GB537204A - A method of and means for adding lead to steel and other ferrous metals - Google Patents

Abstract

537,204. Alloys; foundry ladles. INLAND STEEL CO., and BROADFIELD, W. H. May 18, 1940, No. 8870. Addition to 520,227. [Class 82 (i)] The process described in the parent Specification for adding lead to steel is extended to other ferrous metals such as ingot irons and silicon steels of low carbon content, manganese steels, and nickel-chromium steels, and is also modified in detail in its application to steel and ferrous metals generally. The rate of flow of the lead or its alloy or compound, measured as weight of metal passing in unit time may be about 0.6 per cent. of that of the stream of ferrous metal, and its velocity may be not less than 6 feet per minute. The lead &c. may be passed down a shoot or tube and its rate of flow controlled by adjusting the inclination of the shoot or tube or the size of the hole through which the lead &c. is fed to the shoot etc.; or a stream or shower of lead &c. may be directed into the stream of steel &c. by spraying it by means of air pressure or a centrifugal impeller; or the lead &c. may be fed through an opening in the plug of the ladle from which the steel &c. is flowing. In the form shown in Fig. 1, lead from a hopper 22 the outlet from which is controlled by a shutter 25 passes down an adjustably inclined shoot 14 and impinges against the stream 11 of steel from a ladle 10, a suction hood 13 being provided for extracting fumes ; or lead may be poured into the shoot 14 from a portable hopper having a controlled outlet. The delivery end of the shoot or tube for the lead is spaced away from the stream 11 preferably by not less than one inch. More than one jet of lead may be spaced around the stream 11. In apparatus in which the lead &c. is fed through the plug of the ladle, the plug 52, Fig. 11, may have a conical seating portion 75 associated with a throat 76 of smaller taper, and has an internal metal tube 53 down which the lead may be fed from a shoot 55 mounted similarly to the shoot 14, Fig. 1 ; or the lead may be fed to the top of the tube 53 from a hopper having an outlet controlled by a sliding or lift valve, a seal being provided between the outlet and the top of the tube to prevent the admission of air; the valve may be operated by hand, or automatically by a push rod attached by a spider to the tube 53 so that it will be opened when the plug 52 is opened Entry of the metal into the lower end of the tube 53 is prevented by the sealing of its upper end, or by the provision of a hand or electrically-operated valve at its lower end; or a disc valve 82, Fig. 19, controlled by air pressure from a pipe 79 and by a spring 85, may be opened to admit air pressure to the tube 53 when the metal raises a float 80; or rise of the metal may be made to close an electric circuit whereby the air valve is opened.