Abstract:

Based on the orthogonal cutting experiments,the formation characteristics and deformation mechanism of the pure iron chip at different cutting speeds were investigated,and the effects of such cutting process parameters as the rake angle,the cutting parameters and the cooling/lubrication conditions on the deformation rules of the pure iron chip were revealed by experiments.The results show that (1) the pure iron chip has a significant shear slip deformation characteristic，and the cutting process parameters only affect the deformation of the grains in the pure i- ron chip; (2) at lower cutting speeds,an obvious“sliding-stop-sliding”phenomenon occurs as the chip flows on the rake face,and the grains are seriously broken; (3) however,at higher cutting speeds,the stop phenomenon is reduced and even disappears,and the grains in the pure iron chip show a tensile deformation; (4) as the cutting speed and the rake angle increase,the cutting force and the chip deformation coefficient significantly decrease; (5) with the increase of the feed rate,the cutting force increases while the chip deformation coefficient decreases; and (6) at the same cutting parameters,the cutting force and the chip deformation coefficient are at the minimum under the cutting fluid condition,but they are at the maximum under a dry cutting,The above-mentioned results are useful in selecting suitable cutting process parameters to improve the machinability of pure iron materials.

Key words: pure iron, orthogonal cutting, chip deformation mechanism, cutting force, chip deformation coeffi- cient