1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationBS EN ISO 8251:2011Anodizing of aluminium and its alloys Measurement of abrasion resistance of anodic oxidation coatings (ISO 8251:2011)BS EN ISO 8251:2011 BRITISH STANDARDNation
2、al forewordThis British Standard is the UK implementation of EN ISO 8251:2011. It supersedes BS EN 12373-10:1999 and BS EN 12373-9:1999, which are withdrawn.The UK participation in its preparation was entrusted to Technical Committee STI/32, Anodic oxidation coatings on aluminium.A list of organizat
3、ions represented on this committee can be obtained on request to its secretary.This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. BSI 2011 ISBN 978 0 580 66153 2 ICS 25.220.20 Compliance with a British Standard
4、cannot confer immunity from legal obligations.This British Standard was published under the authority of the Standards Policy and Strategy Committee on 30 April 2011.Amendments issued since publicationDate T e x t a f f e c t e dEUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN ISO 8251 February
5、2011 ICS 25.220.20 Supersedes EN 12373-10:1998, EN 12373-9:1998English Version Anodizing of aluminium and its alloys - Measurement of abrasion resistance of anodic oxidation coatings (ISO 8251:2011) Anodisation de laluminium et de ses alliages - Dtermination de la rsistance labrasion des couches dox
6、yde anodiques (ISO 8251:2011) Anodisieren von Aluminium und Aluminiumlegierungen - Messung der Abriebfestigkeit von anodisch erzeugten Oxidschichten (ISO 8251:2011) This European Standard was approved by CEN on 29 January 2011. CEN members are bound to comply with the CEN/CENELEC Internal Regulation
7、s which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN member. Th
8、is European Standard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC Management Centre has the same status as the official versions. CEN mem
9、bers are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain
10、, Sweden, Switzerland and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG Management Centre: Avenue Marnix 17, B-1000 Brussels 2011 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Mem
11、bers. Ref. No. EN ISO 8251:2011: EBS EN ISO 8251:2011INTERNATIONAL STANDARD ISO 8251:2011(E) ISO 2011 All rights reserved 1Anodizing of aluminium and its alloys Measurement of abrasion resistance of anodic oxidation coatings 1 Scope This International Standard specifies the following three test meth
12、ods: a) abrasive-wheel-wear test method, determining the wear resistance and the wear index of anodic oxidation coatings on flat specimens of aluminium and its alloys; b) abrasive jet test method, comparing the resistance to abrasion of anodic oxidation coatings on aluminium and its alloys with that
13、 of a standard specimen or, alternatively, a reference specimen, by use of a jet of abrasive particles; c) falling sand abrasion method, determining the abrasion resistance with falling sand applied to thin anodic oxidation coatings. The use of these methods for coatings produced by hard anodizing i
14、s described in ISO 10074. 2 Normative references The following referenced 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.
15、ISO 565:1990, Test sieves Metal wire cloth, perforated metal plate and electroformed sheet Nominal sizes of openings ISO 2360:2003, Non-conductive coatings on non-magnetic electrically conductive basis materials Measurement of coating thickness Amplitude-sensitive eddy-current method ISO 6344-1, Coa
16、ted abrasives Grain size analysis Part 1: Grain size distribution test ISO 8486-1:1996, Bonded abrasives Determination and designation of grain size distribution Part 1: Macrogrits F4 to F220 3 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1 te
17、st specimen specimen on which the test is to be carried out 3.2 standard specimen test specimen produced in accordance with the conditions specified in Annex A BS EN ISO 8251:2011ISO 8251:2011(E) 2 ISO 2011 All rights reserved3.3 reference specimen test specimen produced under conditions agreed betw
18、een the anodizer and the customer 3.4 double stroke ds one complete reciprocal movement made by the abrasive wheel 4 Characteristics of abrasion tests There are three kinds of abrasion tests: abrasive-wheel-wear test, abrasive jet test and falling sand abrasion test. 4.1 Abrasive-wheel-wear test Det
19、ermination of the resistance to abrasion by movement of a test specimen relative to an abrasive paper under a specified pressure. The wear resistance or the wear index of the layers of oxide near the surface, or of the whole oxidation coating thickness, or of any selected intermediate zone may be de
