RU2782769C2 - Ultrasound grain grinding - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: invention relates to the field of metallurgy, namely to processing of molten metal for the production of metal casts with a controlled grain size. A device for processing of molten metal contains a structure accommodating molten metal for reception and transportation of molten metal along its longitudinal length, and a cooling unit for the accommodating structure, including a cooling channel for fluid passage. An ultrasound probe is located in the cooling channel in contact with cooling fluid, providing transmission of ultrasound waves through fluid in the cooling channel and through the structure accommodating molten metal to molten metal.

EFFECT: obtaining a cast product with equiaxial grains is provided without formation of columnar crystals and without the need for introduction of grain-grinding additives.

28 cl, 17 dwg

Description

FEDERAL RESEARCH OR DEVELOPMENT STATEMENT

This invention was made with government support under grant No. IIP 1058494 awarded by the National Science Foundation. The government has certain rights in the present invention.

BACKGROUND OF THE INVENTION

FIELD OF TECHNOLOGY TO WHICH THE INVENTION RELATES

The present invention relates to a process for the production of metal castings with a controlled grain size, to a system for the production of metal castings, as well as products obtained using metal castings.

DESCRIPTION OF THE PRIOR ART

Considerable effort has been expended in the field of metallurgy to develop techniques for pouring molten metal into a continuous metal rod or cast products. Both batch casting and continuous casting have been well developed. Continuous casting has a number of advantages over batch casting, although both are widely used in industry.

In the continuous production of metal castings, molten metal passes from a mixing furnace through a series of chutes to the mold of a carousel casting machine, where it is cast into a metal rod. The hardened metal bar is removed from the carousel casting machine and sent to a rolling mill where it is rolled into a continuous rod. Depending on the intended end use of the bar and alloy, the bar may be cooled during rolling, or the bar may be cooled or quenched immediately upon leaving the rolling mill to give it the desired mechanical and physical properties. Techniques such as those described in US Patent No. 3,395,560 (Cofer et al.), the entire contents of which are incorporated here by reference, have been used to continuously process metal products in the form of a rod or rod.

In US patent No. 3,938,991 (Jackson et al.), the entire content of which is incorporated here by reference, it is shown that there has long been a problem with the casting of "clean" metal products. The term "bare metal casting" refers to a metal or metal alloy formed from primary metal elements designed to provide a specific electrical conductivity or tensile strength or ductility, without the inclusion of individual impurities added for the purpose of grain control.

Grain refinement is the process by which the crystal size of the newly formed phase is reduced either by chemical or physical/mechanical means. Grain refiners are typically added to the molten metal in order to significantly reduce the grain size of the solidified structure during the solidification or liquid-to-solidization process.

In fact, International Publication WO/2003/033750 (Boily et al.), the entire content of which is incorporated herein by reference, describes the specific use of "grain-refining additives". This application (hereinafter referred to as the ʹ750 application) describes in the Background section that, in the aluminum industry, various grain refining additives are commonly included in aluminum in order to form alloy. Typical master alloys for use in aluminum casting contain from 1 to 10 wt.% titanium and from 0.1 to 5 wt.% boron or carbon, with the remainder consisting essentially of aluminum or magnesium, with particles of TiB ₂ or TiC dispersed in aluminum matrix. In accordance with the ʹ750 application alloys containing titanium and boron, can be produced by dissolving the required amounts of titanium and boron in the aluminum melt. This is achieved by reacting molten aluminum with KBF ₄ and K ₂ TiF ₆ at temperatures above 800°C. These complex halide salts react rapidly with molten aluminum and provide titanium and boron in the melt.

The ʹ750 application also describes that since 2002 this technique has been used for the production of commercial master alloys by almost all manufacturers of grain refiners. Grain refiners, often referred to as nucleating agents, are still in use today. For example, one commercial alloy supplier Tibor describes that careful control of the cast structure is a major requirement in the production of high quality aluminum alloy products.

Prior to this invention, grain refining additives were recognized as the most effective way to provide a fine and uniform grain structure in the as-cast condition. The following references (the contents of all of which are incorporated here by reference) describe the details of this original work:

Abramov, O. V., (1998), "High-Intensity Ultrasonics", Gordon and Breach Science Publishers, Amsterdam, The Netherlands, pp. 523-552.

Alcoa, (2000), "New Process for Grain Refinement of Aluminum", DOE Project Final Report, Contract No. DE-FC07-98ID13665, September 22, 2000.

Cui, Y., Xu, C. L. and Han, Q., (2007), "Microstructure Improvement in Weld Metal Using Ultrasonic Vibrations, Advanced Engineering Materials", v. 9, no. 3, pp. 161-163.

Eskin, G. I., (1998), "Ultrasonic Treatment of Light Alloy Melts", Gordon and Breach Science Publishers, Amsterdam, The Netherlands.

Eskin, G. I. (2002) "Effect of Ultrasonuc Cavitation Treatment of the Melt on the Microstructure Evolution during Solidification of Aluminum Alloy Ingots", Zeitschrift Fur Metallkunde/Materials Research and Advanced Techniques, v.93, n.6, June, 2002, pp . 502-507.

Greer, A. L., (2004), "Grain Refinement of Aluminum Alloys", in Chu, M. G., Granger, D. A., and Han, Q., (eds.), "Solidification of Aluminum Alloys", Proceedings of a Symposium Sponsored by TMS (The Minerals, Metals & Materials Society), TMS, Warrendale, PA 15086-7528, pp. 131-145 .

Han, Q., (2007), The Use of Power Ultrasound for Material Processing", Han, Q., Ludtka, G., and Zhai, Q., (eds), (2007), "Materials Processing under the Influence of External Fields", Proceedings of a Symposium Sponsored by TMS (The Minerals, Metals & Materials Society), TMS, Warrendale, PA 15086-7528, pp. 97-106.

Jackson, K. A., Hunt, J. D., and Uhlmann, D. R., and Seward, T. P., (1966), "On Origin of Equiaxed Zone in Castings", Trans. metall. soc. AIME, v. 236, pp.149-158.

Jian, X., Xu, H., Meek, T. T., and Han, Q., (2005), "Effect of Power Ultrasoud on Solidification of Aluminum A356 Alloy", Materials Letters, v. 59, no. 2-3, pp. 190-193.

Keles, O. and Dundar, M., (2007). "Aluminum Foil: Its Typical Quality Problems and Their Causes", Journal of Materials Processing Technology, v. 186, pp.125-137.

Liu, C., Pan, Y., and Aoyama, S., (1998), Proceedings of the 5 ^th International Conference on Semi-Solid Processing of Alloys and Composites, Eds.: Bhasin, A. K., Moore, J. J., Young, K. P., and Madison, S., Colorado School of Mines, Golden, CO, pp. 439-447.

Megy, J., (1999), "Molten Metal Treatment", US Patent No. 5,935,295, August, 1999

Megy, J., Granger, D. A., Sigworth, G. K., and Durst, C. R., (2000), "Effectiveness of In-Situ Aluminum Grain Refining Process", Light Metals, pp.1-6.

Cui et al., "Microstructure Improvement in Weld Metal Using Ultrasonic Vibrations", Advanced Engineering Materials, 2007, vol. 9, no. 3, pp. 161-163.

Han et al., Grain Refining of Pure Aluminum, Light Metals 2012, pp. 967-971.

SUMMARY OF THE INVENTION

In one embodiment of the present invention, a molten metal handling apparatus is provided, comprising a molten metal containing structure for receiving and transporting molten metal along its longitudinal length. The device additionally comprises a cooling unit for the host structure, which includes a cooling channel for the passage of a liquid medium in it, as well as an ultrasonic probe located relative to the cooling channel in such a way that ultrasonic waves pass through the liquid medium in the cooling channel and through the structure containing the molten metal in molten metal.

In one embodiment, the present invention provides a method for forming a metal product. This method transports the molten metal along the longitudinal length of the structure containing the molten metal. This method cools the molten metal-containing structure by passing the medium through a cooling channel thermally connected to the molten metal-containing structure, and conducts ultrasonic waves through this medium in the cooling channel and through the molten metal-containing structure into the molten metal.

In one embodiment, the present invention provides a system for forming a metal product. This system includes 1) a molten metal processing apparatus as described above and 2) a controller including data inputs and control outputs and programmed to carry out the steps of the method described above.

In one embodiment, the present invention provides a metal product comprising a cast metal composition having submillimeter grain sizes and comprising less than 0.5 wt% grain refiner additives.

