PURPOSE: To enable the internal surface of a pipe material to be polished uniformly further in a good condition, by arranging magnetic poles in an opening angle of 180° or less so that a magnetic polishing material, supplied into the pipe material to be polished, is strongly distributed to be bridged.
CONSTITUTION: Paired magnetic poles 1, 2 are opposed to the outside of a pipe material (for instance, pipe) P being a material to be polished. The paired magnetic poles 1 and 2 are arranged so that a line, connecting the magnetic pole end part opposed to the peripheral surface of the pipe material P to its axial center, forms an opening angle less than 180°, forming the magnetic field of large intensity ununiformly concentrating in the pipe material 1. This ununiformly concentrating magnetic field orients a granular magnetic polishing material 30, supplied into the pipe material P, to be strongly bridged in the pipe material P. Under this condition, relatively rotating the pipe material P to the magnetic poles 1, 2, the internal surface of the pipe material is polished by this bridge-oriented magnetic polishing material 30.
TAKEDA NOBORU
SUZUMURA TAKEO
SHIMADA MASAAKI
KUREHA ENG KK
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