1、Metallic and other inorganic coatings Evaluation of properties of dark-stain phenomenon of chromated coiled or sheet products Revtements mtalliques et autres revtements inorganiques valuation des proprits du phnomne de tache fonce des produits chroms enrouls ou en tle dacier ISO 2011 Reference numbe
2、r ISO/TR 15922:2011(E) First edition 2012-12-15 ISO/TR 15922 TECHNICAL REPORTISO/TR 15922:2011(E)COPYRIGHT PROTECTED DOCUMENT ISO 2011 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, inc
3、luding photocopying and microfilm, without 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 Publi
4、shed in Switzerland ii ISO 2011 All rights reservedISO/TR 15922:2011(E) ISO 2011 All rights reserved iii Contents Page Foreword iv Introduction v 1 Scope 1 2 Normative references . 1 3 Terms and definitions . 2 4 Information to be supplied by the producer to the user or purchaser . 3 4.1 Essential i
5、nformation . 3 4.2 Additional information . 3 5 Apparatus 3 6 Test methods 4 6.1 General . 4 6.2 Procedures 5 6.3 Qualitative test method for determination of the property of dark stain 5 6.4 Quantitative test method for determination of property of dark stain 6 Annex A (normative) Measurement of co
6、lour intensities 7 Bibliography . 9Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body in
7、terested 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 liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechni
8、cal 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 of technical committees is to prepare International Standards. Draft International Standards adopted by the
9、 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. In exceptional circumstances, when a technical committee has collected data of a different kind from that which is no
10、rmally published as an International Standard (“state of the art”, for example), it may decide by a simple majority vote of its participating members to publish a Technical Report. A Technical Report is entirely informative in nature and does not have to be reviewed until the data it provides are co
11、nsidered to be no longer valid or useful. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO should not be held responsible for identifying any or all such patent rights. ISO/TR 15922 was prepared by Technical Committee ISO/TC 10
12、7, Metallic and other inorganic coatings, Subcommittee SC 8, Chemical conversion coatings. ISO/TR 15922:2011(E)iv ISO 2011 All rights reservedIntroduction The existence of the dark- or black- stain phenomenon related to chromated hot-dip metallic zinc and electroplated-zinc steel products has been k
13、nown, but the cause for the occurrence of this phenomenon so far does not appear to have been rationalized. One possible reason for this incidence is due to the packed or stacked storage conditions of coils and sheets in high temperature, pressure and high relative humidity (RH) conditions. The test
14、 method specified in this Technical Report employs exposure of unstacked specimens to accelerated environmental storage conditions. Specimens made from unstacked product representing the unstressed condition typify the outer surface of the coil-packed product whilst similar specimens, when subjected
15、 to applied stress, temperature and humidity, represent the inner-surface layers of the packed coil and stacked sheet products and signify the stressed condition of those layers. The properties are determined qualitatively by test methods to confirm the presence of chromated layers and quantitativel
16、y by a colorimetric method. The colorimetric method measures the radiance of the surface and analyses the difference in luminosity or intensity before and after the tests are performed. ISO/TR 15922:2011(E) ISO 2011 All rights reserved vTECHNICAL REPORT ISO/TR 15922:2011(E) Metallic and other inorga
17、nic coatings Evaluation of properties of dark-stain phenomenon of chromated coiled or sheet products WARNING This Technical Report may not be compliant with some countries health, safety and environmental legislations and calls for the use of substances and/or procedures that may be injurious to hea
18、lth if adequate safety measures are not taken. This Technical Report does not address any health hazards, safety or environmental matters and legislations associated with its use. It is the responsibility of the producers, purchasers and/or user of this Technical Report to establish appropriate heal
19、th, safety and environmentally acceptable practices and take appropriate actions to comply with any national, regional and/or International rules and regulations. Compliance with this Technical Report does not, in itself, confer immunity from legal obligations. 1 Scope This Technical Report describe