It should be understood that the foregoing general description of the present invention and the following detailed description are exemplary and not limiting of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete understanding of the present invention and many of its attendant advantages thereof will be readily obtained from reading the following detailed description, together with the accompanying drawings, in which:

Fig. 1A is a schematic representation of a casting channel in accordance with one embodiment of the present invention;

Fig. 1B is a photographic view of the base of a casting channel in accordance with one embodiment of the present invention;

Fig. 1C is a composite photograph of the base of a casting channel in accordance with one embodiment of the present invention;

Fig. 1D is a schematic representation of exemplary dimensions for one embodiment of a casting channel;

Fig. 2 is a photographic representation of a mold in accordance with one embodiment of the present invention;

Fig. 3A is a schematic representation of a continuous casting mill in accordance with one embodiment of the present invention;

Fig. 3B is a schematic representation of another continuous casting mill according to one embodiment of the present invention;

Fig. 4A is a micrograph showing macrostructures present in an aluminum ingot;

Fig. 4B is another micrograph showing macrostructures present in an aluminum ingot;

Fig. 4C is another photomicrograph showing macrostructures present in an aluminum ingot;

Fig. 4D is another micrograph showing macrostructures present in an aluminum ingot;

Fig. 5 is a graph showing grain size as a function of casting temperature;

Fig. 6A is a micrograph showing the macrostructure present in an aluminum ingot prepared under the conditions described herein;

Fig. 6B is another micrograph showing the macrostructure present in an aluminum ingot prepared under the conditions described herein;

Fig. 6C is another micrograph showing the macrostructure present in an aluminum ingot prepared under the conditions described herein;

Fig. 7 is another graph showing grain size as a function of casting temperature;

Fig. 8 is another graph showing grain size as a function of casting temperature;

Fig. 9 is another graph showing grain size as a function of casting temperature;

Fig. 10 is another graph showing grain size as a function of casting temperature;

Fig. 11A is a micrograph showing the macrostructures present in an aluminum ingot prepared under the conditions described herein;

Fig. 11B is another micrograph showing the macrostructures present in an aluminum ingot prepared under the conditions described herein;

Fig. 11C is a schematic representation of exemplary dimensions for one embodiment of casting channels;

Fig. 11D is a schematic representation of exemplary dimensions for one embodiment of casting channels;

Fig. 12 is another graph showing grain size as a function of casting temperature;

Fig. 13A is another schematic representation of exemplary dimensions for one embodiment of a casting channel;

Fig. 13B is another graph showing grain size as a function of casting temperature;

Fig. 14 is a schematic representation of a continuous casting machine according to one embodiment of the present invention;

Fig. 15A is a schematic cross-sectional view of one component of a vertical cavity mold casting machine;

Fig. 15B is a schematic cross-sectional view of another component of a vertical cavity mold casting machine;

Fig. 15C is a schematic cross-sectional view of another component of a vertical cavity mold casting machine;

Fig. 15D is a schematic cross-sectional view of another component of a vertical cavity mold casting machine;

Fig. 16 is a schematic diagram of an exemplary computer system for the controls and controllers described herein;

Fig. 17 is a flow chart depicting a method in accordance with one embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Grain refinement of metals and alloys is important for many reasons, including maximizing the casting rate of an ingot of metal, improving resistance to hot tearing, minimizing elemental segregation, improving mechanical properties, in particular ductility, improving the final characteristics of forged products and increasing mold filling characteristics, as well as reduction in the porosity of the ligatures. Typically, grain refining is one of the first processing steps to produce metal and alloy products, especially aluminum and magnesium alloys, which are lightweight materials increasingly used in the aerospace, military, automotive, construction, and packaging industries. Grain refinement is also an important processing step to make metals and alloys suitable for casting by eliminating columnar grains and forming equiaxed grains.

Prior to the present invention, the use of impurities or chemical "grain refiners" was the only way to solve this long known problem of columnar crystal formation in metal castings.

Approximately 68% of the aluminum produced in the US is first cast into an ingot before further processing into sheets, plates, extruded products or foils. The direct-cooling semi-continuous casting (DC) process and the continuous casting (CC) process have been the backbone of the aluminum industry in large part due to their reliability and relative simplicity. One problem in the DC and CC processes is the formation of hot fracture or cracking during the solidification of the ingot. Basically all ingots of metal would be cracked (or incapable of casting) without the use of grain grinding.

However, the performance of these modern processes is limited by cracking prevention conditions. Grain refinement is an effective way to reduce the tendency of an alloy to hot break and thus increase productivity. As a result, significant efforts have been concentrated on the development of effective grain refinement additives that could minimize grain size. Superplasticity can be achieved if the grain size is reduced to the submicron level, which allows not only alloys to be cast at much higher speeds, but also to be rolled/extruded at lower temperatures at higher speeds than currently, which would result in significant cost savings and energy savings.

At present, almost all aluminum castings in the world, both from primary (approximately 20 billion kg) and from recycled aluminum and domestic waste (25 billion kg), are subjected to grain refinement using dissimilar insoluble TiB ₂ cores, having approximately a few microns in diameter, which form nuclei of a fine granular structure in aluminium. One problem related to the use of chemical grain refining additives is the limited grain refining capability. In addition, the use of chemical grain refining additives causes a limited reduction in the size of the aluminum grain, from a columnar structure with linear grain sizes above about 2500 microns to equiaxed grains smaller than 200 microns. The 100 µm equiaxed grains in aluminum alloys seem to be the limit that can be obtained using commercially available chemical grain refiners.

It is widely known that productivity can be greatly improved if the grain size can be further reduced. The submicron grain size results in superplasticity, which makes it much easier to form aluminum alloys at room temperatures.

Another problem related to the use of chemical grain refiners is the generation of defects associated with the use of grain refiners. Although considered necessary in the prior art for grain refinement, insoluble foreign particles are generally undesirable in aluminium, especially in the form of particle agglomerates ("clusters"). Current grain refining additives, which are present in the form of compounds in aluminum alloys, are produced through a complex chain of mining, beneficiation and production processes. The master alloys currently in use often contain potassium aluminum fluoride salt (KAlF) and alumina impurities (dross) which are the result of a conventional aluminum grain refiner manufacturing process. They give rise to local defects in the aluminum (eg "leaks" in beverage cans and "pinholes" in thin foil), lead to tool wear, and lead to surface finishing problems in aluminum. Data from an aluminum cable company shows that 25% of manufacturing defects are due to TiB ₂ particle agglomerates and another 25% are due to dross that is trapped in the aluminum during the casting process. Agglomerates of TiB ₂ particles often break the wire during extrusion, especially when the wire diameter is less than 8 mm.

Another problem related to the use of chemical grain refiners is the cost of the grain refiners. This is especially true for the production of magnesium ingots using zirconium grain refiners. Grain refining using zirconium grain refining additives increases the cost per kilogram of magnesium casting produced by about $1. Grain-refining additives for aluminum alloys cost about $1.50 per kilogram.

Another problem related to the use of chemical grain refiners is the decrease in electrical conductivity. The use of chemical grain refiners introduces excessive amounts of titanium into the aluminum, causing a significant decrease in the electrical conductivity of pure aluminum for cable applications. To maintain a certain electrical conductivity, companies must spend extra money to use purer aluminum for cable and wire.

A number of other methods for grinding grain, in addition to chemical methods, have been explored in the past century. These methods include the use of physical fields such as magnetic and electromagnetic fields, as well as the use of mechanical vibrations. High-intensity, low-amplitude ultrasonic vibration is one of the physical/mechanical mechanisms that has been demonstrated for grain refinement of metals and alloys without the use of impurity particles. However, experimental results such as those in Cui et al, 2007 noted above have been obtained in small ingots of metal weighing up to several pounds subjected to ultrasonic vibration for a short period of time. Little attention has been paid to grain refinement in CC or DC ingot/blank casting processes using high-intensity ultrasonic vibrations.

The technical problems addressed by the present invention for grain refining are (1) transferring ultrasonic energy to molten metal for extended periods of time, (2) maintaining system natural frequencies at elevated temperatures, and (3) increasing the efficiency of ultrasonic grain refining at high temperature. ultrasonic waveguide. Improved cooling of the ultrasonic waveguide and metal ingot (as will be described below) is one of the solutions presented in this paper to solve these problems.

In addition, another technical problem solved by the present invention relates to the fact that the purer the aluminum, the more difficult it is to obtain equiaxed grains during the curing process. Even when using external grain refiners such as TiB (titanium boride) in pure aluminum such as 1000, 1100 and 1300 grade aluminum, it is difficult to obtain an equiaxed grain structure. However, using the new grain refinement technology described herein, an equiaxed grain structure was obtained.

The present invention overcomes the problem of the formation of columnar crystals without the need for the introduction of grain refining additives. The present inventors have surprisingly found that using the controlled application of ultrasonic vibrations to the molten metal as it is cast produces grain sizes comparable to or less than those obtained using current grain refining additives such as TiB master alloy.

