Abstract: A new ramming paste for aluminum reduction cell cathodes is a high swelling cold ramming paste made of a blend of pitch, light oil diluent and an aggregate comprising a mixture of anthracite and crushed anode butts or calcined coke. The presence of the crushed anode butts or calcined coke increases the sodium swelling index of the paste by about four times higher than that of regular ramming pastes. This new high swelling cold ramming paste may also contain an amount of a refractory hard material, such as TiB2.

Abstract: A process of reducing scaling of a metal surface exposed to an aqueous solution from which scale may form after a period of exposure. The process comprises applying a cathodic potential to the surface for at least some of the period of exposure. In some cases, e.g. when an article is made of a ferrous metal, it is advantageous to coat the article with a different metal (e.g. copper or an alloy of copper) before applying the cathodic potential to avoid hydrogen generation and excessive current flow. An article to be protected from scaling may also advantageously be electrically isolated from other parts of an apparatus.

Abstract: The invention relates to a winding tube for winding up bands, films, sheets of metal or similar made of a spiral shaped wound metal strip whose adjacent strip windings overlap at least partially. The metal strip has a corrugated or ribbed profile in the cross-section thereof, whose external corrugated heads (1) are disposed on the outer wall of the winding tube after winding and are wider than the internal corrugated heads (2) disposed on the inner wall of the winding tube after winding.

Abstract: A method for designing a cascade of digital filters for use in the control of an electrolytic reduction cell by specifying the frequency and time response characteristics of the transfer function of the cascade of digital filters. The digital filters are exponential filters. The number of smoothing functions (i.e filters), each having different filter parameter values, is determined according to desired performance characteristics in the frequency and the time domains. These characteristics include: smoothing quality (specifiable in terms of passband, stopband and transition band of the filter frequency response profiles), group delay, and stabilization time. The use of the cascade of digital filters to control a reduction cell. A system for controlling a reduction cell comprising the cascade of digital filters. A process for electrolytic reduction of alumina comprising a step of filtering measurements of an electrical parameter using the cascade of digital filters.

Abstract: An apparatus is provided for the treatment of molten metal, e.g. aluminum, with a particulate treatment agent and a gas. This includes a vessel for holding molten metal, a rotary device for breaking up particulate treatment agent and gas within the molten metal and for dispersing particulate treatment agent and gas within the molten metal contained in the vessel and means for supplying the particulate treatment agent and gas to the rotary device. The rotary device includes a hollow shaft having a rotor with an axial opening fixed to the discharge end of the shaft, this rotor being in the form of an annular plate with a plurality of radially mounted upwardly directed blades projecting from the top face of the annular plate and a plurality of radially mounted downwardly directed blades projecting from the bottom face of the annular plate.

Abstract: When using AA3000 series and AA1000 series aluminum alloys to produce extruded products for heat exchanger applications, by controlling the level of copper and nickel in the alloy to very low levels it is possible to produce excellent corrosion resistance both before and after a brazing cycle. To achieve these results, the copper content should be no more than 0.006% by weight and the nickel no more than 0.005% by weight. A typical alloy of the invention contains about 0.001-0.5% by weight manganese, 0.001-0.7% by weight iron, 0.001-0.02% by weight titanium, 0.001-0.3% by weight silicon, less than 0.006% by weight copper, less than 0.005% by weight nickel and 0.001-0.02% by weight zinc, with the balance consisting of aluminum and incidental impurities. No zinc addition to the alloy is required either by zinc spraying or by alloy addition.

Abstract: The invention relates to a settler for decanting mineral slurries and a method thereof. The settler comprises a tank for holding and decanting a body of slurry to form a thickened slurry as a lower layer and a clarified liquid as an upper layer, the tank having a side wall, a bottom and a top, an outlet for the thickened slurry at the bottom of the tank, an outlet for the clarified liquid layer near the top of the tank, a slurry inlet means near the top of the tank for introducing fresh slurry into the tank, the slurry inlet means having a slurry opening through which fresh slurry joins the body of slurry in the tank, and a stirrer having a generally vertical axis around which the stirrer rotates or reciprocates. The slurry opening is displaced laterally relative to the generally vertical axis of the stirrer and the slurry inlet means is configured to allow the fresh slurry to enter the slurry body without accumulating solids from the fresh slurry at the slurry opening.

