Study on a New Internal Finishing Process by the Application of Magnetic Abrasive Machining : Internal Finishing of Stainless Steel Tube and Clean Gas Bomb

Abstract

In magnetic abrasive machining, the internal finishing of a nonferromagnetic tube is performed by means of the magnetic force generated between magnetic abrasive and the N-S magnetic poles. In this experiment, "mixed-type magnetic abrasive" are applied to finish the internal surface of a tube, in which large iron particles, generating a high finishing pressure, are mixed with magnetic abrasive resulting in finishing. By this new process using the mixed-type magnetic abrasive, the finishing efficiency is increased markedly. In this paper we describe the effects of both the size and the mixed weight percentage of iron particles on the surface roughness of a stainless steel tube. We also describe the application of the new process to the internal finishing of the bottom of a clean gas bomb for practical use. As a result, the surface roughness before finishing, 7 μm R_max, was reduced to 0.2 μm R_max over the entire inner surface of the bottom.