Abstract:
Improving the strength of grey cast iron wheel hubs will improve the safety of automobiles
and have a great significance for energy saving and environmental protection. This paper systematically
compares the calculation results of Python-based precipitation calculation and JmatPro software
simulation with experiments. The results show that with a low mass fraction of niobium (0.098%)
cuboid Niobium Carbide (NbC) precipitates do not form in the liquid phase; however, an elongated
NbC niobium-rich phase may form during the solidification process and in the solid phase. However,
cuboid NbC precipitates can be precipitated from the liquid phase when the niobium mass fraction is
higher (0.27%, 0.46%). These results indicate that with the increasing niobium content the amount,
particle size, and initial precipitation temperature of niobium carbide precipitated in the matrix
structure will increase. According to the observation and statistical analysis of the microstructure,
it is found that tensile strength will be improved with an increase in niobium content due to the
refinement of the graphite and pearlite interlamellar spacing. In this paper, adding less than 0.32% of
Nb to grey cast iron is recommended, considering the comprehensive cost and the effect of niobium
in the material structure.