20、termined by the method described. For most purposes the wear index (see 5.4.3) or the mass wear index (see 5.4.4) will be the most appropriate characteristic to determine. The method is applicable to all anodic oxidation coatings of thickness more than 5 m on flat aluminium or its alloy specimens. T
21、his method is not applicable to concave or convex specimens; these may be examined using the abrasive jet test method which will give an average value for the abrasive resistance of the coating (see 4.2 and Clause 6). NOTE Minimum test specimen dimensions of 50 mm 50 mm are normally required. 4.2 Ab
22、rasive jet test Determination of the resistance to abrasion by the impact of abrasive particles projected onto a test specimen. The mean specific abrasion resistance of anodic oxidation coatings may be determined. NOTE 1 Different batches of the same abrasive are liable to give different results and
23、 for this reason the test is a comparative one. NOTE 2 With a suitably designed abrasive jet and film-thickness-measuring devices with a small probe, it is possible to conduct a depth survey which indicates how abrasion resistance varies through the coating thickness (see Annex B). However, this pro
24、perty is preferably measured using the abrasive-wheel-wear test. The method described is applicable to all anodic oxidation coatings of thickness more than 5 m on aluminium or its alloys. It is primarily intended for surfaces which are not flat. If suitable flat test surfaces are available, the abra
25、sive-wheel-wear test is the preferred method. Production components may be tested without cutting if the apparatus chamber can accommodate these. NOTE 3 This method is particularly suitable for small test specimens because the individual test area required is only about 2 mm in diameter. 4.3 Falling
26、 sand abrasion test Determination of the resistance to abrasion by the impact of freely falling abrasive particles onto anodic oxidation coatings. The method described is applicable to the thin anodic oxidation coatings. BS EN ISO 8251:2011ISO 8251:2011(E) ISO 2011 All rights reserved 35 Abrasive-wh
27、eel-wear test 5.1 Principle The anodic oxidation coatings on a test specimen are abraded, under defined conditions, by reciprocal motion against a strip of silicon carbide paper attached to the outer circumference of a wheel. After each double stroke, the wheel turns through a small angle to bring a
28、n unused portion of the abrasive strip into contact with the test area. The decrease in coating thickness or mass obtained is used to calculate the wear resistance or wear index. This result is compared with that obtained using a standard specimen (see Annex A) or reference specimen (see 3.3). The m
29、ethod normally requires an eddy-current meter with a probe of less than 12 mm diameter. If this is not available, the method of loss in mass should be used. NOTE A complete presentation of the wear characteristics of the anodic oxidation coatings can be obtained by progressively abrading the test ar
30、ea, until the substrate metal is revealed, and then constructing a graph to show the relation between the coating thickness removed and the number of double strokes used. This is referred to as a depth survey of the anodic oxidation coatings (see Annex B). The testing environment should be at room t
31、emperature and the relative humidity should be under 65 %. 5.2 Apparatus 5.2.1 Abrasive-wheel-wear test apparatus The apparatus consists of a clamping device or pressure plate for holding the test specimen (see 5.3.2) level and rigid, and a 50 mm diameter wheel to the outer circumference of which is
32、 attached a 12 mm wide strip of silicon carbide paper (see 5.2.2). The force between the wheel and the test surface shall be capable of being varied from zero to at least 4,9 N with an accuracy of 0,05 N. The abrasive action is produced either by the fixed wheel sliding to and fro in a horizontal pl
33、ane in parallel contact with the test surface over a 30 mm length or, alternatively, by the test specimen sliding in a similar way over the stationary wheel. Typical apparatus is illustrated in Figure C.1. After each double stroke, the wheel is advanced through a small angle to bring a fresh area of
34、 the silicon carbide paper into contact with the surface before making the next double stroke. The angle of rotation is such that, after 400 ds, the wheel will have made one complete revolution. At this stage, the strip of silicon carbide paper shall be renewed. The relative speed of movement shall
