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Typical automotive body structures use resistance spot welding for most joining purposes. New materials, such as Advanced High Strength Steels (AHSS) are increasingly used in the construction of automotive body structures to meet increasingly higher structural performance requirements while maintaining or reducing weight of the vehicle. One of the challenges for implementation of new AHSS materials is weldability assessment. Weld engineers and vehicle program teams spend significant efforts and resources in testing weldability of new sheet metal stack-ups. In this paper, we present a methodology to determine the weldability of sheet metal stack-ups using an Artificial Neural Network-based tool that learns from historical data. The paper concludes by reviewing weldability results predicted by using this tool and comparing with actual test results.

A laboratory wear test is used to evaluate the wear protection properties of new and used engine oils formulated for FFV service. Laboratory-blended mixtures of these oils with methanol and water have also been tested. The test consists of a steel ball rotating against three polished cast iron discs. Oil samples are obtained at periodic intervals from a fleet of 3.0L Taurus vehicles operating under controlled go-stop conditions. To account for the effects of fuel dilution, some oils are tested before and after a stripping procedure to eliminate gasoline, methanol and other volatile components. In addition to TAN and TBN measurements, a capillary electrophoresis technique is used to evaluate the formate content in the oils. The results suggest that wear properties of used FFV lubricants change significantly with their degree of usage.

This paper explores the extent to which standard dilution tunnel measurements of motor vehicle exhaust particulate matter modify particle number and size. Steady state size distributions made directly at the tailpipe, using an ejector pump, are compared to dilution tunnel measurements for three configurations of transfer hose used to transport exhaust from the vehicle tailpipe to the dilution tunnel. For gasoline vehicles run at a steady 50 - 70 mph, ejector pump and dilution tunnel measurements give consistent results of particle size and number when using an uninsulated stainless steel transfer hose. Both methods show particles in the 10 - 100 nm range at tailpipe concentrations of the order of 104 particles/cm3.

The P2000S body structure was designed as part of an advanced research project to determine the feasibility of a high volume, lightweight sport utility vehicle (SUV) that would achieve performance targets of the newly emerging “City SUV” market by developing a unitized (no frame) SUV body structure fabricated principally of aluminum. In order to be viable, this body structure was required to meet all safety, durability, NVH and other functional attributes of a truck while having the ride characteristics of a sedan. This paper describes the P2000S body structure including the structural philosophy, project constraints on the design, manufacturing processes, supporting analyses, assembly processes and unique material and design concepts which resulted in the 50% body structure weight reduction in comparison to similar sized body-on-frame production steel sport utility vehicles.

Gas carburized and quenched low alloy steels typically produce surface microstructures which contain martensite, retained austenite and often NMTP's (non-martensitic transformation products). The NMTP's are caused by a reduction of surface hardenability in the carburizing process from loss of alloying elements to oxidation. Gas carburized low alloy steels such as SAE 8620 with NMTP's on the surface have been shown to have inferior bending fatigue properties when compared to more highly alloyed steels which do not form NMTP's, such as SAE 4615M. One method of minimizing the formation of oxides and eliminating NMTP formation during carburizing and quenching is to use plasma carburizing instead of conventional gas carburizing. In this study the microstructures and bending fatigue performance of plasma carburized SAE 8620 and SAE 4615M is compared to the same alloys conventionally gas carburized and quenched.

The influence of calcium treatment on the mechanical properties of a plain carbon steel (SAE 1050) was investigated. The mechanical properties investigated were tensile and impact strength, fatigue crack growth rate, and the fatigue threshold. Impact testing was conducted at both room temperature and at -40°C. Several heats of both calcium and non-calcium treated steel (SAE 1050) were tested in both the as hot-rolled condition and in the quenched and tempered condition (with a hardness level of HRC = 45). The results of this investigation show no significant difference in the tensile properties or room temperature impact properties between the calcium treated and the non-calcium treated steels. However, the impact strengths of calcium treated steels were slightly higher than that of non-calcium treated steels at -40°C.

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.

Erosion damage to automotive car bodies caused by stones and small sand particles and road debris significantly affects the appearance of paint. Painted engineering plastics as well as precoated sheet steel are affected by erosion phenomenon. Erosion of painted plastic substrates results in cosmetic concerns while that on metal substrates results in cosmetic to perforation corrosion. This work describes a laboratory simulation of erosion of painted plastic substrates by small particles on various paint and substrate types. Gloss loss was used to quantitatively evaluate erosion of painted surfaces. Wear behavior of painted plastic substrates to slag sand impact was evaluated as a function of several variables including paint type (one-component melamine crosslinked (1K) vs. two-component isocyanate crosslinked (2K)), thermal history, and coating modulus. The effect of slag sand type (particle size and chemical composition) was studied.

APPLICATIONS of nuclear energy in automotive manufacture have been made principally in the field of radioactivity. These are grouped under the following categories: radiography, nondestructive testing, gaging and control, tracer techniques, and static neutralizers. Radioactivity techniques are being used in foundry operations to check stock and metal levels in cupolas and distribution of element additives. In steel operations, these techniques are being used to check assimilation of ore-concentrate fines and thickness of rolled sheet steel. Other applications include measurement of pipe and wall thickness in pressure lines and engines, and inspection of castings and welds for internal faults. Radioactive techniques for improving processes, quality, and materials have potentially universal application. Greater industrial access to reactors will permit broader study and speed the development of new applications of radio-activity in industry.

A stress durability test method that incorporates exposure to a corrosive environment has been used to evaluate the performance of adhesively bonded steel joints. For the systems examined, corrosion exposure is more damaging than exposure to humidity alone. The combination of load and corrosion exposure is substantially more severe than either alone. A method for analysis of the data and comparison of the test results for the evaluation of adhesive bond durability is proposed. The dependence of lifetime on load is defined as , where f is the ratio of applied load to initial, unexposed failure load. The exponent n provides a measure of the degree of acceleration of the interfacial degradation processes by load.

