Abstract: A hypoeutectic aluminum silicon casting alloy having a refined primary silicon particle size and a modified iron morphology. The alloy includes 10 to 11.5% by weight silicon, 0.10 to 0.70% by weight magnesium and also contains 0.05 to 0.07% by weight strontium. On cooling from the solution temperature, the strontium serves to modify the silicon eutectic structure as well as create an iron phase morphology change. Such changes facilitate feeding through the aluminum interdendritic matrix. This, in turn, creates a finished die cast product with extremely low levels of microporosity defects. The alloy may be used to cast engine blocks for marine outboard and stern drive motors. Furthermore, when the magnesium levels are adjusted to approximately 0.10 to 0.20% by weight magnesium, propellers having a highly advantageous ductility may be obtained.

Abstract: An apparatus and method to delay the application of pressure on a molten metal front to equalize a pressure gradient present at the molten metal front during pressurized lost foam casting processes, or other pressurized casting processes. A pressure equalization member is placed over a pouring cup to divert the direct application of pressure to molten metal present in the pouring cup. The pressure equalization member allows for increased pressurization rates in such processes, facilitating interdendritic feeding while reducing microporosity and metal penetration defects.

Abstract: A method for casting of metal articles using external pressure and having particular application to lost foam casting of metal articles. A polymeric foam pattern having a configuration corresponding to an article to be cast is placed in an outer flask and the pattern is connected through a polymeric foam gating system to a pouring cup located at the upper end of the flask. The pouring cup has a volume equal to 5% to 75% of the combined volume of the gating system and the pattern. A finely divided inert material, such as sand, is placed in the flask surrounding the pattern and fills the internal cavities within the pattern. The flask containing the pattern is then positioned in an outer pressure vessel having a removable lid and a molten metal is fed into the pouring cup.

Abstract: A composite core structure is used for metal casting in order to form cavities of preselected sizes and shapes within the casting. The composite core has an insoluble support member that can be metallic and a soluble portion disposed around at least a part of the support member. When the composite core is used in a casting process, such as a die casting process, the soluble portion is dissolved after the casting process is complete, and the insoluble portion is then removed from the cavity that was formed through the use of the composite core.

Abstract: An investment cast stainless steel article, such as a marine propeller, is composed of a stainless steel alloy containing from 14.5 to 15.2% chromium, 5.35% to 6.05% nickel and 1.0% to 1.5% silicon.

Abstract: A method of casting hypereutectic aluminum-silicon alloys in an evaporable foam casting process with the application of pressure during the solidification of the alloy. A pattern is formed from a polymeric material having a configuration of an article to be cast. The pattern is supported in an outer mold and unbounded sand surrounds the pattern and fills the cavities within the pattern. The pattern is contacted with a molten hypereutectic aluminum-silicon alloy containing 16% to 30% silicon and having less than 0.8% copper. The molten alloy decomposes the foam pattern with the vapors of decomposition being entrapped within the interstices of the sand. While the alloy is in the molten state, gas pressure is applied to the alloy in the magnitude of 5 to 12 atmospheres to produce a cast alloy having less than 0.03% porosity and a high cycle fatigue strength greater than 13 KSI.

Abstract: A method of producing polymeric foam patterns for use in evaporable foam casting. A positive three-dimensional model of the metal part to be cast is made by a layered prototyping process in which layers of sheet material are bonded in superimposed relation and the contour of the part to be cast is cut into each layer as it is applied to preceding layers to provide the model. A metal, such as copper, is then deposited on the working surface of the model to provide a rigid self-supporting shell having a surface which is the negative image of the part to be cast. The shell, after separation from the model, is then mounted in a die casting mold with the negative surface bordering a die cavity. Beads of a polymeric material, such as polystyrene, are introduced into the die cavity and heated to fuse the beads and provide a foam pattern which is identical in configuration to the metal part to be ultimately cast.

Abstract: A connecting rod for a two-cycle internal combustion engine that is composed of a hypereutectic aluminum-silicon alloy containing more than 12% silicon. The alloy contains precipitated particles of silicon having an average particle size less than 50 microns. In contrast to a hypoeutectic aluminum silicon alloy containing less than 12% silicon, the hypereutectic aluminum-silicon alloy has an endurance limit, so that at stresses below about 15,000 psi there will be no failure of the alloy at multiple cycles, making the alloy suitable for use as a connecting rod in a two-cycle engine, which is only subjected to compressive stress in service.

