Machinability of bainitic steels
Typ
Examensarbete för masterexamen
Master's Thesis
Master's Thesis
Program
Materials engineering (MPAEM), MSc
Publicerad
Författare
Papadopoulos, Pavlos
Modellbyggare
Tidskriftstitel
ISSN
Volymtitel
Utgivare
Sammanfattning
Recently, Volvo Trucks has been exploring various methods to reduce the CO2 footprint of large automotive vehicles. This involves not only limiting the emissions produced during vehicle operation but also minimizing the ecological impact of their manufacturing processes. One promising approach is the adoption of new materials that enable more efficient and lightweight designs. Bainitic steels are a class of materials that could meet these requirements. They offer superior mechanical properties compared to traditionally used steels with a pearlitic-ferritic microstructure, allowing for the design and production of smaller and lighter components without compromising strength. However, their enhanced mechanical properties can present challenges during machining operations.
Thus, the aim of this thesis is to explore the machinability of bainitic steels and compare it with that of the currently adopted pearlitic-ferritic steels. Both materials were characterized in detail, focusing on microstructure evaluation, examination of non-metallic inclusions, and hardness testing. Additionally, a series of face turning operations were performed on each material to obtain data regarding cutting insert wear development, the impact of tool wear on machining forces, the interaction between the workpiece material and the cutting tool, the protective layers formed on the tool surfaces, and the effects of different cutting conditions on machining forces and chip formation. Overall, it was found that tool wear is more aggressive when machining bainitic steels, and machining forces are also higher. The layer formed on the cutting inserts exhibits relatively small differences between the two materials. Furthermore, chip breakability is slightly better during the machining of bainitic steel.
Beskrivning
Ämne/nyckelord
Machinability, , Face turning , Bainitic steel , Micro-alloyed steel , Non-Metallic Inclusions (MNIs) , Tool Wear , Machining forces