US2129703A - Apparatus for producing metal products - Google Patents

Description

Sept. 13, 1938.

J. M. MERLE 2,129,703

APPARATUS FOR PRODUCING METAL PRODUCTS Original Filed May 5, 1954 2 Sheets-Sheet l I Joseph N. MerZq,

extol/MA Sept. 13, 1938. J. M. MERLE APPARATUS FOR PRODUCING METAL PRODUCTS 2 Sheets-Sheet 2 Original Filed May 5, 1954 gay. 9.

M w J Patented Sept. 13, 1938 UNITED STATES 2,129,703 Armmros roa monoome METAL PRODUC Joseph M. Merle, 'larentum, Pa.

Original application May 5, 1934, Serial No. 724,186. Divided and this application July 25,

1935, Serial No. 33,157

9 Claims.

This application is a division of my application filed May 5, 1934, and serially numbered 724,186, and the present invention relates to apparatus for manufacturing cutting tools or other metal 5,: products from molten steel, steel alloys or other metals.

All metal products, with the exception of those made from powdered metals sintered under heat and pressure, originate or are made from molten 10 metal poured into a metal mold, sand mold, rotary mold, or forced under mechanical or air pressure into a mold or a die. However, in every case the molten metal reaches the mold or die in the liquid state and while inside the mold or 15 die it passes from the liquid to the solid state, this change of physical condition involving well known phenomena with certain modifications with-specific metals or alloys.

This common method of production of metal 20 products has a determining influence upon the physical and other properties and characteristics of all commercial metal products either in their cast condition or in their worked condition resulting from forging, rolling, pressing, extruding or mechanical forming, as well as in their heat treated condition, the finished product retaining some of the characteristics of the crystals formed and propagated through the molten metal.

The object of the present invention is to avoid 30 the conditions which. take place. when molten metal passes from the liquid to the solid state in a mold or die since 'I have observed that by forcing molten high speed steel or other steel into molds or dies not in the liquid state but in 35 a fine atomized spray of undercooled but still plastic particles propelled at a relatively high speed, such particles would impact together when contacting with the mold wall or by a section of the product already formed. The tools so formed 40 disclosed a different structure and difierent properties than tools made of steel of the same composition but as now commercially produced by pouring liquid steel into an ingot mold, the ingot being subsequently hammered and rolled.

45 I have also observed that in steel or other metal products so made each of the undercooled atomized particles would solidify spontaneously upon impact while aggregating to other particles previously impacted thereby forming a metal prod- 50 uct of increased density and cohesion, homogeneous in structure and free of the conditions occurring within an ingot when a large mass of molten metal passes from the liquid to the solid state, namely, dendrites, segregation, pipe and.

55 heterogeneity, and further that the grain size of the metal product so formed would be con- :rollled by regulating the size of the atomized pares. l

Also I have observed that the same structure and conditions are obtained by forming the un- 5 dercooled atomized particles not into a mold but through a die, out of which the formed metal product is drawn or stripped at a rate corresponding to the amount of atomized metal formed into it, thereby forming metal products in bars, 10 strips, sheets, or shapes in continuous lengths.

Furthermore, I have observed that steel and other metal products so formed have physical properties no longer comparable to the same metal as at present commercially cast, but better than the properties of the same metal commercially worked by forging, rolling, or extruding. More specifically, cutting tools formed by this method are much better and can withstand a cutting speed two to three times as great as the cutting speed obtainable with tools made of steel of the same composition as at present commercially produced.

In metal products so formed the latent heat of the molten metal is completely dissipated be- 5 fore atomizing and each atomized particle is undercooled slightly below the freezing point, so that a crystal nucleus, extending to a part of or entirely through the particle, has been formed and upon colliding and impacting with other pa'rticles, the metal atoms can find satisfactory arrangements, thus giving a structure free of internal stresses. Each particle also spontaneously crystallizes upon impact without further disturbance due to latent heat dissipation through the crystals formed, thus making metal products of a distinctive and physically new structure, which is retained through subsequent mechanical working operations or heat treatment. This structure for all metals and alloys is characterized by 40 minute spheroid cells of identical size, free of dendritic needles, with impurities located at the grain boundaries, as well as supersaturated alloy components concentrated at the grain boundaries and with precipitating components uniformly distrlbuted as minute particles through the product formed. Thereby a metal product is formed which is uniform in structure under any magnification, more dense and stronger'than similar metal products of the same composition, having the same strength, elongation, elastic limit and reduction of area in every direction and will give a non-directional fracture. Furthermore, the metal products are not subject to any chilling effects from metal molds and are free from denpart of the product.

drites, flow lines, segregation, pipes, shrinkage cavities, etc., and they have the same chemical composition throughout the entire section or any This special structure is retained after forging, rolling, heat treatment and even after welding when using the metal product as a welding rod.