In one aspect of the present invention, equiaxed grains within the cast product are obtained without the need to add impurity particles, such as titanium boride, to the metal or metal alloy to increase the number of grains and improve uniform heterogeneous solidification. Instead of using nucleators, ultrasonic vibrations can be used to create nucleation points. In particular, as will be explained in more detail below, ultrasonic vibrations are transmitted by a liquid medium in order to refine grains in metals and metal alloys and create equiaxed grains.

In order to understand the morphology of an equiaxed grain, consider the growth of an ordinary metal grain in which dendrites grow one-dimensionally and elongated grains are formed. These elongated grains are referred to as columnar grains. If the grain grows freely in all directions, an equiaxed grain is formed. Each equiaxed grain contains 6 primary dendrites growing perpendicularly. These dendrites can grow at the same rate. In this case, the grains appear more spherical if the details of the dendritic features within the grain are ignored.

In one embodiment of the present invention, the channel structure 2 (i.e., the enclosing structure), as shown in FIG. 1A transports the molten metal to a mold (not shown in FIG. 1A), such as, for example, the carousel casting machine detailed below. The channel structure 2 includes molten metal retaining side walls 2a and a base plate 2b. The side walls 2a and the base plate 2b may be separate entities, as shown in the drawing, or may be an integrated unit. Below the base plate 2b is a fluid passage 2c which is filled with fluid during operation. In addition, these two elements can be an integral block.

The ultrasonic probe 2d (or sonotrode or ultrasonic transducer) of the ultrasonic transducer, which delivers ultrasonic vibrations (UV) through the liquid medium and through the base plate 2b into the liquid metal, is connected to the liquid medium passage 2c. In one embodiment of the present invention, the ultrasonic probe 2d is inserted into the fluid passage 2c. In one embodiment of the present invention, more than one ultrasonic probe or an array of ultrasonic probes can be inserted into the fluid passage 2c. In one embodiment of the present invention, the ultrasonic probe 2d is attached to the wall of the fluid passage 2c. Without being bound by any particular theory, a relatively small amount of insufficient cooling (eg, less than 10°C) at the bottom of the channel leads to the beginning of the formation of a layer of small nuclei of purer aluminum. Ultrasonic vibrations from the bottom of the channel create these pure aluminum cores, which are then used as nucleating agents during curing, resulting in a uniform grain structure. Accordingly, in one embodiment of the present invention, the cooling method ensures that a small amount of insufficient cooling at the bottom of the channel leads to the formation of a layer of small aluminum nuclei. Ultrasonic vibrations from the bottom of the channel disperse these nuclei and break the dendrites that form in the undercooled layer. These aluminum cores and dendritic fragments are then used to form equiaxed grains in the mold during curing, resulting in a uniform grain structure.

In other words, the ultrasonic vibrations transmitted through the base plate 2b and into the liquid metal create nucleation points in the metals or metal alloys in order to refine the grain size. The base plate may be a refractory metal or other high temperature material such as copper, iron and steel, niobium, niobium and molybdenum, tantalum, tungsten and rhenium, and their alloys, including one or more of the elements silicon, oxygen or nitrogen. , which can increase the melting point of these materials. In addition, the base plate may be one of a variety of alloy steels such as, for example, H13 steel or low carbon steels.

In one embodiment of the present invention, a wall is provided between the molten metal and the cooling unit, the wall thickness being sufficiently thin (as will be described in more detail below in the examples) such that, in steady state production, the molten metal adjacent to the wall is cooled below the critical temperatures for a particular cast metal.

In one embodiment of the present invention, an ultrasonic vibration system is used to improve heat transfer through a thin wall between a cooling channel and molten metal and to nucleate or break up dendrites that form in the molten metal near the thin wall of the cooling channel.

In the demonstrations below, the ultrasonic vibration source provided 1.5 kW of power at an acoustic frequency of 20 kHz. The present invention is not limited to these powers and frequencies. A wide range of powers and frequencies can be used, although the following ranges are of particular interest.

Power : In most cases, the power is between 50 and 5000 watts for each sonotrode, depending on the dimensions of the sonotrode or probe. These powers are typically applied to the sonotrode in order to ensure that the specific power at the end of the sonotrode is greater than 100 W/cm ² , which is the threshold for causing cavitation in the molten metals. Powers in this region may vary from 50 to 5000 watts, 100 to 3000 watts, 500 to 2000 watts, 1000 to 1500 watts, or may be in any intermediate or overlapping range. Higher powers are possible with a larger probe/sonotrode and lower powers are possible with a smaller probe.

Frequency: Typically, a frequency of 5-400 kHz (or any range in between) can be used. Alternatively, the 10-25 kHz range (or any range in between) may be used. Alternatively, the 15-25 kHz range (or any range in between) may be used. The applied frequency may vary from 5 to 400 kHz, 10 to 30 kHz, 15 to 25 kHz, 10 to 200 kHz, or 50 to 100 kHz, or may be in any intermediate or overlapping range.

In addition, the ultrasonic probe/sonotrode 2d can be constructed similarly to ultrasonic probes used for degassing molten metal, as described in US Pat. No. 8,574,336, the entire contents of which are incorporated herein by reference.

On FIG. 1A, the dimensions of the channel structure 2 are chosen according to the volume flow of the material to be cast. The fluid passage 2c is dimensioned according to the flow rate of the coolant through the channel to ensure that the coolant remains substantially in the liquid phase. The liquid medium may be water. The liquid medium may also be oil, ionic liquids, liquid metals, liquid polymers, or other mineral (inorganic) liquids. The formation of steam, for example in a cooling passage, can impair the transmission of ultrasonic waves into the molten metal to be processed. The thickness and material construction of the base plate 2b are selected according to the temperature of the molten metal, the temperature gradient in the thickness of the base plate, and the nature of the underlying wall of the fluid passage 2c. In the following, more details will be given regarding the thermal factors to be taken into account.

Fig. 1B and 1C are perspective views of the channel structure 2 (without side walls 2a) showing the base plate 2b, the fluid inlet 2c-1, the fluid outlet 2c-2, and the ultrasonic probe 2d. Fig. 1D shows the dimensions associated with the channel structure 2 shown in FIG. 1B and 1C.

During operation, molten metal at a temperature substantially higher than the liquidus temperature of the alloy moves by gravity along the top of the base plate 2b and is subjected to ultrasonic vibrations as it passes through the channel structure 2. The base plate is cooled to ensure that the molten metal near the baseplate will have a temperature close to the sub-liquidus temperature (e.g. less than 5 to 10°C above the liquidus temperature of the alloy, or even below the liquidus temperature, although the casting temperature can be much higher than 10°C in our experimental results ). The temperature of the baseplate can be controlled, if necessary, by using fluid in the duct or by using booster heaters. During operation, the atmosphere around the molten metal can be controlled by means of a shroud (not shown) which is filled or purged with, for example, an inert gas such as Ar, He or nitrogen. The molten metal flowing down the channel structure 2 is typically in a temperature-stop state in which the molten metal is converted from a liquid to a solid. The molten metal flowing down the channel structure 2 exits the end of the channel structure 2 and is poured into a mold, such as the mold 3 shown in FIG. 2. The mold 3 has a molten metal container 3a made of a relatively high temperature material such as copper or steel partially including a cavity region 3b. The mold 3 may have a cover 3c. The mold shown in Fig. 2, can hold approximately 5kg of molten aluminum. The present invention is not limited to this capacity. The mold is not limited to the mold shown in FIG. 2. In one alternative example, a copper mold was used sized to produce conical shaped ingots approximately 7.5 cm in diameter and 6.35 cm high. Other sizes, shapes and materials may also be used for the mold. The mold can be stationary or moving.

The mold 3 may have features of the molds described in US Pat. In particular, as described in the referenced patent and applicable as one embodiment of this invention, a corner filling device or material is used in combination with mold elements such as a wheel and a bandage in order to modify the geometry of the mold so as to prevent corner cracking. due to the curing stresses present in other molds having sharp or square edges. Ablative, conductive, or insulating materials, selected according to the desired change in cure pattern, may be injected into the mold separately from, or attached to, moving mold members such as an endless band or pouring wheel.

In one mode of operation, a water pump (not shown) pumps water into the channel structure 2, and the water exiting the channel structure 2 is sprayed outside the molten metal container 3. In other modes of operation, a separate coolant supply is used to cool the channel structure 2 and the molten metal container 3. In other modes of operation, fluids other than water may be used as the coolant. In the mold, the metal cools, forming a solidified body, which usually shrinks in volume and extends from the side walls of the mold.

Although not shown in FIG. 2, in a continuous casting process, the mold 3 would be part of a rotating wheel and the molten metal would fill the mold 3 through its open end. Such a continuous casting process is described in US Pat. No. 4,066,475 (Chis et al.), the entire contents of which are incorporated herein by reference. For example, in one aspect of the present invention, the continuous casting steps may be performed in the apparatus shown in FIG. 3A. This device includes a feeder 10 which receives molten metallic copper containing common impurities and feeds this metal to the pouring spout 11. The pouring spout includes as a separate addition (or as integral components) the channel structure 2 shown in FIG. . 1A-1B (or other channel structures described herein) in order to provide ultrasonic treatment of molten metal to create nucleation points.

