Also known as strain hardening, work hardening is a process that makes it possible to increase the strength of a metal component with the use of what is known as plastic deformation. Some metals and metal alloys, such as aluminum or copper, are most efficiently strengthened using this particular approach. The essential process involves the creation of specific dislocation movements within the structure of the metal itself that result in retaining all the characteristics of the metal while still equipping the material with additional strengthening.
There are several different processed that may be used to bring about work hardening. In some cases, the process involves the use of heat. This is particularly true in situations when there is a desire to reshape the metal while also adding to the strength of the finished product. At other times, the metal may undergo the plastic deformation using cold rather than heat. In this scenario, the temperature of the metal is reduced to a level that crystallization within the metal occurs, making it possible to bend, squeeze, draw, or shear the metal to create the desired shape and degree of strength.
While the process of work hardening is taking place, the metal is often somewhat malleable, making it easier to work the material into whatever shape is desired. For example, copper that is undergoing the process will be somewhat malleable using either heat or cold to produce the effect. During this period, it is a simple process to stretch, bend or even hammer the copper into whatever shape is desired. Once the hardening process is completed, the copper is highly durable and has the ability to retain its shape over the long-term.
One of the benefits of work hardening is that the process can help reduce the potential for cracking along the surface of the strengthened metal or metal alloy. By employing the process, it is possible to use metals in the creation of devices that are designed to withstand a specific amount of load for a certain period of time. Since work hardening is not a process that can be reversed, the strength is easily measured, making it possible to choose the right metal or alloy for the manufacture of the product.
The advantages of work hardening also include the ability to control the rate of contamination within the metal itself. This in turn aids in strengthening the metal, since the presence of contaminants that could weaken the metal at various points is kept to a minimum. The result is a uniformity of strength that helps to ensure the life of the finished product, assuming that the product is subjected to use that is in compliance with the standards set by the manufacturer.
There are also some disadvantages associated with work hardening that make it a process to avoid in some situations. The metal will be somewhat less ductile after the treatment, making it unfit for the production of certain types of products. In addition, a great deal of force is required as part of the process, whether heat or cold is employed. The directional properties of the metal may also be adversely affected, another factor that may render the metal unusable for certain purposes. For this reason, work hardening may be desirable, based on the nature of the products that will be made from the metal, or be completely undesirable as an event that unintentionally occurs during a manufacturing process.