US3368608A - Bottom casting method - Google Patents

Description

Feb. 13, 1968 J. WOODBURN, JR ,3

BOTTOM CASTING METHOD v Original FilecLJuly 29, 1959 7 Sheets -Sheet l- INVENTORS. 1

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BOTTOM CASTING METHOD 7- .Sheets-Sheet 7 Original Filed July 29, 1959 ha Q 8% $3 9% United States Patent Office 3,368,608 Patented Feb. 13, 1968 3,368,608 BQTTGM CASTING METHQD Blames Woodburn, Jr., Wheaten, Ill., assignor to Amsted Industries Incorporated, Chicago, 111., a corporation of New Jersey Continuation of application Ser. No. 279,682, May 7, 1963, which is a continuation of application Ser. No. 122,061, June 30, 1961, which in turn is a continuation of application Ser. No. 83%,428, July 29, 1959. This application Mar. 7, 1966, Ser. No. 532,452

2 Claims. (El. 164-130) ABSTRACT OF THE DISCLGSURE In a bottom pressure casting arrangement a plurality of elongated molds are moved into proximity with a ladle of molten metal having a pouring tube open at the top and extending downwardly into the molten metal. The molds are provided with an ingate arrangement which is engagea'ble with the pouring tube upon combined rotational and translational movement of the mold.

This application is a continuation of abandoned application Ser. No. 279,682, filed May 7, 1963, as a continuation of abandoned application Ser. No. 122,061, filed June 30, 1961, as a continuation of application Ser. No. 830,428, filed July 29, 1959, now also abandoned.

This invention relates to the production of metal articles, such as steel billets, blooms, or slabs, in pieces of desired cross-sectional dimensions and weights, directly from the molten metal and without the use of a primary mill.

According to prior art practices, steel ingots have been cast and stored in soaking pits. Such ingots have then been reheated, if necesary, and have been hot rolled in a primary mill to elongate the casting and reduce its crosssectional area thereby forming a bloom having a length three or more times its maximum cross-sectional dimension and having a cross-sectional area not substantially in excess of 120 square inches. The blooms have then been rolled to form billets having a cross-sectional area not substantially in excess of 36 square inches and having a length three or more times the maximum cross-sectional dimension. Sometimes ingots are rolled by a primary mill into oblong slabs having a cross-sectional area of the order of from 48 square inches to 360 square inches and having a length three or more times the maximum cross-sectional dimension. Such billets and slabs have then been rolled to form commercial products, such as rods, tubes and sheets.

Previous prior art attempts to eliminate ingots and the necessity for soaking pits by casting blooms, billets (including tube rounds), and/ or slabs on a commercial basis have been unsuccessful, and according to the invention, it has been discovered that such blooms, billets (including tube rounds), and/or slabs can be cast by bottom pouring into an elongated graphite mold and can be rolled into commercial products.

For the purpose of this specification and claims, a bloom is hereby defined as a steel article having a substantially uniform cross-sectional area not substantially in excess of 120 square inches and a length three or more times its maximum cross-sectional dimension; a billet (including a tube round) is hereby defined as a steel article having a substantially uniform cross-sectional area not substantially in excess of 36 square inches and a length three or more times its maximum cross-sectional dimension, and a slab is hereby defined as a steel article having a substantially uniform oblong cross-sectional area of from 48 square inches to 360 square inches and having a length three or more times its maximum cross-sectional dimension.

A primary object of this invention is to eliminate the necessity of the ingot and the primary rolling operations to form blooms, billets and slabs which can be subsequently rolled into commercial shapes such as rods, plates, tubes or sheets.

A further object of the invention is to eliminate the necessity for conditioning the surface of primary mill products and to minimize conditioning of billets.

Yet another object of the invention is to increase yield by eliminating the step of cutting primary mill products into suitable lengths for subsequent rolling.

Another object of the invention is to devise apparatus for handling molds before and after pouring.

Still another object of the invention is to devise an effective and efiicient means for cutting off communication between a mold gate and the source of molten metal when the mold has been filled.

The foregoing and other objects and advantages of the invention will become apparent from a consideration of the following specification and the accompanying drawings, wherein:

FIGURE 1 is a perspective view of a preferred embodiment of the invention utilized in the pouring of a conventional mold;

FIGURE 2 is a top plan View of the novel apparatus;

FIGURE 3 is a side elevational view thereof;

FIGURE 4 is a side elevational view taken from the ri ht of FIGURE 3;

FIGURE 5 is a fragmentary sectional view taken on line 5-5 of FIGURE 4;

FIGURE 6 is a top plan view of a novel mold assembly;

FIGURE 7 is a sectional view on line 7-7 of FIG- URE 6;

FIGURE 8 is a side elevational view of the novel mold assembly;

FIGURE 9 is a fragmentary view partly in section on line 9-9 of FIGURE 6;