Increased use of powder-forged connecting rods in the automotive industry prompted an investigation into the suitability of powders from different suppliers for this application. Specifications developed by North American users call for ultra clean powders to enhance machinability and fatigue life. Powders from four manufacturers were each blended with graphite and lubricant, then pressed, sintered and forged to full density. Metallographic samples were prepared and evaluated for inclusion content. In addition, the powders were mixed to the composition of connecting rods, (C - 0.5%, Cu - 2% and MnS - 0.3%), and were similarly pressed, sintered and forged. Test bars were machined from the forged discs. Uniaxial fatigue tests were performed in the tension-compression mode and strain-life curves were developed. It was determined that all powders examined were very clean and were comparable in their inclusion content.

PROPER protection of metal parts operating as bearing surfaces, or in contact under relatively heavy loads, during the break-in period often means the difference between successful operation and failure. Various surface coatings have been investigated to discover which ones will give this protection. The authors discuss here three types of surface treatment for cast-iron and steel that do give superior wear and scuff resistance.

There has been a substantial increase in the use of advanced high strength steel (AHSS) in automotive structures in the last few years. The usage of these materials is projected to grow significantly in the next 5-10 years with the introduction of new safety and fuel economy regulations. AHSS are gaining popularity due to their superior mechanical properties and use in parts for weight savings potential, as compared to mild steels. These new materials pose significant manufacturing challenges, particularly for welding and stamping. Proper understanding of the weldability of these materials is critical for successful application on future vehicle programs. Due to the high strength nature of AHSS materials, higher weld forces and longer weld times are often needed to weld these advanced strength steels.

The constant challenge for automotive engineers to design vehicles with greater reliability at lower cost has brought powder metallurgy (P/M) to the foreground. This technology provides parts to or near net shape and results in savings of material, energy, capital equipment and floor space. This paper is an extension of SAE reports 850458 and 870133 and describes automotive powder metal components not previously identified. It should help engineers find cost effective applications early in the design stage so that P/M technology can be efficiently adopted. In addition, recent important technological developments in the P/M field applicable to automotive parts are highlighted. In particular, increased reliability achieved through SPC is stressed. A novel blending process is described whereby the alloying ingredients are “glued” to iron powder particles resulting in an increase in P/M quality through improved homogeneity.

Application process, and performance in engine dynamometer and high mileage vehicle fleet durability tests of Plasmaspray coated bore aluminum block engines are discussed. Fuel economy, oil consumption, power and wear data for Ford 4.6L-V8 aluminum block engines utilizing very low cost iron/iron oxide base coatings, and stainless steel/BN solid film lubricant Plasmasprayed coatings are presented. Test results from Ford's 100 hour Piston & Gasket Engine Dynamometer Durability Tests, and Fleet Vehicle Durability Tests show ring/bore wear reductions of more than 40% relative to production cast iron bore systems with Oil Economy averaging more than 13,600 km/l (8000 mi/qt).

Proving Ground cyclic testing was used to evaluate vehicles assembled with electrogalvanized and organic composite coated electrogalvanized steel. These same materials, along with several commonly available precoated steels, were also evaluated as hem flange assemblies on towed trailers at the Proving Ground. Testing was terminated as perforation of some of the assemblies occurred. Pitting depth was used to quantitatively evaluate metal loss.

NVH requirements are critical in new driveline developments. Failure modes due to resonances must be carefully analyzed and potential root causes must have adequate countermeasures. One of the most common root causes is the modal alignment. This work shows the steps to design and optimize a new plastic bracket for an automotive half shaft bearing. This bracket replaces a very stiff bracket, made of cast iron. The initial design of plastic bracket was not stiff enough to bring natural frequency of the system above engine second order excitation at maximum speed. The complete power pack was modeled and NVH CAE analysis was performed. The CAE outputs included Driving Point Response, Frequency Response Function and Modal analysis. The boundary conditions were discussed deep in detail to make sure the models represented actual system.

NODULAR cast iron, so called because the graphite is present as finely dispersed, well-rounded particles, is made in two stages: The first stage consists of the addition of magnesium or other carbide formers, which promote the formation of white iron in one normally solidifying gray. In the second stage a ferrosilicon type of inoculant overcomes the tendency toward white iron and causes the graphite to precipitate out in the form of small spherulites. The methods of making nodular iron, the effect of composition on physical properties, economic factors involved, and potential applications are discussed in this paper.

Procedures are developed for assessing the influence of various material and processing factors on the fatigue performance of leaf springs. Cyclic material properties, determined from smooth axial specimens of spring steel, are used to determine the level and cyclic stability of residual stresses resulting from mechanical processing as well as the amount of permanent deformation associated with presetting operations. A damage parameter, incorporating material properties, residual stress effects and applied stressing conditions, is used to predict failure location, i.e. surface or subsurface, and lifetime as a function of processing sequence. Predictions are found to be in good agreement with experimental bending results.

The development, evaluation, and selection of Plasma spray powder material for the coating of aluminum-alloy engine cylinder block bores was conducted to yield a bore system which provides numerous benefits relative to the present cast iron sleeve system. These include: a reduction in ring/bore wear, friction, and in engine oil consumption as well as a benefit in reduced corrosion. A reduction in engine weight, overall costs, and improvements in machining and honing operations are shown. Alternate thermal spray processes are also described in this investigation. Test evaluation leads to the selection of two plasma powder material spray systems. One system emphasizes low cost relative to the present system. The second system provides significant reduction in friction and ring/bore wear through the introduction of solid lubricant in the material composition.