Question

Grey cast iron generally has poor machinability due to the presence of graphite flakes in it.

(a) True

(b) False

This question was addressed to me during an interview for a job.

This is a very interesting question from Cast Irons in section Foundry Introduction & Materials of Casting-Forming-Welding II

Answer 1

The correct choice is (b) False

For explanation: When the fracture of grey cast iron occurs, the crack path follows the graphite flakes and the fracture surface appears grey in color due to the presence of graphite. The graphite flakes have good damping features and high machinability because the graphite flakes work as a chip breaker and also lubricates the tools or machines.