Abstract: After the fly ash is removed from the flue gases by a separator, it is introduced into a combustion chamber which may be either the primary combustion chamber of the furnace or a separate chamber in a secondary combustion chamber. There, it is burned until only the liquid slag remains and then removed, along with the other liquid slag formed in the furnace by the primary combustion process. Various methods and apparatus are described for carrying out the introduction of the fly ash into the combustion chamber.

Abstract: A steel wire after coming from the mill is brought to a temperature between 850.degree. and 910.degree. C. This is followed by multi-stage water-cooling of the wire in such a manner that the surface of the wire is cooled to below the martensite start temperature while austenite is retained in the core of the wire. The heat retained in the core of the wire serves to partially temper the martensite formed at the surface of the wire. The wire is coiled while the temperature remains substantially constant so that the retained austenite in the core of the wire undergoes an isothermal transformation to fine pearlite. The heat of transformation serves to complete tempering of the martensite. After coiling, the wire is air-cooled to room temperature. The final wire exhibits a structure consisting of an outer layer of tempered martensite and a core of fine pearlite. This structure imparts excellent cold-working characteristics to the wire.

Abstract: A steel wire is rolled while in the austenitic range. Thereafter, the wire is cooled to a temperature between 850.degree. and 910.degree. C. This is followed by multi-stage water-cooling of the wire in such a manner that the surface of the wire is cooled to below the martensite start temperature while austenite is retained in the core of the wire. The latter cooling step brings the temperature of the surface of the wire to below the martensite start temperature in approximately 0.2 seconds. The heat retained in the core of the wire serves to partially temper the martensite formed at the surface of the wire. The wire is then coiled while the temperature remains substantially constant so that the retained austenite in the core of the wire undergoes an isothermal transformation to fine pearlite. The heat of transformation serves to complete tempering of the martensite.