PURPOSE: To obtain a magnet with uniform density distribution and no over- filling by hot-rolling an ingot in a metal capsule, by using pressure roll constituted of a female roller which has ring type grooves on the outer periphery and a male roller which has protrusion engaging with said grooves.
CONSTITUTION: A pressure roll is constituted of a female roller 1a which has ring type groove 2a, 2b on the outer periphery and a male roller 1b which has ring type protrusions closely engaging with said grooves 2a, 2b. Hot-rolling is executed by a closed type box hole mold formed by the grooves 2a, 2b and the protrusions 3a, 3b. An ingot 4 of alloy whose basic components are rare earth elements, iron and boron is encapsulated in a metal capsule 5, and subjected to rolling by using the roller. As a result, the rolling without over- filling is enabled up to a plate thickness reduction ratio of 30%. Thereby, uniform and high magnetic performance is obtained in a section, and a specified plate thickness reduction ratio can be obtained by one time rolling process.
MATSUSHITA TOMIHARU
TAKAHASHI YOICHI
OKI TSUGUAKI
MIYAGAWA MUTSUHIRO
YURI TSUKASA
SHIMODA TATSUYA
SEIKO EPSON CORP