Heat treatment might be a new concept for you. If this is the first time you’ve hired a metal shop to test metals or create new parts, the terminology may go right over your head. Here is an overview of common terms used in heat treatment in Gastonia, NC so you can make informed decisions about your metallurgy needs:
- Aging: This is the process of adding a time-temperature dependency in alloys. Once completed, the end product’s solubility decreases as temperatures drop. Different alloys have varying responses and time-temperature combinations depending on what is needed from them.
- Annealing: This is the process of heating a material to a certain temperature, holding it and then cooling it at a pre-determined rate. As with aging, the temperatures and hold times depend on what needs to be accomplished. Annealing changes the properties and composition of materials and leads to improvements. It can make machining easier, help parts conduct electricity better and even increase stability.
- Baking: This works in almost the opposite way as aging and annealing. When those processes do not work, baking maintains a low heat temperature on the material in order to remove components that prevent it from changing form. Once completed, another process is carried out to complete the job.
- Normalizing: Used for iron-based alloys, normalizing involves heating the material above transformation range and cooling it at room temperature. This removes internal stress that can arise from heat treating and prevents the possibility of metal failure.
- Preheating: Tool steels and other heavy materials are first heated to a high temperature. From there, they undergo further heat treating. Strong metals can be resistant to heat treating attempts, so the preheating softens it further. Metallurgical tests reveal which materials require this additional step.
- Quenching: The cooling step in heat treatment is called quenching. Like preheating or heating, the cooling step also determines the new properties of a material. Types of quenching include direct, fog, hot, interrupted, selective, slack, spray and time quenching. Each offers a different cooling rate that depends on the intended application of the material.
- Stress relieving: This is the final step after quenching, normalizing, machining, cold working, welding or casting. Stress relieving relieves the internal stresses that could compromise functioning later. Materials are heated to a particular temperature and held at that level until the stress elements decrease. This is common with heavy machinery parts and other applications that need to stand up to heavy loads. There are few instances more disastrous than a failed heavy machinery part, so this is a very important step in manufacturing.
- Tempering: Metalworkers take this step when quenching causes additional internal strain. Tempering draws out impurities and hardens the steel. Once complete, the steel or alloy will be more appropriate for its purpose. Like stress relieving, this is common with heavy applications and machinery.
J.F. Heat Treating Inc. offers heat treatment in Gastonia, NC for many industries. When you need machine parts that can stand up to your work or improved material for manufacturing, call us to help you out.