After manufacturing coil springs, internal stresses exist within the steel wire. These stresses can lead to defects and may impact the working lifespan of springs. Stress must be relieved to maximize the elastic properties of the spring alloys. Stress relief is a critical step during the manufacturing process, typically using large belt furnaces and convection ovens. The fluidized bed heat treatment system is an alternative for stress relief of small- and medium-sized coil springs. Springs are suspended in a parts basket and deposited into a fluidized bed furnace, consisting of fine aluminum oxide particles gently mixed by an upward air flow. With its high heat transfer coefficient, fluidized bed relieves the stress in coil springs in significantly less time than other conventional heat treatment methods. Bed temperature is accurately controlled using either electric heaters, with excellent thermal uniformity throughout the working area of the bed. Fluidized bed, with its advantages of uniformity and quick turnaround time, render it the best option for the rapid and efficient stress relief processing of coil springs and heat treatment of other metal components.

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