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The demand for improved fuel economy in both cars and trucks has emphasized the need for lighter weight components. The application of high strength steel to wheels, both rim and disc, represents a significant opportunity for the automotive industry. This paper discusses the Ranger HSLA wheel program that achieved a 9.7 lbs. per vehicle weight savings relative to a plain carbon steel wheel of the same design. It describes the Ranger wheel specifications, the material selection, the metallurgical considerations of applying HSLA to wheels, and HSLA arc and flash butt welding. The Ranger wheel design and the development of the manufacturing process is discussed, including design modifications to accommodate the lighter gage. The results demonstrate that wheels can be successfully manufactured from low sulfur 60XK HSLA steel in a conventional high volume process (stamped disc and rolled rim) to meet all wheel performance requirements and achieve a significant weight reduction.

A pin and disc machine has been modified for the evaluation of silver-steel lubrication characteristics of railroad diesel oils. Use of silver pins on polished steel discs at selected loads and rubbing speeds allows good correlation with known engine behavior. In comparison with wear and friction data obtained by the four ball method, this pin and disc test gives better correlation with engine tests than the Modified Four Ball Test.

A cartridge type pivotal pin and bushing joint has been patented and is being tested and refined both in the laboratory and on construction machinery. It features “dry lubricated” (Teflon) bearings which are assembled and sealed prior to installation. It is suitable for heavy unit loads and use under severe wear conditions, such as in crawler track chains and loader bucket pivotal pin joints. A brief history of U. S. manufactured track pin joints is included to show the progress in extending the service life of these devices.

Engine mounts are an integral part of the vehicle that helps in reducing the vibrations generated from the engine. Engine mounts require a simple yet complicated amalgamation of two very different materials, steel and rubber. Proper adhesion between the two is required to prevent any part failure. Therefore, it becomes important that a comprehensive study is done to understand the mating phenomenon of both. A good linking between rubber and metal substrate is governed by surface pretreatment. Various methodologies such as mechanical and chemical are adopted for the same. This paper aims to present a comparative study as to which surface pretreatment has an edge over other techniques in terms of separation force required to break the bonding between the two parts. The study also presents a cost comparison between the techniques so that the best possible technique can be put to use in the commercial vehicle industry.

This paper describes the results of a series of fatigue studies relating the lives of several weld geometries. Rotating beam and axially loaded specimens were used. A comparison between steel and plastic (polyvinylchloride scale models is made. Using plastic scale models of welded structures for fatigue life determination is the ultimate goal of this work.

“Today, wearing parts are regularly subjected to abnormal loading conditions. They must be able to accept these conditions without failure. In continuous operations, unscheduled downtime greatly increases maintenance costs, not to mention the cost of lost production. White iron castings offer premium abrasion resistance for many of these applications, but are often not used due to the possibility of brittle failure and the difficulty of mechanical attachment. This paper discusses the properties and applications of a composite of martensitic white iron and mild steel. This laminate will accept medium to high impact without loss of service failure, and can be installed by mechanical means or with welded attachment.”

A Computer Aided System (CAS) is developed in order to evaluate off-road wheeled vehicle mobility. The system takes into consideration both vehicle technical parameters and the main specifications of the soil on which the vehicle is expected to operate. Thirty seven vehicle technical parameters organized in nine groups are considered. These groups are: weights, engine parameters, dimensions, performance, transmission, steering, brakes, tires, and self recovery means. The main soil specifications of the soil considered are the soil type (clay, silt, or sand) and the shear and bearing resistance represented by the cone index or the gradient cone index. The evaluation process depends on considering a datum value for each vehicle technical parameter. These datum values or norms are obtained from a statistical analysis study of the technical parameters for a sample of 155 off-road wheeled vehicles representing different schools from all over the world [1].

Predicting fatigue performance in concentrated contacts under thin film (or mixed) lubrication conditions has historically involved various empirical approaches. Typically a lubrication parameter is used in an experimentally derived equation to predict the expected rolling contact performance. However, this model doesn't explain the performance improvements. Enhanced finish bearings have exhibited longer life than standard finish bearings, especially when bearings are operated with thin EHL film. In this paper, the contact surfaces of test bearings were analyzed by using a micro-macro contact model in which the macro-contact was elastic contact, and the micro-contact was elastic-plastic contact. The interior subsurface stress maps were calculated from the real contact surfaces, which included the effects of roughnesses, waviness, and profiles.

Current trends in environmental and emissions regulations are driving changes in new engine systems, and increasing the need for more effectively sealed joints in exhaust systems. At the high temperatures in these exhaust systems it is difficult for traditional gaskets to provide an effective seal, as they degrade at high operating temperatures. This paper introduces a coating that has both excellent temperature stability and good compliance, thus forming an excellent sealing enhancement for metallic layers in exhaust system gaskets. Temperature stability data is presented along with sealing data, which illustrate the superior performance of this material compared to current systems.

A software tool has been developed to aid designers and process engineers in the development and improvement of heat treat processes. This tool, DANTE™, combines metallurgical phase transformation models with mass diffusion, thermal and mechanical models to simulate the heating, carburization, quenching and tempering of steel parts. The technology behind the DANTE software and some applications are presented in this paper.

