Machinability of 100Cr6 bearing steels
Typ
Examensarbete för masterexamen
Master's Thesis
Master's Thesis
Program
Materials engineering (MPAEM), MSc
Production engineering (MPPEN), MSc
Production engineering (MPPEN), MSc
Publicerad
2024
Författare
Andersson, Daniel
Aronsson, Martin
Modellbyggare
Tidskriftstitel
ISSN
Volymtitel
Utgivare
Sammanfattning
The aim of this master’s thesis is to investigate the influence of batch-to-batch microstructural
variations on tool wear evolution when machining 100Cr6 bearing steel
using coated carbides. Furthermore, a secondary aim is to investigate the performance
of coated tool grades coated with different combinations of titanium carbonitride
and alumina when used to machine 100Cr6. Tool life tests under constant
spiral cutting lengths as well as orthogonal cutting tests with in-situ data acquisition
were performed at various cutting conditions to investigate the machinability.
The tool wear results were then correlated with the material and tool characteristics
examined using various methods including light optical microscopy, stereo optical
microscopy, hardness testing, scanning electron microscopy, and energy-dispersive
X-ray spectroscopy.
A notable difference in tool wear evolution was found when machining the steel
batches. The differences in microstructural properties such as the pearlite lamellar
spacing and the measured hardness values were less pronounced, and thus they
cannot solely explain the difference observed in tool performance when machining
different batches of steels. However, the detailed material analysis showed chemical
differences between the batches in terms of calcium and sulphur content, with
corresponding differences in the non-metallic inclusion (NMI) content and type. Differences
in tool wear behaviour when machining the steel batches showed a clearer
correlation with the amount and type of these NMIs. Higher flank wear was observed
when machining the steel batch with lower calcium content, while higher
crater wear evolutions occurred when machining the cleanest batch with considerably
lower sulphur content. Regarding the tool grades and their performance, the
one closest to the current commercial grades (with a nearly equal thickness of alumina
and titanium carbonitride coating layers) suffered the lowest average wear,
whilst the grades having single-layer coatings of either alumina or titanium carbonitride
performed significantly worse.
Beskrivning
Ämne/nyckelord
100Cr6 , machining , machinability , tool wear , inclusion , material characterisation , batch-to-batch variations