PURPOSE: To provide a hollow die for extruding aluminum alloy containing zinc capable of preventing a crack and prolonging the service life of the die without changing a structure so much.
CONSTITUTION: Bridges 19a and 19b on the right and the left sides are members for connecting a mandrel member 13 with an outer cylinder member. The bridges 19a and 19b are provided with a projecting part 23 smoothly projecting on a mandrel member 13 side, and the surface of this projected part 23 is formed with a coating film 25. This coating film 25 is a 3mm thickness layer consisting of Ni alloy having the compositions of 53 Ni, 18.0 Cr, 3.1 Co, 18.5 Fe and 0.18 Si, and the film 25 is strongly joined to the projecting part 23 of the bridges 19a and 19b on the left and the right sides by cladding by welding.
TANAKA YASUYUKI
KUMAZAKI HIDENORI
