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Technical Paper

Machinability of As-Compacted P/M Parts: Effect of Material Chemistry

1998-02-23
980635
Since the advent of P/M technology as a near net shape production process, millions of mechanical components of various shapes and sizes have been produced. Although P/M continues to be one of the fast growing shaping processes, it suffers from the inability to produce intricate geometry's such as internal tapers, threads or recesses perpendicular to pressing direction. In such cases application of machining as a secondary forming operation becomes the preferred alternative. However, machining of P/M parts due to their inherent porosity is known to decrease tool life and increase tool chatter and vibration. Consequently, several attempts have been made to improve the machinability of P/M materials by either addition of machinability enhancing elements such as sulfur, calcium, tellurium, selenium, etc., or by resin impregnation of P/M parts.
Technical Paper

Preparation and Characterization of Nanophase Gold Catalysts for Emissions Control

2008-10-07
2008-01-2639
Various gold catalysts were prepared using commercial and in-house fabricated advanced catalyst supports that included mesoporous silica, mesoporous alumina, sol-gel alumina, and transition metal oxides. Gold nanoparticles were loaded on the supports by co-precipitation, deposition-precipitation, ion exchange and surface functionalization techniques. The average gold particle size was ∼20nm or less. The oxidation activity of the prepared catalysts was studied using carbon monoxide and light hydrocarbons (ethylene, propylene and propane) in presence of water and CO2 and the results are presented.
Technical Paper

Design for 6 Sigma Application in Engine System Integration

2015-09-29
2015-01-2864
With stringent emission regulations, many subsystems that abate engine tailpipe-out emissions become a necessary part for engines. The increased level of complexity poses technical challenges for the quality and reliability for modern engines. Among the spectrum of quality control methodologies, one conventional methodology focuses on every component's quality to ensure that the accumulative deviation is within predetermined limits. This conventional methodology tightens the component tolerance during the manufacturing process and typically results in increased cost. Another conventional methodology that is on the other side of the spectrum focuses on tailoring an engine calibration solution to offset the manufacturing differences. Although the tailored engine calibration solution reduces manufacturing cost for components, it increases the development and validation cost for engines. Given the cost and time constraints, system integration plays an important role in engine development.
Technical Paper

Caterpillar’s Autonomous Journey - The Argument for Autonomy

2016-09-27
2016-01-8005
Today’s business climate and economy demand new, innovative strategies from the initial kickoff of research and development - to the mining of ore from the earth - to the final inspection of a finished product in a mid-western factory. From startup companies with two employees to the largest companies, the world faces new and challenging requirements every day. The demands from companies, customers, executives, and shareholders continue to drive for higher outputs with more efficient use of personnel and investments. Fortunately, the rate of technology continues to exponentially accelerate, which allows those at the cutting edge of technology to capitalize. Caterpillar has been a pioneer in advanced technology since its inception and has been developing the foundation for autonomy over the past four decades.
Technical Paper

Initiating a Values Based Culture at Track-Type Tractors Division of Caterpillar Inc.

1999-03-01
1999-01-0250
During the early 1990s, the Track-Type Tractors Division (TTTD) of Caterpillar Inc. experienced several challenges. The Division faced increasing global competition in the midst of an economic recession. Although intense plant modernization and reorganization occurred in the five previous years, the business unit was not profitable. In 1993, Track-Type Tractors Division instituted its solution -- a change in its culture. Previously, the culture hindered the division’s ability to move forward. This was revealed in a 1992 review detailing the major obstacles inhibiting management from achieving divisional goals. The division leaders recognized that a change in business philosophy, as opposed to further plant modernization, was required to achieve production goals and stay globally competitive.
Technical Paper

Prediction and Measurement of Microstructure and Residual Stresses due to Electron Beam Welding Process

1999-04-14
1999-01-1872
Electron beam (EB) welding process is characterized by an extremely high power density that is capable of producing weld seams which are considerably deeper than width. Unlike other welding process, heat of EB welding is provided by the kinetic energy of electrons. This paper presents a computational model for the numerical prediction of microstructure and residual stress resulting from EB welding process. Energy input is modeled as a step function within the fusion zone. The predicted values from finite element simulation of the EB welding process agree well with the experimentally measured values. The present model is used to study an axial weld failure problem.
Technical Paper

Induction Hardening Simulation of Steel and Cast Iron Components

2002-03-19
2002-01-1557
The induction hardening process involves a complex interaction of electromagnetic heating, rapid cooling, metallurgical phase transformations, and mechanical behavior. Many factors including induction coil design, power, frequency, scanning velocity, workpiece geometry, material chemistry, and quench severity determine a process outcome. This paper demonstrates an effective application of a numerical analysis tool for understanding of induction hardening. First, an overview of the Caterpillar induction simulation tool is briefly discussed. Then, several important features of the model development are examined. Finally, two examples illustrating the use of the computer simulation tool for solving induction-hardening problems related to cracking and distortion are presented. These examples demonstrate the tool's ability to simulate changes in process parameters and latitude of modeling steel or cast iron.
Technical Paper

FD&E Total Life T-Sample Residual Stress Analytical Predictions and Measured Results

2019-04-02
2019-01-0528
The Society of Automotive Engineers Fatigue Design & Evaluation Committee [SAE FD&E] is actively working on a total life project for weldments, in which the welding residual stress is a key contributor to an accurate assessment of fatigue life. Physics-based welding process simulation and various types of residual stress measurements were pursued to provide a representation of the residual stress field at the failure location in the fatigue samples. A well-controlled and documented robotic welding process was used for all sample fabrications to provide accurate inputs for the welding simulations. One destructive (contour method) residual stress measurement and several non-destructive residual stress measurements-surface X-ray diffraction (XRD), energy dispersive X-ray diffraction (EDXRD), and neutron diffraction (ND)-were performed on the same or similarly welded samples.
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