Study on Micro Inclusions in Aluminum Alloy Gearbox for High-speed Train

Author of the article:ZHOU Bin 1 , GONG Jialin 1 , QIN Yiming 2

Author's Workplace：1.CRRC Qishuyan Institute Co., Ltd., Changzhou 213011, China; 2. Geely Baikuang Group Co., Ltd., Baise 533000, China

Key Words：gearbox; inclusion; iron-rich phase; AlSi7Mg

Abstract：In order to improve the reliability of high-speed train gearbox, the morphology and composition of
micro-inclusions in the material of high-speed train gearbox were studied by metallography and EDS analysis. The results
show that the microcosmic inclusions are mainly Fe-rich phases. Magmasoft software is used to simulate the casting process
of gearbox, and it is found that the Fe phase formed is fishbone shape when the solidification is rapid, while the Fe phase
is long needle shape when the solidification is slow. The P-V curve data of the samples show that the crack is more likely
to propagate in the long acicular iron-rich phase samples, indicating that the damage is greater. When designing the foundry
process of the gearbox, drastic cooling measures should be taken in the key areas to reduce the harm of iron and improve
the safety factor of the gearbox.