20、s the methods to evaluate the properties of dark-stain phenomenon observed in chromate conversion-coated coiled and sheet products. Chromate conversion coatings, with trivalent or hexavalent chromium ions, are applied to hot-dip metallic zinc and electroplated-zinc steel products to enhance corrosio
21、n resistance of the components. When zinc-coated packed coiled and sheet products with conversion coatings are unpacked after long-term storage at elevated temperature and high relative humidity (RH), the surface of the sheet products appears tarnished. This discolouration appears as dark or black s
22、tain and influences the appearance and corrosion resistance, when parts are produced using these affected sheets. 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 refere
23、nces, the latest edition of the referenced document (including any amendments) applies. ISO 3613, Metallic and other inorganic coatings Chromate conversion coatings on zinc, cadmium, aluminium- zinc alloys and zinc-aluminium alloys Test methods ISO 3892, Conversion coatings on metallic materials Det
24、ermination of coating mass per unit area Gravimetric methods ISO 4520, Chromate conversion coatings on electroplated zinc and cadmium coatings ISO 6789, Assembly tools for screws and nuts Hand torque tools Requirements and test methods for design conformance testing, quality conformance testing and
25、recalibration procedure IEC 60068-2-30, Environmental testing Part 2-30: Tests Test Db: Damp heat, cyclic (12 h + 12 h cycle) IEC 60068-3-5, Environmental testing Part 3-5: Supporting documentation and guidance Confirmation of the performance of temperature chambers IEC 60068-3-6, Environmental test
26、ing Part 3-6: Supporting documentation and guidance Confirmation of the performance of temperature/humidity chambers ASTM E1347, Standard Test Method for Color and Color-Difference Measurement by Tristimulus Colorimetry ISO 2011 All rights reserved 1ASTM D2244, Standard Practice for Calculation of C
27、olor Tolerances and Color Differences from Instrumentally Measured Color Coordinates 3 Terms and definitions For the purposes of this document, the terms and definitions given in ISO 3613, ISO 3892, ISO 4520, ISO 6789, appropriate parts of ISO 60068 and the following apply. 3.1 dark stain phenomenon
28、 of discolouration of the surfaces of steel packed coil or stacked sheet products during storage at elevated temperature and high relative humidity 3.2 unstacked plate specimen specimen to represent the outer-surface layer of coiled or sheet product that is not stacked 3.3 stacked plate specimen spe
29、cimen to represent the inner-surface layer of coiled or packed sheet product that is stacked NOTE The inner surface is under stress due to stacking. Figures 1 and 2 exhibit inner and outer layers of packed coil and sheet products in stacked and unstacked conditions. aRepresents inner-surface layer o
30、f stacked coil. bRepresents outer-surface layer of stacked coil. Figure 1 Illustration of packed coil product ISO/TR 15922:2011(E)2 ISO 2011 All rights reservedaRepresents inner-surface layer of packed sheet product. bRepresents outer-surface layer of packed sheet product. Figure 2 Illustration of p
31、acked sheet product 4 Information to be supplied by the producer to the user or purchaser 4.1 Essential information When ordering the product in accordance with this Technical Report, the purchaser or user should be provided by the producer with the following information in writing, in, for example,
32、 the contract or purchase order, or on engineering drawings: a) number and distribution of defects, and time elapsing before the appearance of the first sign of defect; b) temperature, relative humidity, applied pressure in N/m 2 and test duration; c) the AQL level and sampling plan used; NOTE Widel
33、y used sampling plans are provided in Technical Reports (see Bibliography). 4.2 Additional information The following additional information should also be provided by the purchaser, when appropriate: a) any deviation from the agreed test procedures; b) whether test samples are packed with vinyl befo
34、re placing them to apparatus used for stacking pressures. 5 Apparatus Normal laboratory apparatus and the following: 5.1 Environmental test cabinet, capable of environmental testing in accordance with IEC 60068-2-30, Test Db: Damp heat, cyclic (12 h + 12 h cycles). Ensure that the conditions inside
