Foundry practices

A method of casting an alloy combining one or more readily oxidizable metals while precluding atmospheric oxygen when casting and wherein alloying of the base alloy with the oxidizable metal takes place in an alloying chamber moments before castings, comprising:

• (a) providing a mold with a casting cavity having means for venting for the escape of air contained therein and communicating with a supply passage through which a non-oxidizing gas may be admitted to the mold cavity;
• (b) positioning an alloying chamber adjacent to the mold cavity, the alloying chamber having a pouring opening in its bottom communicating with the mold cavity, isolating the alloying chamber from the atmosphere with a removable cover having vent passages for the escape of air and having a pouring opening at its top;
• (c) closing the bottom pour opening of the alloying chamber with a plug to isolate the pouring chamber from the mold cavity and disposing in the pouring chamber an unmelted oxidizable metal;
• (d) admitting the non-oxidizing gas to the mold cavity and to the pouring chamber in an amount to displace air therein and, after the air has been so displaced, pouring a body of molten metal from a ladle through the pouring opening at the top of the alloying chamber to impinge atop the oxidizable metal in the alloying chamber, the poured body of metal having a melting point higher than that of the oxidizable metal thereby quickly melting the oxidizable metal and creating the casting alloy in the alloying chamber;
• and
• (e) disclosing the bottom pour opening shortly after the oxidizable metal has been alloyed with the molten metal poured into the alloying chamber whereupon the alloyed metal flows into the casting cavity, thereby displacing the protective atmosphere through the vent passage while concurrently preventing the intrusion of air into the casting cavity.