FIGURE 10 is a side elevational view of the support means for the cut-01f power device;

FIGURE 11 is a sectional view on line 11-11 of FIG- URE 10;

FIGURE 12 is an end elevational view taken from the left of FIGURE 10;

FIGURE 13 is a top plan view of the cut-off slide sup- P FIGURE 14 is a sectional view on line 14-14 of FIG- URE 13;

FIGURE 15 is a top plan view of the cut-off slide;

FIGURE 16 is a sectional view on line 16-16 of FIG- URE 15;

FIGURE 17 is a top plan view of the cut-off insert against which the mold gate seats;

FIGURE 18 is a sectional view on line 18-18 :of FIG- URE 17;

FIGURE 19 is a side elevational view of a novel billet mold assembly to be utilized with the apparatus of FIG- URES 1l8;

FIGURE 20 is a sectional view on line 20-20 of FIGURE 19;

FIGURE 21 is a top plan view of the bottom or drag mold frame shown in FIGURES l9 and 20;

FIGURE 22 is a bottom plan view of the top or cope mold frame shown in FIGURES l9 and 20; and

FIGURE 23 is a sectional view on line 23-23 of FIG- URE 21.

In each of said figures, certain details may be omitted in the interest of clarity where adequately shown in other views.

Describing the invention in detail, a mold assembly generally designated 2 (FIGURE 1) comprises a mold 4 which may be of a chill material, such as graphite or of any other desired ceramic material well known in the art, such as sand or shell. The mold 4, as illustrated, is not a billet mold and it will be understood, as hereinafter described, that a mold for a bloom, a billet, or a slab must be formed of blocks of graphite, although other elongated articles not requiring subsequent rolling may be cast in other types of molds utilizing other features of the inven tion. The assembly 2 also comprises a car 6 to which the mold 4 may be clamped by conventional clamps 7 or by force of gravity. The mold 4 and car 6, during a pouring operation, as hereinafter described, move together as a unit or assembly 2 and may be interconnected in any desired manner.

The car 6 comprises wheels 8 which roll on tracks 10 and also comprises a cut-off or gate closing device generally designated 12. The cut-off 12 is best seen in FIG- URES 6*8 and 13-18, and includes a slide support 14 having an opening or hole 15 with a bushing 16 (FIGURE 7) which may be of any desired material such as graphite, baked clay or shell. The slide support 14 has a cut-out or slot 18 (FIGURE 13) partly defined by an inner edge 20 for a purpose hereinafter described.

A slide or plate 22 preferably of cast iron, copper or any other desired chill material is slidably mounted on the support 14 and comprises an opening or aperture 24 having a bushing 26 similar in form and composition to bushing 16. The slide 22 is supported within a channel 28 (FIGURE 14) of the support 14 and is seated along a surface 30 thereof immediately below shoulders or ledges 32 which define another channel 34 within which is positioned a loose insert 36 (FIGURES 6-7 and 17l8) which is complementary to and removably mounted in an opening 38 of a top plate or panel 49 of the car 6.

The support 14 is releasably interlocked with the panel 40 by means of ears 42 on the support having apertures 44 within which are received lugs 46 on the underside of panel 40. The lugs 46 are slotted to receive wedge keys 48 which are driven to locking position shown in FIGURE 9 and which may be quickly removed by an impact against the small ends of the keys 4-8.

The insert 36 is provided with an opening or aperture 50 having a bushing 52 (FIGURE 7) similar in form and material to bushings 16 and 26, whereby when apertures 15, 24, and 60 are aligned, they define a continuous passage for the flow of molten metal into a gate 54 (FIG- URE 7) of the mold 4.

The assembly 2 rolls along tracks 10 until one wheel strikes a retractible stop 56 (FiGURE 4) pivoted at 55 to an ear 57 on one rail segment lila to locate the apertures 15, 24, and 50 in vertical alignment with the top of a pouring tube 58, the lower end of which communicates with a source of material (no-t shown) to be cast, such as a ladle of molten metal. Under these conditions, the wheels 8 are supported by rail segments 10a which are separable from rails 18 and vertically movable.

The segments 10a are supported by a frame 65) which is in turn supported at its corners, as by conventional worm gear screw jacks 62 operatively connected to a reversible electric motor 64. The jacks are mounted on foundation-supported beams 66 (FIGURES 3 and 4) and raise or lower the frame 60 in response to rotation of the armature shaft 68 of motor 64 in one direction or the other. The frame 60 is guided by rollers 73* (FIGURES 2 and 3) which are mounted on the frame and which engage vertical foundation-supported beams 72. The car the support 14 is clamped by force of gravity or by other means (not shown) against the tapered portion of tube 53 to afford a substantially air-tight seal between the tube and the support 14, whereupon the metal in which the tube 58 is immersed is pressurized (as for example in the manner disclosed by US. Letters Patent No. 2,847,- 739 issued Aug. 19, 1958, to E. Q. Sylvester) to flow the metal upwardly through apertures 15, 24 and 5t? and gate 54 until the mold has been filled. Tilting of the car 5 during pouring is limited by lugs 75 (FIGURE I) mounted on the top of brackets 114, hereinafter described.

