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Technical Paper

Surface Treatments and Characterization of Electroplated and Hot Dip Galvanized Steel Sheets

1996-04-01
91A126
Protection of surfaces is a critical factor in determining the extended service life of a structure in polluted and aggressive environments. In particular, a rapid growth of the technology for the protecting coating of cold rolled steel is experienced, for the use in transport, electric housewares, building and industrial plants. Numerous changes have taken place in the production of zinc coatings on steel in order to improve the corrosion resistance using zinc alloy platings. Our research group collected from the international production a number of selected galvanized steel samples, including electrodeposited zinc alloys, multilayer coatings, hot dip galvanized steels. On the selected materials we established and analyzed morphology, composition, crystal structure, impurity content and distribution, using many surface microanalysis techniques.
Technical Paper

Recycling Automobiles: a Problem of Environment and Resources

1996-04-01
91A130
The socio-economic system is coming to the conclusion that the environment will no longer tolerate and absorb all of man's interventions, and that natural resources no longer constitute a cheap and inexhaustible source of wealth. In this scenario of the limits of nature and ever-increasing environmental costs, we are faced with the problem of recovering and reusing the materials which go into the manufacture of an automobile. The replacement of metal materials with polymer materials leads to a reduction in the re-usable waste, and to an increase in the amount of waste with no economic value, or even with a negative economic value. The use of the non-ferrous and non-aluminous materials in an automobile is beyond the capabilities of new techniques for scrapping automobiles, which means that at the end of their lives, the automobiles must be disassembled, sorted on the basis of the constitute materials, recovered and recycled.
Technical Paper

Application of Shape Memory Heat Engines to Improving Vehicle Fuel Economy

1996-04-01
91A128
Shape memory materials undergo temperature-induced martensitic phase transformations that involve reversible dimensional changes. In performing these changes in shape, the shape-memory material is able to do work against external constraints, and this is the basis for shape-memory low-temperature heat engines. The transformation temperatures on heating and cooling are often not very different (little hysteresis) and are well defined and reproducible. Furthermore, these temperatures can be adjusted by varying the composition of the shape memory alloy. Internal combustion engines dissipate approximately two-thirds of the fuel energy as heat to the exhaust and coolant systems. A low-temperature heat engine could convert a fraction of this heat energy to useful work. This paper discusses the conceptual basis for the application of shape memory heat engines to internal combustion engine powered vehicles. Metallurgical and thermodynamic factors are discussed, as well as engine efficiency.
Technical Paper

State of the Art in the Use of Stainless Steel for Bus and Car Parts Manufacture

1996-04-01
91A127
The paper describes recent developments in the use of stainless steel to make the parts of buses which are most liable to corrosion. Sheet metal is used for the outer panelling, and square and rectangular tubes for the body. The types of steel used and their fabrication are analyzed. Finally, a brief description is given of the stainless steels used to make car exhaust systems.
Technical Paper

Simulors, An Innovative Tool for Molds Development

1996-04-01
91A117
Mold designers and foundrymen spend a lot of time in developing molds without knowing exactly the phenomena which take place inside. Simulor, which has been used in an industrial environment for two years, offers the solution to make foundrymen understand what happens during the filling of the mold and the solidification of the part. Based on navier-stokes and heat transfer equations, simulor provides speed distribution and metal front evolution in the cavity and thermal map in the mold and the part. Some examples with different metals (cast iron, aluminum alloy) cast with various processes (sand or die casting, low pressure or gravity casting) will be given. This new tool will given foundrymen the opportunity to test the mold before having it machined and will also allow reduction in development delays.
Technical Paper

Integration and Validation of Sheet Metal Forming Simulation Computer Programs Into the Design Process

1996-04-01
91A121
In order to improve the design of drawn parts and to reduce the number of trial and error tests, Renault has undertaken the development and the validation of various finite element procedures and codes. This paper describes the function of each software and its level of integration into the design process. One of them is already an operational tool used be planners whilst the others are still in the validation phase. Selected examples show typical applications of the computer programs on automotive parts.
Technical Paper

Particulate Reinforced Aluminum Matrix Composites Obtained By Indirect Squeeze-Casting