In the case of high speed steel, the hard carbide components are disposed in a network around each martensitic crystal thereby imparting to each grain a cutting edge around its periphery and thus accounting for the better cutting properties over steel of the same composition as present commercial products. The distribution of the carbides is entirely uniform, and, in the case of chromium stainless steel, the same structural disposition accounts for better resistance to corrosion.

Molten substances such as molten glass or rocks so formed are also given a distinctly new structure and new properties.

I have also observed that cutting tools can be formed of a layer of high speed steel made from impacted undercooled atomized particles and a layer of strong and tough alloy steel made in the same manner of impacted undercooled particles, the two layers being perfectly bonded together by this method, thereby making a tool strong enough to withstand, without breaking, the increased cutting speed made available with the high speed steel layer of the tool.

Furthermore, finely powdered particles of tungsten, tantalum, titanium or other metal carbide, either one kind or several kinds at the same time, as well as finely powdered particles of diamond, can be dispersed through the atomized particles of high speed steel or other metal, the latter forming a matrix around the hard carbide or diamond particles which impart to the tools very desirable cutting properties. By undercool ing the molten metal below the freezing point before atomizing and impacting the particles, a spongy metal product can be formed with voids uniformly distributed, the size of the voids being controlled by the regulated size of the atomized particles.

I have observed also that nickel, copper, zinc, cadmium, brass, etc., so formed into metal products have very desirable properties for the plating industry, as anodes so formed, on account of their homogeneous fine structure, will corrode uniformly in the plating bath, without leaving any deposit in the tank, thus eliminating the use of diaphragms as at present used, and making a more uniform deposit on the plated produce, free of trapped gas pockets, which will last longer and look better than the deposits as obtained from present commercial anodes.

The physical conditions previously described under which the molten metal is forced into molds or dies or through dies, can be produced by various methods. Three methods are illustrated diagrammatically in the accompanying drawings, it being understood that other methods of undercooling, atomizing and propelling the molten metal can also produce the same results.

In order to more clearly understand the invention, particularly the tools and products, and the method of making them, it will now be described with reference to the accompanying drawings, in which:

Figure 1 is a horizontal top view of a rotary atomizing disc and a part of a stationary circular receiving mold,

Fig. 2 is a vertical sectional view through the rotary atomizer and mold of Fig. 1 and through the receptacle feeding molten metal to the atomizing disc,

Fig. 3 is a vertical sectional view of an inclined atomizing disc with a different mold which can be stationary or rotary, to receive the atomized particles in a spiral spray,

Fig. 4 is a cross sectional view of a product obtained in the machine of Fig. 3,

Fig. 5 is a vertical sectional view of the atomizing disc of Fig. 1 showing the spraying of the atomized metal into a rotary mold for shaped tools,

Fig. 6 is a cross section of a formed tool, made of two metal layers,

Fig. 7 is a cross section of a tool made of three layers of steel,

Fig. 8 is a vertical sectional view of a belt shaped undercooler and atomizer and showing a cross section of a water jacketed mold for continuous metal products.

Fig. 9 is a cross section of the metal belt undercooler and atomizer of Fig. 8,

Fig. 10 is a horizontal elevation of the belt atomizer and mold of Fig. 8,

Fig. 11 is a vertical sectional view of two belt atomizers and a mold for continuous bimetal products,

Fig. 12 is a part sectional and side view of a modified type of machine, similar to Fig. 11 but for metal coatings.

