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The corrosivity of the automotive environment has become more severe in recent years due to increased use of road salts and acid precipitation. Corrosion problems associated with exterior automotive trim include I 1) effect of the trim on the auto-body steel and, 2) corrosion of the trim material itself. In addition to the corrosivity of the automotive environment, factors which cause these problems for a given material include the inherent crevice geometry, attachment requirements and susceptibility to paint damage in this area. Corrosion performance of an exterior trim depends heavily on the material choice.

In order to confirm the behavior of various bumper materials, Texas Instruments conducted a performance field survey of existing bumpers in service. A large fleet of trucks equipped with stainless steel clad aluminum bumpers was identified in order to maximize the data obtained on this material system. The fleet owned and operated by E. W. Wiley Co., Fargo, North Dakota was chosen because of the large number of accessible bumpers in service, the severity of the location and the extensive service of trucks in that fleet. Bumper system included in the survey were stainless steel clad aluminum, chrome plated steel and chrome plated aluminum.

A number of factors are considered important when considering the choice of material for light vehicle bumpers. These include economics, styling, appearance, fabricability, and durability. Additional factors are introduced due to safety, fuel efficiency and environmental issues. As these issues become more stringent, the choice of material becomes more difficult because traditional materials are not able to provide all of the required properties. This paper describes clad materials systems which provide the required properties while introducing weight reduction in bumpers. Specific combinations of stainless steel and aluminum in a clad configuration have been used on automobiles and trucks for many years in a wide range of applications. These clad metal systems have all of the desirable properties of the individual components and provide a light weight alternative to the limitations of traditional materials.