Abstract: A method of producing a casting utilizing an expendable polymeric foam pattern along with unbonded sand having specific thermal properties. The pattern, formed of a material such as polystyrene, has a configuration corresponding to that of the article to be cast. The pattern is placed with an outer flask and unbonded sand surrounds the pattern as well as filling the cavities in the pattern. The sand has a heat diffusivity greater than 1500 J/m.sup.2 /.degree.K./s1/2. The molten hypereutectic aluminum silicon alloy is fed into the flask in contact with the pattern causing the pattern to vaporize with the vapor being entrapped within the interstices of the sand while the molten metal fills the space initially occupied by the foam pattern to produce a cast article. The thermal properties of the sand reduces the particle size of the precipitated primary silicon particles in the casting, thereby increasing the machinability of the casting.

Abstract: A method of producing dimensionally predictable metal castings utilizing an expendable polymeric foam pattern along with unbonded sand having specific thermal properties. The pattern, formed of a material such as polystyrene, has a configuration corresponding to that of the article to be cast. The pattern is placed with an outer flask and unbonded sand surrounds the pattern as well as filling the cavities in the pattern. The sand has a linear expansion of less than 1% from 0.degree. C. to 1600.degree. C., a heat diffusivity greater than 1500 J/m.sup.2 /.degree.K/S1/2, an AFS grain fineness number of 25 to 33, and an AFS base permeability number of 450 to 500. A molten metal, such as an aluminum alloy or a ferrous alloy, is fed into the mold in contact with the pattern causing the pattern to vaporize with the vapor being entrapped within the interstices of the sand while the molten metal fills the space initially occupied by the foam pattern to produce a cast article.

Abstract: A hypereutectic aluminum-silicon alloy cylinder bore liner is produced by feeding the molten alloy into a metal mold having an inner shell sand cup, while rotating the mold at a speed in excess of 1,000 rpm, to cause the molten alloy to be thrown outwardly by centrifugal force to form a cylindrical liner. On solidification of the alloy, discrete silicon particles are precipitated and the use of the sand shell increases the fluid life of the alloy to enable the lighter weight silicon particles to migrate inwardly under the centrifugal force of rotation, to produce a solidified liner having a greater volume fraction of silicon particles in the inner portion of the liner where greater wear resistance is desired.

Abstract: A method of evaporable foam casting of metal articles, such as engine blocks for internal combustion engines. An evaporable foam pattern having a configuration proportionally identical to the article to be cast is positioned in a mold and a finely divided flowable material, such as sand, surrounds the pattern and fills the internal cavities of the pattern. A molten hypereutectic aluminum-silicon alloy containing 16% to 19.5% by weight of silicon and containing a magnesium content in excess of the magnesium solid solubility limit, is fed into the mold and into contact with the pattern. The heat of the molten metal vaporizes the pattern, with the vapor being trapped within the sand and the molten metal filling the void created by vaporization of the pattern to provide a cast article. The high magnesium content in the alloy produces in the solid state a Mg.sub.

Abstract: An internal combustion engine having an engine block containing a plurality of cylinder bores and a piston slidably mounted in each bore. The block is composed of a hypereutectic aluminum-silicon alloy containing from 16% to 30% silicon and having precipitated primary silicon crystals, while the piston is composed of an aluminum-copper alloy containing from 10% to 15% by weight of copper.

Abstract: A hypereutectic aluminum-silicon casting alloy having a refined primary silicon particle size and a modified silicon phase in the eutectic. The aluminum base alloy includes from 19% to 30% by weight of silicon and also contains 0.005% to 0.06% by weight of phosphorus, and 0.15% to 1.15% by weight of titanium. On cooling from solution temperature, the phosphorus serves as an active nucleant for the primary silicon phase, while at a lower temperature, a titanium-aluminum intermetallic compound is formed that is sheathed by the pseudoprimary .alpha.-aluminum and the sheathed particles act as a nucleant to modify the acicular silicon phase in the eutectic. The resulting alloy has primary silicon refinement coupled with eutectic silicon modification.