After the mold has been filled the slide 22 is actuated, as hereinafter described, to cut-off flow of molten metal through the gate, whereupon pressure on the molten metal is released, the rail segments Illa are elevated to mating relationship with rails 19, and the assembly 2 is rolled along the rails past the stop 56 which has previously been pivoted to inoperative position. The stop 56 is then pivoted to operative position and another assembly 2 is rolled into position and poured as heretofore described.

The manner in which the cut-off 12 is actuated can best be seen in FIGURES 8 and 10l2, wherein it will be seen that when the assembly 2 is supported on top of the tube 58, a power device 73 mounted on a cover 30 of a chamber or tank Si containing the molten metal is disposed between the slide 22 and an abutment 82 depending from the underside of panel 4i so that actuation of the device 78, as by hydraulic or pneumatic pressure, to expand the device 78 axially thereof causes a cylinder member 34 of the device 755 to engage the abutment 82 and a ram or piston member 86 of the device 78 to engage the cut-off slide 22.

The device 78 has a limited stroke and at the end of said stroke, the slide 22 is at a position whereat its aperture 2 i is beyond edge 20 of the support 14, whereupon molten metal in aperture 24, is dumped through slot 13 so that the bushing 26 need not be replaced for each pouring operation. Also release of pressure on the mollen metal in the tank 31 dumps the metal in bushing 15 so that it need not be replaced for each pouring operation.

The device 78 is afforded a floating support so that, upon actuation thereof, the forces developed by the device 78 to actuate the cut-otl 12 to closed position are selfcontained within the assembly 2. This novel support comprises a bracket 38 mounted on top of the cover as by welding at 90. The bracket comprises a V-shaped channel 92 within which a complementary slide 94 is positioned. The cylinder member 84 is clamped into the slide 94 by clamp rollers 98 on levers lltltl pivotally fulcrumed at 102 to the slide 94 and actuated by a compression clamping spring 194. The bottom of slide 94, comprises a pin 1116 extending through an elongated slot 168 of the channel 92 and connected to an aligning tension spring liliwhich upon release of the device '78 urges a collar 109 of cylinder member 84 against a stop plate 111 attached to bracket 88, thereby yieldingly holding the cylinder member 84 in proper alignment with the space between slide 22 and abutment 82 as the assembly 2 is lowered to or raised from the position shown in FIGURE 8.

Upon energization of device 78, as heretofore described, the slide 94 permits enough axial movement of the device 78 so that the forces developed thereby are self-contained within assembly 2 and substantially no reactive forces are transmitted to bracket 88 or cover 80.

Upon removal of cylinder 84 from the clamps 98, which can be accomplished by manually lifting the cylinder to compress spring 104, the spring Ill-i is held in position upon bosses 112 of levers 1% by a slight force provided by a tension spring 113 connected to the lower ends of levers 100.

It may be noted that the cover 80 may be clamped to the top of its container 81 by clamp means (not shown) mounted on foundation-supported brackets 114, and the rail segments 19a may be manually removed from and replaced upon the frame 60 to accommodate insertion and removal of the cover 80 and a ladle (not shown) of molten metal into which the tube 58 extends. The construction of the container 81, the ladle (not shown), the cover :80 and tube 58 is per se no part of the present invention and may be of the type in said US. Letters Patent, or if desired may be of any other desired construction and arrangement, with the tube mounted on the cover or elsewhere in communication with the molten metal in the container 81.

It should be noted that bushings 16, 26, and 52 are flanged at their upper ends so that in their aligned position shown in FIGURE 7, the flange of bushing 16 engages slide 22, the flange of bushing 26 engages insert 36 and the flange of bushing 52 engages the mold 4 around its gate 54.

Referring now to FIGURES 19 to 23, which show a modification of the invention, a novel billet mold assembly 116 is disclosed for the casting of steel billets which can be rolled (without any intermediate forming step such as forging or blooming) into commercial products such as wire or rods.

The mold assembly 116 comprises a top frame 117 defined by longitudinal side channels 118 welded to transverse angles 120 and 121. A cope 122 formed of one or more graphite cope blocks 124 is clamped against angles 120 and 121 by clamp bars 126 and bolt and nut assemblies 128. The cope blocks 124 are also clamped by a clamp bar 130 and bolt and nut assemblies 132 (one of which is shown at the left of FIGURE 19) against an abutment angle 134 welded or otherwise secured to the frame channels 118.

