The Relevance of Metallurgy in Engineering and Manufacturing
We live in a material world. Today, it is the role of materials science (Fig. 1) to study, develop, design and operate processes that transform raw materials into useful engineering products intended to improve the quality of our lives. It is often said that material science is the foundation upon which today’s technology is based, and real-world applications would not be possible without the material scientist. With such a broad-ranging scope, the question is, if we really need metallurgical engineers, why are we graduating so few of them? Part of the answer lies in the role metallurgists play in product design and manufacturing. Let’s learn more.
The industrial revolution thrust metals to the forefront of technology, and they have stayed there ever since, becoming the very foundation of our modern society. One cannot envision a life where transportation and communications systems, buildings and infrastructure, industrial machines and tools, and safety/convenience devices are not part of our daily lives. Today, other materials have emerged as complements for (or threats to) metal’s dominance. Composites are one such example.
Metallurgy is the part of materials science and materials engineering that studies the physical and chemical behavior of metallic elements, their intermetallic compounds and their alloys. This definition is all-encompassing and includes the study of processes run in furnaces and ovens, the forging and rolling of metals, foundry operations, electrolytic refining, creation and use of metal powders, welding, heat treatment and much more.
Metallurgy is also the technology of metals: the way in which science is applied to the production of metals (including heat treatment), and the engineering of metal components for use in consumer products and manufactured goods. The production of component parts made from metals is traditionally divided into several major categories:
• Mineral processing, which involves gathering mineral products from the Earth’s crust.
• Extractive metallurgy, which is the study and application of the processes used in the separation and concentration of raw materials. Techniques include chemical processing to convert minerals from inorganic compounds to useful metals and other materials.
• Physical metallurgy, which links the structure of materials (primarily metals) with their properties. Concepts such as alloy design and microstructural engineering help link processing and thermodynamics to the structure and properties of metals. Through these efforts, goods and services are produced.
What is Metallurgical Engineering?
Metals and mineral products surround us everywhere – at home, on our way to and from work and in our offices or factories. They form the backbone of modern aircraft, automobiles, trains, ships, and endless recreational vehicles; buildings; implantable devices; cutlery and cookware; coins and jewelry; firearms; and musical instruments. The uses are endless. While threats abound from alternative material choices, metals continue to be at the forefront and are the only choice for many industrial applications.
Developing new materials, new processes to make them, and testing new theories and models to understand them are the focal points for today’s metallurgist. We have the means to measure properties at the macro, micro, nano and atomic scales, giving us unprecedented access to fuel new developments. The strong dependence of our society on metals gives the profession of metallurgical engineering its sustained importance in the modern world.
It is believed by most that our economic and technical progress into the 21st century will depend in large part on further advances in metal and mineral technology. For example, advancements in energy technologies, such as the widespread use of nuclear fusion, will only be possible by material developments not yet in existence. The future is indeed bright for today’s material scientists and those engineers who chose metallurgy as their career choice.
Why are there so few metallurgists?
The demand for careers in metallurgy is not at the forefront of our educational system due in large part to the inability of the metallurgical community to communicate to management our role in engineering and manufacturing. While metallurgists should be involved in all aspects of modern engineering, this is seldom the case. The reason for this is often centered around a misunderstanding of what we do, which is made more difficult by how we begin the answer to every question with “it depends.” In many cases, this leads management’s belief that other engineering disciplines can replace our skill set. The failure of management to understand what we do is often a failure to understand the engineering life cycle and the interrelationship of engineering disciplines to each other.
Engineering Life Cycle
In the design of any engineered component, it is necessary to fully understand and address two key questions that the metallurgist is best qualified to answer, namely:
1. What must the component endure during service (i.e., what are the product requirements)?
Questions such as the following must be addressed: What are the rigors of the application, and what is the design life? Must the component part provide premier service, or is there an adequate design life involved (i.e., will other factors end its service long before its useful life is expended)? What loading, lubricants, temperature and contaminants are involved? What other service/performance aspects specific to a particular product must also be factored into the selection process?
2. How will the component part be made (i.e., what are the process requirements)?
Questions such as the following must be addressed: How will its basic form be generated, and how will it be heat treated – if at all? Will it be important to introduce particular mechanical properties? If so, how – by heat treatment or mechanical means? Is geometry or surface finishes important? Will special coatings be used? Is dimensional control (stability or stability at temperature) an issue? What other processing aspects, specific to the particular product, must be considered?
Obviously, product/process engineering, performance engineering and metallurgical engineering are not separate entities (Fig. 2). They are highly interdependent, and all these disciplines must be considered. However, one must also recognize that today’s cost demands often require compromises in material and manufacturing selection to meet logistical, supply-chain and inventory requirements. Fortunately, that does not mean that selection needs to be minimized. If done correctly, the needs of all parties can usually be met with excellent success while maintaining realistic economic, manufacturing and performance goals.
The role of the metallurgist is especially important during the engineering stage of product development. A metallurgist’s participation enhances both the design and the capability of a manufacturing process to achieve the desired outcome. During this phase, there is a point at which manufacturing commences. In order to make this decision, input is required from the so-called technology triangle. The role of the metallurgist or metallurgical engineering group is to provide critical input in the following areas:
• Materials selection
• Manufacturing strategy
• Process development
• Equipment selection
• Controls development
• Variability assessment
• Testing criteria
Metallurgists and metallurgical engineers are also responsible for interfacing with manufacturing to meet production demands in an environmentally responsible way by designing processes and products that minimize waste, maximize energy efficiency, increase performance and facilitate recycling. Metallurgists have seldom been viewed as part of the manufacturing mainstream, however, which is another part of the problem. Gone are the days when every manufacturing plant had a chief metallurgist and multiple metallurgists on staff.
It is often said that mechanical, electrical or computer-related problems can always be solved – if one dedicates enough time and money to the task. However, solving a metallurgical problem is not a function of money. Its solution may be impossible to achieve, forcing one to revisit the very design of the product and its end-use. It is for this reason that the metallurgist exists and is the person who must be involved in every product design. As metallurgists, it is our responsibility to make sure that educators and executives understand the role we play. IH
1. The University of Utah (www.metallurgy.utah.edu)
2. The University of Queensland, Australia (www.uq.edu.au)
3. Wikipedia (www.wikipedia.com)
4. The Princeton Review (www.princetonreview.com)
5. New Mexico Tech (www.nmt.edu)
6. Illinois Institute of Technology (www.iit.edu)