Abstract: Molten metal inclusion sensor probes have a sensing passage through which the molten metal passes, while direct current passes through the passage between two electrodes. The passage of an inclusion through the passage changes the resistance in the path, resulting in a pulse indicating its size, and enabling the number of particles in a sample to be counted. Previously the passage has been cylindrical, with or without a conical entrance, or of randomly smoothed profile produced by melting the probe material. High levels of background noise make pulse detection difficult, and operation is improved by the passage decreasing smoothly in cross-section in the flow direction, preferably with a parabolic or elliptical profile, and preferably with the exit of the same profile. The wall surface is formed to a smoothness of better than 1.016 micrometers (40 microinches), preferably 0.254 micrometers (10 microinches), permitting pre-determination of the optimum testing and conditioning currents required.

Abstract: The invention provides molten metal inclusion sensor probes having a sensing passage through which the molten metal passes, while a direct current path is established through the passage between two electrodes. The passage of an inclusion through a central sensing zone within the passage changes the electric resistance in the current path, resulting in a detectable pulse indicating its size, and enabling the number of particles in a sample to be counted. Previously the passage has been cylindrical, with or without a conical entrance to facilitate smooth flow, or of randomly smoothed profile produced by heating the material at the passage mouth until it melts and flows. The flowing metal produces a self-induced magnetic field and electromagnetic force that results in a “conditioning” flow when the current is above a threshold value.

Abstract: A molten metal inclusion sensor probe which is immersed in the molten metal and detects inclusions therein by the electric sensing zone method comprises inner and outer steel tubes disposed one within the other to form an annular gas containing space, the tubes being spaced apart from one another by electrically insulating spacing rings between the two tubes at or adjacent to the opposite ends thereof. The space is vented to the exterior of the outer tube, or in the case of a one-shot probe to the interior of the inner tube. A sensing zone member, which may also act to space the tube lower ends, is mounted by the tubes at their lower ends and provides the sensing zone orifice. In some embodiments the seals between the sensing zone member and the tube lower ends are maintained despite differences in expansion coefficients of the materials.

Abstract: A flow control device comprising a baffle plate and a plurality of dividers radially disposed about a nozzle through which liquid is to be discharged and adapted to space the plate from the nozzle. The device finds particular application in substantially eliminating any entrainment of a supernatant phase such as metallurgical slag or of an oxidizing atmosphere resulting from the formation of vortexing funnels disrupting liquid flow in a draining container.

Abstract: A molten metal inclusion sensor intended for "continuous" use in the testing of steel, i.e. a useful life of at least about 30 minutes, comprises a probe which is detachably connected to a water-cooled support member (35). The probe comprises a tube (30) of heat resistant material, preferably silica, having an inner electrode (31) mounted on its interior wall and an outer electrode (32) mounted on its exterior wall, the molten metal entering the tube interior through an orifice (33) upon its immersion in the molten metal, whereupon the flow of metal with entrained inclusions is monitored by measuring the voltage between the electrodes (31, 32). The electrodes (31, 32) are preferably of graphite and are shaped to fit closely against the walls of the part of the tube (30) that is immersed in the metal and are of a material that retains enough mechanical strength to support the tube (30) as the metal is pumped into and out of interior, the metal remaining hot enough for this pumping to occur.

Abstract: A molten metal inclusion sensor comprises a single use disposable probe which is detachably connected to a support member. The probe may comprise a tube of heat resistant material having an inner electrode mounted on its interior wall and an outer electrode mounted on its exterior wall, the molten metal entering the tube interior through an orifice in its wall past a jet-preventer insert upon its immersion in the molten metal, whereupon the flow of metal with entrained inclusions is monitored by measuring the voltage between the electrodes. Alternatively the tube may be of electrically-conductive heat-resistant material and constitute the inner electrode. The flow may be assisted by a reduced pressure established within the tube, or may be slowed by a positive pressure to maintain the Reynolds number of the flow below 2000.

Abstract: Apparatus for continuous casting includes a tundish for containing molten metal and delivering the metal to a work zone where the metal solidifies as it is moved through the work zone in a continuous casting process. The tundish contains molten metal and includes an outlet and a pervious flow restricting element is positioned in the outlet. The element causes the flow of the metal to be distributed as it flows through the outlet and into the work zone to engage a growing shell of solid metal carried through the work zone by a chilled substrate. The molten metal acts to apply a pressure on the shell and to lubricate the moving shell. The arrangement minimizes exposure of liquid to air and minimizes opportunity for turbulence in the liquid contained in the work zone. A method of continuous casting is also described.

Abstract: The invention provides a new method and apparatus for the detection of non-conductive particulates in molten metals, such as aluminum, gallium, zinc and lead, that can be liquified and drawn into a suitable refractory container. The passage into the container is of very small diameter (about 300 micrometers for aluminum) and it forms part of a current path between two electrodes carrying a current of about 1 to 500 amperes. The path is surrounded by liquid metal which forms an effective Faraday cage screening the path, enabling the passage of a particulate of about 15 micrometers or larger to produce a voltage pulse between the electrodes of greater than 5 microvolts, which is detectable above the inevitable background noise, which is of about that value.

Abstract: The invention provides a new method and apparatus for the detection of non-conductive particulates in molten metals, such as aluminum, gallium, zinc and lead, that can be liquified and drawn into a suitable refractory container. The passage into the container is of very small diameter (about 300 micrometers for aluminum) and it forms part of a current path between two electrodes carrying a current of about 1 to 500 amperes. The path is surrounded by liquid metal which forms an effective Faraday cage screening the path, enabling the passage of a particulate of about 15 micrometers or larger to produce a voltage pulse between the electrodes of greater than 5 microvolts, which is detectable above the inevitable background noise, which is of about that value.

Abstract: The invention provides a loading system for the charge of an annealing furnace of the kind intended for the treatment of a stack of coils mounted one on top of the other with their central cores in register with one another, a protective heat exchange gas atmosphere being circulated around the stack within a cylindrical bell-shaped muffle cover to heat and subsequently cool the charge. The system comprises a diffuser member having a gas impeller at its center that receives gas passing downwards through the coil cores and discharges it radially into the annular space between the stack and the muffle cover in a preferred helical path. The stack rests on a load member placed on the diffuser member, a convector plate is interposed between each pair of superimposed coils and the stack is completed by a top member and a plug member.

Abstract: A melt dispersible, floatable, solid additive for molten metal comprises an elongated body of the additive with a band or bands of a thermal barrier providing material therearound which is preferably heat decomposable and gas evolving at the temperature of the molten metal. When the additive is dropped or released and urged forcibly into the molten metal the formation of a solid casing of the molten metal on the body at the position of the band or bands is retarded so that melted additive is released at the position of the band or bands and the body separates into discrete parts thereby rapidly releasing the additive into the molten metal.