| 摘要 |
PROBLEM TO BE SOLVED: To surely prevent reduction of yield of products caused by cracking generated at the time of an after process by performing preliminary forging work for improving ductility, on a cylindrical impeller raw material formed in such a way that rapidly cooled and solidified aluminum alloy formed by a spray forming method is extrusion-worked within a specified temperature. SOLUTION: An impeller 1 is attached to a rotor shaft 2, and is disposed in a casing 9. In this case, rapidly cooled and solidified aluminum alloy of Al-Fe as a material of the impeller 1 is manufactured by means of such a spray forming method that fused metal is sprayed by inert gas and is stuck simultaneously with rapidly cooled and solidified with cooling speed of 102 deg.C/sec or more. After its manufactured mold is hot-extrusion worked within a temperature of 200 to 600 deg.C, preliminary forging work is performed for improving ductility of a surface layer in both side surfaces of the extrusion raw material. After that, regular forging work acted to an inside of the extrusion raw material, and stamping work using a prescribed mold are performed. |
