| 摘要 |
601,260. Mould materials ; moulds. AUSTENAL LABORATORIES, Inc. June 22, 1945, No. 15995. Convention date, May 31, 1944. [Class 83 (i)] [Also in Group V] A coating surface for a mould comprises a comminuted refractory material, a binder and a film forming material to increase the strength and resistance to water of the coating. A hygroscopic substance, e.g. glycerine, a gelling agent, e.g. sulphuric or other acid, a wetting agent, and a defoaming agent, e.g. octyl alcohol may also be added. The refractory is ground to pass about 200 mesh per inch. A suitable mixture comprises water 290 cc., glycerine 45 cc., waterglass 90 cc., 4.42 per cent hydrochloric acid 65 cc., 6 per cent ammonium alginate solution 15 cc., octyl alcohol 0.3 cc., 7.5 per cent solution of a wetting agent 7.5 cc., and potter's flint 2.3 lbs. Other suitable refractories are alumina, zircon, zirconia, mullite, and magnesia. Other film-forming materials are algin and sodium or other water soluble alginate. The coating is applied to a wax pattern 10 by dipping, painting, spraying &c. then a refractory, 50 to 100 mesh, is sprinkled or otherwise applied and the whole allowed to dry. The pattern is inverted on a waxed plate 17, surrounded by a sleeve 21 of resistant alloy lined with asbestos 22 and paper 23, waxed at 24 to the plate 17. The sleeve is then filled with a mixture of any suitable coarse refractory and any binder, e.g. tetra-ethyl silicate. The mould is then allowed to set and is heated to melt out the pattern. Other examples of mixtures are given.
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