{"id":19868,"date":"2022-12-19T15:30:41","date_gmt":"2022-12-19T13:30:41","guid":{"rendered":"https:\/\/fractory.com\/?p=19868"},"modified":"2024-01-26T13:23:57","modified_gmt":"2024-01-26T11:23:57","slug":"tempering-explained","status":"publish","type":"post","link":"https:\/\/fractory.com\/tempering-explained\/","title":{"rendered":"Tempering Explained – Definition, Process, Benefits and More"},"content":{"rendered":"

Tempering is one of many heat treatment processes for iron-based alloys<\/a>. These processes alter the physical and mechanical properties such as a metal’s internal structure, ductility, hardness, toughness, machinability, formability, elasticity and strength.<\/p>\n

We need these changes to ensure metals are fit for their applications and service environments. Without heat treatment, it is not possible to use metals to their full capacity in most systems.<\/p>\n

In this article, we will explore the tempering process. Let’s begin.<\/p>\n

What Is Tempering?<\/h2>\n

Tempering, also referred to as drawing,\u00a0 is a heat treatment process<\/a> in which the components are heated and held to a set temperature below the critical point<\/a> for a certain duration. The components are then cooled to room temperature in still air.<\/p>\n

Like other heat treatment processes such as annealing and normalising<\/a>, the tempering process alters the metal’s undesirable mechanical properties<\/a> to be more in line with the proposed application.<\/p>\n

Tempering affects the entire component’s mechanical properties from the surface to the core. But partial tempering is also possible in induction plants.<\/p>\n

Tempered metals are useful in applications that need a certain level of flexibility from their components.<\/p>\n

This heat treatment process may also be used to reduce the hardness of recently welded components. The high localised temperature from the welding process can lead to high hardness in heat-affected zones<\/a>. Tempering can help us alleviate these high-hardness sections.<\/p>\n

In theory, tempering can be carried out on a wide range of metals but it is generally associated with carbon steel as few other metals react to this heat treatment method in the same manner as steel.<\/p>\n

When Is Tempering Used?<\/h3>\n

Tempering is most often performed after hardening processes.<\/strong> In these processes, the material is heated above its upper critical temperature followed by a rapid cooling aka quenching operation<\/a>. Quenching is the immersion of steel in oil, hot water or forced air.<\/p>\n

Such an operation makes the material hard and brittle, as brittle as glass in some cases. While we do need high hardness in many applications, the increased brittleness that accompanies it is not as desirable.<\/p>\n

To reduce the brittleness and restore ductility<\/strong>, the metals are reheated, this time to lower temperatures (above 200\u00b0C). This helps us to strike a balance between hardness<\/a> and ductility. The cooling rate during tempering is also slower than quenching.<\/p>\n

For best results, the tempering process must be carried out immediately after quench-hardening. This helps to avoid the brittle characteristics brought out by the hardening process.<\/p>\n

It should be kept in mind that any errors during the process can damage, distort or warp the material.<\/p>\n

Tempering is also carried out when the material is hardened through other means such as a welding process<\/a>. It also works for work-hardened materials. These are materials that have become hard through processes such as bending<\/a>, drilling, forming, punching<\/a> and rolling<\/a>.<\/p>\n

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