Forged scroll part and production process thereof

Abstract

A process for producing an aluminum alloy-made forged scroll part includes a step of casting an aluminum alloy material into a round bar having a diameter of 130 mm or less, the aluminum alloy material comprising 8.0-12.5 mass % of Si, 1.0-5.0 mass % of Cu and 0.2-1.3 mass % of Mg; a step of cutting the aluminum alloy round bar into a stock material for forging; a step of subjecting the stock material to upsetting at an upsetting ratio of 20-70% to form a pre-shaped product that is a workpiece; and a forging step of applying pressure onto the workpiece with a punch at a temperature of 300-450° C. to form a scroll wrap in a direction of the punch pressure, and wherein the forging step includes a single step in which a forged scroll part is press-formed while a back pressure smaller than the punch pressure is applied to an end of the scroll wrap in a direction opposite to the punch pressure direction. With this method, it is possible to produce a forged scroll part capable of suppressing occurrence of coarse primary Si crystals and reducing a variation in height of a wrap in a scroll part and in every scroll part being forged.

Dependencies are inferred from the claim text.