1. Heat treatment is a critical and complex factor in gear manufacturing, which greatly affects the performance of each gear in transmitting power or motion to other components in the assembly. Heat treatment optimizes performance and extends the life of gears in service by altering their chemical, metallurgical and physical properties. These properties are determined by considering gear geometry, power transfer requirements, stresses at various points within the gear under load, duty cycle rates, material types, mating component design and other operating conditions.

2. Heat treatment improves physical properties, such as surface hardness, which imparts wear resistance to prevent simple wear on the tooth and bearing surfaces; heat treatment also improves gear fatigue life by creating subterranean compressive stress to prevent high contact on gear teeth Stress-induced pitting and deformation. These same compressive stresses prevent fatigue failure at the gear root due to cyclic bending.

3. Physical properties such as surface hardness, core hardness, surface depth, ductility, strength, wear resistance and compressive stress distribution can vary greatly depending on the type of heat treatment applied. For any given type of heat treatment, the results can be adjusted to meet specific application requirements by varying process parameters such as heat source, temperature, cycle time, atmosphere, quench medium, and tempering cycles.