Patent GB-645305-A (GB)
Title: Continuous casting of metal
IPC: B22D11/06
Filed: 1948-05-05
Abstract: 645,305. Continuous casting machines. ROBERTSHAW-FULTON CONTROLS CO, May 5, 1948, No. 12390. Convention date, July 7, 1947. [Class 83 (i)] In a method of continuously casting ingots, the molten metal is supplied to a mould, the opposite sides of which are moved to convey the ingot downwardly, the mould is cooled to solidify the metal, the friction of the ingot in the mould is reduced, and the speed of movement of the ingot is adjusted with respect to the rate of pouring of the molten metal so as to maintain the surface of the molten metal in the mould at an approximately constant level just below the level of ingress of the molten metal. The mould comprises two hollow stationary edge members 51, 59, which diverge downwardly to reduce the frictional effect between them and the mould, and two series of bars 31, 32 secured to endless chains 29, 30, 43 which are driven from a motor 79 through a speed-changing device 80. The device 80 is driven by a reversible three-phase electric motor 81 connected to relay circuits including a pair of electrodes 111, 112 supported in the mould, the electrode 111 being slightly longer than the electrode 112 which extends slightly below the level of the aperture 57 through which molten metal is poured from a spout 58 supported by the member 51. In operation, the motor 79 drives the device 80, in its slowest speed position, to move the mould bars 31, 32 downwardly over the edge members 51, 59. A dam member 107 is then moved downwardly until it approaches the level of the aperture 57 when the motor is stopped. The electrodes 111, 112 are then supported in the mould, the machine re-started and molten metal introduced into the spout 58. The metal interlocks with dovetail slots in the member 107 which is moved downwards with the mould bars 31, 32. As the ingot leaves the machine, it is supported by a member 102 and further downward movement of the ingot is counterbalanced by weights 104, 105. The device 80 normally runs at its lowest speed which is slightly below the rate of pouring from the spout 58. Should the rate of pouring increase during casting so that the molten metal contacts the electrode 112, the motor 81 is energized and increases the speed of the device 80 to increase the speed of movement of the bars 31, 32 and of the ingot. The speed of movement of the ingot increases until the molten metal no longer contacts the electrode 112 when the motor 81 is de-energized and stops. If, as a result, the level of the molten metal drops below that of the lower end of the electrode 111, the motor 81 is energized and reversed. The device 80 is now driven to reduce the speed of the bars 31, 32 and of the ingot. Speed reduction continues until the level of the molten metal again contacts the electrode 111 when the motor 81 is stopped. The movement of the bars 31, 32 is retarded by brake bands 23. A gas jet 97 covers the spout 58 to prevent oxidation of the molten metal and maintain the temperature adjacent the spout 58 at approximately pouring temperature. Coating moulds.-The mould bars 31, 32 are coated with lubricant, preferably graphite and kerosene, by means of jets 71 to which air under pressure is supplied. Each mould bar may be provided with a shield 77 to prevent deflection of the lubricating spray. Cleaning, drying, and cooling moulds.-The mould bars 31, 32 are dried by means of air jets 66, cleaned by rotary brushes 67, and cooled by water jets 78. The mould bars 51, 59 are cooled by water circulated therewithin.