GB644841A - Hollow cast crankshafts - Google Patents

Abstract

644,841. Casting composite articles; casting processes. FIFE, J. G. (Meehanite Metal Corporation). May 24, 1948, No. 14001. [Class 83 (i)] In casting a hollow crank-shaft about a strengthening insert, this is made of or coated with a metal or alloy which prevents excessive diffusion of carbon from the crank-shaft into the insert. This may be made of copper nickel, copper, tin, &c. of sufficient thickness to prevent any fusion, of steel coated with copper or nickel or of alloy steel, e.g. containing about 1 per cent of silicon. The insert may be made from sheet or by casting or machining &c. It may be of barrel form and with external projections 21, recesses, or roughening or be perforated. Its thickness should not much exceed one sixth the thickness of the adjacent cast section in the case of ferrous or one fifth in the case of non-ferrous metal. To produce the desired structure in the cast metal, the insert 10 may be filled or lined with a layer of metal or alloy 22, Fig., 2, having such a melting point that, in casting it wi 11 vapourize or melt and flow out as shown in F:g. 7, and thick enough to absorb the desired amount of heat. In Fig. 3 the filling 20 is granular. If lined, the insert should be at least <SP>1</SP>/ 64 inch thick and if unlined <SP>1</SP>/ 32 inch. A filling of a heat-absorbing salt or salts may be used instead of metal. The ends 18, Fig. 7, of each insert supported by the mould material 13 are finally machined away. A single insert 23, Fig. 8, may be used to core out adjacent crank-pins 24 and the intervening web.