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Most creep studies are conducted to determine steady state creep rate and time to failure. However, the priority for the designer is to predict the amount of total creep, being the sum of primary and secondary creep elongations, for a given service life under given loads and temperatures, for example 0.5% elongation after 3000h. An assessment of total creep behavior of industrially important zinc alloys has been conducted, and correlation/prediction curves produced. Another important property, related to creep, is stability after ageing, both for unloaded and also loaded castings. Recently developed relationships between natural and artificial ageing, and the correlation of mechanical property changes for different periods of artificial ageing with natural ageing will be presented.

Craters in galvannealed coatings on steel sheet are depressions caused by non-uniform diffusive growth. Correlations have been sought between “crater” densities in galvannealed sheet steel and friction, powdering, and paint adherence, as relevant to the appearance, corrosion resistance and processing of auto body panels. Crater densities were established on a series of samplings from major producers, and related to frictional measurements from a binder-radius simulator, powdering levels from bend testing, and paint adherence assessments from a stone-chipping test. Results suggest that increased crater density decreases powdering, but does not aid in lubrication. In fact, decreased powdering could be correlated with increased friction levels. A strong correlation was found between increased crater density and increased paint adherence.

Alloy 3, Alloy 5, ACuZinc 5, and ZA-8 were tested at five temperatures between −40 C and room temperature to determine impact properties. Izod impact energy data was obtained in accordance with ASTM D256. Unlike ASTM E23, these samples were tested with a milled notch in order to compare with plastic samples. In addition, flexural data was obtained for design use. Fatigue stress-life (S-N) curves and fatigue limits of die cast zinc Alloy 2, Alloy 3, Alloy 5, ACuZinc 5, and ZA-8 were determined using the rotating bend test. Fatigue limits for Alloy 3, Alloy 5, and ACuZinc 5 appeared to be higher and the fatigue limit for ZA-8 appeared to be lower than the values reported in the literature. The improvement in properties for Alloy 3, Alloy 5 and ACuZinc 5 is related to the presence of the die cast skin.

Zinc alloys, either cast or wrought, are used in many structural and decorative applications in automotive products. This paper describes the metallurgy of the most important of these alloys, paying particular attention to the role of major alloying elements on development of useful properties. Prospects for future developments are also described.

High damping capacity materials are useful in attenuating vibrations in mechanical structures such as functional automotive bracketry. The intrinsic damping properties of zinc alloys have only recently been systematically measured. Low and high frequency damping experiments have been conducted on die cast zinc alloys. and damping capacity has been measured as a function of temperature at high frequencies. The alloys show excellent damping properties over the range from 5 Hertz to a few hundred Hertz. for service applications from 40-80°C (104-176°F).

Galfan is a new generation zinc-5% aluminum-mischmetal alloy coating for steel offering opportunities for greater fabrication flexibility and upgraded corrosion performance in automotive applications. The formability of Galfan is equivalent to that of electrogalvanized steel, based on laboratory tests and automotive component fabrication. Corrosion resistance of Galfan exceeds that of hot dip and electrogalvanized, including performance in automotive industry tests. Automotive production applications for deep drawn and stamped components in France and Germany are based on the ability to meet dual performance requirements for upgraded formability and corrosion resistance. First U.S. Galfan applications are on 1985 model Ford cars and light trucks for transmission oil cooler line and power steering line tubing.