35、the working area of the test chamber are identical at all points, within the specified tolerances, including the immediate vicinity of measurement sensing devices. The chamber should conform to the requirements of IEC 60068-3-6. Ensure that no condensed water is allowed to drop on the specimens. ISO
36、/TR 15922:2011(E) ISO 2011 All rights reserved 3As specified in IEC 60068-2-30, the properties and dimensions of the test specimens should not influence the conditions within the chamber. 5.2 Photoelectric absorptiometer (colorimeter), with a filter having a mean transmission of 520 nm. The absorpti
37、ometer should be used with an absorption cell of optical path length 10 mm. 5.3 Apparatus for application of constant pressure. It is used to simulate stacking conditions. Parts of the apparatus are made from high corrosion resistance material, such as plastic. The apparatus to simulate stacking con
38、ditions (Figure 3) should be placed in the appropriate working area, in accordance with IEC 60068-3-5. a) Cross section view b) Setting torque tool Key 1 specimens 2 socket wrench 3 torque adjustment Figure 3 Apparatus to simulate stacking conditions 6 Test methods 6.1 General The test surface, prio
39、r to the following tests, should be free of all contaminants, finger prints and other extraneous stains. If the surface is coated with thin oil, it should be removed prior to the tests by degreasing using a suitable solvent at room temperature (not exceeding 35 C). For test purposes, the samples sho
40、uld not be subjected to be forced drying at temperatures in excess of 35 C. Treatment in alkaline solutions should not be performed as chromate conversion coatings are broken down by alkalis. Test materials are selected from chromate conversion-coated (ISO 4520) hot-dip zinc and zinc electroplated s
41、teel products. The test methods for the qualitative test for the determination of dark- or black- stain properties is given in 6.3 and quantitative method by colorimetric method is given in 6.4. ISO/TR 15922:2011(E)4 ISO 2011 All rights reserved6.2 Procedures Sectioning test specimens of 120 mm 80 m
42、m dimensions from the outer and inner surfaces of unstored or unstacked and unpacked coiled or sheet products. The test specimens are to be selected from unstacked sheets to satisfy the AQL level of the sampling plan see 4.1 c) and assemble the test specimens in accordance with ISO 6789. Assess the
43、presence of trivalent or hexavalent chromium content of each chromated test sample in accordance with ISO 3613. Calculate mass per unit area of the coating in accordance with ISO 3892. Place unstacked specimens in an environmental test cabinet for the test duration. The temperature, humidity, applie
44、d pressure to reproduce stacked condition, and duration period of test should be as designated by the specification covering the material or product being tested see 4.1 b). Unless specified otherwise, conditions are as follows. Temperature (60 1) C Humidity (95 % 1 %) RH Applied Pressure (147 0,98)
45、 N/m 2 Period 24 h, 48 h, 72 h, 96 h, 120 h, 240 h, 500 h, 1 000 h 6.3 Qualitative test method for determination of the property of dark stain 6.3.1 Test method The specimens from outer and inner surfaces of unstored, unstacked products are exposed to the agreed temperature, pressure and humidity se
46、e 4.1 b) or, alternatively, to the condition specified in 6.2, for an agreed duration, to replicate respective unstacked and stacked products in stored conditions. For comparison purposes, also expose specimens without chromate conversion coating similarly. Criteria for evaluation to this test are:
47、a) appearance after test; b) distribution of defects per sq cm, (black or stain, white rust, etc.); c) time elapsing before the appearance of the first sign of defect; d) mass per unit area of the coating. 6.3.2 Test report The test report should contain the following information: a) a reference to
48、this Technical Report, ISO/TR 15922; b) detailed information of the test methods, including temperature, relative humidity, applied pressure in N/m 2and test duration; c) number of samples tested; d) mass per unit area of conversion coatings; e) appearance after test; f) distribution of defects per
49、sq cm (black stain , white rust, etc.); ISO/TR 15922:2011(E) ISO 2011 All rights reserved 5g) time elapsing before the appearance of the first sign of defect; h) dates of the tests and date of the report. 6.4 Quantitative test method for determination of property of dark stain 6.4.1 Test method The specimens from outer and inner surfaces of unstored, unstacked products are exposed to the agreed temperature, pressure and humidity see 4.1 b) or, alternatively, to the condition specified
