Abstract
To clarify the mechanism of steel wool cutting, the effect of metallurgical factors such as strength, micro-structure, and nonmetallic inclusions, on the machinability of the steel wool wire were investigated from the viewpoint of the microscopic fracturing of the material in the vicinity of the tip of the cutting edge. The results obtained are as follows :
(1) The shear deformation of the material in the plastic deformation zone is preceded by microscopic fracturing along the grain boundaries which are elongated by cold drawing with a high total reduction of area.
(2) The metallurgical factors making the grain boundaries embrittle, such as coarse ferrite/pearlite structure, more than 80% total reduction in area by cold drawing, etc., improve the machinability of steel wool wire.
(3) Changing the composition of nonmetallic inclusions to that characterized by low melting points, andreducing the total amount of nonmetallic inclusions are effective for the improvement of the machinability of steel wool wire.
