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In cold and heavy snowfall regions such as Europe and North America, substantial quantities of rock salt are spread on roads for the prevention of icy road surfaces and car slipping so that winter transportation can be assured. Such salt however promotes corrosion not only of automotive bodies but also of automotive parts. Automotive piping is no exception, leading to the need for new surface treatment. With a view toward finding a promising substitute for Zn plating which has been used for many years, various high corrosion resistance surface treatments have been compared. This paper reports the results of the comparison.

Cadmium has been identified by the United States Army's Tank and Automotive Command as a threat to worker health and the environment. Based on already completed cadmium substitute testing, an evaluation program was conducted to quantify the performance of environmentally acceptable, multi-layer coatings that could be directly substituted for cadmium on threaded fasteners. The performance issues investigated included coating system lubricity and corrosion control performance. Data were generated from both natural marine atmosphere exposure tests and laboratory evaluations. Test specimens were prepared by applying sacrificial plating layers and lubricous topcoat materials to commercially available 1/2-20 UNC Fine, Grade 5 fasteners. Experimental analyses included realistic torque-tension curve development, marine atmosphere exposure testing, and ASTM B 117 salt fog evaluations.

In this study Al-Si-Mg alloy sheets containing various amounts of Si and Mg were subjected to an anodic electrolysis test, and the relationship between intergranular corrosion susceptibility and addition of Si and Mg in aluminum alloy was investigated. Generation of intergranular corrosion was determined by both composition of alloy and temperature of heat treatment and was considered to accelerate when Mg2Si particles percipitated on grain boundary.

For the last few decades PVC-plastisols have been one of the most common process materials in the automotive production used as adhesives, sealants or for various coating processes. A high standard of performance has been reached. But recently raised concerns about chlorine containing substances created in fire and combustion arose search of alternatives to PVC-products. Intensive work led to various possibilities to substitute today's PVC-plastisols by using polymers free of halogens. As a main target, concentration was given to similar technical performance as well as to same easy application as with PVC-plastisols. Although investigations referring to polyurethanes gave excellent technical results the price/performance ratio was rather unacceptable. For some applications plastisols based on pure acrylic ester (co)polymers are very valid substitutes especially for body-in-white purposes. But for paint shop applications the cost for the basic raw material was seen to be too high.

Increasing service-life requirements for automobile and truck exhaust system components and the problem of potentially severe corrosivity of cold-end exhaust system condensate have greatly increased interest in the use of advanced construction materials for cold-end components. Studies on dynamometer test systems have shown that condensate can exhibit relatively high soluble salt content and variable pH ranging from mildly alkaline to appreciably acidic depending mainly upon driving conditions, catalytic converter mode of operation, air/fuel ratio and fuel chemistry. In these circumstances, there is considerable interest in determining the advantages afforded by aluminized stainless steel and various grades of stainless steel as construction materials. The primary goal of the present study was to achieve realistic relative materials behavior in laboratory testing by simulating realistic chemical/physical muffler environmental conditions.

Alcohol-blended fuel is receiving increasing attention for its ability to provide cleaner automotive exhaust gas. Alcohol-blended fuel is however more corrosive than conventional gasoline and tends to corrode the materials of a fuel system. Use of nylon tubes or stainless steel tubes is now studied but is still accompanied by the unsolved problems of gas penetration and higher cost. As a technique pertaining to alcohol-blended fuel, single-wall tubes having excellent corrosion resistance have been developed by forming a Ni-base double plating layer on the inner walls of fuel pipes. Their corrosion resistance was evaluated using alcohol-blended fuel and the like.

