Astm stp 1239 1995

STP 1239 Atmospheric Corrosion W W Kirk and Herbert H Lawson, Editors ASTM Publication Code Number (PCN): 04-012390-27 ASTM 1916 Race Street Philadelphia, PA 19103 Printed in the U.S.A qSTl Copyright by ASTM Int'l (all rights reserved); Sun Dec 27 14:49:08 EST 2015 Downloaded/printed by University of Washington (University of Washington) pursuant to License Agreement No further reproductions authorized Library of Congress Cataloging-in-Publication Data Atmospheric corrosion / W.W Kirk and Herbert H Lawson, editors (STP ; 1239) Includes bibliographical references and index ISBN 0-8031-2015-X I Corrosion and anti-corrosives I Kirk, W W., 1932II Lawson, Herbert H., 1926llI Series: ASTM special technical publication ; 1239 TA418.74.A86 1995 620.I'1223 dc20 95-3231 CIP Copyright 1995 AMERICAN SOCIETY FOR TESTING AND MATERIALS, Philadelphia, PA All rights reserved This material may not be reproduced or copied, in whole or in part, in any printed, mechanical, electronic, film, or other distribution and storage media, without the written consent of the publisher Photocopy Rights Authorization to photocopy items for internal or personal use, or the internal or personal use of specific clients, is granted by the AMERICAN SOCIETY FOR TESTING AND MATERIALS for users registered with the Copyright Clearance Center (CCC) Transactional Reporting Service, provided that the base fee of $2.50 per copy, plus $0.50 per page is paid directly to CCC, 222 Rosewood Dr., Danvers, MA 01923; Phone: (508) 750-8400; Fax: (508) 750-4744 For those organizations that have been granted a photocopy license by CCC, a separate system of payment has been arranged The fee code for users of the Transactional Reporting Service is 0-8031-2015-X/95 $2.50 + 50 Peer Review Policy Each paper published in this volume was evaluated by three peer reviewers The authors addressed all of the reviewers' comments to the satisfaction of both the technical editors and the ASTM Committee on Publications, To make technical information available as quickly as possible, the peer-reviewed papers in this publication were prepared "camera-ready" as submitted by the authors The quality of the papers in this publication reflects not only the obvious efforts of the authors and the technical editors, but also the work of these peer reviewers The ASTM Committee on Publications acknowledges with appreciation their dedication and contribution to time and effort on behalf of ASTM, Printed in Philadelphia March 1995 Copyright by ASTM Int'l (all rights reserved); Sun Dec 27 14:49:08 EST 2015 Downloaded/printed by University of Washington (University of Washington) pursuant to License Agreement No further reproductions authorized Foreword This publication, Atmospheric Corrosion, contains papers presented at the symposium of the same name, held in Fort Worth, TX on 15-16 Nov 1993 The symposium was sponsored by ASTM Committee G-l on Corrosion of Metals W W Kirk of Ivanhoe, NC and Herbert H Lawson of Lawson Consultants, Inc in Middletown, OH presided as symposium chairmen and are editors of the resulting publication Copyright by ASTM Int'l (all rights reserved); Sun Dec 27 14:49:08 EST 2015 Downloaded/printed by University of Washington (University of Washington) pursuant to License Agreement No further reproductions auth Contents O v e r v i e w - - w W KIRK AND H H LAWSON vii CORROSIVITY OF ATMOSPHERES Time of Wetness and Dew Formation: A Model of A t m o s p h e r i c Heat T r a n s f e r s w DEAN AND D B REISER Acid Deposition Effects of Materials: Evaluation of Electric Contact Materials after F o u r Years of E x p o s n r e - - J TIDBLAD, C LEYGRAF, AND V KUCERA II An A p p r o a c h to the Modeling of A t m o s p h e r i c Corrosion -s B LYON, C W WONG, AND P AJIBOYE 26 Results of ISO C O R R A G P r o g r a m : Processing of One-Year Data in Respect to Corrosivity Classification D KNOTKOVA, P BOSCHEK, AND K KREISLOVA 38 Analyses of F o u r Years of Exposure Data from the USA Contribution of ISO C O R R A G P r o g r a m - - s w DEAN 56 WEATHERING STEELS AND COATED STEELS Effects of Silicon and Nickel Contents on the Atmospheric Corrosion Resistance of ASTM A588 W e a t h e r i n g SteeI H E TOWNSEND 85 Atmospheric Corrosion Rates of W e a t h e r i n g Steels at Test Sites in the Eastern United States-Effect of E n v i r o n m e n t and Test-Panel O r i e n t a t i o n s K COBURN, M E KOMP, AND S C LORE 101 Atmospheric Corrosion of Bolted Lap Joints M a d e of W e a t h e r i n g S t e e l - D KNOTKOVAAND J VLCKOVA 114 A Study of Rust Morphology, Contamination of