Micro Cutting Process of Ultra Fine Grain Steels.

The paper discusses the effect of the crystal grain size of materials on the micro cutting processes. The cutting process of ultra fine grain carbon steel, which consists of 0.5 μm sized grains, is compared with those of the larger grain steels. The micro cutting tests were performed to measure the cutting force with changing the cutting thickness. The cutting force of the ultra fine grain steel is larger than that of the large grain steel corresponding to the hardness change of materials. The specific cutting forces remarkably increase when the cutting thickness becomes less than 10 μm. The shear angle of the ultra fine grain steel is larger than that of larger grain steels in small cutting thickness. The uniform chip formation is also observed with fine surfaces in cutting of the ultra fine grain steel. [ABSTRACT FROM AUTHOR]