ES333227A1 - Apparatus for casting metal wheels - Google Patents

Abstract

A mould 10 for casting railway car wheels comprises cope 11 and drag 12 parts made of a "permanent" material, e.g. graphite, the thin sections of the mould cavity being lined, 30, 31, with insulating refractory material to enable the cast metal to solidify directionally from the outer thicker sectioned tread part of the wheel through the thin sections towards the centre. The linings 30, 31 prevent rapid chilling of the poured metal in the thin sections of the mould cavity and allows the mould 10 to be filled from a single central combined gate-riser 25. The linings 30 may be a ceramic material, e.g. comprising colloidal silica, citric acid, magnesium sulphate and kyanite or may be sand bonded by oil or sodium silicate or resin bonded. The linings 30, 31 are only used once and are replaced on the permanent graphite mould parts by methods indicated in Figs. 4-8 (not shown). These include injecting the lining material between a mould part and a pattern, applying the lining material in a slurry and spreading by a revolving profiled plate (Fig. 4), or, in the case of sand linings, air blowing through ducts (Fig. 7). The ceramic linings are cured by heat, using the residual heat of the cope and drag from previous casting operations. The sand linings are mechanically interlocked to the graphite mould parts by providing grooves and holes (Fig. 8). The hole may have blocking screens (203A), (204A), (205A), (Fig. 8) to prevent sand being lost therethrough during blowing of the sand. The mould 10 comprises a hub core 60 and an insulating pouring sleeve 56 in the riser 25. In applying a ceramic material to the graphite blocks the colloidal silica, citric acid, and kyanite are mixed, kyanite being added until the viscosity reaches approximately 82 degrees Be1, then the magnesium sulphate solution is added which controls the time in which the mix gels. The linings are cured in an oven at 400 F. for several hours.