The pouring spout 11 directs the molten metal to a peripheral recess on the rotating ring 13 of the mold (for example, the mold 3 shown in Fig. 2 without the cover 3c). An endless flexible metal band 14 surrounds a part of the mold ring 13, as well as a part of a set of band positioning rollers 15 in such a way that the continuous casting mold is defined by a recess in the mold ring 13 and a metal band 14 covering it between points A and B. A cooling system is provided for cooling the device and effecting a controlled solidification of the molten metal during its transport on the rotating ring 13 of the mold. The cooling system includes a plurality of lateral conduits 17, 18, and 19 located on the side of the mold ring 13, as well as internal and external conduits 21 and 22 of the shroud, respectively, located on the inner and outer sides of the metal shroud 14 in the place where it surrounds the mold ring. The pipeline network 24, having suitable valves, is connected for the supply and withdrawal of coolant to various conduits to control the cooling of the device and the solidification rate of the molten metal. For a more detailed demonstration and explanation of this type of device, see US Pat. No. 3,596,702 (Ward et al.), the entire contents of which are incorporated herein by reference.

Fig. 3A also shows a controller 500 which controls the various parts of the aluminum continuous casting system shown in this figure. As will be discussed in detail below, the controller 500 includes one or more processors with programmed instructions for controlling the operation of the continuous casting system shown in FIG. 3A.

With this design, the molten metal is fed from the pouring trough 11 into the mold at point A and is solidified and partially cooled during its transport between points A and B by circulating coolant through the cooling system. Thus, by the time the cast bar reaches point B, it takes the form of a solid bar 25. This solid bar 25 is removed from the casting wheel and fed to a conveyor 27 which conveys the cast bar to the rolling mill 28. It should be noted that at point B, the cast bar 25 is only cooled to a temperature sufficient to solidify the bar, and the bar is still at an elevated temperature to be immediately rolled. Rolling mill 28 may include a tandem array of stands that sequentially roll bar into continuous rod 30 that has a substantially uniform circular cross section.

Fig. 3B is a schematic representation of another continuous casting mill in accordance with one embodiment of the present invention. Fig. 3B is a perspective view of a continuous rod (CR) manufacturing system and includes a sidebar showing an enlarged view of the pour trough. The CR system shown in FIG. 3B is characterized as a pour wheel and shroud system that has a water-cooled copper pour wheel 50 and a flexible steel shroud 52. the steel band 52 extends approximately half way around the casting wheel 50 in order to close the casting cavity. In one embodiment of the present invention, the casting cavity and a flexible steel band that covers the casting cavity form a mold cavity 60 . In one embodiment of the present invention, tundish 62, tundish 64, and metering device 66 feed molten aluminum into the casting cavity while wheel 50 is rotated. in front of the spill point. The molten metal is typically held in place by a steel band 52 until the solidification process is complete. As the wheel spins, the aluminum (or cast metal) solidifies. The cured aluminum is exited by the stripper shoe 70 from the wheel 50. The wheel 50 is then wiped down and the cast lubricant reapplied before fresh molten aluminum is introduced.

In the CR system shown in FIG. 3B, the pouring chute includes as a separate addition (or as integral components) the channel structure 2 shown in FIG. 1A-1B (or other channel structures described herein) in order to provide ultrasonic treatment of molten metal to create nucleation points.

Fig. 3B also shows a controller 500 (already mentioned above) which controls the various parts of the aluminum continuous casting system shown in this figure. The controller 500 includes one or more processors with programmed instructions for controlling the operation of the continuous casting system shown in FIG. 3A.

As noted above, the mold may be stationary, such as those used in sand casting, plaster casting, shell casting, investment casting, reusable mold casting, injection molding, etc. While the following is described with respect to aluminum, the present invention is not limited thereto, and other metals such as copper, silver, gold, magnesium, bronze, brass, tin, steel, iron, and their alloys may use the principles of the present invention. Additionally, metal-matrix composites can use the principles of the present invention to control the final grain sizes in cast objects.

Demos:

The following demonstrations demonstrate the usefulness of the present invention and are not intended to limit the present invention to any of the specific dimensions, cooling conditions, capacities and temperatures described below, unless used in the claims.

Using the channel structure shown in FIG. 1A-1D and the mold shown in FIG. 2, the results of the present invention have been documented. Except as noted below, the channel structures had base plates 2b approximately 5 cm wide and 54 cm long, creating a vibratory path approximately 52 cm long (ie, approximately equal to the length of the liquid cooling channel 2c). The thickness of the base plate varied as noted below, but for the steel base plate, the thickness was 6.35 mm. As the steel alloy, 1010 steel was used. The height and width of the liquid cooling channel 2c were approximately 2 cm and 4.5 cm, respectively. The cooling fluid was water supplied at approximately room temperature and at a flow rate of approximately 22-25 L/min.

1) No grain-refining additives and no ultrasonic vibration

Fig. 4A and 4B are macroscopic views of a pure aluminum ingot cast without grain refining additives and without ultrasonic vibration of the present invention. Cast samples were formed at pour temperatures of 1238˚F or 670˚C (see Fig. 4A) and 1292˚F or 700˚C (see Fig. 4B), respectively. The mold was cooled by spraying water on it during the curing process. A steel channel having a thickness of 6.35 mm was used for the channel structure shown in FIG. 4A-4D. Fig. 4C and 4D are macroscopic views of a pure aluminum ingot cast without grain refining additives and without ultrasonic vibration of the present invention. Cast samples were formed at pour temperatures of 1346°F or 730°C (see Fig. 4C) and 1400°F or 760°C (see Fig. 4D), respectively. The mold was again cooled by spraying water on it during the curing process. On FIG. 4A-4D, the casting speed was approximately 40 kg/min.

Fig. 5 is a graph showing measured grain size as a function of casting temperature. Grains show crystals that are columnar and have grain sizes ranging from mm to tens of mm with a median grain size of greater than 12 mm to greater than 18 mm depending on casting temperature

2) Without grain-refining additives and with ultrasonic vibration

Fig. 6A-6C are macroscopic views of a pure aluminum ingot cast without grain refining additives and with ultrasonic vibration of the present invention. Cast samples were formed at pour temperatures of 1256°F or 680°C (see Fig. 6A), 1292°F or 700°C (see Fig. 6B), and 1328°F or 720°C (see Fig. 6C), respectively. The mold was cooled by spraying water on it during the curing process. A steel channel having a thickness of 6.35 mm was used for the channel structure used to form the samples shown in FIG. 6A-6C. In these examples, molten aluminum flowed through a steel channel (5 cm wide base plate) at a distance of approximately 35 cm over the top surface. The ultrasonic vibration probe was mounted under the top side of the steel channel structure and positioned at a distance of approximately 7.5 cm from the end of the channel structure from which the molten aluminum was poured. On FIG. 6A-6C, the casting speed was approximately 40 kg/min. The ultrasonic probe/sonotrode was made of a Ti alloy (Ti-6Al-4V). The frequency was 20 kHz and the ultrasonic vibration intensity was 50% of the maximum amplitude, approximately 40 µm.

Fig. 7 is a graph showing measured grain size as a function of casting temperature. These grains show crystals that are columnar and have grain sizes less than 0.5 µm. These results show that the ultrasonic treatment of the present invention is as effective in producing equiaxed grains of pure metal as grain refining additives Tibor (compound containing titanium and boron). See, for example, FIG. 13 showing data for samples containing Tibor grain refiners.

In addition, the effect of the present invention was obtained even for higher casting speeds. Using a casting speed of 75 kg/min through a steel channel (with a base plate 7.5 cm wide) with a flow distance of approximately 52 cm on the top surface, the ultrasonic treatment of the present invention was as effective in forming equiaxed grains of pure metal as grinding grains. Tibor additives. Fig. 8 is a graph showing measured grain size as a function of casting temperature at a casting speed of 75 kg/min.

Similar demonstrations were made using a copper base plate having a thickness of 6.35 mm and the same horizontal dimensions as described above. Fig. 9 is a graph showing measured grain size as a function of casting temperature at a casting speed of 75 kg/min using the copper channel discussed above. The results show that the grain refinement effect for copper is better when the casting temperature is 1238°F or 670°C.

Similar demonstrations were made using a niobium base plate having a thickness of 1.4 mm and the same horizontal dimensions as described above. Fig. 10 is a graph showing measured grain size as a function of casting temperature at a casting speed of 75 kg/min using the niobium channel discussed above. These results show that the grain refinement effect for niobium is better when the casting temperature is 1238°F or 670°C.

