| 摘要 |
PURPOSE:To obtain molds of extremely high dimensional accuracy by electrically heating the sand mold consisting of the molding sand obtd. by adding binders and a good electrical conductor material to wet sand treated with an electrolyte soln. and a mold coat consisting of a refractory mold coating material. CONSTITUTION:A refractory mold coating material is coated on the surface of a pattern 1 to form a mold coat 2, and the molding sand obtd. by adding and mixing inorg. and org. binders and a good electrical conductor material to and with the wet sand treated in an electrolyte soln. is cast thereon, whereby a sand mold 3 is formed. The mold coat 2 and the sand mold 3 are heated electrically over the entire part via electrodes 4, whereby the transfer of the moled coat to the sand mold and the dehydration and consolidation of the sand mold are effected simultaneously. The mold coating material of graphite type, zircon type or the like is used, and this is used after it is mixed with an aq. soln. of NaOH, etc. The wet sand treated with an aq. soln. of NaOH, etc. is used for the molding material after it is mixed with an inorg. binder such as bentonite and an org. binder such as starch and a good electrical conductor material. |
