Patent GB-421539-A (GB)
Title: Improvements in and relating to metal working
IPC: B22D11/06
Filed: 1933-05-16
Abstract: 421,539. Rolling. HAZELETT METALS, Inc., 292, Madison Avenue, New York, U.S.A. May 16, 1933, Nos. 14190 and 14191. Convention dates, May 16, 1932 and May 3, 1933. [Class 83 (iv)] [See also Groups XII and XXXVII] A furnace 51 is tilted by hand or automatically to supply a pool of molten metal between rolls 29, 32, Fig. 6, the uniformity of product being gauged by the rate of solidifying as indicated by the torque required to drive the rolls as they work on softer or harder, i.e. more solid metal. Fig. 1 shows diagrammatically the lay out, in which the molten metal is formed and rolled in rolls 1, 2, and issues as a strip through reducing gases 15 and proceeds without reheating through a normalizing furnace 17, a pickling tank 18, washing tank 19, a straightening mill 20 and shears 21 which cut off pieces and pass them to a press 22 for forming the finished articles. In Fig. 6 the furnace 51 is tilted about its pivot 58 by a hydraulic piston 65, Fig. 11, when the operator, watching the armature of the roll motor operates the control valve 126. The metal running down the spout 62 through its submerged end may be kept hot by burning gases from a tube 76 and the metal in the pool is likewise kept hot by gases from a tube 77. The pool may be surrounded by an inert atmosphere. The rolls are thermostatically cooled by water jets from pipes 103, supplied from a valve 114, Fig. 10, operated by a solenoid 122, controlled by a thermo couple 116-119 and a relay 121. The rolls also have vapour wipers 110 and metal scrapers 102. The flanges 46 of the roll 29 form the enclosing side of the metal pool and are roughened to grip the edge of the metal and rub against a spring pressed graphite block to prevent molten metal from adhering to them. In a modification the roll shells 130, Fig. 12, are of larger diameter than their driving shafts to allow space for cooling water on the inside at 137 as well as on the outside. The cooling water may be distributed over the length of the roll by hand controlled valves to give uniform temperature on the flanges. An air blast or oil may be used to keep the molten metal from flowing away at the roll end flanges and provide extra cooling. In sheet rolling the pass may be shaped to roll slightly thicker at the sides to compensate for flange cooling and also thicker at the middle. The metal is heated in the furnace 51 by a transformer 55, 56 in which the metal in the U-shaped passage 53 forms the secondary for heating. Fig. 17 shows a mechanical torque indicator in which the mill motor 168 can rock slightly about a pivot 170 and so move a lever system to a dial 188. The rate of pouring of the metal or the rate of supply of cooling water to the rolls or other factor governing the extent of solidification of the metal between the rolls may be controlled automatically by coupling such mechanism (not described fully) to a control motor 201, Fig. 19 responsive to changes in degree of solidification as indicated by torque and therefore current taken by the roll motor 193. When the current taken by the roll motor 193 falls below the value predetermined for the relay 231, switch 205 is moved so that the control motor 201 starts in a forward direction until the current exceeds the predetermined value for the second succeeding relay 233, and then rests. If the current again rises above the predetermined value for relay 234 the control motor 201 is reversed, until the current decreases below the value for relay 232 when the motor 231 again rests, and so on for the other overload relays 234, 235 which, on excessive overload, short circuit the resistances 215-217 in the armature circuit of motor 201 to increase its speed and expedite the return to normal. 205 is the reversing and control switch for the motor 201, and 222 is the normally open switch which when closed by relay action cuts out resistances 217, &c., in the armature circuit of the motor 201 thus controlling its speed, direction of rotation and stopping and starting. The motor 201 could be coupled to the pouring apparatus &c., (no details of coupling described).