Liquid quenchants, properties and range of application, new research and development in the field of liquid quenchants
According to DIN EN 10052 quenching is defined as “Cooling a part faster than with still air”. The quenching media commonly used for heat treatment of steel and aluminium parts are water, brine, aqueous polymer solutions, quenching oils, molten salts and pressurized gases such as air, nitrogen, hydrogen and helium.
Quenching is a very important part of the total heat treatment process and its success. The heat transfer characteristics of the quenchant strongly influence the parts´ microstructure after heat treatment, the resulting mechanical properties of the quenched component but also the amount of internal stresses and distortion.
The choice of the quenching, its proper use and adaptation to the specific component, heat treatment installation and heat treating process is mandatory to make sure that the heat treated part meets the well defined requirements for safe, consistent and longtime functioning. Last not least an optimized quenching process helps to minimize the costs for heat treatment and rework.
In this paper the main liquid quenching media like quenching oils and polymer quenchants are presented with their physical and chemical properties and their main applications. Moreover the reasons for new research and developments are shown as well as an outlook to current developments in regards to these kind of quenchants but also to heat treatment technologies as well as environmental, health and safety aspects.