Porosity by Backscattered Electron Imaging J SIMANCAS, K L SCRIVENER, AND M MORCILLO 137 Corrosion Evaluation of Automotive Trim Material A SABATA, G S DRIGEL, AND T L COOPER 152 The Influence of M a r i n e E n v i r o n m e n t s on Metals and Fabricated Coated Metal Products, Freely Exposed and Partially Sheltered -G A KING AND D J O'BRIEN 167 Copyright by ASTM Int'l (all rights reserved); Sun Dec 27 14:49:08 EST 2015 Downloaded/printed by University of Washington (University of Washington) pursuant to License Agreement No further reproductions authorized METALS AND ALLOYS Long-Term Atmospheric Corrosion in Spain: Results After 13 to 16 Years of Exposure and Comparison with Worldwide Data M MORCILLO, J SIMANCAS, A N D S FEL1U 195 Reaction Sequences in Atmospheric Corrosion of Zinc ODNEVALL A N D C L E Y G R A F 215 Galvanic Protection of Steel by Zinc under T h i n Layer Electrolytes -x G ZHANG A N D E M VALERIOTE 230 Corrosion Study of Carbon Steel and Zinc-Comparison Between Field Exposure and Accelerated T e s t s - - E J O H A N S S O N AND J G U L L M A N 240 Atmospheric Corrosion in Ibero-America: The M I C A T Project M MORCILLO 257 Author Index 277 Subject Index 279 Copyright by ASTM Int'l (all rights reserved); Sun Dec 27 14:49:08 EST 2015 Downloaded/printed by University of Washington (University of Washington) pursuant to License Agreement No further reproductions authorize Overview From the standpoint of economics, safety, and aesthetics, the importance of atmospheric corrosion and its control is well recognized More structures and materials are exposed to the atmosphere than to any other environment It is not surprising, therefore, that a vast body of literature exists on the performance of materials in the atmosphere and the characterization of such environments (See the previous ASTM symposia covered in the special technical publications (STP) listed at the end of this introduction.) Society interests in the performance of materials in the atmosphere were active well before the formation of Committee G-1 on Corrosion of Metals in 1964 The International Organization for Standardization (ISO) has also been very active in the development of standards for atmospheric testing methods and classification of atmospheres It seemed a natural follow-up for Subcommittee G01.04 to organize another symposium on Atmospheric Corrosion, held in November 1993 in Dallas, Texas The 16 papers presented there are included in this STP The truly international scope of interest for this symposium was emphasized with three papers each from Sweden and Spain, two from the Czech Republic, one each from the United Kingdom, Canada, and Australia, and five from the United States All of the basic metals and alloys used in construction: carbon steel, stainless steel, weathering steel, zinc, copper, and aluminum, were included in the subject matter For many years, an overwhelming desire to predict material performance in the atmosphere has been at the heart of many research programs, two of which are included here in an attempt to model atmospheric corrosion and corrosivity An ISO program to characterize different atmospheres as to corrosivity toward basic metals is also described in two papers Increased problems and concern with acid deposition and its effects on corrosion, along with a study of marine corrosion as a function of location and distance from salt water, round out the various subjects covered in this symposium Using symposia such as this and those previously held has permitted wide participation and comprehensive coverage of the subject Two continuing goals of Committee G-1 are "the promotion and stimulation of research" and "the collection of engineering data relating to the corrosion of metals." These are also goals of Subcommittee GO 1.04 on Atmospheric Corrosion As indicated by the long-term testing programs discussed herein and in previous literature, it can be anticipated that future symposia on similar subject matter will be necessary The difficulties in determining and understanding the complexity of atmospheric variables and their interactions are certain to provide interest and concern to the world of engineering The editors are grateful to their fellow members of Committee G-1 for their assistance and encouragement in the organization of this symposium and the production of this volume We appreciate very much the support and guidance of the ASTM publications staff Listed below are six STPs resulting from various symposia held since 1956 9 9 9 STP STP STP STP STP STP 175 Symposium on Atmospheric Corrosion of