Abstract
Since the invention of the vacuum furnace in the 1950s and up until the 1970s, its primary use was for annealing aerospace components. In the 1980s, vacuum equipment began to be used for heat treating tools and dies. By the 1990s, the need for faster quenching of high-alloy steels led to the development of vacuum furnaces capable of quenching at pressures up to 20 bar. Prior to this, only certain hot-work steels and a few tool steels with small cross-sections could be satisfactorily hardened in vacuum furnaces. Today, it is understood that simply increasing quenching pressure does not necessarily yield optimal results. Modern vacuum furnace technology allows for the precise design of the entire quench curve to maximize material performance while minimizing distortion. Continuous advancements and new concepts, such as multi-directional cooling systems, separate quenching chambers, and integrated cryo-cooling systems, have led to oxidation-free and low-distortion vacuum heat treatment for a wide range of parts and materials. This paper demonstrates how modern vacuum furnace designs and processes can improve quenching and cooling. It includes proven heat treatment results and examples from the international tool and die industry, which has been utilizing this technology over the past 25 years.