In another demonstration of the present invention, it has been found that changing the offset of the ultrasonic probe from the exit end of channel 3 provides a way to change the grain size without the addition of grain refining additives. Fig. 11A and 11B for the niobium wafer described above at respective pour temperatures of 1346°F or 730°C (FIG. 11A) and 1400°F or 760°C (FIG. 11B) show a much coarser grain structure when the distance of the ultrasonic probe from exit end was increased from 7.5 cm to 22 cm. FIG. 11C and 11D are schematics of the experimental positioning and displacement of the ultrasonic probe with which data on the effect of displacement of the ultrasonic probe was collected. Offsets below 23 cm or further are effective in reducing grain size. However, the window (ie range) for casting temperature decreases as the distance between the probe/sonotrode position and the metal mold increases. The present invention is not limited to this range.

Fig. 12 is a graph of measured grain sizes as a function of casting temperature at a casting speed of 75 kg/min and using the niobium channel discussed above, but with the distance of the ultrasonic probe from the exit end increased to 22 cm. This graph shows that the grain size is strongly depends on casting temperature. Grain sizes become much larger and columnar crystals partially appear when the pour temperature is higher than approximately 1300°F or 704°C, while grain sizes are nearly equivalent to other conditions at a pour temperature of less than 1292°F or 700° C.

In addition, at higher temperatures, the use of grain refiners generally results in smaller grain sizes than at lower temperatures. The average grain size in the ingot subjected to grain refinement at 760° C. was 397.76 µm, while the average grain size in the sonicated ingot was 475.82 µm, with a grain size standard deviation of approximately 169 µm and 95 µm, respectively, showing that the ultrasonic vibrations produced more uniform grains than Al-Ti-B grain refiners.

In one particularly attractive aspect of the present invention, at lower temperatures, sonication is more effective than the addition of grain refiners.

In another aspect of the present invention, casting temperature may be used to control grain size changes in ingots subjected to ultrasonic treatment. The inventors of the present invention have found that the grain size decreases with decreasing pouring temperature. The present inventors have also found that equiaxed grains are formed using ultrasonic vibration when the melt is cast into a mold at temperatures within 10° C. above the liquidus temperature of the cast alloy.

Fig. 13A schematically shows the configuration of the enlarged free end. In the enlarged riser configuration shown in FIG. 13A, the length of the free end of the niobium channel is increased from 1.25 cm to approximately 12.5 cm, and the ultrasonic probe is positioned 7.5 cm from the end of the tube. The enlarged free end is realized by adding a niobium plate to the original free end. Fig. 13B is a graph showing the effect of casting temperature on grain size produced when using a niobium channel. The obtained grain sizes were effectively equivalent to the shorter free end when the casting temperature was less than 1292°F or 700°C.

The present invention is not limited to applying the use of ultrasonic vibrations simply to the channel structure described above. In most cases, ultrasonic vibrations can induce nucleation at those points during the casting process at which the molten metal begins to cool from the molten state and enter the solid state (i.e., where it is in the temperature stop state). In other words, the present invention, in various embodiments, combines ultrasonic vibration with temperature control so that the molten metal near the surface to be cooled has a temperature close to the liquidus temperature of the alloy. In these embodiments, the surface temperature of the chilled plate is low enough to induce nucleation and crystal growth (formation of dendrites) while ultrasonic vibration nucleates and breaks up dendrites that may form on the surface of the chilled plate.

Alternative Configurations

Accordingly, in the present invention, ultrasonic vibrations (other than those introduced into the channel structure noted above) can be used to induce nucleation at the entry point of the molten metal into the mold by an ultrasonic vibrator, preferably connected to the entry into the mold by a liquid coolant. This choice may be more attractive in stationary form. In some casting configurations (eg vertical cavity casting) this choice may be the only practical solution.

Alternatively, or in addition, the ultrasonic vibrations can induce nucleation in a trough that delivers molten metal to the channel structure or that delivers molten metal directly into the mould. As before, the ultrasonic vibrator is preferably connected to the trough and thus to the molten metal by means of a liquid coolant.

Moreover, in addition to using the ultrasonic vibration treatment of the present invention in casting into the stationary molds and continuous rod-type molds described above, the present invention is also useful in the casting mills described in US Pat. No. 4,733,717, the entire contents of which are incorporated herein by links. As shown in FIG. 14 (reproduced from this patent), the continuous casting and hot forming system 110 includes a casting machine 112 that further includes a casting wheel 114 having a peripheral recess, a flexible band 116 driven by a plurality of guide wheels 117 that move the flexible band 116 against the casting wheel 114 on part of its circumference so as to cover the peripheral recess and form a mold between the shroud 116 and the pouring wheel 114. As molten metal is poured into the mold through the pouring spout 119, the pouring wheel 114 rotates and the shroud 116 moves with the casting wheel 114 to form a moving mold. The pouring spout 119 includes as a separate addition (or as integral components) the channel structure 2 shown in FIG. 1A-1B (or other channel structures described herein) in order to provide ultrasonic treatment of molten metal to create nucleation points.

The cooling system 115 of the casting machine 112 causes the molten metal to uniformly solidify in the mold and exit the pouring wheel 114 as a cast rod 120.

From the pouring machine 112, the cast rod 120 passes through the heating means 121. The heating means 121 functions as a heater to increase the temperature of the rod 120 from the solid casting temperature to the hot forging temperature, that is, from about 1700°F or 927°C to about 1750°F or 954°C. Immediately after preheating, bar 120 passes through conventional rolling mill 124, which includes stands 125, 126, 127, and 128. Mill stands 124 provide primary hot forming of the cast bar by sequentially compressing the preheated bar until it is reduced to desired transverse size and shape.

Fig. 14 also shows a controller 500 which controls the various parts of the continuous casting system shown in this drawing. As will be discussed in detail below, controller 500 includes one or more programmed instruction processors for controlling operation of the copper continuous casting system shown in FIG. fourteen.

Furthermore, in addition to using the ultrasonic vibration treatment of the present invention in stationary mold casting and wheel-type continuous casting systems described above, the present invention is also useful in vertical cavity mold casting machines.

Fig. 15 shows selected components of a vertical cavity molding machine. These components and other aspects of the vertical cavity molding machine are described in more detail in US Pat. No. 3,520,352, the entire contents of which are incorporated herein by reference. As shown in FIG. 15, the vertical cavity casting machine includes a molten metal casting cavity 213 which is generally square in the illustrated embodiment, but which may be round, elliptical, polygonal, or any other suitable shape, and which is limited vertical, mutually intersecting first wall portions 215 and second or corner wall portions 217 located at the top of the mold. The fluid retaining sheath 219 surrounds the walls 215 and corners 217 of the casting cavity at some distance from it. The shell 219 is configured to receive a cooling fluid, such as water, through the inlet conduit 221 and to discharge the cooling fluid through the outlet conduit 223.

While the first wall portions 215 are preferably made of a high thermal conductivity material such as copper, the second or corner wall portions 217 are made of a lower thermal conductivity material such as, for example, a ceramic material. As shown in FIG. 15, the corner portions 217 of the wall have a generally L-shaped or corner cross-section, and the vertical edges of each corner are beveled downward towards each other. Thus, the corner member 217 terminates at some suitable level in the mold above the mold discharge side which is between the cross sections.

In operation, the molten metal flows out of the tundish into the casting mold, which performs vertical reciprocating movements, and the cast metal strip is continuously withdrawn from the casting mold. The molten metal is first cooled in the mold by contact with the cooler walls of the mold, which can be thought of as the first cooling zone. Heat is rapidly removed from the molten metal in this zone and a sheath of solidified material is believed to form completely around the central pool of molten metal.

In the present invention, a channel structure 2 (or a structure similar to that shown in FIG. 1) could be provided as part of a casting apparatus for transporting molten metal to the casting cavity 213. In this configuration, the channel structure 3, with its ultrasonic probe, sonicates the molten metal in order to create nucleation points.

In one alternative configuration, the ultrasonic is positioned relative to the fluid containment sheath 219 so that it preferably enters the cooling medium circulating in the sheath 219. As before, the ultrasonic vibrations can induce nucleation in the molten metal, for example, in its temperature-stop state, in which the molten metal is converted from a liquid to a solid state as the cast strip of metal is continuously withdrawn from the casting cavity 213 .

Temperature control

As noted above, in one aspect of the present invention, ultrasonic vibrations from an ultrasonic probe are transmitted to a liquid medium in order to better refine grains in metals and metal alloys and promote more uniform solidification. The ultrasonic vibration is preferably transmitted to the liquid metal via an intermediate liquid cooling medium.

Without wishing to be bound by any particular theory, the following discussion illustrates some of the factors that affect ultrasonic contact.