Abstract: The invention relates to a method and apparatus for forming metal containers. The method involves introducing a knockout element (110) into the container body through the open end, providing a forming die shaped to reduce the diameter of the sidewall of the container body (100) when the open end of the container body (106) is forced therein to produce a neck portion of reduced diameter on the container body, driving the open end of the container body into the forming die (108), retracting the knockout element through the neck portion as the neck portion is formed, and removing the container body (106) from the forming die (108) and knockout element (110). In the invention, the driving of the open end of the con tai ner body into the forming die and/or the movements of the knockout element are carried out under computer numerical control, preferably employing linear motor drives, thereby enabling the driving or movement to be optimized for the container body and the neck portion formed thereon.

Abstract: An improved method is described for adding alumina to a Söderberg or pre-bake type electrolytic cell fed by schedule crust breaking. Instead of adding the full amount of alumina required following each crust breaking, as is traditional, the standard dose of alumina is now split into two smaller doses. Thus, a major proportion, e.g. about 50 to 90% by weight, of the theoretically required alumina to sustain the electrolysis between crust breakings is added following a crust breaking. The electrical resistance of the electrolyte is monitored between crust breakings, and if the resistance begins to rapidly increase indicating the approach of an anode effect, the anodes are activated into a pumping action thereby breaking the crust adjacent the anodes, allowing alumina to flow into the molten electrolyte, and also creating a stirring action within the molten electrolyte. This lowers the resistance such that any anode effect is avoided until the next full crust breaking.

Abstract: A device re-shapes formed wire after processes such as annealing where wire is wound on bobbins. The device includes a reservoir for containing lubricant having a first open end and a second open end. The first end of the reservoir is closed by a guide mechanism for guiding the wire into the reservoir. The second end of the reservoir is closed by a wire shaping for shaping the wire when the wire is pulled therethrough. The wire shaping mechanism reduces the cross-sectional area of the wire by no more than 24%.

Abstract: An apparatus for treating molten metal includes a treatment vessel for holding molten metal and a removable cover or hood for the vessel. Sealing means are provided between the cover and the vessel to provide a gas tight treatment zone. The sealing means include mating peripheral flanges on the vessel and cover, with the cover flange having two spaced annular sealing strips for contacting the vessel flange and a metal annular splash protector. These sealing strips include a thermal barrier strip formed of a deformable fibrous refractory material to provide a gas tight, a thermal barrier between the interior of the vessel and the exterior and a metal annular strip upon which the cover is supported on the vessel with the cover flange at a fixed distance above the vessel flange and the thermal barrier strip is compressed therebetween to a controlled degree.

Abstract: Disclosed is a system for providing consistent lubricant and/or gas flow through multiple permeable perimeter walls in a casting mold table. One or more of the properties of the perimeter walls indicative of the lubricant flow or gas flow rates through the perimeter walls are predetermined and the sizing of the surface area of the delivery conduits providing the lubricant or the gas are determined based on a correlation to the properties related to the measured or estimated lubricant flow rate and/or measured or estimated gas flow rates through the perimeter walls.

Abstract: A method of forming a bottle-shaped or other contoured metal container by subjecting a hollow metal preform having a closed end to internal fluid pressure to cause the preform to expand against the wall of a die cavity defining the desired shape, and advancing a punch by means of a backing ram into the die cavity to displace and deform the closed end of the preform either before or after expansion begins but before it is complete. The pressure-subjecting step is performed by simultaneously subjecting the preform in the die cavity to independently controllable internal and external positive fluid pressures and varying the difference between them to control strain rate. Apparatus for performing the method includes a split die with plural split inserts disposed in tandem to define the die cavity wall and heaters respectively inserted within the preform and arranged to heat the backing ram.

Abstract: A process of producing an article having a surface provided with an optical diffraction grating such that the surface generates visible color when illuminated with diffuse white light. The process involves deforming a starting material to produce the article having the surface and, during the deforming step, impressing a diffraction relief pattern on the surface by a tool provided with a bearing surface having a corresponding surface relief pattern of parallel lines that contacts the surface of the article under pressure. While the diffraction relief patter is being impressed, the surface is caused to slide in a direction of movement relative to the bearing surface of the tool. The invention also relates to the article.

