Common steel heat treatments include annealing, normalizing, quenching and tempering. They adjust steel’s internal microstructure by controlling heating temperature, holding time and cooling rate, thus improving mechanical performance.
The main purposes of heat treatment are to optimize steel properties. It adjusts hardness and toughness to suit machining and service conditions, removes internal residual stress to avoid deformation and cracking, and refines grain structure to stabilize material quality and enhance fatigue resistance.
Each process has practical applications. Annealing softens steel for easy processing. Normalizing refines microstructure and improves structural steel strength. Quenching and tempering increase hardness and wear resistance, suitable for gears, tools and load-bearing parts. These treatments help steel meet industrial usage requirements.