Do metal castings need heat treatment?

Do metal castings need heat treatment?

Metal casting, a superflexible and versatile process, finds a wide range of industrial applications. At VR Foundries, we manufacture parts for anything from automobile, textile, to hydraulic industries through to general engineering industries.
While you can find most of the aluminium castings go in the form of ‘as cast’ state, a number of applications need greater mechanical characteristics or several properties which the ‘as cast’ condition cannot offer.

Every casting and manufacturing industry will have diverse requirements when it boils down to the final casting. There are several characteristics of a material: hardness, abrasion resistance and hardness.

One can add one or more of these properties through heat treatment of castings:  a number of fluctuations (or lack off) and extreme heats that enhance a material’s metallurgical properties to give the required effect.

The following are some of the techniques employed to produce the required casting, whatever be the work:

  1. Quenching:
    This process, without a doubt, is one of the most commonly employed methods when it comes to metal working. Red hot metal is quenched into water or oil for rapid cooling, resulting in the change of metallic structure. The process is done for the material to become more abrasion resistant and harder than it was previously. However, it may also give it a brittle nature.
  2. Annealing:
    This is the process of heating the metal up to almost melting point temperatures, and then cooling it naturally. The material’s structure is relaxed, making it comparatively less brittle. The process is generally performed after quenching for the hardness to be retained, but it frees up the internal stress and prevents it from turning out to be very brittle.
  3. Age hardening:
    This is another technique in which the casting is subject to prolonged heat treating (about 20 hours). It is bit complicated in that it prevents free dislocation of the molecules, thereby leading to comparatively greater yield strength and lesser ductile strength.

Heat treatment of all materials, including aluminium, has to be carried out with the right balance. This is because, during heat treating, there is fluctuation in the properties of metals involved. The ‘harder’ the metal becomes, the more malleable it turns out. The less malleable and softer the material will be, the less hard it turns out.

Talk to us, as we will work out on the material requirements, and plan a suitable strategy to manufacture quality castings, as per your requirements.