Non-ferrous Metals, 1956 435 Metal Corrosion in the Atmosphere, 1968 558 Corrosion in Natural Environments', 1974 646 Atmospheric Factors Affecting the Corrosion of Engineering Metals, 1978 767 Atmospheric Corrosion of Metals, 1982 965 Degradation of Metals in the Atmosphere, 1987 W W Kirk H H Lawson Kirk Corrosion Consulting, Ivanhoe, NC; symposium chairman and editor, Lawson Consultants, Inc., Middletown, OH; symposium chairman and editor vii Copyright by ASTM Int'l (all rights reserved); Sun Dec 27 14:49:08 EST 2015 Downloaded/printed by University of Washington (University of Washington) pursuant to License Agreement No further reproductions authorized Corrosivity of Atmospheres Copyright by ASTM Int'l (all rights reserved); Sun Dec 27 14:49:08 EST 2015 Downloaded/printed by University of Washington (University of Washington) pursuant to License Agreement No further reproductions authorized Sheldon W Dean I and David B Reiser I TI~ HHAT 07 ~TR88 TRANBFHR ~ DEW FOI~WATION: l NODIL OF A~Og)HHRIC Dean, S W and Reiser, D B., "Time of Wetness and Dew Formation: A Model of Atmospheric Heat Transfer," Atmospheric Cer~ rosion, ASTM STP 1239, W W Kirk and Herbert H Lawson, Eds., American Society for Testing and Materials, Philadelphia, 1995 REFERENCE: Time of wetness is a critical factor in atmospheric corrosion Dew is a major contributor to time of wetness In normal atmospheric exposures, dew formation is a result of radiative cooling of exposed surfaces below the dew point of surrounding air The extent of radiational cooling of an object is affected by the effective sky temperature, the presence of clouds, the view of other surfaces at different temperatures, and air movement by wind or natural convection adjacent to the cooling surfaces This paper models the temperature of a boldly exposed panel as a function of humidity and air current velocity The model predicts a maximum panel temperature depression of approximately 16~ below ambient air temperature in still air For wind velocities of 4.5 m/s (i0 mph) radiational cooling lowers the panel temperature 3~ below ambient air temperature Abstractx Ke~rdsz cooling, atmospheric corrosion, time of wetness, dew formation, wind velocity radiational Atmospheric corrosion is an important degradation process affecting metallic materials Most investigators agree that atmospheric corrosion takes place only during the time that the metal is wet with liquid moisture Dew is an important contribution to the formation of surface moisture films Vernon [i] proposed that surface wetness occurs when a critical relative humidity (RH) is exceeded His work suggested that this critical RH is between 80 and 90% Mansfeld [i] and others have proposed lower critical RH values depending on the hygroscopicity of iAir Products Fellow and lead materials engineer, respectively, Air Products and Chemicals, Inc., 7201 Hamilton Blvd., Allentown, PA 18195 Copyright by ASTM Int'l (all rights reserved); Sun Dec 27 14:49:08 EST 2015 Copyrigh~1995by www.astm.org Downloaded/printed byASTM International University of Washington (University of Washington) pursuant to License Agreement No further reproductions authorized ATMOSPHERIC CORROSION the salts on the metal surface C o r r o s i o n of m e t a l s and alloys: C l a s s i f i c a t i o n of c o r r o s i v i t y c a t e g o r i e s of a t m o s p h e r e s (ISO 9223) s p e c i f i e s that time of w e t n e s s be c a l c u l a t e d from RH data as the time for w h i c h RH > 80% and the t e m p e r a t u r e is above 0~ G r o s s m a n [~] p r o p o s e d a model w h e r e dew f o r m a t i o n r e s u l t e d from r a d i a t i o n a l cooling, m a k i n g the model m o r e d e p e n d e n t on heat transfer c o n s t r u c t s rather than h y g r o s c o p i c i t y c o n s i d e r a t i o n s The p u r p o s e of this p a p e r is to e x a m i n e the concept of a heat t r a n s f e r model b a s e d on m o r e recent c o r r e l a t i o n s of sky t e m p e r a t u r e to d e t e r m i n e if this a p p r o a c h m i g h t p r o v i d e a m o r e a c c u r a t e a p p r o a c h to e s t i m a t i n g time of w e t n e s s from m e t e o r o l o g i c a l data UEAT TI~NSFZR MODZL C o n s i d e r a object e x p o s e d to the night sky The u p p e r s u r f a c e of the o b j e c t w i l l b e c o m e wet w i t h dew if its t e m p e r a t u r e drops b e l o w the dew p o i n t of the s u r r o u n d i n g air R a d i a t i v e heat t r a n s f e r b e t w e e n the object and the sky p r o v i d e s a m e c h a n i s m for a s u r f a c e to b e c o m e colder