1996-04-01
91A115
Indirect squeeze casting technology is one of the most attractive fabrication techniques of near net shape components constituted by aluminum matrix composite (AMC) materials. AMCs reinforced with both continuous and discontinuous ceramic elements have been mainly produced by infiltration of porous preforms. Nevertheless, a further promising production route offered by this technique is given by the possibility to employ ingots of pre-reinforced aluminum alloys containing ceramic particles (silicon carbide or alumina); ingots are remelted and, under suitable operative conditions, high quality composite castings of simple and complex shape are produced by squeeze casting. The present paper describes the results of an extensive experimental work carried out by Alures-Centro Tecnico Porcessi on a pilot plant scale employing a vertical squeeze casting machine with a clamping force of 315 tons.
Technical Paper

Implications of Future Scrap Car Handling for Design of Cars

1996-04-01
91A124
In this paper the socio-economic and technical problems of the handling of car wrecks are discussed. The recovery of metals as a goal for shredder operations will increasingly be supplemented with the recovery of other materials such as polymers. In order to deal economically and technically with polymer materials, it is necessary to know in advance which type of wreck handling will be used. Also optimization of shredder operations allow less freedom to incorporate a variety of materials when compared with selective dismantling or disassemble of cars. It is argued that various technical solutions have to be accompanied by increased cooperation along the firms that are connected to the handling of car wrecks. Cooperation between the scrap context and designers is essential, in order to optimize dismantling practices according to criteria of environmentally preferred solutions.
Technical Paper

Critical Compression Loads on Aluminum Honeycomb Panels

1996-04-01
91A131
The purely theoretical evaluation of critical compression loads seems complex and not very reliable in the case of honeycomb panels, on account of the numerous parameters in play and their complex interrelationships. This report provides the designer with a fast tool for preliminary calculations, consisting of a finite-element mathematical model with elastic-linear code (which can be processed using a PC), which makes it possible to obtain information very closely resembling the real situation.
Technical Paper

Microarc Oxidization Process--A Perspective Technology Used for the Obtention of Qualitative Ceramic Coatings

1996-04-01
91A108
A perspective microarc oxidization (MAO) technology used for the obtention of ceramic coatings is described. The coat formation mechanism and its phase composition and revealed conformably to aluminum alloys. The results of the analysis of MAO-coatings are given by their cohesive strength with respect to the substrate and microhardness distribution within ceramic layer thickness. The examples of practical use of coatings are given and possible perspectives of MAO-technology inculcation are outlined.
Technical Paper

Manufacture of Automotive Components By Semi-Liquid Forming Process

1996-04-01
91A113
Semi-liquid forming process, applied to pressure die-casting, permits to obtain low cost components with high qualitative characteristics and adequate mechanical performances. The technology is based on the employment of material with globular microstructure (flow-cast alloys) obtained subjecting a metal alloy at the time of solidification to an elevated shear rate. Such microstructure permits the accomplishment of conventional forming processes at temperatures in solidification range. The particular fluid-dynamic properties of the semi-liquid slurry and the lower injection temperature allow to obtain casting with improved soundness, without need of impregnation, and to extend die life. The present work describes the Weber (Magneti Marelli) activity of the process industrialization and some applications for the manufacture of automotive components.
Technical Paper

Evaluation of Advanced Aluminum Alloys and Mmc Obtained By Means of a Spray Depositon Approach

1996-04-01
91A112
The paper review some recent efforts, made by the aluminum industry, towards the development of new advanced alloys for aerospace applications; unconventional production technologies and MMC occupy an outstanding position in this context. Raid solidification processes are currently used for obtaining advanced alloys and, among them, the powder metallurgy route is one of the most commonly applied, since it has reached a considerable level of maturity. Experimental results of PM materials are shown and discussed in order to appreciate the potentialities of this class of materials and some recent further progress is shown: the spray deposition approach (osprey process). After having described the main features of the osprey process, some results obtained at the Department of Aerospace Engineering of Pisa about the development of high strength Al-alloy and MMC obtained by means of the osprey process are shown.
Technical Paper

Casting and Characterization of An Aluminum Alloy Car Engine Bracket Produced By Squeeze Casting Technology

1996-04-01
91A114
The following paper describes the experimental activity regarding the setting-up and characterization of a car engine bracket in Al-Si12Cu2FeZn-F alloy produced by the new technology squeeze casting. LExperimentation was carried out at the Alures squeeze casting pilot plant. Static and dynamic characterization (fatigue resistance on test samples and the component itself) was carried out at Teksid and Fiat Auto. Characterization test have demonstrated the considerable advantages offered by the new technology compared with conventional production processes.
Technical Paper

