Abstract: A method of operation of a twin roll casting apparatus to produce thin gauge sheet metal at high-production rates. The method includes simultaneously adjusting various operating parameters, such as the roll speed, tip position, roll gap, molten metal input temperature and exit strip tension. In an iterative fashion, the strip gauge is reduced in steps while increasing the speed of the rolls and pulling the tip back out of the roll bite. In conjunction with the aforementioned adjustments, the temperature of the molten metal input to the feed tip is gradually reduced to ensure proper solidification at higher speeds. A set of pinch rolls closes on the exit strip at a certain gauge thickness to apply a drag to the strip in order to ensure proper coil wind-up tension.

Abstract: A method of operation of a twin roll casting apparatus to produce thin gauge sheet metal at high-production rates. The method includes simultaneously adjusting various operating parameters, such as the roll speed, tip position, roll gap, molten metal input temperature and exit strip tension. In an iterative fashion, the strip gauge is reduced in steps while increasing the speed of the rolls and pulling the tip back out of the roll bite. In conjunction with the aforementioned adjustments, the temperature of the molten metal input to the feed tip is gradually reduced to ensure proper solidification at higher speeds. A set of pinch rolls closes on the exit strip at a certain gauge thickness to apply a drag to the strip in order to ensure proper coil wind-up tension.

Abstract: A powder coating line for coating either coiled strip or pre-sheared and punched blanks is provided. In order to coat strip a catenary portion of the strip is suspended through a powder coating subsystem which includes a powder coating booth and a curing oven. The coated strip is the recoiled onto a rewind reel. In the alternative, the strip may be stopped and sheared at an input region and presheared blanks introduced to the powder coating subsystem. The blanks are placed on a belt conveyor, which transports them into the powder coating booth. The blanks are then passed in a conveyor through the powder coating booth and over for subsequent restacking. After passing out of the oven, and before coiled or stacking occurs, the strip or blanks pass through a quench and an air dryer. The powder coating subsystem can be incorporated into a larger pre-treating, cleaning, embossing or post-processing line.

Abstract: A continuous strip coating machine has top and bottom applicator rolls and a backup roll adjacent the top applicator roll. A lift roll to lift the strip of material and thus vary the angle of wrap of the strip about the bottom applicator roll is provided. The use of the lift roll in turn varies the pressure between the strip and the roll and thus the thickness of the coating applied to the strip bottom. Thickness may be measured indirectly by measuring pressure of the strip on the applicator roll. Thickness may also be measured directly. Oscillations of the strip in a drying oven may also be sensed and compensated for. Feedback control is used with the thickness measuring techniques to control the coating thickness by varying angle of wrap, relative speed between the applicator roll and strip, and/or nip pressure between the applicator roll and a transfer roll that transfers coating material to the applicator roll.

Abstract: The crown of roll cast sheet is regulated by controlling the crown of the work rolls in a roll casting machine producing the sheet. The work roll crowns are controlled by providing differential cooling between the center and the ends of the rolls. The work rolls contain inlet and outlet water plenums which are connected to channels within the perimeter of the rolls. Water flow to the center and ends of the work rolls is controlled by movable sleeves within the plenums. In a first position of the sleeves, water is permitted to flow proportionally through all areas to the work rolls providing an even removal of heat from the rolls. In a second position, a greater portion of water flows through the center portion of the work rolls resulting in increased removal of heat from the center areas, reducing the temperature of these areas and the crowning of the of the work rolls.

Abstract: An oven for drying and curing a film of paint, ink, or the like on a continuous strip of metal has a non-rectangular, and preferably oval, elongated oven chamber without sharp internal corners. By avoiding sharp corners in the oven, air flow is more uniform and deposits of condensed fumes are minimized. In some embodiments no internal bracing structure required. The absence of internal structure is permitted by the oven's walls, oval shaped in transverse cross section, which result a naturally self supporting structure. Cleaning nozzles may be provided for washing the inside of the oven without need for people to enter the oven.

Abstract: Thickness of metal sheet being cast is continuously controlled by passing a light beam through the gap between the casting machine rolls and measuring the amount of light passing through. The width of the gap is controlled in response to the measured light. To prevent interference in the hostile environment of a casting machine, the light is transmitted along an enclosed path and air is blown through the enclosed path into the roll gap. Both the thickness can be controlled in this way, and the profile can be controlled by axially shifting at least one of a pair of non-cylindrical work rolls.

Abstract: The feed tip is provided by a pair of spaced apart refractory bodies defining a feed path for the molten metal. Each refractory body has an upstream portion and a downstream edge and the bodies taper, in cross-section, in a direction towards the downstream edge. A discharge gap for the molten metal is defined by the downstream edges of the refractory bodies. The refractory bodies are made from a recently developed material which is a blend of aluminosilicate fibers, silicon powder and a boron constituent, preferably boron nitride.

Abstract: A method is provided for continuously casting aluminum alloys having more than two percent total alloying elements by a combination of casting at thinner gauges and much higher speeds than usual. Since remelting in the caster is avoided, sheet quality is vastly improved, surface ripples are avoided, and casting rate increased as much 50%. The method is characterized by the thickness of the cast sheet being in the range of from 4 to 5.8 millimeters and the casting rate being in the range of from 1.3 to 1.9 meters per minute. Chlorides in the molten metal are coalesced and oxides filtered to keep the inclusion rate in the cast sheet very low.

Abstract: A dual drive sheet casting machine for casting metal sheet has a pair of water cooled rolls between which the metal is cast. Each roll of the casting machine is driven by a separate motor, with one motor being a master and the other a slave driven at a controlled percentage of the speed or current of the master motor. Differential current to the two motors indicates sticking or microsticking of metal to the rolls. When the magnitude of the differential current exceeds a high limit indicating sticking, the master roll is slowed to eliminate the sticking. When the magnitude of differential current passed by a band pass filter between one half and ten Hertz exceeds a selected maximum indicating microsticking, the rotational speed of the master roll is decreased. After making a change in roll speed, the control circuit is disabled for an interval to permit the casting machine to regain stability.

Abstract: A method is provided for continuously casting aluminum alloys particularly useful for computer memory disk stock by a combination of casting at thinner gauges and much higher speeds than usual. Sheet quality is vastly improved, surface ripples are avoided, and casting rate increased as much as 50%. The method is characterized by the thickness of the cast sheet being in the range of from 4 to 6 millimeters and the casting rate being in the range of from 0.8 to 1.8 meters per minute. Chlorides in the molten metal are coalesced and oxides filtered to keep the inclusion rate in the cast sheet very low.