Sustainable production of case-hardened powertrain parts through high temperature carburizing

Research question

Low-pressure carburizing (LPC) at high temperature is regarded as a more sustainable technology compared to the atmospheric gas carburization to produce case-hardened steel parts for powertrains. The processing time is shorter and despite higher processing temperatures, the energy consumption is substantially reduced. It also leads to reduced gas consumption and lower emissions of CO₂ and CO. Despite being a rather mature technology, the full potential of the LPC technology is not yet utilized. The reason is a limited understanding of the microstructure evolution at elevated temperatures in the LPC process and ability of controlling it, particularly with respect to grain growth.

The goal of this project is to develop an approach where the alloy composition and the process conditions are optimized simultaneously to enable microstructural control during LPC while maintaining the material properties required for powertrain parts. The foci are on grain growth mechanisms and how they are affected by the temperature-time evolution and chemistry. The project is planned to combine computational and experimental approaches to increase the understanding of, and ability to control, grain boundary migration in steels at conditions typical for LPC and high temperature carburizing.

Sustainability aspects

The project aims to increase the process temperature during LPC to reduce process time, improve productivity, and enhance the business case for low-pressure carburizing. The project aligns with UN Sustainable Development Goal 12 by reducing process gases and CO₂ emissions. Moreover, LPC is often associated with gas quenching, which is a cleaner process than oil quenching. It also addresses goal number 3 “Good Health and Well-Being” as conventional gas carburizing releases some carbon monoxide in the workshop. Even if the quantities of carbon monoxide are very small and not dangerous, it is not recommended for pregnant women to be near carburizing furnaces, which in effect touches the goal number 5 “Gender Equality”.