Fe-3.5%Si粗大結晶の切削機構

Abstract

This paper describes the cutting mechanism of large crystals of Fe-3.5%Si crystallographically. The experiment was conducted under the two-dimensional cutting. The large crystals (average diameter is about 5 mm) were produced through the strain anneal method. The orientation of the crystals were determined by the Laue X-ray back reflection method.The main results obtained are as follows:(1) In spite of two dimensional cutting, the side force (force component acting in direction normal to the side plane of a workpiece) occurs because the slip deformation takes place three-dimensionally.(2) The cutting force and the chip formation mechanism are divided into three types according to the difference in the orientation of crystal against the cutting direction; (a) Cutting force is stable and continuous chip generates without built-up edge. (b) Cutting force and chip thickness increase gradually with the advance of cutting. (c) Cleavage fracture occurs.(3) There is good agreement between the observed shear angle and the expected one based on the assumption that shear deformation occurs in the slip system {011}〈111〉 and {112}〈111〉.(4) Cleavage fracture occurs with a small angle difference between the direction of the resultant cutting force and the direction of intersection of the cleavage plane {011} and the side plane of a workpiece.(5) In the case of stable cutting, the shear stress in shear plane (τ) is related to the shear strain (γ) by the following equation. τ=13+39γ (kg/mm2).