What is tempering in metallurgy?

Tempering in metallurgy refers to the process of reheating a hardened metal to a specific temperature and then allowing it to cool, which improves the toughness of the material without significantly affecting its hardness. This process is typically performed after hardening, where the metal has been subjected to techniques such as quenching to increase hardness. However, this increase in hardness can make the metal brittle. By tempering, the internal stresses are reduced, and the microstructure is modified, resulting in enhanced ductility and toughness, making the metal more suitable for various applications while maintaining a desirable level of hardness.

This understanding of tempering is crucial for materials engineers and metallurgists, as it allows them to tailor the properties of metals for specific uses, balancing hardness and toughness. The right tempering temperature and duration can vary depending on the type of metal and the desired characteristics.