Due to the expertise required and expense of buying a quality annealing equipment or employing an annealing service provider, annealing services are commonly outsourced. The annealing process is simply a heat treatment process that involves altering metal properties so that it can be used for various processes. Such materials include copper, brass, silver and steel which undergo the annealing process to make them more ductile, softer and relieve the interior stresses among many more. Most of the annealing equipment provided by metal treating industries or manufacturers offer services such as bright annealing, stainless steel annealing, normalizing, tempering and stress relief.
The annealing services are also widely applied on different stainless steel alloys. Bright annealing is carried out to remove stress and increase ductility while maintaining the stainless steel surface quality. The preservation of the surface quality is done in a continuous furnace or a vacuum furnace with atmospheric control features to provide an oxygen-free atmosphere. These helps to prevent oxidation from taking place. Hence, the process reduces ductility of the stainless steel by heating and slowly cooling it. Since the process decreases the brittleness of the material, it is often applied to metals that need higher cold working properties.
The stress relief process discharges stress that decreases a metal’s tensile strength and cold working properties. The process is also applied to metals that have been machined, formed, cold worked, flame cut and weld fabricated. Low heat stress relief is the most commonly used method since it lessens the stress without compromising the mechanical properties or corrosion resistance. Normalizing is also an annealing process that refines the crystal structure of a stainless steel to help improve its mechanical properties. The process takes place through heating steel to a given temperature above its critical point then briefly soaking it water before letting it cool down in the open air. Stainless steel responds better to hardening after normalizing has taken place.
The tempering process reduces the hardness of the material as well as the stress from the build up during the quenching process. The method is preferably used after the metal has undergone rapid cooling a process also known as quench annealing. These helps to prevent carbide formation on the grain boundaries. The rapid cooling can produce hardness or unwanted stress on the metal, hence the need to the use tempering to relieve the conditions by slowly reheating and cooling the metal. Other annealing equipment and services may include stabilizing annealing, full annealing and process annealing.