US2874427A

US2874427A - Insert mat for ingot molds and manufacture thereof

Info

Publication number: US2874427A
Application number: US498193A
Authority: US
Inventors: Harrison D Sterick
Original assignee: Individual
Current assignee: Individual
Priority date: 1955-03-31
Filing date: 1955-03-31
Publication date: 1959-02-24
Anticipated expiration: 1976-02-24

Description

Feb. 24, 1959 H. D. STERICK 2,874,

INSERT MAT FOR INGOT MOLDS AND MANUFACTURE THEREOF Filed March 51, 1955 .115 20 l W A I 24. dus

INVEN TOR. HHPPJJOM 0 37-5 210K.

BY M, M 1 42514.1

United States Patent INSERT MAT FOR INGOT MOLDS AND MANUFACTURE THEREOF Harrison D. Sterick, Pittsburgh, Pa.

Application March 31, 1955, Serial No. 498,193

8 Claims. (Cl. 22-139) This invention is for a mat of the type which is used at the bottom of an ingot mold to protect the stool or mold bottom, and is for an improvement in such mats designed to overcome their floating or working upwardly off the mold stool or bottom.

The use of metal mats or plate-like bodies in the bottom of ingot molds is highly desirable.- These mats, resting as they do on the stool or the bottom of the mold, first serve to protect the stool from erosion by the hot metal. Secondly, because they usually have an extended surface area. exposed to the hot metal, they accelerate the chilling and freezing of the metal at the bottom of the ingot. Also they reduce splashing of the metal against the sides of the mold. Since the lower end of the ingot is cropped before the ingot is used, the volume of good metal displaced by the mat, and which is subsequently lost by cropping, is saved. Finally, since the cropped end of the ingot is used for melting scrap, the metal which is in the mat is eventually salvaged. Sometimes mold inserts of 'this character are simple plates or disks of metal. However the most satisfactory mats are those which present an extended area to the metal. One desirable form of mat is made by winding a strip of metal into a coil or mat, and variations of this involve the use of corrugations. in the strip, or the use of two strips, one plain and one corrugated, so that the surface of the mat has numerous small interstices into which the hot metal will flow and quickly freeze. Still other variations involve. forming the mat of two strips, one of which is wider than the other, so that the top surface ofthe' mat hasa continuous spiral groove, the bottom of which is closed by the narrow strip, and the margins of which are formed by the projecting edge of the wider strip.

It is also desirable inmany instances to provide these mats with a refractory plug at the bottom thereof to be enteredinto the knock-out opening of a closed bottom ingot mold.

A common failing of insert mats is that while they effectively serve their purpose, they are likely to be displaced when the metal is initially poured into the ingot mold, and as the pouring continues they tend to float or rise up and are trapped in the ingot well above the bottom end. This of course is a serious difliculty because the homogenity of the metal in the ingot is destroyed and the whole ingot must be scrapped. This difficulty is especially true in the case of expensive alloy steels where the scrapping of a complete ingot may represent a substantial operating loss. The occurrence of these floaters, as such floating of the mat is called, is quite infrequent, but their occurrence cannot be predicted or anticipated, and consequently notwithstanding the admitted value of these mats under normal conditions of use, many operators are afraid to use them because the disadvantage of one floater may offset the economies of their repeatedly successful use. Words, the risk of a floater is sufliciently prevalent to deter the wide use of mats in pouring ingots.

In other- Various attempts have been made to overcome this difiiculty, but they have not been successful. While the mats have about the same specific gravity as the molten metal and therefore do not tend to float in a quiet pool of metal, the disturbance of the mat when the metal is initially poured into the mold is the cause of the floating. This can occur from two sources. One is that the metal being poured into the mold strikes alongside the insert, washing against it with considerable force, thereby tending to raise it from the surface of the stool, and of course once the metal gets under the mat, its lifting effect is greatly accelerated. Also the metal dropping several feet into the mold hits the insert with great force, and if it hits on the edge of the insert it tends to tip the insert, lifting the edge which is remote from the point of contact with the metal away from the surface of the stool or bottom of the mold.

If the mat is of a type having a plug of refractory on the under face, the attachment of the mat to the plug is a difficult problem.

My invention has for its object to prevent or minimize the likelihood of the mat floating by a very simple and inexpensive expedient which Will be of negligible cost. A further object of my invention is to provide a mat with an attached plug and method of forming same.

According to my invention the periphery of the mat is surrounded by a downwardly and outwardly-sloping edge producing a flared effect that is very thin at the bottom, and the side slopes upwardly and inwardly to 7 the top of the mat surface. This accomplishes two purposes. First it presents a tapered surface to the wash of the metal across the surface of the mold bottom or stool so that the metal, instead of striking a perpendicular wall, thus tending to push or lift the mat, encounters an incline up which it readily flows. Furthermore, as the metal starts to flow over the incline, its weight superimposed on the weight of the mat, tends to hold the mat on the stool. The second effect of this shape is to increase the diameter of the mat at the bottom over that at the top, and thereby give it a stability to resist tipping when the edge of the mat is under the impact of the falling metal.

My invention further contemplates the winding of the mat upon a core pin, firmly anchored in a refractory plug which functions not only in the forming of the mat, but in securing the mat and ceramic together.

My invention may be more fully understood by refer ence to the accompanying drawings which illustrate certain specific embodiments of my invention, and in which:

Fig. 1 is a side elevation with a part in section of one form of mat embodying my invention;

Fig. 2 is a side elevation of the mat shown in Fig. l, but with a refractory plug attached thereto;-

Fig. 3 is a side view, partly in section, of a mat wherein the rim is separately formed from the mat and the mat inserted therein;

Fig. 4 is aside view of the pin used in making the mat shown in Fig. 2; and

Fig. 5 is a transverse section through a portion of the machine used for making the mat shown in Fig. 2.