Paper describes analysis of the design process of modern automotive LPG and CNG containers. Over decade experience in the field of both computer based analysis as well as in the real conditions testing has been collected and presented in the paper. Authors present the potentials of modern FEM methodologies in the optimization and production of lightweight steel containers. It has been proved that the most sophisticated numerical analysis have to be followed by the construction verification, particularly considering direct exposure to fire. Bonfire test have become obligatory for both liquid and compressed gases containers. Properly chosen fire protection system, together with the adequate level of quality of materials applied for its production together with proper directing of the gas flowing out from safety devices are the essential factors defining gas containers fire safety.

Adjuster rings are used in commercial vehicle axle assembly to preload differential bearings and provide support in the axial direction. Adjuster along with the carrier and bearing cap combined to form a threaded joint. Adjuster with external threads engages with internal threads formed in carrier and bearing cap. Preload in differential assembly maintains the system rigidity and helps to maintain an optimized hypoid gear engagement. An adequate preload is important to achieve a desirable bearing life. Reduction in thread engagement at adjuster joint fully or partially will cause a reduction in preload and can lead to gear misalignment. This can cause severe durability concerns. In some cases, it is observed that under vehicle operating loads adjuster ring is backed off from its assembled condition by bending the split pin (split pin is, positive lock, used to maintain adjuster position) and adjuster threads were stripped off.

Pinion bearing loads of a heavy duty rear truck axle were determined by Finite Element Method Analysis (FEM). The results were compared with measured loads. This report describes the method used to measure bearing loads, the FEM model used, and the comparison of the results.

This paper presents some of the history of the Spacemetal process development; a discussion of the core forming machine, a description of the welder where corrugated core and facing sheets are joined; the quality control process employed for inspecting the finished product; and some of the material properties and applications. FOREWORD Development of a production process and the machines for fabrication of a resistance welded steel sandwich was made by Missile Division, North American Aviation, Inc. Development was carried forward under contract AF 33(600)-26154 from the Manufacturing Methods Branch, Industrial Resources Division of the Air Materiel Command USAF.

METHOD of selecting sbaetiasfraicntogrsy for the transmissions and final drives of pneumatic-tired tractors that depends on a knowledge of average operating conditions is reported by John Borland. The well-known method of rating bearings on a fatigue basis is, according to tests carried out by Mr. Borland, a reasonably accurate way of predicting bearing life when loading conditions are definitely established. However, the tables that have been compiled by the bearing manufacturers are satisfactory for determining bearing life only of bearings subjected to a constant load at a constant speed. Since tractor transmissions are subjected to as many different loading conditions as there are speed changes provided in the tractor, tractor transmission bearings cannot be selected directly from these tables. They must be used in conjunction with the formula for determining a factor called weighted life.

A method for the analysis of a damaged bearing is described. An emphasis is placed on obtaining complete and accurate application information; conducting a thorough visual examination; making physical measurements as necessary; and conducting metallurgical tests. The method has been used for tapered roller bearings as well as a variety of other components of various steel types and processing histories.

In an effort to reduce the design cycle time and to meet increasingly demanding applications, an improved procedure for bearing retainer design has been introduced. This paper discusses a methodology which allows the designer to predict the life and failure modes of a retainer under application conditions. Specific attention is given to the case of fatigue of the retainer due to the dynamic interactions between the retainer, rolling elements and races. The methodology which has been developed for the life prediction of retainers is based on the dynamic loads and retainer structural integrity. Central to this technique is the ability to predict the loads imposed on the retainer as a function of design and application conditions. The bearing analysis code ADORE has been used for this purpose. The technique will be discussed by means of an example.

The titanium alloy system offers a range of properties conducive to weight/space savings. These properties include high strength, low elastic modulus and low density, which uniquely suit them for spring applications. By utilizing titanium in various spring designs, suspension engineers can save up to 60% of the weight and 20-30% of the space for a comparable steel spring. The primary impediment to widespread titanium part production and use in the past was cost. A new low cost titanium alloy system designed specifically for suspension and drive train application has been tested and proved to limit this cost problem. Working with titanium in their suspension designs, engineers will save significant weight/space over comparable steel and aluminum components.

This paper describes method which experimentally reproduces the most prevalent bearing fatigue failure modes experienced in ball and roller bearing applications. Generally, bearing fatigue life is divided into two groups. One is a surface-originating type of fatigue. The other is a subsurface-originating type of fatigue. The mechanism of each type of fatigue has been studied. Bearing materials were developed for long-life based on the study of the mechanism of fatigue. However, the condition of the evaluation method, or life test, may be different from the actual application conditions. For instance, the subsurface-originating type of fatigue is tested under extremely heavy loads. The surface-originating type of fatigue is tested with severely contaminated lubrication. There is the possibility that the evaluation methods do not simulate the failure modes that are actually present in the field.

To reduce heat transfer between hot gas and cavity wall, thin Zirconia (ZrO2) layer (0.5mm) on the cavity surface of a forged steel piston was firstly formed by thermal spray coating aiming higher surface temperature swing precisely synchronized with flame temperature near the wall resulting in the reduction of temperature difference. However, no apparent difference in the heat loss was analyzed. To find out the reason why the heat loss was not so improved, direct observation of flame impingement to the cavity wall was carried out with the top view visualization technique, for which one of the exhaust valves was modified to a sapphire window. Local flame behavior very close to the wall was compared by macrophotography. Numerical analysis by utilizing a three-dimensional simulation was also carried out to investigate the effect of several parameters on the heat transfer coefficient.