than the s u r r o u n d i n g air W h e t h e r this local c o o l i n g r e s u l t s in dew f o r m a t i o n d e p e n d s on b o t h the amount of s u b c o o l i n g p o s s i b l e and on the h u m i d i t y of the s u r r o u n d i n g air The s u b c o o l i n g itself is a f f e c t e d by the local h u m i d i t y a n d by w i n d or n a t u r a l convection As a s u r f a c e cools, w i n d a n d n a t u r a l c o n v e c t i o n will s u p p l y heat to the surface, c o u n t e r a c t i n g the r a d i a t i v e transfer to the sky For a h o r i z o n t a l l y e x p o s e d panel, the e n e r g y b a l a n c e is: (I) A where: Q= heat A= area, ~= Stefan-Boltzmann F = s = flux, W m2 v i e w factor emissivity constant for r a d i a t i v e of r a d i a t i n g assumed constant = 5.6686 x 10 -8 W m -2 K -4 = 0.1713 x 10 -8 Btu hr -I ft -2 ~ exchange = for this g e o m e t r y (panel) Tai r = a b s o l u t e air temperature, K Tsky = absolute K sky temperature, Tpane I = a b s o l u t e panel hc = surface, dimensionless = 0.8 for this w o r k temperature, c o n v e c t i v e h e a t transfer K coefficient, W m -2 K -I Copyright by ASTM Int'l (all rights reserved); Sun Dec 27 14:49:08 EST 2015 Downloaded/printed by University of Washington (University of Washington) pursuant to License Agreement No further reproductions authorized MORCILLO ON THE MICAT PROJECT 265 ~_ 0,8 12 16 20 24 ll!ll{llll!lll{ I 28 32 36 40 44 48 52 56 60 64 68 64 68 72 52 56 60 64 68 72 72 Test s i t e s ~ 0 - ~ s~I 6O -~ 40 == - 20 ,111 I o,~t, ,, - L t , h 12 , 16 20 24 28 32 36 40 44 48 52 56 60 Test s i t e s 250 200 150 1001 O 12 16 20 24 28 32 36 40 44 48 Test s i t e s P, data in p r o g r e s s FIG Time of w e t n e s s (TOW), S02, and Cl" a v e r a g e values d u r i n g the three 1-year e x p o s u r e sequences at the d i f f e r e n t test sites Copyright by ASTM Int'l (all rights reserved); Sun Dec 27 14:49:08 EST 2015 Downloaded/printed by University of Washington (University of Washington) pursuant to License Agreement No further reproductions authorized 266 ATMOSPHERIC CORROSION 400 o 300 ~3 o i- o "~ 200 ~" 100 12 16 20 24 28 32 36 40 44 48 52 56 60 64 56 60 64 68 72 68 72 Test sites 14 12 E ,o 10 o ~ rt ~ d _z a ,,dl,,,l,,, 12 16 20 i J 24 28 i,,]ii11~i 32 36 40 ,ll,, I , 44 48 b , I , 52 , , Test sites P, d a t a in p r o g r e s s FIG A v e r a g e a n n u a l c o r r o s i o n d a t a of l o w - c a r b o n steel and zinc for the t h r e e 1-year e x p o s u r e s e q u e n c e s at the d i f f e r e n t t e s t sites Copyright by ASTM Int'l (all rights reserved); Sun Dec 27 14:49:08 EST 2015 Downloaded/printed by University of Washington (University of Washington) pursuant to License Agreement No further reproductions 267 MORCILLO ON THE MICAT PROJECT 10 s ~8 o" ,,ill 12 16 20 24 28 32 36 40 44 !! !!,i ,ll 48 52 56 60 64 68 72 Test s i t e s "E 0'1 '- "-' r t"" ~ z _,1 < ~, ,' 12 '~'' 16 ;,',, 20 ',''' 24 28 "'' 32 , mP 36 P 40 ' P' i ' I ' ' "l ' " ' ' ! 44 48 ~' 52 56 lill, 60 64 68 72 Test sites P, data in p r o g r e s s FIG A v e r a g e annual c o r r o s i o n d a t a of c o p p e r aluminum for the three 1-year e x p o s u r e sequences at d i f f e r e n t test sites and the Copyright by ASTM Int'l (all rights reserved); Sun Dec 27 14:49:08 EST 2015 Downloaded/printed by University of Washington (University of Washington) pursuant to License Agreement No further reproductions authori 268 ATMOSPHERIC CORROSION DISCUSSION Models for p r e d i c t i n g the corrosion d a m a g e of m e t a l s in the a t m o s p h e r e are useful for a n s w e r i n g questions regarding the durability of metallic structures, d e t e r m i n i n g the economic costs of damages a s s o c i a t e d w i t h the d e g r a d a t i o n of materials, and acquiring k n o w l e d g e about the effect of environmental variables on corrosion kinetics The s p e c i a l i z e d literature offers a large number of damage functions that relate the a t m o s p h e r i c c o r r o s i o n rate to e n v i r o n m e n t a l data [13 - 16] In this paper an attempt is also m a d e to corrosion data with meteorological and parameters correlate pollution Statistical Analvsis W i t h the aim o b t a i n e d damage functions a s t a t i s t i c a l analysis was performed with the aid of commercially a v a i l a b l e computer software [17], following the p r o c e d u r e in a previous p a p e r [16]; individual data c o r r e s p o n d i n g to each e x p o s u r e sequence were considered in the analysis Table shows the high v a r i a b i l i t