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A Statistically Designed Study of Atmospheric Corrosion Simulating Automotive Field Conditions Under Laboratory Conditions - Final Volvo Report on the AISI Cosmetic Corrosion Set of Materials
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Abstract
An extensive atmospheric corrosion test program to simulate automotive field conditions has been successfully completed. This paper focuses on the corrosion results from the widely exposed AISI set of correlation panels for cosmetic corrosion. Eight factorially designed 12-week tests have been performed in the laboratory, using high performance test equipment, capable of simulating diverse outdoor conditions. The results have been compared with those of outdoor scab exposures and reference panels on vehicles, running in Canada and Sweden.
The influences of six corrosive test variables on the response creep-back from scribe on the painted panels are demonstrated, based on a statistic evaluation of the test matrix. All higher settings of the introduced accelerating test variables have each resulted in a decrease in the test correlation with on-vehicle exposures. A high degree of correlation regarding on-vehicle exposure was reached when the test conditions were comparatively mild (acceleration factor < 10). However, to achieve a high degree of correlation to the Volvo outdoor scab test, the test conditions corresponded to the high settings of the variables. The results of the test program clearly suggest that the predictability of a test is generally improved when simulating outdoor conditions under mild acceleration combined with linear extrapolation instead of forcing the corrosion process in order to establish the postulated damage within a comparatively short time. From the results of the statistical design in the high performance equipment, simplified test methods, suitable as standards for the small scale laboratory, have been worked out. The results of the AISI set from two such tests are presented. One provides excellent correlation to on-vehicle behaviour.
The scribe creep propagation for zinc and zinc-iron coated materials are convincingly shown to be inversely related to the zinc-coating thickness, both in the eight Volvo tests and in field conditions on vehicle. Hence, the paint undercutting is directly determined by the progress of the dissolution front of the zinc coating and the anodic consumption rate of zinc is constant. A plausible explanation for this effect is that the overall corrosion rate is limited by constant-rate oxygen reduction, either in the scribe (at limited undercutting) or by a stabilised cathodic zone tailing the anodic dissolution front (at extensive creep-back from scribe).
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Citation
Ström, M. and Ström, G., "A Statistically Designed Study of Atmospheric Corrosion Simulating Automotive Field Conditions Under Laboratory Conditions - Final Volvo Report on the AISI Cosmetic Corrosion Set of Materials," SAE Technical Paper 932338, 1993, https://doi.org/10.4271/932338.Also In
References
- Townsend H.E. McCune D.C. Neville R.J. Granata R.D. Schumacher W.A. SAE Tech Paper Series No. 912275 1991
- Davidson D.D. Schumacher W.A. SAE Tech paper series No. 912284 1991
- Ström M. Ström G. van Ooij W. J. Sabata A. Edwards R.A Ramamurthy A. C. SAE Tech Paper series No. 912282 1991
- Unconfirmed minutes and Committee correspondence, SAE Automotive Corrosion and Preventive Committee - Division 3 and Task Force group on Corrosion in the Automotive Application Committee of the American Iron and Steel Institute.
- Ström M. Ström G van Ooij W.J. Sabata A Knueppel B.A. Ramamurthy A.C. Proc. of the 2nd Int. Conf on Zinc and Zinc alloy coated steel sheet GALVATECH '91 Amsterdam 1992 521 527
- Svensson J. E. Johansson L-G Corros. Sci. 34 5 1993 721 740
- van Ooij W. J. Sabata A. Ström G. Corrosion Resistant Automotive Sheet Steels Allegra L. World Materials Congress Chicago 1988 75
- Smith D. M. Whelan G.W. SAE Tech papers series No. 870646 1987
- Stratmann M. Ber. Bunsenges. Phys. Chem. 94 1990 626
- Johansson E. Swedish Corrosion Institute
- Shastry C.R. Townsend H.E. Corrosion 45 2 1989 103
- van Ooij W.J. Andersson H.J Ström G. Polymeric Mat. Sci. Eng. 58 1988 22
- Massignon D. Dauchelle D. Proc. of the 1st Int. Conf on Zinc and Zinc alloy coated steel sheet GALVATECH ′89 1989 Tokyo
- Amirudin A Jernberg P. Thierry D. 12th Int. Corrosion Congress Houston, Texas 1993