tok koko kk ok Disclosure to Promote the Right To Information c ‘Whereas the Parliament of India has set ous ta provide a practical regime of right ta information for citizens to secure access ta information under the control of public authorities, in order to promote transparcecy and accountability in the working of every public authority, ‘and whereas the attached publication of the Bureau of Indian Standards is of particular interest to the public, particularly disadvantaged communities and those engaged in the pursuit of education and knowledge, the attached public safety standard is made available to promote the timely dissemination of this information in an aceurate manner to the public, be a a mm ee ee me ee me ee ee me meBLANK PAGEIs : 6009 - 1970 ( Reaffirmed 2006 ) Indian Standard METHOD FOR EVALUATION OF RESULTS OF ACCELERATED CORROSION TESTS (Fourth Reprint JANUARY 1998 ) UDC 620.197.6:620.199 @ Copyright 197) BUREAU OF INDIAN STANDARDS MANAK BHAVAN, 9 BAHADUR SHAH ZAFAR MARG NEW DELHI 110002 June 1971IS : 6009 - 1970 ‘( Reaffirmed 1992) Indian Standard METHOD FOR EVALUATION OF RESULTS OF ACCELERATED CORROSION TESTS Metallic Finishes Sectional Committee, SMDC 23 Chairman Representing Dr S. KeisHNaAMURTHY Indian Telephone Industries Ltd, Bangalore Members Dr S. N. Anant Narayan International Nickel (India } Pvt Ltd, Bombay Suet A. K. Brrmant S. Mitra and Company, Bombay Suet H.C. Sampart ( Alternate ) Suri K, G. GHANDRASHEKARAPPA Indian Telephone Industries Ltd, Bangalore Suri AHINDRA CHATTERJEE Canning Mitra Phoenix Ltd, Bombay Suri S. V. Kutxarnt ( Alternate ) Sari D. K. Coarrerjee Sen-Raleigh Ltd, Asansol Cuemist AND Metatuureorst, ICF, Ministry of Railways PERAMBUR Cuemist AND Metauuureist-II, RDSO, Lucknow ( Alternate ) Suri Kantivat T. Data Kohinoor Electro-Giiders, Bombay Surt Javenpra K. Darat ( Alternate ) Suri Dine Pau Guest, Keen, Williams, Ltd, Calcutta Suet P. N. GANDHI The Indian Tube Company (1953 ) Ltd, Jamshedpur Suri P. Mirra { Alternate ) GenerAL Manacer, Posts and Directorate General of Posts & Telegraphs, Calcutta TELEGRAPHS WorKsHOPS, CALCUTTA Deputy General Manacer ( Alternate ) Suet K. J. Jacos Trivandrum Rubber Works Ltd, Trivandrum Suri k. K. Samuer ( Alternate ) Suri M. N. Kesart Bharat Electronics Ltd, Bangalore Suri K. Gururayja { Alternate ) Suet U. G. KR. Menon Ministry of Defence (R & D) Surr §. L. N. AcHaryu.u (‘Alternate ) Suer B. K. Murtuy Indian Aluminium Company Ltd, Calcutta Suri N, GopatketsHnan ( Alternate ) Suri J. C. Nanaia Arim Metals Industries Pvt Ltd, Calcutta Suri $, K. Nanora ( Alternate ) Suri S$. PANCHPAKESAN T. 1. Cycles of India, Madras Dr K. 8. RajacoPaLan Central Electrochemica! Research Institute (CSIR ), Karaikudi Suet B. A. Sxenor ( Alternate ) Suri N. M. Raju Hindustan Motors Ltd, Calcutta ( Continued on page 2 ) BUREAU OF INDIAN STANDARDS MANAK BHAVAN, 9 BAHADUR SHAH ZAFAR MARG NEW DELHI 1100021S : 6009 - 1970 ( Continued from page 1 ) Members Representing Suri V. Ramaswamy Ministry of Defence ( DGI) Suri M. Y, Borker ( Alternate ) REPRESENTATIVE Grauer & Weil (India } Ltd, Bombay Suri R. K. Roxane The Premier Automobiles Ltd, Bombay Suri P, K. DesHPanpe ( Alternate } Sunt N. C. Roy Geep Flashlight Industries Ltd, Allahabad Suet R, A. Suan Ronuk Industries Ltd, Bombay Kumar? Maipura A. SHAH ( Alternate ) Suri A. SOUNDRARAJ Directorate General, Ordnance Factories ( Ministry of Defence ), Galcutta Suet Y. 8. Trivepr ( Aliernate } ( Bombay ) Suri V. KarsHwan ( Alternate ) ( Calcutta } Suet D. 8. Tanpon Nationa! Metallurgical Laboratory (CSIR), Jamshedpur Suri C. D, VARGHESE Hindustan Aeronautics Ltd, Bangalore Super R. K. Srivastava, Director General, ISI ( Ex-officio Member ) Deputy Director (Struc & Met) Secretary Suri §. L. Bau Deputy Director ( Met ), ISIIS : 6009 - 1970 Indian Standard METHOD FOR EVALUATION OF RESULTS OF ACCELERATED CORROSION TESTS 0 FOREWORD 0.1 This Indian Standard was adopted by the Indian Standards Institution on 22 December 1970, after the draft finalized by the Metallic Finishes Sectional Committee had been approved by the Structural and Metals Division Council. 0.2 In Indian Standards related to metallic coatings, accelerated corrosion tests, such as CASS, Corrodkote and Acetic Acid Salt Spray Test have been included. It has, therefore, become necessary to define acceptable levels of performance of coatings, other than those anodic to the basis metal, that have been subjected to accelerated corrosion tests. 0.3 This method is employed only on articles which have not already been rejected on simple inspection on the ground of the size or grouping of individual corrosion defects as required by the relevant Indian Standard. 0.4 For the purpose of rounding off, rules as described in IS : 2-1960* shall be applicable, 1. SCOPE 1.1 This standard specifies a rating system that provides a means of defining levels of performance of coatings, other than those anodic to the basis metal, that have been subjected to accelerated corrosion tests. This method takes into account only corrosion of the basis metal. 2. DEFINITIONS 2.0 For the purpose of this standard, the following definitions shall apply. 2.1 Significant Surfaces —In general, significant surfaces are those surfaces that are visible and subjected to wear or corrosion or both, or surfaces on which the coating is otherwise functionally necessary. The designation of the significant surfaces shall be agreed upon by the manufacturer and the purchaser, and may be indicated *Rules for rounding off numerical values ( revised ). 