The various parts of the machine can be described by detailing the operation of the machine,'and as to Figs. 1 and 2 it is as follows:

The molten metal I 4 in the receptacle I 3 runs out through a series of holes i5, whose number. size, and shape have an influence on the degree of undercooling desired. This molten metal contacts with the rotary disc I on the circumference line 2, Fig. 1, this part or section of the disc having already a considerable peripheral speed which prevents the molten metal from adhering to or burning the atomizing disc which would probably take place if the metal contacted with the center of the disc. The atomizing disc I is composed of two parts, an upper part 6 and a lower part I with a water jacket 8 therebetween fed by a water flow. The water is fed to the disc by the pipe 9 through the center of the shaft 9' of the disc and runs out through the space 9 in the shaft between the stationary water pipe 9 and the center bore 8 of the shaft.' The water flow will maintain the atomizing disc at a constant temperature and also remove the heat imparted to the disc by the molten metal. The atomizing disc I is rotated at high speed in ball bearing l0 and other bearings,

not shown, and is driven by suitable means, not

shown, associated with the shaft 9. metal falling on the revolving disc on the circular line 2 forms a film on the upper part 6 of the disc extending from the line 2 to the periphery of the disc, and while in such film state the metal loses heat by contact with the cooled surface of the disc. The thus undercooled metal film on leaving the periphery of the disc breaks up into a fine spray of atomized particles which are propelled at a high speed in a direction precisely at relative to the axis of rotation of the disc. As a spray traveling at high velocity, the particles enter the stationary circular mold i6 through a circular slit I8 which is exactly in the path of the traveling spray. These particles solidify upon impact in the mold and fill up the mold cavity 4. In the form of construction shown in Figs. 1 and 2, the exact amount of molten metal sufficient to fill the mold The molten i ii part l1.

cavity is poured into the receptacle I3. When all the molten metal has been atomized and sprayed, the top part I6 of the mold I6 is lifted from the bottom part I1. The cast products, which may be an integral circular unit or in two or more sections, three being shown in Fig. 1, by placing separating pieces in the mold, are stripped from the The casting or the sections may have a fin molded thereon corresponding to the feeding slit if excessmetal has been poured, but since the slit is only a few thousandths of an inch wide, it can easily be broken or cut away and the sections may be straightened in straightening rolls, if necessary. The plates I I and I2 on the mold parts I6 and I1 completely close the space in which the disc rotates, and no air is admitted while the molten metal is being poured. In this Way the atomized particles, while being propelled as a spray from the disc to the mold cavity, are not subjected to possible oxidation, and preferably the air contained adjacent the disc is pumped out by means of pipe I9, so that the undercooling, atomizing, and impacting are carried out in a vacuum. If desired, hydrogen, a mixture of hydrogen and nitrogen, illuminating gas, or blue gas can be forced into the space adjacent the disc and in the mold cavity, if such gases are beneficial to the metal being sprayed and cast.

The undercooling of the metal, the size of the atomized particles, and the velocity at which the particles are propelled can be regulated at will. The flow of molten metal from the receptacle I3 depends on the number and cross sectional areas of holes I5 and can be made of such size and number as to feed from 50 to 500 lbs. or more of molten metal per minute. When using a rotary disc having an outside diameter of 12", the molten metal can be made to drop on the circular line 2 on the upper part 6, which line may vary from 2 to in diameter. This varies the time during which the film of moving molten metal is in contact with the upper surface 6 of the disc I, and also the temperature of the surface 6 of the disc may be regulated by varying the flow of water, which can be maintained at a low temperature or at a temperature of about 300 F. The speed of the rotary disc can vary in practice from 1,800 R. P. M. to 6,000 R. P. M., as the higher the speed the thinner the film of metal formed, and the smaller the size of the particles of metal sprayed from the disc, and also the greater their velocity and impacting power. With these regulations, the grain size of the metal product can be controlled and products of increased density and increased strength over present commercial products can be produced. Furthermore, by reducing the fiow of molten metal from the receptacle and increasing the length of its travel over the surface of the disc, the metal is undercooled below the freezing point and the film breaks in particles already partly solid or entirely solid, and these particles, due to their velocity, impact into a solid but spongy metal product with uniform voids between the particles. If, for instance, the undercooled solid particles are not collided and impacted together within a short distance after leaving the rotary disc to form a solid product, but are allowed to travel a distance of several feet before impacting against the walls of the chamber, they will not impact together but will be collected as powdered metallic particles. Depending on the speed used and the amount of undercooling, these particles may be formed in granules of any desired weight or as a fine metallic powder the former being used for metal packing and the latter to make metallic paint or for use in powder metallurgy. This spray of atomized undercooled particles, as shown in Fig. 2, being made either in an airtight space or chamber or under a vacuum, or this chamber being filled with a neutral gas, the granules or particles are not subject'to oxidation. Furthermore, a special gas, such as ammonia gas, can be used which will dissociate under the heat of the particles, and when using steel or another alloy capable of nitriding, the granules or particles will attain a hard nitrated surface which is useful in several commercial applications. The disposition shown permits the handling of metals or alloys of low melting point, as well as metals or alloys of high melting point, by adapting the conditions of flow, undercooling and atomizing to suit the various metals or alloys. It is further noted that practically none of the molten metal is lost as by heads, pipes, or gates, which have to be cut off from the solid product formed.

