Abstract: A billet is transported through an improved furnace by convention means and is heated in the furnace by an external burner unit in which fuel and air are combusted together and then injected at a high velocity into a semi-cylindrical chamber of the furnace tangentially to the billet so as to create a hot vortex of gases circulating around the billet along the length of the furnace. The temperature of the hot gas vortex within the furnace is sensed by means of a thermocouple placed close to the billet surface but not in contact with it so as to sense the temperature of the billet as a function of the temperature of the circulating gas. The temperature of the injected gas is thereby controlled to heat the billet to a desired temperature and then maintain it at that temperature.

Abstract: A reverberatory furnace which has an external passage for recycling hot exhaust gases from the furnace chamber back to the main burner port, means for introducing additional air or oxygen into the recycling passage, and a main burner which supplies fuel plus up to 50 percent of the air or oxygen required for total combustion into the furnace chamber so that the air or oxygen added to the recycling passage is thereby preheated by the exhaust gases and mixes with the fuel-rich mixture from the burner to provide complete combustion of the exhaust gases while simultaneously reducing the cost of the fuel requirement because of the preheating effect of the exhaust gases on the additional supply of air or oxygen.

Abstract: A high efficiency aluminum scrap melting system is provided in which a portion of the hot combustion gases employed to melt the aluminum in a hearth is recycled through scrap-receiving preheat compartments to preheat scrap and volatilize contaminants as the scrap is fed to the hearth, the remainder of the hot combustion gases leaving the hearth as hot exhaust gases being optionally employed through a recuperator to preheat air which is fed to a combustion burner system used to burn hydrocarbon fuel and provide heat for the overall system. Energy available in the contaminants also supplements the energy supply to the system.

Abstract: A modified type 3004 aluminum alloy is provided characterized by an improved combination of cold workability and physical properties having particular use in the deep drawing of containers, such as beverage cans, and the like, said alloy containing a relatively high level of manganese ranging by weight from about 1.6 to 3 percent. The improvement is particularly apparent in the production of chill cast shapes (sheet metal stock), such as by the continuous casting of the alloy between a pair of water-cooled rolls.