Abstract:
A quantity of titanium (5) is heated in a crucible (1) to provide a melt (5), and a layer of slag (7), containing an ionizable titanium compound, such as titanium dioxide, along with ionizable slag constituents, is disposed on the top of the melt (5). The slag (7) is then heated to a molten state by direct current plasma arc heating with the melt (5) being anodic. After the slag (7) is molten, the polarity of the plasma arc heating is reversed so that the melt (5) is cathodic, causing the slag (7) to act as an electron transfer layer so that the titanium dioxide of the slag (7) is reduced to titanium and any dissolved oxygen in the melt (5) is converted to an ionic species of oxygen at the interface between the slag (7) and the melt (5). The resulting liquid titanium is combined with the melt (5), while the ionic species of oxygen is carried upwardly through the slag (7) and released from the slag layer (7) by an oxidation process. Additional quantities of titanium dioxide can be added to the slag (7) to continually convert the titanium dioxide to titanium under the reverse polarity plasma arc heating.
Abstract:
PROBLEM TO BE SOLVED: To provide an aluminum-silicon alloy having reduced microporosity. SOLUTION: The aluminum-silicon alloy die cast alloy fundamentally comprises, in mass percent: 6 to 20% silicon, 0.05 to 0.10% strontium, 0.40% maximum iron, 4.5% maximum copper, 0.5% maximum manganese, 0.6% maximum magnesium, 3.0% maximum zinc and the balance aluminum. The alloy has a very low iron content and relatively high strontium content that prevents soldering to dies. The alloys of the present invention also have a modified eutectic silicon and modified iron morphology, when iron is present, resulting in low microporosity and high impact properties. COPYRIGHT: (C)2006,JPO&NCIPI
Abstract:
A nickel containing hypereutectic aluminum-silicon sand cast alloy is disclosed herein containing 18-20% by weight silicon, 0.3-1.2% by weight magnesium, 3.0-6.0% by weight nickel, 0.6% by weight maximum iron, 0.4% by weight maximum copper, 0.6% by weight maximum manganese, 0.1% maximum zinc and balance aluminum. The alloy may have a more narrow nickel content of 4.5%-6.0% by weight, and up to 2% by weight cobalt. The alloy may be substantially free from iron, copper and manganese. The alloy of the present invention is preferably sand cast, and most preferably lost foam cast with a pressure of 10 ATM to produce engine parts with high thermal properties that are easily machined.
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 disclosure is made of a process for the production of metal castings with predictable dimensions, a consumable or lost polymer-foam pattern being used in conjunction with unbound sand with special thermal properties. The pattern, which is formed, for example, from a material such as polystyrene, has a configuration which corresponds to that of the object to be cast. The pattern is arranged in an outer box mould and unbound sand surrounds the pattern and fills the cavities in the pattern. The sand has a linear expansion of less than 1% from 0 DEG C to 1600 DEG C, a thermal diffusivity of more than 1500 J/m / DEG K/s an ASF grain-size number of 25 to 33 and an ASF basic permeability number of 450 to 500. A molten metal such as an aluminium alloy or an iron-containing alloy is fed into the mould and into contact with the pattern with the effect that the pattern vaporises or turns to gas, the vapour or gas being trapped within the interstices of the sand while the molten metal fills the space originally occupied by the foam pattern to give a cast object. The physical properties of the sand ensure that the objects to be cast have more precise and predictable tolerances.
Abstract:
A method of producing a metal 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 linear expansion of less than 1% from 0.degree.C to 1600.degree.C, a particle size of 0.001 inch to 0.015 inch, and a heat diffusivity greater than 1500 J/m2/.degree.K/s1/2. A molten metal, such as a hypoeutectic or hypereutectic aluminum silicon 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. The physical properties of the sand enable articles to be cast having more precise tolerances.
Abstract:
METHOD OF CASTING HYPEREUTECTIC ALUMINUM-SILICON ALLOYS USING A SALT CORE 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:
HYPEREUTECTIC ALUMINUM-SILICON ALLOY HAVING REFINED PRIMARY SILICON AND A MODIFIED EUTECTIC 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 0.05% 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 nickel containing hypereutectic aluminum-silicon sand cast alloy is disclosed herein containing 18-20% by weight silicon, 0.3-1.2% by weight magnesium, 3.0-6.0% by weight nickel, 0.6% by weight maximum iron, 0.4% by weight maximum copper, 0,6% by weight maximum manganese, 0.1% maximum zinc and balance aluminum. The alloy may have a more narrow nickel content of 4.5%-6.0% by weight, and up to 2% by weight cobalt. The alloy may be substantially free from iron, copper and manganese. The alloy of the present invention is preferably sand cast, and most preferably lost foam cast with a pressure of 10 ATM to produce engine parts with high thermal properties that are easily machined.
Abstract:
A nickel containing hypereutectic aluminum-silicon sand cast alloy is disclosed herein containing 18-20% by weight silicon, 0.3-1.2% by weight magnesium, 3.0-6.0% by weight nickel, 0.6% by weight maximum iron, 0.4% by weight maximum copper, 0,6% by weight maximum manganese, 0.1% maximum zinc and balance aluminum. The alloy may have a more narrow nickel content of 4.5%-6.0% by weight, and up to 2% by weight cobalt. The alloy may be substantially free from iron, copper and manganese. The alloy of the present invention is preferably sand cast, and most preferably lost foam cast with a pressure of 10 ATM to produce engine parts with high thermal properties that are easily machined.