In-line, high-volume, low-distortion, precision case hardening for automotive, transmission and bearing industry
Gears are commonly made of steel and have teeth with a hard surface and a flexible core which provides suitable strength and service life. These properties are usually obtained by heat treatment often on the basis of carburizing and quenching. In addition to the positive effect on the mechanical properties, heat treatment is related to deformation hardening, which negatively impacts the quality and significantly increases the costs of production while corrective hard machining is applied. For this reason, the aim is both to minimize distortion and to increase the repeatability of deformation particularly in mass production.
This article will look at the major causes of deformation during traditional heat treatment and methods of their control, correction and elimination. A single-piece case hardening system will be presented which allows individual adjustment to the size and shape of the particular gear in order to minimize hardening distortion and ensures ideal repeatability of results throughout the gears series. It is a compact system designed for high-volume heat treatment of gears in a lean manufacturing configuration ready for implementation within machining centers. Additionally the article will discuss the operational aspects and the costs and productivity.