Auto-body steel

In the winter of 1984-1985, test samples on Plexiglass plates were exposed in each of the test cities. These included samples of bare weighed auto-body steel, weighed galvanized steel, and painted auto-body steel with stainless steel trim. Where painted panels were involved, cut edges were coated in the stainless steel trimmed panels, the ends of the stainless steel bolts used for electrical continuity were coated as well. Nylon bolts were used to attach the other test specimens to the Plexiglass plate which was mounted on the front bumper of an automobile. 

Galvanic couples of stainless steel trim with painted auto-body steel produced very dramatic differences in cosmetic corrosion between cities, as seen in Figure 10. Numerical corrosion ratings are listed in Table IV. The decreasing order of aggressiveness is ... 

Figure 7. Typical appearance of bare auto-body steel following one season exposure in Detroit.

Figure 10. Visual comparison of stainless steel/painted auto-body steel galvanic couples, one season exposure. Right to left Boston, Dallas, Detroit, Montreal.

Table IV. Rating of SS Trim/Painted Auto Body Steel...

Table V. Corrosion Data for Auto-Body Steel in Poultice Test...

The section on metallic corrosion clearly indicates that the conventional method of classification of environments into marine, industrial, and rural no longer is adequate. More specific information is needed about the actual chemical components in the atmosphere as well as humidity and other factors. Specific environments also are addressed in the metallic corrosion section. For example, the automotive environment in the northeastern United States is particularly severe because of the combination of acid deposition and the use of road de-icing salts. These factors exert a synergistic effect on the corrosion behavior of auto-body steel and on exterior anodized aluminum automobile trim. 

Baboian, R. (1989). Corrosion behavior of painted galvanized auto-body steel in contact with exterior automotive trim. Galvatech 89, Iron and Steel Institute, Japan, pp. 297-305. 

FIG. 3—Cosmetic corrosion (outside-ln) with red rust at painted auto-body steel. 

No. 1 Busheling. This scrap is a clean prompt iadustrial scrap limited to about 30 cm (12 ia.) ia any dimension. It iacludes new factory busheling such as sheet clippings and stampiags (free of old auto body and fender stock) metals which have been coated, limed, or vitreous enameled and electrical steel containing more than 0.5% siUcon. 

Zinc yellow became an important corrosion-inhibiting pigment for aircraft during World War II. However, the war production rate of 11,000 t/yr has not since been reached. Now, 2inc yellow is widely used for corrosion inhibition on auto bodies, light metals, and steel, and in combination with red lead and ferric oxide for stmctural steel painting. 

Figure 6.8 Clavanic corrosion of painted steel auto body panel in contact with stainless steel wheel opening molding (Baboian)5...

Carbon steel Iron, carbon Auto bodies, machinery... 

Auto body corrosion adjacent to stainless steel trim occurs in environments where de-icing salts are used. The effects of acid deposition combined with road salts produces a synergystic effect on the degradation of automobiles. (Photo by Robert... 

Vertical and horizontal exterior auto body panels have always represented a tremendous opportunity for plastics. In fact, plastics have been very successful in penetrating fender applications in Europe and North America. Although steel remains the dominant material for fenders, the benefits of plastics such as weight reduction, dent resistance, and styling flexibility override cost disadvantages. 

The adhesives in Table 5 have many industrial applications. For example, EC-3535 B/A has been used to bond aluminum extrusions into auto roofs while EC-3532 B/A has been used to bond vinyl clad wire to printed circuit board. Urethane adhesives have also been us ed to bond polyester molded resin to the steel frame in Corvette auto bodies. 

Fig. 1.5 Trends of coated steel sheets for auto body production in Japan (Nomi and Fukui, 1991).

Automobile Industry. Throughout most of the twentieth century a major consumer of steel has been the automotive industry, particularly in the United States. Steel has been, and continues to be, the chief constituent of car bodies, and hot-rolled sheet steel has become a staple of the auto industry. Steel use in this industry grew after World War II, but a decline developed during the latter decades of the century. Because of the oil and environmental crises, cars were, on the whole, downsized, and steel began to be replaced by plastics and aluminum to reduce weight and increase eneigy efficiency. The steel industry... 

Advancements in materitJs have been one of the most important factors in the development of corrosion-resistant automobiles. For automobile body and chassis parts, use of precoated sheet steel in critical areas, as demonstrated in Fig. 5, is one of the most effective methods of combating corrosion. Early on, hot dip gttlvanized steel and Zincro-metal coated steel were used to prevent perforation corrosion from the inside out in auto-body applications. Today a wide range of materi tls is used including hot dip and electrodeposited zinc, zinc-iron, zinc-nickel, and zinc-nickel/ organic composite coated steel. Other materials include aluminum and aluminum-zinc coated steels for exhaust systems and some structural components, teme (tin-lead) coated steel for fiiel tanks, and tin coated steel [23-25],... 

New alloys have been introduced for specific automobile applications including type 434 stainless steel for exterior trim, type 409 and 430 stainless steels for exhaust systems, and 6XXX and 7XXX aluminum aUoys for auto body and structural parts. Use of aluminum for body panels such as hoods and deck lids has prompted the development of new processing techniques for this material. 

Liquid to solid, and vice versa. As the temperature drops further, the particles move slower and become fixed in position in the process of freezing the opposite change is called melting, or fusion. In common speech, freezing implies low temperature because we think of water. But, molten metals, for example, freeze (solidify) at much higher temperatures and have medical, industrial, and artistic applications, such as gold dental crowns, steel auto bodies, and bronze statues. 

Once you ve repaired a ding, scratch, or dent, it s time to paint over the repair. The layers of auto body paint go from steel panel, to primer, to color, to clear coat. If you re looking to repaint a scratch, first check the depth of the scratch. What color is it If you see the car s color, follow the sanding instructions on page 371 and then just apply a layer of clear coat. If you see primer that is different from the car s color, apply color and clear coat. If you see bare steel (or very discolored plastic), you ll have to apply all three. Unless you have an unusual car, your auto shop should have the matching paint. 

Exacor An ES for Evaluating Corrosion Risks and Selecting Precoated Steel Sheets for Auto Bodies... 

---