spraytempering

Spray tempering is a heat treatment process used to improve the mechanical properties of certain materials, particularly steels. It involves rapidly heating a localized area of a steel component to its austenitizing temperature, followed by a rapid quench in a liquid medium. The key characteristic of spray tempering is the use of a spray of quenching fluid, such as water or oil, directed precisely at the heated zone. This localized heating and rapid cooling result in the formation of a fine martensitic or bainitic microstructure in the tempered region, leading to increased hardness, strength, and wear resistance.

The process typically begins with induction heating or flame heating to raise the temperature of the desired surface or area of the component. As the target temperature is reached, the spray nozzle delivers a precisely controlled stream of quenching fluid. The spray allows for finer control over the cooling rate and the extent of the tempered zone compared to immersion quenching. This precise control is crucial for achieving the desired metallurgical structure without introducing excessive residual stresses or distortion.

Spray tempering is often employed for components that require localized hardening, such as camshafts, crankshafts, gears, and valve seats. It offers advantages over other hardening methods, including faster processing times, reduced energy consumption, and the ability to treat complex geometries with less risk of distortion. The depth of hardening and the resulting microstructure can be adjusted by varying the spray intensity, temperature of the quenching fluid, and the speed of the spray relative to the workpiece.