Annealing Heat Treatment Process, Part 2

Annealing Heat Treatment Process, Part 1
September 19, 2018
All You Need to Know About Alloys, Part 1
November 3, 2018
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Annealing Heat Treatment Process, Part 2

Craft jewelery making with flame torch.

In part one of this two-part blog, we discussed some of the basics and metal types that can be put into the annealing process. This process, which involves heat treatment designed to increase the ductility of a metal while decreasing its hardness and making it more formable, has several uses across steel and other metal types.

At Wasatch Steel, we can help you with processes like annealing for any of our steel products. Today, we’ll go over the exact process of annealing, for which there are three stages. We’ll also talk about some of the popular application areas where annealed metal is used.

Recovery

It may sound counterintuitive, but the first stage of the annealing process is called recovery. During this stage, the metal being used is placed into a heating device like a stove or furnace. The goal here is to raise the temperature to a high enough level where internal residual stresses are relieved – these stresses can otherwise form cracks or other complications in metals if they aren’t protected against.

Recrystallization

The heating process continues during the recrystallization stage, which actually ramps up the temperature being used. The ideal range here is a level slightly above the recrystallization temperature, but still below the metal’s melting temperature. As a result of this step, new grains will form in the metal that are not susceptible to the same kinds of already-present stresses we discussed in the recovery stage.

Grain Growth

As this grain growth continues in earnest, we move to the final stage of the annealing process. To help with the development of these new grains, the metal will be allowed to cool at a specified rate – this helps control the specific grain growth and ensure they develop properly. This leaves the metal capable of going through further processes down the line if needed by improving the ductility of metal while decreasing the hardness that can make it tougher to work with.

Primary Uses of Annealed Metals

There are several areas where annealed metals are used commonly:

  • Wire: There are many cases where metal wire needs to be drawn down from its original size to a smaller size. Annealing is the perfect process for this.
  • Welding: During welding, components of the process may create the kinds of residual stresses we mentioned above, which you want to avoid if altering the physical properties of the metal. Annealing, however, helps recreate uniform physical properties throughout the metal.
  • Stamping: Annealing is used for work-hardened materials like sheet metal that have gone through stamping or cold drawn bar stock.
  • Machining: There are various metal working processes that lead to high amounts of displacement or heat. In these cases, annealing is often used afterward.

For more on annealing steel, or to learn about any of our steel products or steel services, speak to the pros at Wasatch Steel today.