Preferably, the flow of coolant is provided at a sufficient rate to properly cool the metal in the vicinity of the cooling plate (less than 5-10° C. above the liquidus temperature of the alloy, or slightly below the liquidus temperature). Thus, one feature of the present invention utilizes these cold plate conditions and ultrasonic vibration in order to reduce the grain size in a large amount of metal. Previous techniques using ultrasonic vibration for grain refinement only worked for small amounts of metal at short casting times. The use of a cooling system ensures that the present invention can be used for a large amount of metal for a long time or for continuous casting.

In one embodiment, the flow rate of the cooling medium is preferably, but not necessarily, sufficient to prevent the formation of a pocket of water vapor due to heat transfer through the base plate and walls of the cooling channel, which can destroy ultrasonic contact.

Considering the heat flow from the molten metal into the cooling channel, the baseplate (by designing its thickness and material) can be configured to support most of the temperature drop from the molten metal temperature to the cooling water temperature. If, for example, the temperature drop across the thickness of the baseplate is only about 100°C, then the rest of the temperature drop will be localized at the water/steam interface, potentially impairing ultrasonic contact.

In addition, as noted above, the base plate 2b of the channel structure can be attached to the wall of the fluid passage 2c, allowing different materials to be used for the two members. In this aspect of the design, materials with different thermal conductivity can be used to distribute the temperature drop appropriately. In addition, the cross-sectional shape of the liquid passage 2c and/or the surface finish of the inner wall of the liquid passage 2c can be adjusted to increase heat exchange with the cooling medium without forming an intermediate vapor phase. For example, surface protrusions may be intentionally provided on the inner wall of the liquid medium passage 2c in order to promote bubble boiling characterized by the growth of bubbles on a hot surface that form at discrete points on a surface whose temperature is only slightly above the temperature of the liquid.

metal products

In one aspect of the present invention, products incorporating cast metal composition can be produced without the need for grain refining additives and still have sub-millimeter grain sizes. Accordingly, cast metal compositions containing less than 5% grain refining additives can be produced while still having submillimeter grain sizes. Cast metal compositions containing less than 2% grain refining additives can be produced while still having submillimeter grain sizes. Cast metal compositions containing less than 1% grain refining additives can be produced while still having submillimeter grain sizes. In one preferred composition, the grain refiners are less than 0.5%, or less than 0.2%, or less than 0.1%. Cast metal compositions can be obtained that do not contain grain refining additives at all, and yet have submillimeter grain sizes.

Cast metal compositions can have a variety of submillimeter grain sizes depending on a number of factors, including "bare" or alloyed metal composition, casting speeds, casting temperatures, and cooling rates. The list of grain sizes available for the present invention includes the following. For aluminum and aluminum alloys, grain sizes range from 200 to 900 microns, or from 300 to 800 microns, or from 400 to 700 microns, or from 500 to 600 microns. For copper and copper alloys, grain sizes range from 200 to 900 µm, or from 300 to 800 µm, or from 400 to 700 µm, or from 500 to 600 µm. For gold, silver or tin, or their alloys, grain sizes range from 200 to 900 microns, or from 300 to 800 microns, or from 400 to 700 microns, or from 500 to 600 microns. For magnesium and magnesium alloys, grain sizes range from 200 to 900 µm, or from 300 to 800 µm, or from 400 to 700 µm, or from 500 to 600 µm. In addition to these ranges, the present invention is also able to provide intermediate values. In one aspect of the present invention, low concentrations (less than 5%) of grain refining additives may be added to further reduce the grain size to between 100 and 500 microns. Cast metal compositions may include aluminum, copper, magnesium, zinc, lead, gold, silver, tin, bronze, brass, and their alloys.

The cast metal compositions may be drawn or otherwise formed into bars, rods, sheets, wires, billets, and pellets.

Automated control

The controller 500 shown in FIG. 3A, 3B and 14 may be implemented by the computer system 1201 shown in FIG. 16. Computer system 1201 can be used as controller 500 to control the above mentioned pouring systems or any other pouring system or device using ultrasonic processing of the present invention. While it is shown in Fig. 3A, 3B, and 14 as one controller, controller 500 may include discrete and separate processors communicating with each other and/or dedicated to one particular control function.

In particular, the controller 500 may be specifically programmed with control algorithms that perform the functions depicted in the block diagram shown in FIG. 17.

Fig. 17 is a block diagram, the elements of which may be programmed or stored in a computer-readable medium or one of the data storage devices discussed below. The block diagram shown in FIG. 17 depicts the method of the present invention for creating nucleation points in a metal product. In step 1702, the program element controls the operation of transporting molten metal in a temperature stop state in which the metal is converted from a liquid to a solid along the longitudinal length of the molten metal-containing structure. In step 1704, the program element controls the operation of cooling the molten metal containing structure by passing a liquid medium through the cooling channel. In step 1706, the program element controls the operation of transmitting ultrasonic waves through the liquid medium in the cooling channel and through the molten metal containing structure into the molten metal. In this element, the ultrasonic waves have a frequency and power that cause nucleation points to appear in the molten metal, as discussed above.

Elements such as molten metal temperature, casting speed, coolant flow through the cooling channel and mold cooling, as well as elements related to the control and drawing of cast metal through the mill, are programmed using standard programming languages (discussed below) to create custom processors. , containing instructions for applying the method of the present invention to create nucleation points in a metal product.

More specifically, the computer system 1201 shown in FIG. 16 includes a bus 1202 or other communication mechanism for exchanging information, as well as a processor 1203 coupled to bus 1202 to process that information. Computer system 1201 also includes main memory 1204, such as random access memory (RAM) or other dynamic memory device (eg, dynamic RAM (DRAM), static RAM (SRAM), and synchronous DRAM (SDRAM)), coupled to bus 1202. to store information and instructions executed by the processor 1203. In addition, the main memory 1204 may be used to store temporary variables or other intermediate information during the execution of instructions by the processor 1203. The computer system 1201 further includes a read-only memory (ROM) 1205 or other static memory (eg, programmable static memory (PROM), erasable programmable static memory (EPROM), and electrically erasable programmable static memory (EEPROM)) connected to bus 1202 to store static information and instructions for the processor 1203.

Computer system 1201 also includes a disk controller 1206 coupled to bus 1202 for controlling one or more storage devices for storing information and instructions, such as a hard disk drive 1207 and a removable media drive 1208 (e.g., floppy disk drive, drive compact disc (CD) read-only, CD-ROM drive with read-write capability, CD-ROM drive with automatic disc changer, tape drive and removable magneto-optical drive). Storage devices can be added to the 1201 computer system using a suitable interface (e.g., Small Computer System Interface (SCSI), Integrated Device Electronics (IDE), Evolved IDE (E-IDE), Direct Memory Access (DMA), or Ultra-DMA). ).

Computer system 1201 may also include application specific logic devices (eg, application specific integrated circuits (ASICs)) or configurable logic devices (eg, simple programmable logic devices (SPLDs), complex programmable logic devices (CPLDs), and field programmable gate arrays (FPGAs). )).

Computer system 1201 may also include a display controller 1209 coupled to bus 1202 to control a display, such as a cathode ray tube (CRT), to display information to a computer user. The computer system includes input devices such as a keyboard and a pointing device for interacting with a computer user (e.g., user interaction with controller 500) and providing information to processor 1203.

Computer system 1201 performs some or all of the processing steps of the present invention (such as, for example, those described in connection with providing vibrational energy to liquid metal in a temperature-stop state) in response to processor 1203 executing one or more sequences of one or more instructions contained in memory, such as main memory 1204. Such instructions may be read into main memory 1204 from another machine-readable medium, such as hard disk 1207 or removable media drive 1208. One or more processors in a multiprocessor arrangement may also be used to execute sequences of instructions contained in main memory 1204. In alternative embodiments, hardware may be used instead of or in combination with software. Thus, the embodiments are not limited to any particular combination of hardware and software.

As noted above, computer system 1201 includes at least one computer-readable medium or memory for storing instructions programmed in accordance with the teachings of the present invention, as well as for storing data structures, tables, records, or other data described herein. Examples of computer-readable media are CDs, hard drives, floppy disks, magnetic tape, magneto-optical disks, programmable read-only memory (EPROM, EEPROM, flash EPROM), DRAM, SRAM, SDRAM, or any other magnetic media, CDs (for example, CD-ROM) or any other optical media, or other physical media, carrier wave (described below), or any other media that can be read by a computer.

Stored on any computer-readable medium or combinations thereof, the present invention includes software for operating the computer system 1201, for operating the device or devices for implementing the present invention, and for computer system 1201 to interact with a user. Such software may include, but is not limited to, device drivers, operating systems, development tools, and application software. Such computer-readable media further include a computer program product of the present invention for performing all or part (in the case of distributed processing) of the processes performed in practicing the present invention.

