High Surface Speed Turning and Boring of PM Carbon Steel

This paper is discussing how a specific machining problem was resolved. The part is an engine cylinder liner made of PM steel. The liner had to be machined by the engine manufacturer after it was cast in place in an aluminum engine block. The liner was bored in a customized transfer machining line, with the machining parameters set for boring of gray cast iron or eutectic aluminum engine bore.

The developed technology permits machining of PM carbon steel at surface speed at or above 700 m*min-1 in both wet and dry condition using CBN (cubic boron nitride) material in the insert. The liner is surface treated in the bore prior to the aluminum casting process and the liner material has an elevated content of iron sulfide (FeS) enhancing the machinability of the liners. The cost of machining is today in parity to conventional products. There are still options for further improvements.