Engineering systems and components are the result of a complex chain of actions, starting with a design to match the functional demands: there are often multiple stages in the manufacturing process, as well as essential quality assurance methods for the component and system.
All steps in the process have their own special significance. Optimum outcomes and cost-effectiveness depend heavily on the way in which they are orchestrated and managed as an integrated sequence. At given times and in given circumstances the relative importance of each step may be viewed differently, but the heat treatment and surface engineering processes in the manufacturing stage are almost always critical. While mining, primary extraction and materials production processes have an undeniably macro-scale industrial influence on economics, society and the environment - and they tend to receive most attention in the public media - heat treatment and surface engineering processes actually make machines and systems function. Also, these heat treatment and surface engineering processes themselves represent a complex balance of materials, technology, energy and environmental factors to achieve an optimum combination of industrial feasibility and economic and social viability.
Thus, heat treatment and surface engineering processes are crucial elements in virtually the whole of engineering and manufacturing. They are especially, but by no means exclusively, relevant to metals. A combination of correct selection and control of the processes is essential for the safe, economic, and environmentally acceptable operation of components and systems; this and a proper understanding of them in their engineering context is central to optimum design and performance of components and systems in, for example, vehicles, aircraft, oil rigs, agricultural machinery. The panel on the next page gives an idea of the broad industrial significance.