Abstract: Aluminum alloy die castings combine good as-cast strength with good as-cast ductility, without any heat treatment. The alloy comprises 2.75 5.25 wt. % magnesium, 1.85-3.15 wt. % zinc, 0.65-1.2 wt. % manganese, 0.10-0.18 wt. % iron, less than 0.10 wt. % copper, less than 0.10 wt. % silicon, less than 0.20 wt. % titanium and the balance aluminum and incidental impurities and furthermore the percent by weight magnesium is greater than or equal to the percent by weight zinc. A particularly high strength version of the alloy comprises 4.75%-5.25 wt. % magnesium and 2.85-3.15 wt. % zinc. A particularly high ductility version of the alloy comprises 2.75-3.25 wt. % magnesium, 1.85 2.5 wt. % zinc.

Abstract: A process is described for producing an aluminum alloy sheet having excellent bendability for use in forming panels for automobiles. An aluminum alloy containing 0.50 to 0.75 by weight Mg, 0.7 to 0.85% by weight Si, 0.1 to 0.3% by weight Fe, 0.15 to 0.35% by weight Mn, and the balance Al and incidental impurities, is used and is semi-continuously cast into ingot. The cast alloy ingot is subjected to hot rolling and cold rolling, followed by solution heat treatment of the formed sheet. The heat treated sheet is quenched to a temperature of about 60-120° C. and the sheet is then coiled. This coil is then pre-aged by slowly cooling the coil from an initial temperature of about 60-120° C. to room temperature at a cooling rate of less than 10° C./hr.

Abstract: A process is described for treating molten metal with a particulate treating agent. A melt of a metal, e.g. aluminum, is provided in a treatment vessel such as a ladle and a mixing impeller is positioned substantially below the surface of the molten metal. The impeller comprises a plate with a series of spaced blades extending from the surface of the plate. This impeller is adapted to provide high shear mixing with minimum vortex. While rotating the impeller on a substantially vertical axis, particulate treating agent is fed by way of an injection tube below the surface of the molten metal and into the region between the axis and periphery of the impeller. This causes a high shearing action in the region of the blades whereby the treating agent is quickly broken down into finely divided droplets that are at least partially molten and which are circulated within the molten metal.

Abstract: A belt cooling and guiding apparatus for a casting belt of a twin belt caster. The cooling and guiding apparatus comprises at least one nozzle having a support surface facing a reverse surface of the casting belt (a surface opposite to a casting surface in the casting mold), provided with a continuous slot in the support surface arranged transversely substantially completely across the casting belt. The slot allows for delivery of cooling liquid to the reverse surface of the belt in the form of a continuous film having uniform thickness and velocity of flow when considered in the transverse direction of the belt. This allows for even cooling transversely of the belt. The nozzle arrangement is also provided with a drainage opening for removal of cooling liquid downstream from the continuous slot, and a vacuum system associated with the drainage opening for applying suction to the drainage opening.

Abstract: The recoiling temperature of a metal strip from a continuous heat treatment line is controlled by continuously passing the metal strip through an accumulator system where it passes around spaced accumulator rolls. While travelling through the accumulator, the metal strip is subjected to ambient cooling air and the length of aluminum strip travelling through the accumulator determines the amount of cooling that takes place. The length of the metal strip in the accumulator is in turn controlled by varying spacing between the accumulator rolls around which the metal strip travels. The spacing is preferably controlled by a programmed controller in response to temperature signals.

Abstract: A method of fabricating an article from a blank of material (e.g., aluminum alloy sheet) having anisotropic deformation properties, with tooling which has been designed by predicting flow and deformation of the blank using an analysis which decouples the anisotropic deformation properties of the blank. The method calculates the response of a small amount of the blank using crystal plasticity theory. The blank can be represented as a mesh having a plurality of elements. A strain path is predicted for each element using finite element analysis (FEA), and a stress-strain curve is defined for each element by performing a material point simulator (MPS) calculation for each element using its respective strain path. A second FEA is then carried out on the elements using the respective stress-strain curve for each element. The stress-strain curve for each element may be defined by assigning to each element a curve which lies between an upper bound curve and a lower bound curve, using various methods.