| 摘要 |
PURPOSE:To obtain a highly accurate product by forming a hard magnetic reference rod for a magnetic recording type measuring machine by mixing Mn-, Fe-, Ni- and Cu-powders in a definite ratio and applying pressure, sintering or hot extrusion to the resulting mixture along with inevitable impurities. CONSTITUTION:A powder comprising 1.0wt% or less of Mn, 2-30wt% of Fe, 10-40wt% of Ni and the remainder of Cu and inevitable impurities are ground to a particle size of 200 mesh or less and reduced in a hydrogen stream while the reduced powder is compressed under static water pressure to be molded into a round rod shape. Subsequently, the green compact is sintered at 1,000-1,150 deg.C in inert gas or hydrogen gas. In place of press sintering, the aforementioned mixture is received in a copper pipe and hermetically sealed and subjected to hot extrusion at 950-1,020 deg.C in an extrusion ratio of 0.9 or more. Next, diameter reduction processing or ageing treatment is applied to the molded one. By this method, a highly accurate magnetic scale having uniform magnetic characteristics and generating no distortion is obtained.
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