Fig. 3 shows a rotary atomizing disc as used in connection with a billet or slab mold, the axis of the disc not being set at 90 with the axis of the shaft rotating it but at an angle depending upon the height of the billet or slab to be made, the mold 20 and 2| being horizontal. In this position the spray from the rotary disc I travels in a straight line, indicated by the arrows, exactly 90 to the axis of rotation, and will build up the section of the billet or slab by distributing an even amount of particles spirally throughout the height or width of the product formed. The mold parts 20 and 2I are stationary or can be rotated atlow speed. Thebillets formed have good surfaces, are of uniform structure, free of pipe shrinkage cavities, and are ready for rolling. A vertical shaft is shown, but in view of the high velocity used, gravity has no effect on the molten metal poured over the rotary disc, and therefore the shaft of this disc can be in any position which may be more convenient for the operation of the process.

Fig. 4 shows a section of a product or casting made by pouring successively into receptacle I3 of Fig. 1, first one type of metal, for example stainless steel 24, then another type of metal 25, such as low carbon steel, then stainless steel 24 again, if desired, so that a billet or slab is formed in the mold of Fig. 3 having a core 25 of low carbon steel and faces 24 of stainless steel, the layers being perfectly bonded together by the velocity of impact without any impurities, slags, or oxides at the junction of the various layers.

This operation can be accomplished as illustrated in Figs. 1 and 2 in a closed space, or in a vacuum, or under the influence of useful gases.

In the same manner, copper clad slabs and billets with a thin layer of copper perfectly bonded to a steel core and various kinds of bimetal slabs and billets can be made, and in every case the junction between the distinct metals or alloys is free of gases, oxides, and other impurities and the products will roll or forge without any rupture or separation at the junction of the distinct metals.

Fig. 5 shows the same rotary disc and pouring receptacle as Figs. 1 and 2, but the atomized spray is received in mold 21 and 28 which is also rotated by means of pulley 32, the direction of rotation being the same or the opposite to the direction of rotation of the rotary disc. The mold g1 and 28 has cavities each corresponding to the shape of the formed tools or other products, there being two or more of these cavities to receive the spray from the rotary disc. When making cutting to l of two layers of steel, first high speed steel of any of the commercial compositions is poured into receptacle I3 and this steel is formed into a film, undercooled and atomized, and these particles when reaching the mold cavities on account of the rotation ofmold 21 and 28 form a layer 35 parallel to the axis of rotation of the mold. Then a tough alloy steel, such as chrome-nickel steel or chrome-vanadium steel is poured into receptacle l3 and also undercooled and atomized, and this steel is sprayed into a layer 36 adhering to the layer 35 of high speed steel until the tool cavities of the mold are filled up. The second steel is poured in the receptacle before the high speed steel has entirely drained out, so that particles of both kinds of steel are intermingled at the junction of one to the other through a thickness of a few thousandths of an inch, thus making the two layers so inseparably bonded that they cannot be'parted by any mechanical means. To receptacle l3 may be attached another receptacle 26, through which fine powdered material such as diamond powder or metallic carbides can be introduced at the same time that the high speed steel is poured, so that the powdered material will be carried out on the film of molten metal and evenly dispersed into it. When the metal breaks into a spray, the atomized metal particles and the powdered carbides are both propelled together at the same speed and will impact and aggregate together in the layer formed in the rotary die or mold. This provides the tool with hard particles uniformly dispersed through a matrix of either high speed steel or some other binding metal, such as cobalt, nickel, high strength bronze, etc. Through receptacle 26 another molten metal can be poured, for example lead, and through receptacle I3 bronze can be poured, so that an increased amount of lead can be dispersed through the bronze base metal as finely divided particles to improve the properties of the bronze for bearing purpose. Finely powdered graphite can be used for the same purpose and dispersed through the base metal. 'The foregoing describes some of the products which can be produced by building them of undercooled atomized particles instead of starting from a molten metal poured into a mold.