y of the c o r r o s i o n and e n v i r o n m e n t a l data used in the statistical treatment Data were fitted to a linear equation C = a, + a2T + a3RH + aaP + a TOW + ~ S + aTCl (I) w h e r e the a i coefficients (i = to 7) are constants, C(~m for steel, zinc and copper, and g/m for aluminium) is the annual corrosion, T is the temperature annual a v e r a g e (~ RH is the relative h u m i d i t y annual average (%), P is the total annual volume of p r e c i p i t a t i o n (mm), TOW is the time of w e t n e s s (annual fraction), S is the annual a v e r a g e of S02 p o l l u t i o n (mgS02/m2.d), and Cl is the annual a v e r a g e of c h l o r i d e p o l l u t i o n (mg C l / ~ d ) Equation is quite simple Probably, other c o m b i n a t i o n s b e t w e e n the different v a r i a b l e s m a y y i e l d b e t t e r fits; yet in this w o r k using as simple r e l a t i o n as p o s s i b l e was the goal One possible w a y of i m p r o v i n g the above linear e q u a t i o n is by introducing terms m a d e up of p r o d u c t s of two variables (e.g RH x CI, S x TOW, etc.) In a d d i t i o n to the simultaneous use of all the c o r r o s i o n data, the present study included a separate t r e a t m e n t of data from rural atmospheres, including in the c a t e g o r y of a t m o s p h e r e s those with annual pollution a v e r a g e s less than i0 mg S02/m2.d and mg Cl/m2.d, the lowest p o l l u t i o n c a t e g o r i e s a c c o r d i n g to ISO 9223 [!] The goodness of fit of experimental data to a p r o p o s e d m o d e l is often m e a s u r e d by the statistical R z, i.e., the square of the c o r r e l a t i o n coefficient (R) b e t w e e n the observed values of the dependent variable and those p r e d i c t e d from the fitted line Copyright by ASTM Int'l (all rights reserved); Sun Dec 27 14:49:08 EST 2015 Downloaded/printed by University of Washington (University of Washington) pursuant to License Agreement No further reproductions authorized MORCILLO ON THE MICAT PROJECT TABLE 269 C h a r a c t e r i s t i c s of the c o r r o s i o n and e n v i r o n m e n t a l data used in statistical treatment Material and number of data Steel (N= 137) Variable Mean Smallest value Largest value C (um) 50.0 1.0 T (~ 19.4 -3.1 28.1 RH (%) 72.6 33.3 91.1 p (mm) 1077.7 13.0 4656.0 TOW (annual fraction) 411.2 0.47 0.00 S (mgSO2/m:.d) 14.58 0.00 83.10 Cl 26.00 0.00 359.80 C (mgCl/m2.d) (~m) 1.69 0.09 0.95 8.06 T (~ 18.5 -3.1 28.1 RH (%) 72.6 33.3 91.1 (nun) 916.2 13.0 2624.0 p Zinc (N=I20) TOW (annual fraction) 0.46 0.00 S (mgSOJm2.d) 14.15 0.00 83.10 Cl 24.66 0.00 359.80 C (mgCl'/m2.d) (~m) T (~ 8.22 -3.1 (%) 73.0 33.3 91.1 P (mm) 997.6 13.0 3677.0 TOW (annual fraction) 28.0 0.46 0.00 S (mgso2/m2.d) 13.67 0.00 83.10 Cl 24.15 0.00 359.80 (mgC1-/ma.d) C (g/m:) Aluminium (N = 115) 0.09 18.2 RH Copper (N = 115) 1.64 0.95 0.92 0.00 0.95 5.43 T (~ 18.1 -3.1 28.0 RH (%) 72.5 33.3 91.1 P (mm) 943.6 13.0 2624.0 TOW (annual fraction) 0.46 0.00 S (mgSO:/m: d) 14.73 0.00 83.10 C1 24.34 0.00 359.80 (mgCl/m2 d) 0.95 Copyright by ASTM Int'l (all rights reserved); Sun Dec 27 14:49:08 EST 2015 Downloaded/printed by University of Washington (University of Washington) pursuant to License Agreement No further reproductions authorized 270 ATMOSPHERIC CORROSION One way of assessing the relative importance of i n d e p e n d e n t v a r i a b l e s is to c o n s i d e r an i n c r e a s e in R w h e n a variable is entered into an equation that already c o n t a i n s the o t h e r i n d e p e n d e n t v a r i a b l e s A l a r g e c h a n g e in R2 indicates that the new variable provides unique information about the dependent variable that is not available from the other independent variables in t h e equation The procedure for selecting variables was the well-known stepwise technique, which involves the s e q u e n t i a l i n t r o d u c t i o n of all t h e i n d e p e n d e n t v a r i a b l e s starting from the one with the largest positive or negative correlation with the dependent variable The value of t h e F s t a t i s t i c w a s u s e d to d e t e r m i n e w h e t h e r t h i s f i r s t v a r i a b l e a n d e a c h of t h o s e s u c c e s s i v e l y i n t r o d u c e d s h o u l d r e m a i n in t h e r e g r e s s i o n e q u a t i o n or be e x c l u d e d f r o m it In t h i s way, o n l y a f e w of t h e independent variables appeared to be i m p o r t a n t (Equations 2-13 in T a b l e s 3-7) F i n a l l y , it s h o u l d b e k e p t in m i n d t h a t g r e a t c a u t i o n m u s t be u s e d in m a k i n g