PURPOSE: To produce castings of which the outside surface is resistant to abrasion and the core part is strong and tough easily and inexpensively in the composite castings of cylindrical or columnar shapes, by forming a high hardness layer contg. WC particles on the outside surface of the outer layer to one body.
CONSTITUTION: Molten metal for an outer layer is cast into a rotary metal mold 2 from a ladle 4 through a trough 5 or the like, whereby the outer layer 8 of a composite roll is cast centrifugally. In the stage of casting the layer 8, WC powder 6 which is plated with Ni, Ni-P, Ni-B, Cu, etc. and is in an ordinary temp. or is preheated to proper temps. is added thereto. The WC powder added to the molten metal for the outer layer separates by gravity during the time until the outer layer solidifies on account of a difference in specific gravities under exertion of centrifugal forces in the molten metal for the outer layer, thus forming a high hardness layer 7 contg. the WC particles on the outside surface of the outer layer in one body. When the layer 8 solidifies, molten metal for a core material consisting of a mild strong and tough material is cast therein in the manner similar to that in the prior art, whereby the layer 8 and the core part as well as neck parts 9 are melt-stuck to one body.
HASHIMOTO TAKASHI
FUNAKOSHI ATSUSHI
| JPS5215047A | 1977-02-04 | |||
| JPS55113851A | 1980-09-02 |