Preface to the 1992 Edition
Friction, lubrication, and wear (FL&W) technology impacts many aspects of daily life, from the wear of one’s teeth to the design of intricate, high-speed bearings for the space shuttle. Nearly everyone encounters an FL&W problem from time to time. Sometimes the solution to the problem is simple and obvious—disassembling, cleaning, and relubricating a door hinge, for example. Sometimes, however, the problem itself is difficult to define, the contact conditions in the system difficult to characterize, and the solution elusive.
Approaches to problem-solving in the multidisciplinary field of tribology (that is, the science and technology of FL&W) often present a wide range of options and can include such diverse fields as mechanical design, lubrication, contact mechanics, fluid dynamics, surface chemistry, solid-state physics, and materials science and engineering. Practical experience is a very important resource for solving many types of FL&W problems, often replacing the application of rigorous tribology theory or engineering equations. Selecting “the right tool for the right job” was an inherent principle in planning the contents of this Volume.
It is unrealistic to expect that specific answers to all conceivable FL&W problems will be found herein. Rather, this Handbook has been designed as a resource for basic concepts, methods of laboratory testing and analysis, materials selection, and field diagnosis of tribology problems. As Volume Chairman, I asked the Handbook contributors to keep in mind the question: “What information would I like to have on my desk to help me with friction, lubrication, or wear problems?” More than 100 specialized experts have risen to this challenge, and a wealth of useful information resides in this book.
The sections on solid friction, lubricants and lubrication, and wear and surface damage contain basic, tutorial information that helps introduce the materials-oriented professional to established concepts in tribology. The Handbook is also intended for use by individuals with a background in mechanics or lubricant chemistry and little knowledge of materials. For example, some readers may not be familiar with the measurement and units of viscosity or the regimes of lubrication, and others may not know the difference between brass and bronze. The “Glossary of Terms” helps to clarify the use of terminology and jargon in this multidisciplinary area. The discerning reader will find the language of FL&W technology to be somewhat imprecise; consequently, careful attention to context is advised when reading the different articles in the Volume.
The articles devoted to various laboratory techniques for conducting FL&W analyses offer a choice of tools to the reader for measuring wear accurately, using these measurements to compute wear rates, understanding and interpreting the results of surface imaging techniques, and designing experiments such that the important test variables have been isolated and controlled. Because many tribosystems contain a host of thermal, mechanical, materials, and chemical influences, structured approaches to analyzing complex tribosystems have also been provided.
The articles devoted to specific friction- or wear-critical components are intended to exemplify design and materials selection strategies. A number of typical tribological components or classes of components are described, but it was obviously impossible to include all the types of moving mechanical assemblies that may experience FL&W problems. Enough diversity is provided, however, to give the reader a solid basis for attacking other types of problems. The earlier sections dealing with the basic principles of FL&W science and technology should also be useful in this regard.
Later sections of the Handbook address specific types of materials and how they react in friction and wear situations. Irons, alloy steels, Babbitts, and copper alloys (brasses and bronzes) probably account for the major tonnage of tribological materials in use today, but there are technologically important situations where these workhorse materials may not be appropriate. Readers with tribomaterials problems may find the sections on other materials choices, such as carbon-graphites, ceramics, polymers, and intermetallic compounds, helpful in providing alternate materials-based solutions. In addition, the section on surface treatments and modifications should be valuable for attacking specialized friction and wear problems. Again, the point is to find the right material for the right job.
This Volume marks the first time that ASM International has compiled a handbook of FL&W technology. The tribology research and development community is quite small compared with other disciplines, and the experts who agreed to author articles for this Volume are extremely busy people. I am delighted that such an outstanding group of authors rallied to the cause, one that ASM and the entire tribology community can take pride in. I wish to thank all the contributors heartily for their much-appreciated dedication to this complex and important project in applied materials technology.
Metals and Ceramics Division
Oak Ridge National Laboratory