In this thesis, it comes true that cryogenic turning takes the place of grinding by hard turning 45 hardened steel index cutter of hornesses alloy on CAK6150C CNC lathe. On the basis of establishing planar cutting model and cutting equation, comparing with the transmutation coefficient of the chip, measuring orthogonally the dynamic cutting force , analyzing the rigidity of technical system in frequency chart , measuring contrastively the surface roughness of the workpieces , and researching on the mecha...