What Is Annealing in Metal?

As anyone in the metal industry will tell you, not all metals are created equal. But that’s because metals are made differently depending on their unique uses. For example, tempering and annealing are methods of heat-treating metal, but both have their differences when it comes to the desired outcome. 

For the purposes of this article, let's focus on the definition of annealed metal, the process for annealing metal, and how it's used.

Annealing Definition

By definition, annealing involves heating a material and allowing it to cool slowly to remove stresses and make it easier to work with. When a metal material is heated, its physical properties alter to increase its ductility and reduce its hardness. More specifically, the metal is heated above its recrystallization point, causing atoms to shift in the crystal lattice and recrystallize as the metal cools. 

ANnealing Metal Process

The annealing process takes place in a metallurgical furnace and is typically performed at an integrated or reroll mill. Three main stages occur during the annealing process:

• Recovery stage — The initial heating of a metal to the temperature point where the metal can relax and become malleable.
• Recrystallization stage — The stage when a metal is heated above its recrystallization point but lower than its melting point for new grains to develop without forming preexisting stresses.
• Grain growth stage — During this stage, grains forming during the recrystallization stage fully develop. By controlling the cooling process, the grain growth yields a more ductile and less hard material.

Pros and Cons of Annealing

Annealing serves many purposes, but it also isn’t the right process for every application. Below are the pros and cons of annealing. 

Annealed Metal Uses

Common metals that undergo annealing include steel, cast iron, and other varieties like aluminum, copper, and brass. After metals are annealed to improve formability, machinability, and reduce stresses, they are used in various applications where metals are worked on several times or formed into complex parts and structures. Here are a few examples:

• Sheet metals are annealed to allow for better machining, bending, punching, forming, or cutting.
• Metals often undergo annealing after being cold-worked to restore their original properties.
• Annealing helps improve the electrical conductivity of certain metals
• Annealed metals are commonly used in manufacturing objects, including springs, washers, saw blades, antennas, and other components used in hand tool manufacturing.
• Due to their high-yielding strength, annealed metals are incredibly resilient, making them widely used in small aircraft manufacturing.

Your Source for Annealed Metal

Mead Metals is an ISO-certified metal service center providing a wide range of products and finishing services for manufacturers around the U.S. We offer annealed spring steel in an array of grades, including bright annealed spring steel sheets and thicknesses running from 0.010” to 0.187”. Whether you need annealed steel in low or high-volume sizes, we can make it happen. Start the process by submitting a free Mead Metals Quick Quote today.