The electrochemical and corrosion behavior of metals in aqueous environments has received substantial attention. However, relatively little work has been devoted to the electrochemistry and corrosion of metals in non-aqueous environments. Now, with greater pressures to increase fuel efficiencies and decrease exhaust emissions, alternatives and additives to gasoline (including methanol and ethanol) are receiving increased attention from government agencies and automobile manufacturers. Unfortunately, fundamental studies of the corrosion behavior of metals in these solutions are scarce. The objective of the present work is to investigate the electrochemical and corrosion behavior of iron in methanolic solutions containing Cl, H+, SO42-, and H2O. To accomplish this, a full factorial design test matrix was developed to systematically evaluate the effects of these impurities on the corrosion behavior of iron.

Government clean air regulations have prompted much interest in the automotive industry in alternative fuels for lower emission vehicles. Methanol fuels have become the primary focus of the auto companies in meeting these challenges. Even though the corrosiveness of methanol and commercial methanol fuel blends is well recognized, no systematic investigations on the relative corrosion behavior of metals and their coatings in these solutions are available. The purpose of the present study is to determine the relative corrosion rates for metals, plated metals, and otherwise coated metals that were exposed to ionic and water contaminated methanol/gasoline fuel mixtures. The results are described for samples that were immersed in M15 and M85 test fuels for between 2000 to 8000 hours under static laboratory conditions at 40°C. The primary measure of corrosion was mass loss, which was used to generate corrosion rates, where possible, for each of the specimens.

Corrosion resistance of Zn-SiO2 composite coated steel has been investigated both in the wet/dry cyclic corrosion test and in the accelerated atmospheric corrosion test (modified Volvo test). In this investigation, perforation corrosion test were carried out using cathodic electrocoated lapped-panel models. Zn-SiO2 composite coated steel has shown good perforation resistance as well as good cosmetic corrosion resistance. Polarization measurements for the Zn-SiO2 composite coating have indicated the inhibition of both anodic and cathodic reaction. The inhibition of these reactions becomes more marked as corrosion of the coating progresses. From the microstructural analysis of the coating after the corrosion tests, excellent corrosion resistance of Zn-SiO2 composite coated steel is attributed to the chemically stable corrosion product consisting of zinc hydroxide and SiO2 particles.

The paper reports on the introduction of a tricationic prephosphating process for electrolytically galvanized steel strip (EZ sheet). The properties achieved by way of prephosphating are described. The aspects of corrosion protection, paint adhesion and formability are discussed, as well as questions concerning development and application, the practical worth of prephosphating from the point of view of the auto industry.

In recent years, automotive component manufacturer's use of autodeposited coatings has dramatically increased due to the performance, cost-effectiveness, versatility and environmental advantages that this technology offers. Although historically used to coat only steel substrates, the increased use of zinc and zinc alloy coatings presents further market opportunity for autodeposition of coatings. Due to differences in chemical reactivity between steel and zinc, obtaining high quality coatings by acidic chemical deposition (autodeposition) has required some process development innovations. In this paper, the procedure of coating deposition on galvanized surfaces is described and compared to the deposition on steel. Corrosion performance of autodeposited coatings on galvanized steel is evaluated by a cyclic corrosion test and compared to the performance of another widely used coating for galvanized substrates.

Transition materials consisting of steel clad aluminum have been used to join aluminum and steel. This technique allows joining by resistance spot welding since the clad transition material allows the actual transition from one metal to the other to occur at the clad bond interface. Welding studies show that in the recommended range of weld parameters, high strength joints are produced. A wide range of corrosion tests have been used to determine the durability of these joints in automotive environments. Results show that the use of transition material in joining aluminum to steel or EG steel eliminates galvanic corrosion.

Vehicle corrosion costs the public billions of dollars each year. The severity of vehicle corrosion is strongly affected by the amount of salt to which the vehicles are exposed. The main sources of the salt causing vehicle corrosion are the atmosphere and road salting. Some geographical areas experience minimal corrosion problems, but in other areas the corrosion problems are more severe. Knowledge of the severity of corrosion in a given geographical area is important when decisions are made about corrosion prevention and when corrosion related recalls/modifications are initiated. The object of this paper is to review the existing literature on corrosiveness in various geographical areas and propose a rational corrosion severity map.