35、be (40 2) ds per minute. The number of double strokes can be registered by means of a counter, and provision is normally made for the apparatus to switch off automatically after a preset number of double strokes has been reached (400 ds maximum). The test surface shall be kept free from loose powder
36、 or abrasion detritus during the test. 5.2.2 Abrasive strip The abrasive strip consists of P320 silicon carbide paper (in accordance with ISO 6344-1) 12 mm wide. Its length shall be such that it covers the abrasive wheel without overlapping, and it shall be either bonded or mechanically clamped into
37、 position. NOTE P320 paper is 45 m grade (320 mesh). 5.2.3 Eddy-current meter An eddy-current meter with a suitable diameter probe is described in ISO 2360. 5.3 Procedure 5.3.1 Standard specimen Prepare the standard specimen using the method specified in Annex A. BS EN ISO 8251:2011ISO 8251:2011(E)
38、4 ISO 2011 All rights reserved5.3.2 Test specimen Cut a suitably sized test specimen from the item to be tested without damaging the area to be tested. Test dimensions of 50 mm 50 mm are usually required. 5.3.3 Calibration of apparatus 5.3.3.1 Select and mark the area of the standard specimen (see 5
39、.3.1) to be abraded. Accurately measure the anodic oxidation coating thicknesses in each of at least three positions along the test area by means of the eddy-current meter (see 5.2.3) in accordance with the method specified in ISO 2360 and calculate an average thickness value (d1). 5.3.3.2 Clamp the
40、 standard specimen into position on the apparatus (see 5.2.1). 5.3.3.3 Attach a new strip of silicon carbide paper (see 5.2.2) to the circumference of the abrasive wheel. Adjust the abrasive wheel, in accordance with the manufacturers instructions, so that it gives uniform abrasion across the width
41、of the test area. Adjust the force between the wheel and the test surface to 3,9 N 0,1 N. 5.3.3.4 Allow the apparatus to run for 400 ds or an adequate number of double strokes corresponding to the coating thickness and the kind of aluminium alloys. Keep the abrasive action uniform by adjusting and m
42、aintaining the alignment of the abrasive wheel in accordance with the manufacturers instructions. Continuously remove any abrasion detritus by suction, blowing or frequent wiping with a fine brush. 5.3.3.5 Remove the standard specimen from the apparatus, wipe carefully to remove any loose oxide and
43、determine the average thickness of the coating at the test area (d2) using the eddy-current meter in accordance with 5.3.3.1. A 3 mm length at one extremity of the test area may be subject to extra wear because of the continual wheel rotation which takes place at this point; this area should be igno
44、red when taking the thickness measurements. 5.3.3.6 Carry out at least two further determinations on the standard specimen in test areas that do not overlap, using the procedure specified in 5.3.3.1 to 5.3.3.5. 5.3.3.7 Calculate the wear rate for the standard specimen (see 5.4.3) from the average of
45、 the determinations. 5.3.4 Determination Take the test specimen (see 5.3.2) and carry out the procedure specified in 5.3.3.1 to 5.3.3.6 using abrasive strips from the same batch as that used for the calibration. If the test specimen is not rigid, bond it firmly with an adhesive to a rigid metal shee
46、t with a flat surface before carrying out the determination. Calculate the wear rate for the test specimen and, from the wear rates for the standard specimen and for the test specimen, calculate the wear index in accordance with 5.4.3. 5.3.5 Use of a reference specimen 5.3.5.1 General Because of the
47、 relatively high abrasion resistance of integral colour anodized specimens, testing of these finishes normally requires the use of a reference specimen produced by the same process (see 3.3) in a comparative-wear-testing method (see 5.3.6). BS EN ISO 8251:2011ISO 8251:2011(E) ISO 2011 All rights res
48、erved 55.3.5.2 Initial determination Carry out an initial determination in accordance with 5.3.4. If the thickness loss in the test area is less than 3 m, adjust the abrasion conditions either by increasing the force between the wheel and the test specimen surface, or by employing a coarser grade of
49、 silicon carbide paper. Alternatively, an increased number of double strokes may be used. Unless a depth survey is being carried out (see Annex B), the abrasion conditions should be adjusted to give a coating thickness loss of (5 3) m after 400 ds. If loss of mass is to be determined, the mass equivalent of (5 3) m coating thickness is required to be known. This necessitates an assumption to be made about the coating density or, alternatively, this should be estimated by means of ISO 2106. 5.3.5.3 Determination Determ
