Heat Treatment

Metal heat treatment is a controlled process used to alter the physical, mechanical, and sometimes chemical properties of metallic materials through heating and cooling. The process involves subjecting metal parts or components to specific temperature ranges for predetermined periods of time, followed by controlled cooling. Heat treatment can enhance properties like hardness, strength, toughness, and even improve certain manufacturing characteristics. 

Heat treatment can take place in conjunction with the casting process.

Annealing: Annealing involves heating the metal to a specific temperature and then slowly cooling it. This process relieves internal stresses, improves machinability, and enhances ductility. It is often used to soften metals after extensive cold working, making them easier to work with. 

Quenching: Quenching rapidly cools the metal after it has been heated to a critical temperature. This process "freezes" the atomic structure, resulting in increased hardness. However, quenching can also make the metal more brittle, so it's often followed by tempering. 

Tempering: Tempering is a process that follows quenching. It involves reheating the metal to a specific temperature, which is lower than the quenching temperature, and then allowing it to cool. Tempering reduces the brittleness induced by quenching and imparts improved toughness and ductility to the metal. 

Hardening: Hardening involves heating the metal to a specific temperature and then rapidly cooling it, typically through quenching. This process increases the metal's hardness and wear resistance. Different metals require different hardening procedures. 

This is the process that I used on my 1-2-3 Block project

Normalizing: Normalizing is similar to annealing but involves cooling the metal in still air after heating it to a critical temperature. This process refines the grain structure and improves uniformity in material properties. 

Carburizing: Carburizing is a case-hardening process where carbon is introduced to the surface of a low-carbon steel by heating it in a carbon-rich environment. This forms a harder outer layer while maintaining the toughness of the core.