Modern quenching oils for low-pressure carburizing processes Requirements – properties – applications

Braun Rainer - BURGDORF GmbH & Co. KG (Germany)

According to DIN EN 10052, quenching is defined as “cooling a workpiece at a greater speed than in still air”.

The quenching process and the quenching product in use are therefore of great importance for the success of the heat treatment process, affecting the resulting material structure and mechanical properties of the heat-treated parts, as well as the height of residual stresses and dimensional and shape changes.

The proper choice of the quenching product, its adaptation to the range of parts and material specifications but furthermore to the existing equipment and process technology is the precondition for reliable and consistent hardening results, reaching the defined requirements for the parts and its subsequent function.

In the last years, low-pressure carburizing (LPC) with subsequent oil quenching has become more and more important in industrial applications as a direct alternative to high-pressure gas quenching processes.

The paper provides an overview of the requirements for the quenching oils and its necessary properties resulting from the LPC-Process. Special attention will be drawn to the possibilities of pressure adjustment to influence the quenching effectiveness and the heat transfer properties. In addition, practical applications are presented.