| 摘要 |
1,144,873. Casting processes; casting composite articles. DOW CHEMICAL CO. 25 Feb., 1966 [5 March, 1965], No. 8494/66. Heading B3F. Molten metal or a molten mixture of metals, e.g. Mg or an alloy thereof or an Al alloy around 700-760‹ C., is drawn into a mould or into the pores or interstices of a porous or agglomerated body by the vacuum created by the reaction of at least one metal component of the melt with each gaseous component (excluding any rare gases present) of atmosphere in the mould, pores or interstices since all openings to the mould, or all the pores, are inserted in the metal. For example, with air in the mould &c., some of the Mg forms a small amount of oxide and nitride to remove the air, assisted if necessary by shaking or vibrating the mould. A mould with a small inlet may be heated before charging, e.g. it may be both preheated and filled by immersion in the melt. A piece of sponge iron or coke may be merely immersed in molten Mg after heating. The impregnated sponge iron may be used as a ferroalloy. Powders of W, Mo, Ta, silicon carbide, aluminium oxide or boron may be placed in the mould in order to be impregnated. Felts of iron, steel or graphite, or steel or iron wool or bundles of wires of these metals or of W, Mo or Ta or fibres of W, Mo, Ta, asbestos, carbon or boron may be impregnated. Moulds of graphite, carbon, steel, and iron are mentioned and particular examples refer to a glass mould filled with silicon carbide grains and submerged, after preheating to 700‹ C., in an A1 base alloy containing 5% Mg at 760‹ C. for two hours and to stainless steel cables of many wires compressed and with a metal tube around them, heated to 650‹ C. and submerged in Mg at 730‹ C. for 30 minutes. |