The machine code devices of the present invention can be any interpreted or executable code engine, including, but not limited to, scripts, interpreted programs, dynamic link libraries (DLLs), Java classes, and fully executable programs. In addition, parts of the processing of the present invention can be distributed to improve efficiency, reliability and/or cost.

As used herein, the term "computer-readable medium" refers to any medium that participates in providing instructions to the processor 1203 for their execution. Computer-readable media can take many forms, including, but not limited to, non-volatile media, volatile media, and transmission media. Non-volatile media includes, for example, optical, magnetic, and magneto-optical disks such as hard disk 1207 or removable media drive 1208. The volatile media includes dynamic memory such as the main memory 1204. The transmission media includes coaxial cables, copper wires, and fiber optics, including the wires that make up the bus 1202. The transmission media may also take the form of acoustic or light waves, such as used for radio and infrared data transmission.

The computer system 1201 may also include a communications interface 1213 coupled to a bus 1202. The communications interface 1213 provides a two-way data connection to a network link 1214 that connects to, for example, a local area network (LAN) 1215 or another communications network 1216, such as the Internet. For example, communication interface 1213 may be a network interface card for connecting to any packet data LAN. As another example, communication interface 1213 may be an asymmetric digital subscriber line (ADSL) card, an integrated digital communications network (ISDN) card, or a modem to provide a data connection to an appropriate type of communication line. Wireless connections may also be used. In any such implementation, communication interface 1213 sends and receives electrical, electromagnetic, or optical signals that carry digital data streams representing various types of information.

Network connection 1214 typically provides data transfer over one or more networks to other data devices. For example, network connection 1214 may provide a connection to another computer via a local area network 1215 (eg, LAN) or through provider equipment that provides communication services via communication network 1216. In one embodiment, this capability allows the present invention to have a plurality of controllers 500 described above connected network for purposes such as plant-wide automation or quality control. Local area network 1214 and communication system 1216 use, for example, electrical, electromagnetic, or optical signals that carry digital data streams, as well as the associated physical layer (eg, category 5 cable, coaxial cable, optical fiber, etc.). The signals across the various networks and the signals on the network connection 1214 and through the communication interface 1213 that carry digital data to and from the computer system 1201 may be implemented in baseband or carrier wave based signals. Modulating signals carry digital data as unmodulated electrical pulses that comprise a stream of digital data bits, where the term "bits" is to be considered broadly as meaning a symbol, where each symbol conveys at least one or more bits of information. The digital data may also be used to modulate a carrier wave, for example in amplitude, phase and/or frequency offset, which encode signals propagating along conductive media or transmitted as electromagnetic waves through a propagation medium. Thus, the digital data may be sent as direct unmodulated data over a "wired" communication channel and/or may be sent within a predetermined frequency band different from the base band by modulating the carrier wave. Computer system 1201 may transmit and receive data, including program code, via network(s) 1215 and 1216, network connection 1214, and communication interface 1213. In addition, network connection 1214 may provide a connection via LAN 1215 to a mobile device 1217, such as a personal digital assistant (PDA), laptop or mobile phone.

General Statements of the Present Invention

The following statements of the present invention provide one or more characteristics of the present invention and do not limit the scope of the present invention.

Formulation 1. An apparatus for handling molten metal, comprising a molten metal enclosing structure for receiving and transporting molten metal along its longitudinal length; a cooling unit for the host structure, which includes a cooling channel for the passage of a liquid medium in it, as well as an ultrasonic probe located relative to the cooling channel in such a way that ultrasonic waves pass through the liquid medium in the cooling channel and through the structure containing the molten metal into the molten metal.

Formulation 2. An apparatus according to Formulation 1, in which the cooling channel cools the molten metal adjacent to the cooling channel to sub-liquidus temperatures (either below or less than 5-10°C above the liquidus temperature of the alloy, or even below the liquidus temperature ). The wall thickness of the cooling channel in contact with the molten metal must be thin enough to ensure that the cooling channel can actually cool the molten metal adjacent to the cooling channel to this temperature range.

Formulation 3. An apparatus according to Formulation 1, wherein the cooling channel contains at least one of water, gas, liquid metal, and machine oils.

Formulation 4. An apparatus according to Formulation 1 wherein the enclosing structure comprises side walls holding molten metal and a base plate holding molten metal.

Formulation 5. An apparatus according to Formulation 4, wherein the base plate contains at least one of copper, iron or steel, niobium, or a niobium alloy.

Formulation 6. The device according to the formulation 4, in which the base plate contains ceramics.

Formulation 7 A device according to Formulation 6 wherein the ceramic comprises silicon nitride ceramic.

Formulation 8. A device according to Formulation 7 wherein the silicon nitride ceramic contains sialon.

Formulation 9. The device according to the formulation 4, in which the side walls and the base plate form an integrated unit.

Formulation 10. The device according to the formulation 4, in which the side walls and the base plate contain different plates of different materials.

Formulation 11. The device according to the formulation 4, in which the side walls and the base plate contain different plates of the same material.

Formulation 12. The device according to the formulation 1, in which the ultrasonic probe is located in the cooling channel closer to the output end of the contact structure than to the input end of the contact structure.

Formulation 13. The device according to the formulation 1, in which the enclosing structure contains a niobium structure.

Formulation 14. The device according to the formulation 1, in which the enclosing structure contains a copper structure.

Formulation 15. The device according to the formulation 1, in which the enclosing structure contains a steel structure.

Formulation 16. The device according to the formulation 1, in which the enclosing structure contains ceramics.

Formulation 17 A device according to Formulation 16 wherein the ceramic comprises silicon nitride ceramic.

Formulation 18. A device according to Formulation 17 wherein the silicon nitride ceramic contains sialon.

Formulation 19 An apparatus according to Formulation 1 wherein the enclosing structure contains a material having a melting point higher than that of the molten metal.

Formulation 20. The device according to the formulation 1, in which the enclosing structure contains a material different from the material of the base.

Formulation 21. An apparatus according to Formulation 1 wherein the containing structure includes an outlet end configured to deliver said molten metal with said nucleation points into a mold.

Formulation 22. An apparatus according to Formulation 21, wherein the mold is a mold in the form of a pouring wheel.

Statement 23 An apparatus according to Statement 21 wherein the mold is a vertical cavity mold.

Statement 24 An apparatus according to Statement 21 wherein the mold is a stationary mold.

Formulation 25. An apparatus according to Formulation 1 wherein the enclosing structure comprises a metallic material or a refractory material.

Formulation 26 An apparatus according to Formulation 25 wherein the metallic material comprises at least one of copper, niobium, niobium and molybdenum, tantalum, tungsten and rhenium, and their alloys.

Formulation 27 An apparatus according to Formulation 26 wherein the refractory material contains one or more of silicon, oxygen or nitrogen.

Statement 28 An apparatus according to Statement 25 wherein the metallic material comprises alloy steel.

Formulation 29. The device according to the formulation 1, in which the ultrasonic probe has an operating frequency of 5 to 40 kHz.

Formulation 30. A method for forming a metal product, comprising: transporting molten metal along a longitudinal length of a structure containing molten metal; cooling the molten metal-containing structure by passing the medium through a cooling channel thermally connected to the molten metal-containing structure; and transmitting ultrasonic waves through the carrier in the cooling channel and through the molten metal enclosing structure into the molten metal.

Formulation 31. The method according to Formulation 30, wherein conveying molten metal comprises conveying molten metal in said containment structure having sidewalls retaining molten metal and a base plate supporting molten metal.

Formulation 32. The method according to Formulation 31, wherein the side walls and the base plate form an integrated unit.

Formulation 33. The method according to Formulation 31, wherein the side walls and the base plate comprise different plates of different materials.

Formulation 34. The method according to Formulation 31, wherein the side walls and the base plate comprise different plates of the same material.

Formulation 35. The method according to formulation 30, wherein transmission of ultrasonic waves comprises transmission of said ultrasonic waves from an ultrasonic probe which is located in the cooling channel closer to the outlet end of the contact structure than to the input end of the contact structure.

Formulation 36. The method according to Formulation 30 wherein transporting the molten metal comprises transporting the molten metal in a niobium containment structure.

Formulation 37. The method according to Formulation 30, wherein transporting molten metal comprises transporting molten metal in a copper contact structure.

Formulation 38. The method according to Formulation 30, wherein transporting molten metal comprises transporting molten metal in a copper containment structure.

Formulation 39. The method according to Formulation 30, wherein transporting molten metal comprises transporting molten metal in a structure containing a material having a melting point higher than that of the molten metal.

Formulation 40. The method according to Formulation 30, wherein transporting molten metal comprises delivering said molten metal to a mold.