In the sample test accounted for in this article, 650 cars of 18 different makes were inspected with respect to resistance against perforation corrosion. The method applied - that of sawing out body parts from collision-damaged cars and inspecting internal open surfaces and crevice surfaces - allows corrosion attack to be discovered at an early stage. The results show great differences in corrosion resistance between different makes of car. For some makes, severe crevice corrosion was found on three-year-old vehicles, whereas other makes included six-year-old vehicles without any severe attacks. The results also show that the makes with the best corrosion resistance had a favorable construction, combined with the use of precoated material with a certain thickness of the zinc or zinc-alloy layer and the use of anti-rust agents with good penetration properties.

The advancement of numerical methods for acoustics has enhanced the ability to make meaningful predictions of acoustic responses in vehicle passenger compartments, such as those found in automobiles, trucks, and construction equipment. A design objective of growing importance is to isolate the occupants from both structural and air-borne noise. This paper presents how an indirect boundary element formulation can be used to study the effect of holes on the transmission of air-borne sound, and how design changes effect the transmission of sound through heater and air conditioning ducts. The theoretical background of the indirect formulation is also presented. The significance of this method is that it can include openings in the model while considering the acoustic medium on both sides of the mesh. It is also computationally superior to the direct method because the assembled matrices are symmetric.

This paper summarizes the techniques and guidelines which were used to reduce the driver perceived noise level of a 145-210 HP series of agricultural tractors. Graphs of case study test results and comments on subjective noise quality are provided to guide the acoustic novice through the complexities of the vehicle sound environment in a methodical problem solving format.

This paper outlines a transient wave mechanism from an impact machinery such as punch press via computational and experimental methods. Results from the boundary element method to predict the transient acoustic field are compared with experiment by use of the fiber-optic surface acoustic intensity probe. The computational method combines an explicit and implicit methods to enhance the numerical stability and accuracy. The fiber-optic surface acoustic intensity probe which combines optical fibers and microphone will be discussed to illustrate the validity of the experimental method and hence numerical results. The improvement of the acoustic intensity probe performance will also be discussed to eliminate the phase error at higher frequency measurement and to increase the sensitivity and linearity. The comparison of the results will be described to demonstrate the capability and accuracy of the methods to identify the transient noise source generated from the impact noise.

One of the challenges in lubricant development is to adequately model performance across a broad range of potential lubrication and wear regimes that are encountered in use. Since wear in a given application is dependent on both rolling and sliding speeds, it is desirable to determine lubricant performance as a function of these variables. The use of a new test machine and methodology permits the construction of performance maps which define the transitions between lubrication regimes - hydrodynamic/elastohydrodynamic (EHD), EHD/mixed film and mixed film/boundary. This paper describes a method of mapping out the performance of a lubricant over a range of rolling and sliding velocities. Lubrication and wear performance is characterized for an ester base reference fluid (Herco-A) and two commercially available gear oils based on a petroleum oil and a poly(alpha olefin).

Although considerable research has been performed to quantitatively compare the relative fire-resistance afforded by different hydraulic fluids in various industrial applications, new standards reflecting these developments is still incomplete. The objective of this paper is to provide an overview of the classical tests that have, and are currently, used to quantify relative fire safety of fluids. This will be complemented by a discussion of recent test developments that could be incorporated into future standards.

The selection of a proper fluid to be used in a hydraulic system is an important part of any design effort. The hydraulic fluid must normally transmit, transform, and control the power from the system input to the output. In addition, the fluid is expected to provide lubrication and antiwear protection to many of the other components in the system. Although there are at least 22 parameters which describe a hydraulic fluid, most of these parameters are well defined. However, the antiwear and lubrication properties of a hydraulic fluid deserve more discussion. There are several test methods which have been developed to assess the antiwear properties of liquids. Most of these procedures are intended to evaluate fluids other than those directed toward use in a hydraulic system. This paper will present a bench type wear test method designed to overcome the recognized problems of other wear test procedures.