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Quality assurance (QA) in motor vehicle emissions inspection/maintenance (I/M) programs is a continuing concern, especially in decentralized programs with hundreds or even thousands of licensed stations. The emissions analyzers used in such stations are an important focus of governmental QA efforts because of the central role of analyzers in determining which vehicles need to be repaired. Therefore, the In-use performance of I/M emission analyzers has a large impact on the quality of 1/M programs as a whole. This paper reports on the results of an investigation in California designed to determine in-use performance of emission analyzers in the field. The investigation was designed to evaluate both drift rates and the ability of analyzer systems with automatic gas calibration capability to correct analyzer responses outside of accepted tolerances.

This paper, confined to the application of hard chrome plated liners to high-speed four-stroke diesel and gasoline engines, illustrates the increase in their popularity in the United Kingdom, and the advanced production methods which make this economically possible. The need for balanced engine life has long been apparent and is even more important today, the growth of motor transport having outstripped repair facilities. Iron bore life has been surpassed by improvement in the life of other component parts in the modern diesel engine. The provision of hard chrome plated liners can restore the balance. Further development and turbocharging of diesel engines has shown the need for a bore material capable of preventing scuffing and galling at elevated temperatures. Hard chrome has already proved itself in four-stroke engines under these conditions.

In today’s Automotive world, there is NO need to advocate “Light weighting”. Government policies for carbon footprint reduction combined with high safety standards are driving OEMs to adopt advanced manufacturing technologies. Steel hot forming is selected as most preferred way to reduce weight as it is easy to adopt and commercially known. It had many advantages compare to conventional cold stamping of standard and high tensile steel. The process consists of heating blank to nearly 1000 °C and quenching it in tool to for martensitic structure. Higher strength up to 2000 MPa can be achieved by this process. There are many examples where part weight is reduced by 15 to 20 % by this method. But Steel hot forming has limitation as specific density of steel is still high. Thus, there is limitation to its weight reduction capability. For further reduction, OEMs have started exploring Aluminium hot forming.

This specification covers the characteristics of glass beads used for peening, and provides for standard glass bead size numbers.

This specification covers the characteristics of glass beads used for peening, and provides for standard glass bead size numbers.

THE PURPOSE of this experiment was to determine the role of residual stresses in fatigue strength independent of other factors usually involved when residual stresses are introduced. It consisted of an investigation of the influence of residual stresses introduced by shotpeening on the fatigue strength of steel (Rockwell C hardness 48) in unidirectional bending. Residual stresses were varied by peening under various conditions of applied strain. This process introduced substantially the same amount and kind of surface cold working with residual stresses varying over a wide range of values. It was found that shotpeening of steel of this hardness is beneficial primarily because of the nature of the macro-residual-stresses introduced by the process. There is no gain attributable to “strain-hardening” for this material. An effort was made to explain the results on the basis of three failure criteria: distortion energy, maximum shear stress, and maximum stress.*

For over a decade, industry prognosticators have been predicting that the use of plastics by automakers would soon surpass the deployment of metals in automobiles, While there is no denying that plastics have made inroads, it recently has become apparent that metal will retain its position as the prime car material for the foreseeable future. One reason for the revised forecast is the development of improved zinc coatings for the automotive industry. Such material as electrogalvanized and Galfan™ are shaping up as steel's saviors when it comes to ensuring that metal will continue to play the major role on car assembly lines. Meanwhile on the other side of the equation, developments in zinc die casting technology have taken the edge off plastics' forward thrust into both functional and decorative car part applications.

Copper and brass radiators have served the automobile industry for many years using traditional fabrication processes. Demand for newer and stronger radiators with lighter weight for the modern vehicles prompted investigation of alternate materials. Properties of zinc alloys and their compatibility with brass suggested these could be used for radiator manufacture. Many zinc alloy compositions were investigated in the initial studies, because a solder alloy has to have many positive attributes. The first screening studies evaluated the ability of the solder to spread over copper and brass surfaces, representing tube, fin, and header materials. The second most important feature was the melting range of the developed alloy. In order to retain the anneal resistance of the fin and temper in the tube it was desirable to have a zinc solder with a melting temperature at 800°F or less.