3IS : 6009 - 1970 on the drawings, The surfaces on which a controlled deposit ordinarily cannot be obtained, such as holes, recesses, angular bases, are normally exempt from the requirements for significant surfaces, unless they are specifically designated as such. When such areas are designated as significant surfaces and the thickness requirements are to be met, the manu- facturer and the purchaser shal! recognize the necessity for either thicker deposits on the more accessible surfaces or special racking. Special racks may involve the use of conforming, auxiliary, Interior, or bipolar electrodes, Nore — Significant surfaces generally may be defined as those parts of the visible surface that can be touched with a sphere of diameter either 20 mm or as agreed upon by the manufacturer and the purchaser. 2.2 Corrosion Spot — A surface corrosion defect at which the coating 1s penetrated as indicated by the appearance of basis metal, corrosion products or lifting of the coating. Discolouration or other surface defects, which do not penetrate the coating, do not count as corrosion spots. The size ofa corrosion spot is the area of the penetration through the coating and no that of associated staining. 3, SAMPLING 3.1 The batch should be sampled in the manner required by the relevant specification. The total significant surface area of the sample should be in excess of 5 000 mm?. 3.2 If the individual articles forming the sample have a significant surface area smaller than 5 000 mm, the sample for assessment should comprise a sufficient number of individual articles to obtain a total significant surface area equal to or greater than this area. 3.3 If the rating number required by the relevant specification is > 8, the total significant surface area of the sample should exceed 10 000 mm’. 4, EXAMINATION OF SAMPLE AFTER TEST 4.1 The sample should be examined in its condition at the end of the test or after rinsing in running water, if i. is necessary to remove the residue of the test medium. Corrosion products may be removed subsequently, to enable the size of individual corrosion spots to be assessed. 4.2 For the purpose of evaluation, divide the area of the significant surface of the sample hypothetically into squares of 5 mm size. This is easily done by placing a graticule, made of fully flexible transparent plastics material, on the sample so as to give the most favourable result, that is, the highest rating. 4.3 Count the number ( V) of 5 mm squares in the significant area of the sample and the number (2) of such squares containing one or more 4IS : 6009 - 1970 corrosion spots. When evaluating the total area of sample, squares more than half occupied should be counted as full squares and those less than half occupied should be ignored. 4.4 Ifa spot appears to lie in more than one square, it should be counted only once in the evaluation, but cracks traversing more than one square should be counted for each square entered. 5. SUITABILITY OF SAMPLES FOR EVALUATION 5.1 If ten or more corrosion spots can be included in any two adjacent 5 mm squares, or any spots are present of area greater than 2°35 mm?, the sample shall be considered unsuitable for assessment. For long cracks traversing more than one 5 mm square, the sample shall be considered unsuitable for assessment if the area of the crack in any one square exceeds 2°5 mm?, 5.2 If the sample consists of more than one individual article, and gross differences in the degree of corrosion are evident between these. individual articles, the sample shail be considered unsuitable for assessment. 6. INITIAL RATING NUMBER 6.1 Determine the frequency of the spots as a percentage from the expression: Frequency = 100 x a ( see 4,3) Allocate a rating number to the sample according to the following table: Frequency, Percent Rating Number 0 (no corrosion spots) 10* Over 0 up to 0°25 Q* Over 0°25 ,, ,, O'5 g* Over 05 upto ! 7 Over } w a 2 6 Over 2 a wy OF 5 Over 4 » » 8 4 Over 8 » » 16 3 Over 16 is we 32 9 Over 32 sy OF l Over 64 0 "See 3.3.IS : 6009 - 1970 7. REDUCTION OF INITIAL RATING FOR LOCAL CONCENTRATION OF CORROSION SPOTS ON LARGER ARTICLES 7.1 Samples Comprising Individual Articles with Areas for Assess- ment Greater than 2 500 mm* — Find the 50x50 mm area showing the greatest number of corrosion spots. Count the number of 5 mm squares in this area which are occupied by corrosion spots. Reduce the initial rating obtained by the method given in 6 by one unit for each ten squares thus obtained. 8. EXAMPLES FOR THE RATING SYSTEM Example I Total number of 5 mm squares in sample area = 400 Number of squares containing corrosion spots = 48 Percentage of squares containing corrosion spots = [2 Rating number from table ( see 6 } = 3 Greatest number of squares with corrosion spots in any area of 50 x 50 mm {see 7) = 17 Final rating number = 3 — a =- 3 — 2 (rounded off) = ] Example 2 Total number of 5 mm squares in sample area = 400 Number of squares containing corrosion spots = 1 Percentage of squares containing corrosion spots == 0°25 Rating number from table ( see 6 ) = 9 Greatest number of squares with corrosion spots in any area of 50 X 50 mm ( see 7) = 1 Final rating number =9-—O= 9BUREAU OF INDIAN STANDARDS Headquarters. 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