PURPOSE: To arrange short fibers in the peripheral direction of a tube and to reduce thermal expansion in the radial direction by performing ring rolling work after forming an FRM billet of a thick wall tubular shape by pressure casting.
CONSTITUTION: A thick wall tubular preform 11 is made and is preheated. The preheated preform 11 is set in a metal mold 15 and an aluminum molten metal 17 is poured into the mold 15. A billet 13 is formed by pressuring the metal 17 to impregnate the preform 11 with the metal 17. A pressure roller 112 and a mandrel roller 114 rotate the billet 13 around the axis in the direction shown by the arrow with the billet 13 pressured and held between the rollers 112 and 114. By such method, the billet 13 is hardly elongated in the axial direction and is mainly elongated in the peripheral direction, so that random directions of reinforcing short fibers 19 of the billet 13 are aligned with the peripheral direction.
MAE SHIGENORI
TSUNODA TAKAYUKI
URAI TAMAMI
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