c o r r o s i o n p r e d i c t i o n s f o r v a l u e s of t h e i n d e p e n d e n t v a r i a b l e s t h a t are m u c h l a r g e r or s m a l l e r t h a n t h o s e u s e d to d e r i v e t h e s e e q u a t i o n s ( T a b l e 2) T A B L E - - R e l a t i o n s h i D s b e t w e e n the a n n u a l of l o w - c a r b o n s t e e l a n d t h e e n v i r o n m e n t a l Equations Remarks C~ = 0.012 P + 0.94 S + 1.06 Cl 3.9 (R = 0.78) (Eq 2) C~ = Cl (2.9+0.0006 P-0.03 RH) + 1.9 S x TOW + 8.07 (R = 0.84) Analvtical corrosion parameters (Eq 3) c~ = carbon steel annual corrosion (~m) RH = relative humidity annual average (%) P = annual precipitation (mm) TOW = time of wetness (annual fraction) S = SO pollution annual average (mg SO2/m2.d) Cl = chloride pollution annual average (mgCl/m2.d) R = multiple correlation coefficient Results T h e s t a t i s t i c a l t r e a t m e n t of t h e w h o l e d a t a set b y t h e linear model accounts for 61, 42, 48 a n d 45% of t h e variance in c o r r o s i o n of m i l d steel, zinc, copper and a l u m i n i u m , r e s p e c t i v e l y (Eqs 2,4,6, a n d in T a b l e s 3-6) Copyright by ASTM Int'l (all rights reserved); Sun Dec 27 14:49:08 EST 2015 Downloaded/printed by University of Washington (University of Washington) pursuant to License Agreement No further reproductions auth MORCILLO ON THE MICAT PROJECT By using binary interaction terms main effect terms of the environmental 3,5,7 and in Tables 3-6), the fits substantially Only a low improvement found in the best cases (mild steel and TABLE Relationships between of zinc and the environmental Equations (Eq 4) C ~ = TOW (0.Ii S + 0.02 Cl) + 0.03 RH - 0.003 S x T - 2.09 (R = 0.72) (Eq 5) TABLE Relationships between of copper and the environmental Equations Cc = 0.049 2.57 (R = 0.69) the annual parameters corrosion c ~ = zinc annual corrosion (~m) T = temperature annual average (eC) RH = relative h u m i d i t y annual average (%) TOW = time of w e t n e s s (annual fraction) S = SO p o l l u t i o n annual average (mg SO2/m2.d) C1 = chloride p o l l u t i o n annual average (mgCl/m2.d) R = multiple c o r r e l a t i o n coefficient the annual parameters corrosion Remarks RH + 0.03 S + 0.01 Cl(Eq 6) Ccu = RH (0.04 + 0.0002 el) + 0.05 S x TOW - 1.64 (R = 0.71) together with the variables (Eqs not improve of 10% have been zinc) Remarks C ~ = 2.73 TOW + 0.017 C1 + 0.03 (R = 0.65) 271 C a = copper annual corrosion (~m) RH = relative h u m i d i t y annual average (%) TOW = time of w e t n e s s (annual fraction) S = SO p o l l u t i o n annual average (mg SO~/m2.d) Cl = chloride p o l l u t i o n annual average (mgCl/m2.d) R = multiple c o r r e l a t i o n coefficient (Eq 7) Copyright by ASTM Int'l (all rights reserved); Sun Dec 27 14:49:08 EST 2015 Downloaded/printed by University of Washington (University of Washington) pursuant to License Agreement No further reproductions authorized 272 ATMOSPHERICCORROSION TABLE Relationships between the of aluminium and the environmental Equat ions Remarks C m = 1.32 TOW - 0.07 T + 0.03 S + 0.008 Cl + 0.94 (R = 0.67) Cm (Eq 8) = 0.06 (S x TOW - T) + 0.009 Cl + 1.40 (R = 0.66) (Eq 9) c~ = aluminium annual corrosion (g/m 2) T = temperature annual average (~ RH = relative humidity annual average (%) TOW = time of wetness (annual fraction) S = SO pollution annual average (mg SO~/m2.d) Cl = c h l o r i d e pollution annual average mgCl/m2.d) R = multiple correlation coefficient TABLE Relationships between the carbon, zinc, copper and aluminium the environmetal parameters Materials and number of data Steel (N = 13) zinc (N = Equations CFe = 0.90 (R = 0.48) Czn = 3.04 (R = 0.63) Ca = (R = Aluminium (N = 36) annual corrosion of in r u r a l a t m o s p h e r e s lowand Remarks T -3.41 (Eq.10) TOW - 0.06 35) Copper (N = 37) annual corrosion parameters 0.02 (Eq.ll) RH 0.52) C^~ = 0.33 (R = 0.33) - 0.80 (Eq.12) TOW + 0.06 C = annnual corrosion (in ~ m f o r s t e e l , z i n c and copper, and g/m for aluminium) T = temperature annual average (~ RH = relative humidity annual average (%) TOW = time of wetness (annual fraction) R = multiple correlation coefficient (Eq.13) Copyright by ASTM Int'l (all rights reserved); Sun Dec 27 14:49:08 EST 2015 Downloaded/printed by University of Washington (University of Washington) pursuant to License Agreement No further reproductions au MORCILLO ON THE MICAT PROJECT 273 It should be noted that the variance accounted for in the regression equations decreases sharply if the statistical treatment is applied to rural atmospheres only (Table 7), which is in