Rehardenization

Rehardenization is a heat treatment process applied to steel that has previously undergone hardening. The purpose of rehardenization is typically to re-establish the desired hardness or to alter the microstructure for improved properties. It involves heating the steel to its austenitizing temperature, followed by quenching. The original hardened structure, usually martensite, is transformed back into austenite, which then, upon cooling, transforms into a new hardened structure. This new structure may have different characteristics compared to the original hardened state, depending on the cooling rate and the specific steel composition. Rehardenization can be used to correct issues with insufficient hardness from an initial hardening process or to achieve a specific combination of strength and toughness. It is important to note that repeated rehardenization cycles can sometimes lead to grain growth and increased brittleness, so careful control of the process parameters is crucial to avoid detrimental effects on the material.