Milling cutters, hobs, rock drills, core drills, rotary saws, and other tools can be formed in the same manner having a hard cutting steel alloy or abrasion resisting alloy on the outside surface, and a core of tough and strong steel or other metal inside. Furthermore, as in ordinary die casting machines, inserts, such as metallic or of some other materials, can be placed into the die to become a part of the casting after the molten metal has been impacted.

Fig. 6 shows a forming tool, finished to grinding sizes, of a layer of high speed steel 35 with or without carbides or diamond powder dispersed into it and a layer of tough steel 36 for the support of the tool.

Fig. '7 shows a bar for twist drills, made of a central layer 31 of high speed steel or other cutting material and two sectors 38 of a tough steel which will render the drill unbreakable.

Figs. 8 to 10 show a band undercooler and atomizer, the band being made of a steel or other metal ribbon similar to the band of a band saw or of some non-combustible material but preferably having a section as shown in Fig. 9. This band 42 runs over grooved pulleys 43 and 44 at high speed by means of a driving grooved pulley 45 which is connected to a motor or to a belt drive by means of shaft 55. The molten metal is poured into receptacle 39 whose nozzle contacts with the groove 51 of the band 42 at 4|. This receptacle 39 is supported over the frame 54 of the machine. A steady flow of molten metal is drawn through nozzle 55 and is propelled in the groove 51 of the band 42. The film formed in the band is very thin and when the band turns over pulley 44 this film under its velocity breaks into a fine spray of undercooled metal particles and is propelled into mold 41, this forming a solid metal product of any desired section or shape depending upon the shape of the mold. This mold can be water-jacketed by means of the jacket 48 with inlet 59 and outlet 49 to maintain the mold at a constant temperature. A pair of rolls 52 and 53 draws the solid bar formed at a rate of speed depending on the weight of metal flowing per minute from nozzle 4| and of the section of the metal product formed. The velocity of the atomizing band can be made to vary to correspond to the same peripheral speeds indicated for the rotary disc of Figs. 1 and 2, thus producing the same undercooling and atomizing conditions and the same characteristics as indicated in the foregoing in metal products formed in continuous lengths. The band 42 passes through a cooling liquid 46 in a depression 49 in the frame 54 to maintain the band at a constant temperature to receive a film of molten metal, thus maintaining constant conditions of operation. With this design, strips of sheet metal or other shapes of any thickness and width can be formed, as indicated, the no le of receptacle 39 and the band being made ide enough to form the metal film in the proper shape, depending on the finished metal product desired. Furthermore, the rolls 52 and 53 will pull the formed strip, sheet or shape at a rate of speed depending on the amount of molten metal fed by the receptacle nozzle. The undercooled atomized particles can be thrown against the surface of a strip of metal and form a coating, or they can be collected as granulated or powdered metal particles if a long funnel is substituted in place of the mold 41.

Fig. 11 shows a construction in which two band atomizers 42' are arranged to spray a metal product 5| of two layers, drawn in continuous length. Suitable covers 41' keep the metal films free from contact with air and a vacuum can be created if desired, or some other gas can be forced into the space to prevent oxidation or to induce desired chemical reactions with the molten metal used. The different metals are placed in the receptacles 39 placed over the bands.

