Observations of deformation in the orthogonal machining of a mild steel

The paper describes an experimental investigation of the nature of the deformation zone in machining mild steel. A ‘quick-stop’ device having an exceedingly high deceleration was used to collect chip root specimens for examination by a scanning electron microscope. It is shown that microcrack formation plays a significant role in the cutting of a two-phase material, such as steel. The interrelationship between microcracks and chip type is examined and the influence of microcrack formation on the surfaces of the newly machined workpiece and of the chip is considered.