The Role of Liquid Metal Embrittlement on the Chip Disposability of Steel

This investigation was carried out to verify the role of liquid metal embrittlement by Pb, Bi and Te on the chip disposability of steel. A computer program using finite difference method to calculate average chip temperature was made, and the results were compared with chip morphology and fractography. It has been verified that the average chip temperature exceeds the melting points of Pb and Bi in most of the cutting conditions tested. As a result, liquid metal embrittlement takes place which reduces the ductility of chip. Consequently, the chip can be broken easily, and its disposability is improved. On the other hand, the Te addition does not improve chip disposability, because the chip temperature does not exceed the melting point of PbTe or the eutectic point of MnS-MnTe. Further, liquid Ag does not embrittle steel, and thus no improvement in chip disposability is observed.