Toothed Couplings for Diesel Engines: An Example of Steel Substitution With Fiber Reinforced Plastics

1996-04-01
91A100
The replacement with plastic of an important component, formerly in steel, in the timing drive of a heavily duty diesel engine has been studied and realized. The substituted part is the toothed coupling connecting the injection pump to the timing drive. Torque that stresses the coupling has been measured with laboratory tests. The tooth stresses have been calculated with FEM analysis. Finally, fatigue tests have been carried out directly on the engine at different loadings. The test results are consistent with the predicted behavior of this component.
Technical Paper

Reliability Improvement of Automotive Components By Surface Modification

1996-04-01
91A104
In this paper, several detailed studies on the surface properties of coatings are explained in order to make function of surface modification become more effective. As surface coatings, eletroless nickel plating, organic thin film, nitriding and antireflection coating by ultra fine particles are examined. Discussion of optimum production conditions and surface conditions for each coating is introduced.
Technical Paper

Actuation and Fastening With Shape Memory Alloys in the Automotive Industry

1996-04-01
91A103
As a result of a phase transformation, shape memory alloys can change their shape when the temperature changes. This unusual effect can be utilized in actuation and fastening components for automotive applications. Springs made from Ni-Ti shape memory alloys change their rate in a predetermined temperature range due to a significant change in the elastic modules of the material. They can be used as sensor-actuators in pressures control valves or oil cooler by-pass valves in automatic transmissions or to compensate for oil viscosity changes in shock absorbers or thermal expansion of dissimilar materials in gear boxes. If the recovery is constrained, i.e., shape memory element is physically prevented from returning into its original shape, a potentially high stress is generated. This effect is used in fastener rings. Fasteners made from Ni-Ti alloys provide high reliability and easy installation for braid terminations, locating of shaft mounted components, connectors and hose clamps.
Technical Paper

Ceramic Coating for Aluminum Engine and Components

1996-04-01
91A105
The trend toward lighter vehicles for improved performance has recently introduced the use of aluminum and plastic materials for vehicle bodies and drive trains. In particular, the aluminum alloy block foar engine application is certain to reappear. The soft aluminum cylinder liner will require additional treatment before acceptance. Three possible approaches appear to solve the aluminum cylinder liner dilemma. These approaches are: 1) use of high silicon aluminum such as the 390 aluminum; 2) insert or cast steel liners into the aluminum engine block; and 3) ceramic coat the low cost standard aluminum engine block. Each has known advantages and disadvantages. It is the purpose of this paper to present the merits of option 3, the ceramic coated aluminum cylinder bore, from the standpoint of low weight, cost, and tribological effectiveness. The advantages of approaches 1) and 2) are obvious. High temperature after treatment of the ceramic engine components is not required.
Technical Paper

Antiwear Properties and Applications of Thin Hard Coatings

1996-04-01
91A106
Different techniques, like PVD, CVD, ion implantation, are increasingly used to produce thin film layers of ceramic compounds to modify the surface properties of metals, carbides, ceramics or polymeric components for specialized conditions or in severe conditions of use. Carbides, nitrides, oxides, etc. have been deposited on the most varied supports to solve problems of high temperature, erosion, corrosion, diffusion and conductivity or electrical resistance. The fields of thin hard coating applications are: tools, dies, punches, mechanical components (for antiwear deposits), structures (for anticorrosion), optics (reflecting or absorbing layers) and microelectronics. In this paper we will present the principal characteristics of different thin hard coating layers and processes, and the principal applications in the anti-wear field.
Technical Paper

Engineering Plastics for Novel Automotive Applications

1996-04-01
91A093
Not only have engineering thermoplastics secured an accepted place in automotive manufacture, but also their penetration of areas traditionally the sole domain of metals, is growing. One group of materials in particular is driving this trend; that of advanced thermoplastic composites. Used primarily in non-appearance, semi-structural parts, thermoplastic composites are opening the way for engineering polymers to be used in large components such as tailgates, technical fascia's or front end modules, side doors and bonnets, amongst many other novel applications whose engineering criteria could previously be met only by steel. This paper will look at both the new opportunities for engineering plastics in automotive applications and at the materials capable of economically satisfying their demands
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