agreement with results obtained in a previous paper [16] In the best case (zinc) the statistical treatment accounts for ca 40% of the variance A significant effect of S02 and C l pollutants have been observed in the corrosion values of different materials (Eqs 2-9 in Tables 3-6) The effect of chlorides seem to be associated with the relative humidity for copper and with the time of wetness for zinc The effect of sulfur dioxide seems to be associated with the time of wetness in the four materials, which was found in a previous paper [16] CONCLUSIONS In the paper an update of annual atmospheric corrosion data for low-carbon steel, zinc, copper, and aluminum obtained in a corrosion stations network on the IberoAmerica region are reported The network included a wide spectrum of climatological and pollution conditions General damage functions for low-carbon steel, zinc, copper, and aluminum in terms of simple environmental parameters were obtained The goodness of fit does not increase substantially as a result of including the effect of some binary interactions between the independent variables in the statistical treatment In the best cases, the regression equations account for up to 71% of the variance of mild steel, 52% of zinc, 50% of copper, and 45% of aluminum If the statistical analysis is rectricted to the rural atmospheres then the unexplained variance is even lower ACKNOWLEDGMENTS The authors wish to express their gratitude to the Programa Iberoamericano de Ciencia y Tecnologia para el Desarrollo (CYTED) for financial support granted for the realization of this work They are also indebted to Liboria Mariaca (Mexico) for her cooperation in the statistical data processing Members of the working group participating in the project: B Rosales (Argentina), L Uller and M Marrocos (Brazil), G Joseph (Chile), A Valencia (Colombia), J Fernando Alvarez (Costa Rica), A Cabezas (Cuba), J Pe~a (Ecuador), J Urruchurtu and J Genesca (Mexico), A de Bosquez and A Hassel~ (Panama), G Salas (Peru), E Almeida and M Ferreira (Portugal), M Morcillo (Spain), S Rivero (Uruguay) and M.R Prato (Venezuela) Copyright by ASTM Int'l (all rights reserved); Sun Dec 27 14:49:08 EST 2015 Downloaded/printed by University of Washington (University of Washington) pursuant to License Agreement No further reproductions authorize 274 ATMOSPHERIC CORROSION REFERENCES [!] Uller, L and Morcillo, M., Proceedinos 3rd Iberoamerican Congress on Corrosion and Proteccion, Vol i, ABRACO, Rio de Janeiro, 1989, p 462 [2] Uller, L and Morcillo, M., Proceedings llth International Corrosion Conaress Vol AIM, Milano, 1990, p 2.35 [3] Knotkova, D and Vrobel, L Proceedings llth International Corrosion Congress, Vol 5, AIM, Milano, 1990, p 5.581 [4] Kucera, V., Coote, A.T., Kenriksen, J., Knotkova, D., Leygraf, C, and Reinhardt U., Proceedings llth International Corrosion Congress, Vol 2, AIM, Milano, 1990, p 2.433 [5] ISO 8565, "Metals and alloys Atmospheric corrosion testing General requirements for field tests" International Standards Organization, Geneve [6] ASTM G50, "Conducting atmospheric corrosion tests on metals" American Society for Testing of Materials, Philadelphia, 1991 [!] ISO 9223, "Corrosion of metals and alloys Clasiffication of corrosivity of atmospheres", International Stantards Organization, Geneve, 1991 [8] ASTM G92, "Characterization of atmospheric test sites" American Society for Testing of Materials, Philadelphia, 1991 [9] ISO 9225, "Corrosion of metals and alloys Corrosivity of atmospheres Methods of measurement of pollution", International Standards Organization, Geneve, 1991 [10] ASTM G91, "Monitoring atmospheric $02 using the sulfatation plate technique" American Society for Testing of Materials, Philadelphia, 1991 [II] ISO 9226, "Corrosion of metals and alloys Corrosivity of atmospheres Method for determination of corrosion rate of standard specimens for the evaluation of corrosivity", International Standards Organization, Geneve, 1991 [12] ASTM GI, "Preparing, cleaning, and evaluating corrosion tests specimens" American Society for Testing of Materials, Philadelphia, 1991 Copyright by ASTM Int'l (all rights reserved); Sun Dec 27 14:49:08 EST 2015 Downloaded/printed by University of Washington (University of Washington) pursuant to License Agreement No further reproductions authorized MORCILLO ON THE MICAT PROJECT 275 [13] S Haagenrud, J.f Henriksen and F Gram, "Doseresponse functions and corrosion mapping for a small geographical area", Report, Norwegian Institute for Air Research, Lillestrom, Norway, 1986 [I 44] V Kucera, S Haagenrud, L Atteraas