In-line, High-volume, Low-distortion, Precision Case Hardening for Automotive, Transmission and Bearing Industry

摘要

Gears and bearings are part of mechanical power transmission devices used in machinery and vehicles. They are produced on a massive scale, and for the automotive, transmission and bearing industry and global annual output reaches billions pieces. 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 precision and repeatability of the process results particularly in mass production. A single-piece flow case hardening system based on low pressure carburizing (LPC) and high pressure gas quenching (HPGQ) will be presented. The system which allows individual adjustment to the size and shape of the particular part in order to minimize hardening distortion and ensures ideal repeatability of results throughout the parts series. It is a compact system designed for high-volume heat treatment of parts in a lean manufacturing configuration ready for implementation within machining centers.