The mold assembly .116 also comprises a bottom frame 136 defined by longitudinal side channels 138 welded to longitudinal angles 104 and transverse angles 141 and 143. A drag 142 formed of one or more graphite drag blocks 144 is seated against the angles 140 and is clamped by a clamp bar 146 and bolt and nut assemblies 148 (one of which is shown at the left of FIGURE 19) against an abutment angle 147 welded or otherwise secured to frame 136.

The frames V117 and 136 are interconnected by readily releasable means, such as bolt and nut assemblies 149 to clamp the cope 122 and drag 142 together to define a casting cavity 151 in the shape of a conventional billet between 2-0 and 30' feet in length and approximately square in cross-section, measuring between 2 and 6 inches on a side.

The upper end of the assembly 116 is provided with a block 148a of graphite having an opening 150' connected to cavity 151 and to a riser cavity 152 of another graphite block 14812 clamped on top of block 148a as by bolt and nut assemblies 153 one of which is shown at the left of FIGURE 19.

The lower end of the cope 122 is provided with a graphite block 152a having a gate 155 connected to the lower end of the cavity 151 and to apertures 15, 24 and 50 (FIGURE 7) of the cut-off 12 on a car 2a substantially identical with the car 2 previously described except that the car 2a preferably has only one pair of wheels 8a because the drag 142 is pivotally supported at its opposite end by a pivot bar 154 welded to channels 138 and pivotally mounted in a V-shaped channel 156 of a car 158 having wheels 160 mounted on the rails 10. The rail segments a and their elevating and lowering mechanism, as well as the pouring and cut-off mechanism, are disclosed in- FIGURES 1 to 18, and are not shown in detail in FIG- URES 19 and 21.

Thus, it will be understood that when the rail segments 10:: are lowered to connect the gate 155 with the pouring tube 58, as heretofore described, a pivoting action takes place between assembly 116 and rail segments 10:: by means of wheels 80, and also pivoting action takes place between car 158 and assembly 116 by means of pivot bar 154.

In actual practice, billets and slabs have been poured at a metal flow rate of about 65 pounds per second. These billets were approximately 30 feet in length and were square in cross-section, approximately 3% inches on a side. The cope 122 and drag 142 forming the mold in which such billets were cast were formed of graphite blocks machined on their mating surfaces as seen in FIGURE 20 to define the mold cavity 151. The graphite produces a very fine dendritic structure at the surface of the casting, and according to the invention, it has been discovered that graphite is a critical mold material for pressure pouring of products such as blooms, billets, or slabs which are to be rolled; however, for other elongated castings other mold materials can be used.

In a mold having a cavity of about 30 feet in length or more, the longitudinal axis of the mold is preferably at an angle of the order of 24 or less with respect to horizontal.

If desired, the blocks 148a and 1481) may be eliminated, and the upper end of cavity 151 may be closed by a gas-permeable chill which is substantially impermeable to flow of molten steel therethrough, so that there is no need to cut a riser from the top of the billet. Such a chill may be formed of graphite with holes therethrough of the order of A; inch or less in diameter.

Also, if desired, the top of the mold can be closed after pouring by a cut-off mechanism 12 such as heretofore described.

It should be noted that the flow rate of the molten steel must be less than that at which turbulence occurs 1n the mold cavity and subject to that limitation should be as fast as possible.

I claim:

1. A method of pressure casting metal articles in successive elongated molds comprising the steps of positionmg each of said successive elongated molds in an inclined position with respect to the horizontal so as to have the pouring end of said elongated mold lowermost, successively guiding each mold to the pouring station in a manner so as to present said pouring end of said mold above said pouring station at a substantial distance there from, coupling said pouring end of said mold to said pouring station by rotating the pouring end of said mold generally about the other end of said mold and at the same time moving said mold in a linear direction thereby effecting both rotation and translation of said mold, filling the mold with metal, rotating the pouring end of said mold back to its original position, guiding the filled mold away from said pouring station to a suitable cooling area, and repeating the steps with the next succeeding mold.

2. A method of pressure casting metal articles in successive elongated molds comprising the steps of successively aligning each mold with a pouring station in a manner so as to position the pouring end of said mold above said pouring station at a substantial distance therefrom, connecting said pouring end of said mold to said pouring station by rotating said mold so that said pouring end of said mold becomes lowermost and said elongated mold is in an inclined position with respect to the horizontal, filling the mold with metal, rotating the pouring end of said mold back to its original position, separating the filled mold and said pouring station, and repeating the steps with the next succeeding mold.

References Cited UNITED STATES PATENTS 2,119,242 5/1938 Flammang et al 164-119 2,131,955 10/1938 Johnson 164-311 3,015,863 l/l962 Strom ct al 164-337 J. SPENCER OVERHOLSER, Primary Examiner.

R. S. ANNEAR, Assistant Examiner.

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