In Fig. 12 the parts not shown of the machine are the same as in Fig. 11. The band atomizer has a cover 41 to eliminate contact with air, and as in Fig. 2, a tube can be used to create'a vacuum or pump a neutral gas into the active space. The two undercooling and atomizing bands 42 form the atomized metal as a coating simultaneously on both surfaces of a strip or sheet metal plate 52' which is drawn by bands 42. The thickness of the coating is regulated by the flow of the metal from the receptacle nozzles and the speed at which the strip or sheet is pulled by the bands 42'. This coating, being made of particles impacted under high velocity and free of oxidation, will form, on the clean surface of the sheet or strip, a more adhering coating than by dipping the sheet in molten metal. This coating has disflnctly new characteristics and a new structure and increased resistance to rust and corrosion on account of the fact that it is formed of atomized undercooled particles strongly bonded together under impact and further bonded to the metallic surface of the sheet or strip by pressure of rolls 53'. This application is 'a division of my copending application Serial No. 724,186, filed May 5, 1934.

I claim as my invention:

, 1. In combination in a metal forming apparatus, a receptacle for molten metal, means for delivering molten metal therefrom in the form of a consolidated stream, means for substantially extracting the latent heat from such molten metal while supporting it in a stream of film-like proportions moving at a high'velocity comprising a cooled, movable support having a metal support surface positioned to receive said consolidated stream while said support is moving at a high velocity, means for continuously moving said support at a uniform high velocity and so that each portion of said supporting surface moves in a plane defining direction while supporting and abstracting heat from such metal, and a mold positioned to receive metal so cooled as it is projected from said surface.

2. In combination in a metal forming apparatus, a receptacle for molten metal, means for delivering molten metal therefrom in the form of a consolidated stream, means for substantially extracting the latent heat from such metal while supporting it in a stream of fllmlike proportions moving at a high velocity, comprising an endless band having a metal support surface positioned to receive such consolidated stream while said band is moving at a high velocity, means for driving said band in the direction of its length and at a uniform high velocity, means for so supporting said band that the metal support surface thereof moves in a plane defining direction while supporting metal thereon, and a mold positioned adjacent said band to receive the partially cooled metal projected therefrom.

3. In combination in a metal forming apparatus, comprising a receptacle for molten metal, means for delivering molten metal therefrom in the form of a consolidated stream, means for substantially extracting the latent heat from such metal while supporting it in a stream offilm-like proportions moving at a high velocity, comprising an endless band so mounted thatthe surface of one portion thereof receives such stream and defines a plane along which the metal of such stream is moved while in contact with said band, means for driving said band in the direction of its length and at a uniform high velocity, and a mold located adjacent said band to receive the partially cooled metal projected therefrom.

4. In combination in a metal forming appara tus, means for delivering molten metal in the form of a substantially uniform consolidated fiow, an endless band so mounted that one strand thereof receives said fiow and the metal receiving surface thereof defines a plane along which such metal moves as it moves with said band, means for driving said band in the direction of its length and at a uniform high velocity, and a mold positioned adjacent such belt to receive metal from such strand. I

5. In combination in a metal forming apparatus, means for delivering molten metal in the form of a consolidated stream, an endless band so mounted that one strand thereof receives such stream and the metal receiving surface thereof defines a plane along which such metal moves as said band is driven, means for driving said band in the direction of its length and at a high velocity, and means for cooling said band as it is so driven.

6. In combination in a metal forming apparatus, means for delivering molten metal in the projected form of a consolidated substantially uniform stream, an endless band so mounted on rotatable supports that one strand thereof intercepts such fiow and provides a metal support surface substantially defining. a plane, means for driving said band in the direction of its length and at a high velocity and means for subjecting said band to a cooling medium as it is so driven.

7. In combination in a metal forming apparatus, means for delivering molten metal in theform of two substantially uniform consolidated streams. a separate movable endless band intercepting each such stream and adapted to support the metal thereon in the form of a film-like stream moving at a high velocity, means for driving each band in the direction of its length and so that each such film-like stream is projected toward the other, and a heat dissipating agent positioned to receive both such streams.

8. In combination in a metal forming apparatus, means for delivering molten metal in the form of a consolidated uniform stream, means for converting said flow into a stream of film-like proportions moving at a high velocity and substantially abstracting the latent heat therefrom, coma molten metal receptacle until it is received in said mold.

' JOSEPH M. MERLE.

Images