How Do Investment Castings Benefit from Annealing?

Date: March 23, 2022

At Dean Group, not only do we manufacture quality castings, but we also offer additional processes, treatments and finishes designed to enhance their properties. This means you always get a product that meets your specifications and unique requirements.

One of the additional processes we provide is annealing. This heat treatment can make a metal more malleable and workable – there are many benefits to heat treatments, and annealing is no exception, so take a look at what this process is and the benefits it offers.

annealed metal

What is Annealing?

As mentioned, annealing is a process that decreases the hardness of a metal or alloy (and refines its grain microstructure), meaning materials become more ductile and easier to work with. This is a heat treatment that changes the crystal structure of the material, and it's usually done after other processes, such as hardening.

There are three steps to annealing: the recovery (the metal or alloy is heated to a high temperature), the recrystallisation (the material is heated above its recrystallisation temperature) and the gain growth (the material is cooled at a specific rate, becoming more malleable) stages.

Several materials can undergo this process. For example, aluminium, steel and copper can all be annealed, which means you don't have to compromise on the metals you really need for your project.

The Benefits of Annealing

There are many reasons why certain investment castings have to undergo further treatments, including annealing. Processes like this change the material's physical, mechanical and often chemical properties, allowing it to be more durable, stronger, and so much more.

The advantages of opting for annealing include:

  • The ability for materials to become easier to bend, press or, otherwise, form. Hard metals can be brittle, meaning they can break when put under pressure; this would mean having to choose another metal for your project or to scrap the original design entirely if a particular material can't be turned into a complex shape. Annealing removes this risk because it's more difficult for the material to break or fracture.
  • Annealing helps with machinability, too, since it can help to reduce the wear on the tool used.
  • This process also gets rid of residual stresses that could lead to cracking or other issues. Removing them helps the metal to be more uniform and durable.
  • Another thing to consider is that annealing provides resistance to corrosion, ensuring that your castings can be used in harsh or adverse conditions.
  • Annealing can also enhance the magnetism and electrical conductivity of castings, which can be incredibly useful depending on why you need them.

One of the downsides of annealing is that this treatment can take up some time, depending on the metals undergoing the process. For example, materials that have to be annealed at very high temperatures will take longer to cool.

Applications for Annealing

As an investment casting company, we know that not all products need to undergo a process like annealing, but there are several applications for those that do. Annealed metals and alloys can be used in high-pressure or high-stress areas, for example, and annealing can be used to reverse the hardening process as well.

Sheet metal can be annealed in order to recover its ductility so that it can be stretched, cut or bent without breaking or cracking. Metal wire that's been cold drawn can also be annealed because the heat treatment removes the stresses in the grains and enhances its mechanical properties.

In addition to this, annealing tends to be used in sectors where it is vital for metals to be shaped into complex designs or re-worked several times.

annealing metal for jewellery

Additional Processes at Dean Group

Castings, whether manufacturing through our aluminium investment casting (ELITE), our premium-grade investment casting or our commercial-grade investment casting process, may have to be put through other treatments in order to improve their natural properties.

Not only do we provide heat treatments like annealing at Dean Group, but we also offer several surface finishes that will enhance your products and boost their visual appeal. We've also written a guide to anodising, and why it's so important in investment casting, which can help you to further understand why some additional treatments and processes are needed.

With our comprehensive service, you don't have to shop around to find another company to finish your castings. You can also rest assured that we prioritise quality above everything, meaning your castings will perform well for a very long time.

We can advise on the right materials for your project, help you to tweak your concept, validate your design, advise on the best investment casting process for you, and suggest the treatments that are best suited for your products and their applications, so get in touch for more information; we're happy to help!

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