and J Gullman, "Corrosion of steel and zinc in Scandinavia with respect to the classification of the corrosivity of atmospheres", in Degradation of Metals in the Atmosphere ASTM STP 965, S.W Dean and T.S Lee, Eds., American Society for Testing and Materials, Philadelphia, 1986, pp 264-281 [15] M Benarie and F.L Lipfert "A general corrosion function in terms of atmospheric pollutant concentrations and rain pH" Atmospheric Environment, Vol 20, 1986, pp 1947-1958 [16] Feliu, S., Morcillo, M., and Feliu Jr., S., "The prediction of atmospheric corrosion from meteorological and pollution parameters - I Annual corrosion", Corrosion Science, Vol 34, No 3, 1993, pp 403-414 [17] BMDP Statistical Software Copyright by ASTM Int'l (all rights reserved); Sun Dec 27 14:49:08 EST 2015 Downloaded/printed by University of Washington (University of Washington) pursuant to License Agreement No further reproductions authorized STP1239-EB/Mar 1995 Author Index M A Morcillo, M., 137, 195, 257 Ajiboye, P., 26 O B O'Brien, D J., 167 Odnevall, I., 215 Boschek, P., 38 C R Coburn, S K., 101 Cooper, T L., 152 Reiser, D B., D S Dean, S W., 3, 56 Drigel, G S., 152 Sabata, A., 152 Scrivener, K L., 137 Simancas, J., 137, 195 F Feliu, S., 195 T G Gullman, J., 240 Tidblad, J., 11 Townsend, H E., 85 J V Johansson, E., 240 Valeriote, E M., 230 Vlckova, J., 114 K King, G A., 167 Knotkova, D., 38, 114 Komp, M E., 101 Kreislova, K., 38 Kucera, V., 11 W Wong, C W., 26 L Z Leygraf, C., 11, 215 Lore, S C., 101 Lyon, S B., 26 Zhang, X G., 230 277 Copyright by ASTM Int'l (all rights reserved); Sun Dec 27 14:49:08 EST 2015 Copyright* 1995byby ASTM lntcrnational www.astm.org Downloaded/printed University of Washington (University of Washington) pursuant to License Agreement No further reproductions authorized STP1239-EB/Mar 1995 Subject Index A Accelerated tests, 152, 240 Acid deposition, 11, 101 Aluminum, 38, 56, 195, 257 and zinc alloy, 167 ASTM standards A 242:101 A 588: 85, 101 G 101:85 Automotive trim material, 152 Electrochemical impedance spectroscopy, 152 Electrolytes, thin layer, 230 Electron imaging, backscattered, 137 Energy dispersive X-ray analysis, 137 F Flat specimens, 38 G B Galvanic action, 230 Backscattered electron imaging, 137 H Helix specimens, 38 Humidity, C Carbon steel, 101, 114 Chloride, 215 Chloride candle, 56 Chromium, 152 Classification system, 38, 56 Climate chamber, 240 Condensation, 3, 26, 56, 240 Copper, 11, 38, 195, 257 copper-bearing steel, 101 CORRAG program, 38, 56, 257 COR-TEN A, 101 COR-TEN B, 101 Cracking, micro, 167 Crevice corrosion, 114 Crystal structure, 215 CYTED, 257 Ibero-American Map of Atmospheric Corrosiveness, 257 International Organization for Standardization CORRAG, 38, 56, 257 J Joints, bolted lap, 114 M MICAT project, 257 Models and modeling atmospheric corrosion, 26 atmospheric heat transfer, Multiple linear regression analysis, 56 D Dew formation, Droplet evaporation, 26 Dry deposition, 215 E N Electrical contact materials, acid deposition effects, 11 Nickel, 11, 85 279 Copyright by ASTM Int'l (all rights reserved); Sun Dec 27 14:49:08 EST 2015 Downloaded/printed by University of Washington (University of Washington) pursuant to License Agreement No further reproductions authorized 280 ATMOSPHERIC CORROSION P Polyvinylchloride, 167 Polyvinylfluoride, 167 Porosity, 137 Protection area, 230 Protection distances, 230 R Radiational cooling, Rainwater washing, corrosion effects, 26 Reaction sequences, 215 Regression analysis, 195 Residual thickness, 114 Resistive control, 26 Rust morphology, 137 T Time of flight mass spectrometer, 152 Time of wetness, 3, 56 Tin, 11 TOFSIMS, 152 Transmission tower, 114 U Ultrasound measurement, 114 Ultraviolet degradation, 167 United Nations Economic Commission for Europe, 11 W Scanning electron microscope, 152, 215 Science and Technology for Development (CYTED), 257 Silicon, 85 Silver, 11 Statistical verification, 38 Steel, 38, 114, 137 A 588, 85, 101 carbon, 240 low carbon, 185, 257 stainless, 152, 167 zinc coated, 230 Sulfation plate, 56 Sulfur dioxide, 215 Sulfur pollutants, 11 Weathering steel, 85, 101, 114 Wetting, 26, 240 time of wetness, 3, 56 Wind velocity, X X-ray analysis, 137 X-ray diffraction, 240 X-ray photoelectron spectroscopy, 215 Z Zinc, 38, 195, 240, 257 alloy, 167 coated steel, 230 panels, 215 Copyright by ASTM Int'l (all rights reserved); Sun Dec 27 14:49:08 EST 2015 Downloaded/printed by University of Washington (University of Washington) pursuant to License Agreement No further reproductions authorized X Ln ! 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