DIN 34804-2002 Fasteners - Change of appearance of black surfaces《紧固件 黑色表面的外观变化》.pdf

1、October 2002 Translation by DIN-Sprachendienst.English price group 5No part of this translation may be reproduced without prior permission ofDIN Deutsches Institut fr Normung e. V., Berlin. Beuth Verlag GmbH, 10772 Berlin, Germany,has the exclusive right of sale for German Standards (DIN-Normen).ICS

2、 21.060.01!%)TZ“2064955www.din.deDDIN 34804Fasteners Change of appearance of black surfaces,English translation of DIN 34804:2002-10Verbindungselemente Vernderungsgrade von schwarzen Oberflchen,Englische bersetzung von DIN 34804:2002-10lments de fixation Changement daspects des surfaces noires,Tradu

3、ction anglaise de DIN 34804:2002-10www.beuth.deDocument comprises 6 pagesIn case of doubt, the German-language original shall be considered authoritative.10.13 DIN 34804:2002-10 2 A comma is used as the decimal marker. Contents Page Foreword 2 1 Scope 2 2 Pre-test surface conditions 3 3 Degree of ch

4、ange of appearance .3 4 Assessing the change of appearance in black surfaces .4 5 Determining the degree of change of appearance in black surfaces .4 Annex A (normative) Reference images .5 Foreword This standard has been prepared by FMV-2.6 Oberflchenschutz of the Normenausschuss Kunststoffe (Plast

5、ics Standards Committee). 1 Scope This standard specifies a classification system for changes of appearance of black surfaces of fasteners after a procedure of corrosive testing that shall be agreed upon. This standard applies to coatings such as: electroplated coatings of zinc or zinc alloys with b

6、lack passivation; electroplated coatings of zinc or zinc alloys with a conversion coating and a surface layer; electroplated coatings of zinc and zinc alloys with a surface layer; zinc flake coatings with a surface layer. DIN 34804:2002-10 3 2 Pre-test surface conditions Typical pre-test surface con

7、ditions are shown in Figures 1 to 4. In Figures 1 to 4 the fact has been taken into account that fasteners in most cases are exposed to mechanical pre-stress before assembly, caused either during mass-handling or during transportation on vibrating conveyors, which may cause abrasion to coatings, esp

8、ecially on the edges, or may lead to coatings being damaged by impact marks. Figure 1 Figure 2 Figure 3 Figure 4 3 Degree of change of appearance Any assessments of the change of appearance shall be based on the colour characteristic for the coating system. Changes are in essence induced by white co

9、rrosion products as a result of the impact of corrosion on coatings. These changes can be system-related or brought about by damaged coatings after their application. The assessment of substrate corrosion is not covered in this standard. DIN 34804:2002-10 4 The extent to which black surfaces have ch

10、anged as a result of corrosive stress shall be identified with the help of reference images, to which degrees of change as in Table 1 have been assigned. Table 1 Classification of degrees of change of appearance Degree of change Code Reference image (see Annex A) S0 Pre-test surface condition (see F

11、igures 1 to 4) S1 A.1 S2 A.2 S3 A.3 S4 A.4 S5 A.5 S6 A.6 S7 A.7 S8 A.8 S9 A.9 S10 A.10 The degree of change of a surface is to be determined by comparison with the reference image, and the one that most closely resembles the surface to be assessed shall be selected. The areas to be used for assessin

12、g the changes of appearance are the head surface for screws and bolts, the widths across flats for nuts and the washer surfaces for washers. 4 Assessing the change of appearance in black surfaces The change of appearance in black surfaces shall be determined after the parts have been exposed to a co

13、rrosive test, and by comparison with Figures A.1 to A.10, see Annex A. Exposure to mechanical, thermal or chemical stress conditions that are likely to occur under service conditions and which are to be applied before the corrosion test, may be the subject of further agreement. The change of appeara

14、nce shall be assessed by the unaided eye at reading distance. 5 Determining the degree of change of appearance in black surfaces The degree of change shall be determined according to Annex A in combination with a corrosive test to be agreed upon. EXAMPLE Degree of change of appearance DIN 34804-S3 a

15、fter 120 hours exposure to a salt spray test. DIN 34804:2002-10 5 Annex A (normative) Reference images NOTE The reference images A.1 to A.10 illustrate degrees of changes of appearance, using hexagon nuts with flange as an example. Other types of screws, bolts, nuts and washers shall be classified s

16、imilarly. Figure A.1 Degree of change of appearance S1 Figure A.2 Degree of change of appearance S2 Figure A.3 Degree of change of appearance S3 Figure A.4 Degree of change of appearance S4 DIN 34804:2002-10 6 Figure A.5 Degree of change of appearance S5 Figure A.6 Degree of change of appearance S6 Figure A.7 Degree of change of appearance S7 Figure A.8 Degree of change of appearance S8 Figure A.9 Degree of change of appearance S9 Figure A.10 Degree of change of appearance S10