Composite ingot free from defects - made by casting molten metal round solid metal core coated with varnish to prevent oxidn.

摘要

Composite metal ingots are made, where a core metal(a) with a surface free from an oxide layer is coated with a film(b) of organic material contg. C and H, to obtain a film (b) 50-3000 mu m thick. The coated core(a,b) is then suspended in a mould, and moulten metal(c) of the same or different compsn. to metal(a) is fed upwards via bottom pouring to fill the mould and make an ingot(a,c). The ingot(a,c) is rolled or forged into a semi-finished prod. which is hot worked and opt. cold worked. Film(b) is pref. a drying varnish or synthetic resin, esp. 100-3000 mu m thick. During casting, a non-oxidising atmos. is pref. used in the mould, which is closed to preclude entry of air. The bottom end of the core(a) is pref. 5-30cm. above the bottom of the mould; and the molten metal(b) is poured to a height of min. 5cm. above the top of core(a). Provides an inexpensive method for mfg. composite ingots, where film(b) burns to form gas which reacts with any O2 present and blows inclusions and foam to the top of the mould so a sound bond is obtd. between metals(a, c).