and definitions For the purposes of this document, the terms and definitions given in ISO 21227-1 and the following apply. 3.1 delaminated area area from which a paint or paint system has detached 3.2 corroded area substrate area from which a paint or paint system has detached and which has sub
26、sequently been attacked by corrosion 4 Principle A grey scale or colour image is produced from the digital optical image of a surface damaged by delamination or corrosion around a scribe. In the simplest case, this image is converted into a binary image (thresholding). The damaged area is measured a
27、nd the mean and maximum width of delamination or corrosion is determined. In addition, the shape of the zone affected by delamination or corrosion around a scribe can be identified using digital optical imaging. Copyright International Organization for Standardization Provided by IHS under license w
28、ith ISO Licensee=IHS Employees/1111111001, User=Wing, Bernie Not for Resale, 05/08/2007 08:17:59 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 21227-3:2007(E) 2 ISO 2007 All rights reserved 5 Requirements 5.1 General The assessment shall be carried out under the condi
29、tions specified in ISO 21227-1. 5.2 Illumination The illumination shall be such that the damaged areas can be clearly distinguished from the undamaged areas. Because of the high contrast, corrosion can be easily recognized under diffused reflection illumination after stripping the coating. When dete
30、cting delamination without previously removing the coating, directional reflection illumination can be of advantage because of the low contrast. 5.3 Resolution The minimum resolution shall be 6 pixels per millimetre. NOTE Different resolutions, in particular in the case of damage involving a large n
31、umber of fissures, can lead to different values for the damaged areas. If a resolution deviating from the resolution specified above is used, this shall be stated in the test report. 6 Calibration By adjusting the optical imaging system, it is possible to digitize a damaged area. By calibrating the
32、scale in both X and Y directions (e.g. with graph paper graduated in millimetres), the previously generated binary image can be measured with sufficient accuracy to obtain the width of the delamination or corrosion. When using a reference scale based on pictorial standards, calibration should be per
33、formed with these images. In this case, an interlaboratory test should be conducted to determine the correlation between visual assessment and digital optical imaging. 7 Procedure Prepare the test panels for digital evaluation following the procedure given in ISO 4628-8. Using the previously calibra
34、ted digital optical imaging system, take a picture of the test panel area containing the scribe and of the adjacent damaged area. After suitable threshold setting and detection, the digital image delivers a value for the damaged area including the area of the scribe. The scribe length on the assesse
35、d area shall also be determined. The start and end of the scribe and the corresponding damaged area are not assessed. If the test panel contains several scribes or zones to be assessed (e.g. two intersecting scribes), they may be treated as sections of a single scribe, and the relevant areas and scr
36、ibe lengths may be added to one another. The area of intersection is not assessed. If the scribe width is not known, it shall be measured. If the scribe width cannot be measured, it shall be set to the same value (preferably zero) for all comparative samples, and this value shall be quoted in the te
37、st report. Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=IHS Employees/1111111001, User=Wing, Bernie Not for Resale, 05/08/2007 08:17:59 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 21227-3:2007(E) ISO 2007 A
38、ll rights reserved 3 8 Evaluation 8.1 General Unlike visual assessment of delamination or corrosion area, digital optical imaging can directly determine the size of an area of any shape (see Figure 1); Ad, Ac, dmax and cmax are evaluated and d and c are then calculated. Consequently, subsequent asse
39、ssments will be more precise and reproducible. Key As area of the scribe in the area of evaluation Ad area of delamination including the evaluated area of corrosion and area of the scribe Ac area of corrosion including the evaluated area of the scribe w width of the scribe l evaluated length of the
40、scribe dmax, l maximum width of delamination on the left side of the scribe dmax, r maximum width of delamination on the right side of the scribe cmax, l maximum width of corrosion on the left side of the scribe cmax, r maximum width of corrosion on the right side of the scribe Figure 1 Image with a
41、ll parameters required for assessment 8.2 Mean width of delamination or corrosion With the known scribe width w, calculate the scribe area As, using Equation (1): s Awl= (1) Calculate the mean delamination width d, in millimetres, using Equation (2): ds 1 2 AA d l = (2) Copyright International Organ
42、ization for Standardization Provided by IHS under license with ISO Licensee=IHS Employees/1111111001, User=Wing, Bernie Not for Resale, 05/08/2007 08:17:59 MDTNo reproduction or networking permitted without license from IHS -,-,- ISO 21227-3:2007(E) 4 ISO 2007 All rights reserved Calculate the mean
43、corrosion width c, in millimetres, as given in Equation (3): cs 1 2 AA c l = (3) where As is the evaluated scribe area in the area of evaluation, in square millimetres; Ad is the evaluated area of delamination and corrosion, including the scribe area, in square millimetres; Ac is the evaluated area
44、of corrosion, including the scribe area, in square millimetres; l is the evaluated scribe length, in millimetres. 8.3 Rating in accordance with ISO 4628-8 To allow comparison with the visual evaluation, the value determined through image evaluation from the width of the delaminated or corroded area
45、around the scribe shall correspond to the numerical rating scale from 0 to 5 as specified in ISO 4628-8. The relationship between the width, in millimetres, and the numerical rating is given by Equation (4): 0,505 NR 0,409 (or )edc = or NR0,81 1,98ln(or)dc=+ (4) where d is the mean delamination widt
46、h, in millimetres; c is the mean corrosion width, in millimetres; NR is the numerical rating (grade). For further details, see Annex A. 9 Precision In an interlaboratory test, seven samples with different degrees of delamination damage were assessed by six laboratories both visually and using differ
47、ent digital optical imaging systems. The relative standard deviation of the laboratories in determining the mean width of delamination from analysis of the damaged area was on average 9 % for all samples. The individual laboratories worked with different resolutions. The mean deviation of the visual
48、 assessment compared to digital image processing was 15 %. However, it should be noted that the mean relative standard deviation of the individual laboratories for the visual assessment was 31 %. Both procedures, visual assessment and digital optical imaging, ranked the samples in the same order for delamination width. The mean relative standard deviation of the individual laboratories for determining the shape of the delamina