Formulation 41. The method according to Formulation 40, wherein conveying molten metal comprises delivering said molten metal with said nucleation points into a mold.

Formulation 42. The method according to Formulation 41, wherein transporting the molten metal comprises delivering said molten metal with said nucleation points into a mold in the form of a pouring wheel.

Formulation 43. The method according to Formulation 41, wherein transporting the molten metal comprises delivering said molten metal with said nucleation points to a stationary mold.

Formulation 44. The method according to Formulation 41, wherein transporting molten metal comprises delivering said molten metal with said nucleation points into a vertical cavity mold.

Formulation 45. The method according to formulation 30, wherein the transmission of ultrasonic waves comprises the transmission of said ultrasonic waves with said frequency from 5 to 40 kHz.

Formulation 46. The method according to formulation 30, wherein the transmission of ultrasonic waves comprises the transmission of said ultrasonic waves with said frequency from 10 to 30 kHz.

Formulation 47. The method according to Formulation 30, wherein the transmission of ultrasonic waves comprises the transmission of said ultrasonic waves with said frequency from 15 to 25 kHz.

Formulation 48. The method of Formulation 30, further comprising solidifying molten metal to produce a cast metal composition having submillimeter grain sizes and comprising grain refinement additives in an amount of less than 5% of the composition.

Formulation 49. The method according to Formulation 48 wherein the curing comprises producing said cast metal composition comprising grain refining additives in an amount of less than 1% of the composition.

Formulation 50. A system for forming a metal product, comprising a device for processing molten metal in accordance with any of the formulations 1-29; and a controller including data inputs and control outputs and programmed with control algorithms that perform any of the steps described in statements 30-49.

Formulation 51 A metal product which is (or formed from) a cast metal composition having submillimeter grain sizes and incorporating grain refining additives in an amount of less than 0.5%.

Formulation 52 A product according to Formulation 51 wherein the composition includes grain refiners in an amount of less than 0.2%.

Formulation 53 A product according to Formulation 51 wherein the composition includes grain refiners in an amount of less than 0.1%.

Formulation 54 A product according to Formulation 51 wherein the composition does not include grain refiners.

Formulation 55 A product according to Formulation 51 wherein the composition comprises at least one of aluminium, copper, magnesium, zinc, lead, gold, silver, tin, bronze, brass, and their alloys.

Formulation 56 A product according to Formulation 51 wherein the composition is formed into at least one of bar stock, rod, sheet material, wire, billets, and pellets such that the product is a cast product as defined herein. , formed from cast material and containing less than 5% grain refiner additives. In one preferred embodiment, the cast product has equiaxed grains. In one preferred embodiment, the cast product has grain sizes of 100-500 µm, 200-900 µm, or 300-800 µm, or 400-700 µm, or 500-600 µm, such as in an aluminum alloy or aluminum casting. For copper and copper alloys, grain sizes range from 100 to 500 µm, from 200 to 900 µm, or from 300 to 800 µm, or from 400 to 700 µm, or from 500 to 600 µm. For gold, silver or tin, or their alloys, the grain sizes range from 100 to 500 microns, from 200 to 900 microns, or from 300 to 800 microns, or from 400 to 700 microns, or from 500 to 600 microns. For magnesium and magnesium alloys, grain sizes range from 100 to 500 microns, from 200 to 900 microns, or from 300 to 800 microns, or from 400 to 700 microns, or from 500 to 600 microns.

Formulation 57 An aluminum product comprising (or formed from) a cast aluminum metal composition having submillimeter grain sizes and including less than 5% grain refining additives.

Formulation 58 A product according to Formulation 57 wherein the composition includes grain refiners in an amount of less than 2%.

Formulation 59 A product according to Formulation 57 wherein the composition comprises less than 1% grain refining additives.

Formulation 60 A product according to Formulation 57 wherein the composition does not include grain refiners. The product of Formula 57 may also be formed into at least one of bar, rod, sheet, wire, billets, and pellets such that the product is a cast product as defined herein, formed from a cast material and includes less than 5% grain refiner additives. In one preferred embodiment, the cast aluminum product has equiaxed grains. In one preferred embodiment, this product, after casting, has grain sizes of 100-500 µm, 200-900 µm, or 300-800 µm, or 400-700 µm, or 500-600 µm.

Statement 61: A system for forming a metal product, comprising 1) means for transporting molten metal along the longitudinal length of the molten metal-containing structure, 2) means for cooling the molten-metal-containing structure by passing a medium through a cooling channel thermally connected to the molten metal-containing structure, 3) means for transmitting ultrasonic waves through the carrier in the cooling channel and through the molten metal enclosing structure into the molten metal, and 4) a controller including data inputs and control outputs and programmed with control algorithms that perform any of the steps described in paragraphs 30-49.

Numerous modifications and variations of the present invention are possible in light of the above teachings. Therefore, it should be understood that within the scope of the appended claims, the present invention may be practiced otherwise than as specifically described herein.

Claims (40)

1. Device for processing molten metal, containing: a molten metal containing structure for receiving and transporting molten metal along its longitudinal length; a cooling unit for the host structure, including a cooling channel for passing a liquid medium therein; an ultrasonic probe located in the cooling channel for contact with the liquid medium so that the ultrasonic waves pass through the liquid medium in the cooling channel and through the structure containing the molten metal into the molten metal. 2. The apparatus of claim. 1, in which the cooling channel provides cooling of the molten metal so that the molten metal adjacent to the cooling channel reaches a sub-liquidus temperature. 3. The apparatus of claim. 1, in which the enclosing structure includes side walls that hold the molten metal, and a base plate in contact with the molten metal. 4. The apparatus of claim 3, wherein the base plate contains at least one of niobium or a niobium alloy. 5. The apparatus of claim 3, wherein the base plate comprises ceramic. 6. The device of claim 5 wherein the ceramic comprises silicon nitride ceramic. 7. The device of claim 6 wherein the silicon nitride ceramic contains sialon. 8. The device according to claim. 3, in which the side walls and the base plate are made in the form of separate elements connected to each other, while the side walls contain a material different from the material of the base plate. 9. The apparatus of claim. 1, in which the ultrasonic probe is located in the cooling channel closer to the outlet end of the containing structure than to the input end of the containing structure. 10. The device of claim. 1, in which the enclosing structure contains niobium. 11. The apparatus of claim. 1, wherein the containing structure contains copper. 12. The device according to claim. 1, in which the enclosing structure contains steel. 13. The apparatus of claim. 1, in which the enclosing structure contains ceramics. 14. The device of claim 13 wherein the ceramic comprises silicon nitride ceramic. 15. The device of claim 14 wherein the silicon nitride ceramic contains sialon. 16. The device of claim. 1, in which the containing structure contains a material having a melting point higher than that of the molten metal. 17. The apparatus of claim. 1, wherein the containing structure includes an outlet end configured to deliver said nucleated molten metal into a mold. 18. The apparatus of claim. 17, wherein the mold is a casting mold in the form of a pouring wheel. 19. The apparatus of claim 17 wherein the mold is a vertical cavity mold. 20. The apparatus of claim 17 wherein the mold is a stationary mold. 21. The device according to claim. 1, in which the enclosing structure contains a refractory material. 22. The apparatus of claim 21, wherein the refractory material comprises at least one of copper, niobium, niobium and molybdenum, tantalum, tungsten and rhenium, and their alloys. 23. The apparatus of claim 22 wherein the refractory material contains one or more of silicon, oxygen or nitrogen. 24. Apparatus according to claim 23, wherein the refractory material comprises alloy steel. 25. The device according to claim 1, in which the ultrasonic probe has an operating frequency of 5 to 40 kHz. 26. Method for processing molten metal, comprising: transporting the molten metal along a longitudinal length of the molten metal-containing structure; cooling the molten metal-containing structure by passing the medium through a cooling channel thermally connected to the molten metal-containing structure; and transmitting ultrasonic waves through the medium in the cooling channel and through the molten metal containing structure into the molten metal by positioning the ultrasonic probe in the cooling channel in contact with the liquid medium. 27. Molten metal processing system, comprising: molten metal processing device according to claim 1 and a controller including data inputs and control outputs and programmed with one or more control algorithms that control at least one of transporting the molten metal, cooling the molten metal, and transmitting ultrasonic waves to the molten metal. 28. Molten metal processing system, comprising: means for transporting molten metal along the longitudinal length of the molten metal-containing structure; means for cooling the molten metal-containing structure by passing the medium through a cooling channel thermally connected to the molten metal-containing structure; means for transmitting ultrasonic waves through the medium in the cooling channel and through the molten metal containing structure into the molten metal, comprising an ultrasonic probe in contact with the cooling medium; and a controller including data inputs and control outputs and programmed with one or more control algorithms that control at least one of transporting the molten metal, cooling the molten metal, and transmitting ultrasonic waves to the molten metal.

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