Which process involves heating and slowly cooling metal to soften it?

The process that involves heating and slowly cooling metal to soften it is known as annealing. In annealing, a metal is heated to a specific temperature where its structure becomes more malleable and any internal stresses are relieved. This heating process is followed by a controlled cooling phase, which allows the metal to achieve a softer and more ductile state, improving its workability and reducing brittleness.

Annealing is particularly important in manufacturing processes where metals are shaped or formed, as it helps to ensure that they can be manipulated without cracking or breaking. The controlled cooling is critical because it allows the metal to recrystallize into a uniform structure, enhancing its overall properties.

In contrast, the other processes mentioned serve different purposes in metallurgy. Quenching, for example, involves rapid cooling to harden the metal, often making it more brittle. Tempering is a process used to reduce the brittleness of quenched metals but is not primarily aimed at softening them. Normalizing is similar to annealing but is typically performed at higher temperatures and generally results in slightly harder metal compared to annealing, as it is focused on refining grain structure rather than softening.

Thus, the focus on heating and controlled cooling to soften metal distinctly characterizes annealing