Abstract: A method of high pressure casting of hypereutectic aluminum-silicon alloys using a salt core to form wear resistant articles, such as engine blocks. To produce an engine block, one or more solid salt cores are positioned within a metal mold with the space between the cores and the mold defining a die cavity. A molten hypereutectic aluminum-silicon alloy containing more than 12% silicon is fed into the die cavity and on solidification of the molten alloy, precipitated silicon crystals are formed, which are distributed throughout the wall thickness of the cast part and also on the surface bordering the salt cores which constitute the cylinder bores in the cast block. The salt cores are subsequently removed from the cast block by contact with a solvent such as water.

Abstract: A pattern for use in casting a rotatable shaft, such as a crankshaft for an internal combustion engine. The pattern includes an evaporable foam pattern section composed of a material such as polystyrene and having a configuration conforming to the crankshaft to be cast. The evaporable foam pattern section includes a plurality of cranks connected by bearing areas, and tubular metal inserts formed of bearing quality steel are disposed around each bearing area and around the pin areas of the cranks. In the casting process, the pattern is placed in a mold and surrounded with a finely divided material such as sand. When molten ferrous metal is fed into contact with the pattern, the pattern will vaporize with the vapor passing into the interstices of the sand while the molten ferrous metal will occupy the void created by the vaporized foam to produce a cast crankshaft having bearing quality steel inserts at the bearing and pin areas.

Abstract: A lost foam casting system (2) is provided with vacuum lift of molten metal (16) to an evaporative foam pattern assembly (8) surrounded by unbonded particulate media such as sand (6) in a flask (4). A gas permeable member (34, 70) formed of randomly oriented ceramic fibers is provided between the sand and a vertical fill passage (20) to apply vacuum from the sand to the fill passage such that molten metal is vacuum lifted through the fill passage to the foam pattern assembly. The foam material is vaporized by the heat of the molten metal as the metal advances upward and is replaced by the metal in the shape of the pattern assembly.

Abstract: A hypereutectic aluminum silicon alloy having an improved distribution of primary silicon in the microstructure. The alloy is composed by weight of 20% to 30% silicon, 0.4% to 1.6% magnesium, up to 1.4% iron, up to 0.3% manganese, 0.25% copper maximum and the balance aluminum. With this composition the aluminum silicon alloy system exhibits near zero shrinkage on solidification, a similarity of the liquid aluminum-silicon alloy and the primary silicon during the early stages of primary silicon precipitation, and thereby minimizes floatation of the precipitated primary silicon and to provide a more uniform distribution of the primary silicon in the microstructure and increase the wear resistant characteristics of the alloy.

Abstract: A method of casting utilizing an evaporable foam system with a hypereutectic aluminum silicon alloy. The molten alloy is introduced into a mold in contact with an evaporable foam pattern formed of polystyrene, or the like. The heat of the molten alloy will decompose and vaporize the pattern and the vapor will enter the interstices of the surrounding sand, while the molten alloy will fill the void caused by the vaporization of the pattern. By casting the molten alloy into contact with the evaporable foam material, a more uniform distribution of primary silicon is obtained in the cast alloy and the heat of crystallization caused by precipitation of silicon crystals on solidification of the alloy will temporarily slow the solidification rate of the alloy, thus increasing the time for elimination of pattern residue vapors from the molten alloy.

Abstract: A method of producing titanium. A quantity of titianium is heated in a crucible to provide a melt, and a layer of slag, containing an ionizable titanium compound, such as titanium dioxide, along with ionizable slag constituents, is disposed on the top of the melt. The slag is then heated to a molten state by direct current plasma arc heating with the melt being anodic. After the slag is molten, the polarity of the plasma arc heating is reversed so that the melt is cathodic, causing the slag to act as an electron transfer layer so that the titanium dioxide of the slag is reduced to titanium and any dissolved oxygen in the melt is converted to an ionic species of oxygen at the interface between the slag and the melt. The resulting liquid titanium is combined with the melt, while the ionic species of oxygen is carried upwardly through the slag and released from the slag layer by an oxidation process.