The extrusion of zinc alloys, with special reference to zinc-titanium alloys, is described. Parameters for this process are defined. The excellent tensile and creep properties obtained in a typical extruded zinc-titanium alloy are presented. Extruded zinc with a quality copper-nickel-chrome plated finish offers a new approach to the production of automotive trim and of similar products.

Many papers have been written for SAE on electrochemical metallizing, a modern term for “selective” or “brush” plating. These papers have dealt primarily with the aerospace industry, including the use of non-embrittling cadmium LHE® coatings for corrosion protection on aircraft. Shadowed by 30 years of successes in the aerospace industry, electrochemical metallizing corrosion protection in the automotive industry is often overlooked. Specifically, the use of selectively applied zinc coatings for corrosion protection on wheel hubs during manufacture has proven integral at several European automotive manufacturers. In the past, environmental conditions have corroded both the hubs and wheels of automobiles. Quite often the corrosion is in the microscopic gap between the hub and the wheel, which over time causes the wheel to seize and prevents removal. This has been frustrating to both stranded motorists and shop mechanics.

AS PART of its continuing research to improve the die casting process, International Lead Zinc Research Organization, Inc. has prepared a computer program, “Computer-Aided Design for Zinc Die Casting Dies,” which will enable a die caster to design the metal flow system for a die within a matter of minutes—simply and more accurately than ever possible, previously. It is helping convert what has been an art into a science.

The role of zinc die castings in the materials marketplace has changed significantly in the last generation. In response to a shift in the available market, the industry has made major advances intended to improve competitiveness in both traditional and non-traditional areas. Better efficiency and performance have been achieved by the application of new methods and technologies. The ZA alloys, introduced to die casting during the last decade, have markedly expanded the capabilities of both zinc and the die casting process. This paper presents a review of several zinc die castings used in automatic applications.

Zinc die casting products and metal casting processes continue to evolve for the benefit of end users. Through cooperative global research programs continuous improvements are still being made to the broad range of excellent mechanical properties, easy castability and the wide choice of finishes available for zinc die castings. Recent advances will be highlighted with case histories specific to automotive applications.

Because of the drastic chilling involved in die casting and the fact that the solid solubilities of both aluminum and copper in zinc change with temperature, these alloys are subject to some aging changes, one of which is a dimensional change. Both of the alloys undergo a slight shrinkage after casting, which at room temperature is about two-thirds complete in five weeks. It is possible to accelerate this shrinkage by a stabilizing anneal, after which no further changes occur. The recommended stabilizing anneal is 3 to 6 h at 100 °C (212 °F), or 5 to 10 h at 85 °C (185 °F), or 10 to 20 h at 70 °C (158 °F). The time in each case is measured from the time at which the castings reach the annealing temperature. The parts may be air cooled after annealing. Such a treatment will cause a shrinkage (0.0004 in per in) of about two-thirds of the total, and the remaining shrinkage will occur at room temperature during the subsequent few weeks.

Traditional and new zinc-based casting alloys for functional and decorative applications are reviewed. Their compositions and standard alloy specifications are described, and recommendations for casting process selection and prototyping of applications are offered. The information presented shows the versatility achievable with zinc alloys. It is aimed at helping part designers make the most effective use of zinc for their component requirements.

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).

SIMILAR SPECIFICATIONS—UNS Z33521, former SAE 903, ingot is similar to ASTM B 240-79, Alloy AG40A; and UNS Z33520, former SAE 903, die casting is similar to ASTM B 86-76, Alloy AG40A. UNS Z35530, former SAE 925, ingot is similar to ASTM B 240-79, Alloy AC41A; and UNS Z35531, former SAE 925, die casting is similar to ASTM B 86-82a, Alloy AC41A.

The ZA series of zinc alloys produce high strength die castings with the same cast-to size capability as the well proven SAE 903 alloy. The enhanced properties have been utilised in the two engine components described in this paper. ZA 27 has been used for the tooth belt drive camshaft pulley of a motorcycle engine and ZA8 has been used for the temperature resistant housing of a car ignition distributor.