Annealing Heat Treatment Process, Part 1

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Annealing Heat Treatment Process, Part 1

Jeweler processing metal bar by heating it up

Whether we’re talking about steel or several other kinds of metal, there’s often a desire to change the mechanical properties during a project. Metals have certain properties to begin with based on their composition, but many of these can be altered to some degree or another, and one of the most common processes here is heat treatment.

At Wasatch Steel, our steel services include various processing formats to help you get the exact properties and applications you require from our steel. One heat treatment format that’s regularly used is called annealing, which has a few specific purposes and processes. In part one of this two-part blog, we’ll go over all the basics you need to know about annealing when you buy custom steel from us.

Annealing Basics

The primary goal of the annealing heat treatment process is to increase the ductility of a given metal while also decreasing its hardness. Essentially, you’re attempting to make it a bit more malleable while also sacrificing a small amount of strength.

During annealing, the crystal structure of the metal being worked on has its dislocations reduced – this is what leads to these changes in hardness and ductility. It’s a process often completed after hardening or cold working has already taken place, with the goal of stopping a brittle failure or improving formability for future processes.

Why is it Done?

What are the reasons why you would want to increase ductility and lower hardness levels in your metal? There are a few:

  • Improving machinability: Wearing concerns aren’t just for the metals that are being worked on in a given project – they’re also for the tools being used. If your metal is too brittle, for instance, tool wear is a common result. Less hardness in metal through the annealing process lowers this risk.
  • Formability increase: Another quality of harder, more brittle metals is trouble bending or pressing them without fracturing materials and creating major issues. Through annealing, though, you can make these kinds of form changes easier to achieve.
  • Residual stress removal: Residual stresses are the result of various form changes, and can create cracks or other issues in metal. Annealing lowers the risk of these stresses taking place to begin with.

Metals Used

The only basic requirement for whether a metal can be annealed or not is whether it’s capable of being altered using heat treatment at all. Most types of steel fall under this classification, as do most types of iron and cast iron. There’s a bit more variation in other metal types, but you can find forms of aluminum, copper, brass and other metals that will do well with the annealing process.

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