Referring to Fig. 1, it shows a mold insert of the type heretofore used, in which the mat is formed of two or more strips wound together about a common center into a tight spiral. The strips may be of the same or different Widths, the latter being preferred, and the mat is flat on the bottom. Both strips may be smooth, both corrugated, or one may be smooth and one corrugated. In this view 2 designates the mat generally, 3 is one strip, here being shown as the wider one, and 4 is the other strip. Except for economy and improved quality by using different strips, the mat, so far as the present invention is concerned, could be wound from a single strip.

After the mat has been formed, the outermost convolution is welded upon itself as indicated at 5. The mat is then processed to deform the edge so that the mat flares downwardly and outwardly, having a sloping, preferably slightly concave peripheral contour, as indicated at 6. This shaping of the edges can be done in a press with appropriately contoured dies, or by rolling or forging.

When the mat is placed on the stool in an open bottom ingot mold, it is preferably substantially centered in the mold. It will be seen that if the falling metal strikes the stool to one side of the insert, the metal flow when it strikes the edge of the insert will be deflected upwardly, riding up onto the insert tending to hold it down against the stool rather than flowing against a vertical edge as it does at the present time, which tends to tilt the insert upwardly. A slight concavity in the con- .tour has the advantage of causing the metal to roll over.

on itself, creating a desirable condition. Likewise if the falling metal hits on the edge of the insert as shown in Fig. 1, the insert, because of its greater area at the bottom, will be more stable and have less tendency to tip up under the initial impact of the metal.

In Fig. 2 I have shown a mat such as shown in Fig. 1, which preferably but not necessarily has the sloped edge of Fig. 1, but which is provided with a ceramic plug by means of which it can be secured in the bottom of a closed end mold, such molds having a tapered opening therein in which an expendable ceramic plug is customarily inserted.

In this figure, 8 designates the mat which, like the mat of Fig. 1, is formed of coiled strip metal, and which is here shown with a sloped periphery 9. The metal coil is wound upon a metal pin 10, this pin having a barbed or roughened end 11 force fitted into a ceramic plug 12. The pin is bifuracted at 13 so that the ends of the strip or strips are inserted in the bifurcation for winding the coil about the pin. The ends of the pin are preferably long enough so that after the coil is formed, they can be bent down and overlie the top of the mat and be tack welded thereto to give the coil rigidity, or prevent it from coning when it is being handled. These overturned ends are designated 14 in Fig. 2 and may be either shorter or longer than here illustrated.

Th Plugs used in different molds are of different sizes, and in Fig. I have illustrated the manner of forming the mats with plugs of different sizes. In this figure, 15 is a flat turntable having a collar 16 on the under surface. At the bottom of the collar is a plate 17, thecollar and plate forming a well 18 at the center of the plate. The plate has a central opening 19 therein with a recessed lip around the opening, this lip having one or more holes 20 therein. An adapter 21 has a cup 22 and an outwardly turned flange 23. This flange has one or more depending pins 24 thereon that enter the holes 29. The top of the flange 23 is flush with the top of the turntable 15. The cup 22 may have a set screw 22' in the side wall thereof. The turntable is carried on and rotated by a shaft 25 secured by a coupling 26 to the plate 17.

In use, the pin 19 is driven into the previously formed plug 12. The plug 12 is then set into an adapter cup 22 of a suitable size and the set screw 24 tightened against it. The adapter is then dropped into the center of the turntable, after which the ends of the strips from which the mat is to be formed are inserted inthe bifurcation of the pin and the turntable rotated. The pin of course turns with the table. Different sizes of adapters are used with different sizes of plugs, and the well 18 is deep enough and wide enough to cover the normal required size range.

When the mat has been coiled, it is welded as at 5 in Fig. 1 before being removed from the turntable. The ends of the pin may then be bent over and welded, and

the mat, plug and pin, all expendable form a unit. If the mat is to then have the edge deformed, this may be done and the arms 14 will secure the coil during such edge deforming.

The plug anchors the mat in the mold so that it cannot float, and the sloped edges, where provided, aid in keeping the mat and plug in place.

Instead of deforming the edge of the mat continuously around its periphery, the deforming dies or other means for shaping the edge portion of the mat may be such as to produce an annular series of downwardly and outwardly-sloping valleys or produce a kind of a sloped scallop effect in the periphery of the mat. The only advantage of having the edge sloped at intervals instead of continuously is that the former is cheaper.

In Fig. 3 I have shown a mat formed as heretofore described, but with perpendicular edges, set into a separate rim which is of triangular section, so that this rim provides both the beveled surface which is desired, and constitutes means for holding the mat against unwinding. In this view 30 designates the mat, 31 is an annular which may be formed of sheet metal, or which may be cast or otherwise formed, having a fiat interior wall 32, and a downwardly and outwardly sloping exterior wall 33. The interior diameter of the annulus is sufiicient to allow the mat 30 to be slipped therein, and to be tightly fitted therein. This annulus 31 may be used with a mat having a plug thereon of the form shown in Fig. 2. The mats shown in Figs. 1 and 3 may also have bifurcatedstarting pins, and of course may be provided with ceramic plugs at the base, as shown in Fig. 2.

While I have shown certain specific embodiments of my invention, it will be understood that various detail changes and modifications are contemplated in the construction of the parts within the contemplation of my'invention and under the scope of the following claims.

I claim:

1. An ingot mold insert comprising a disk shaped flat metallic body formed of metal strip wound into a coil adapted to rest on the surface at the bottom of a mold, and an annulus surrounding the body having an outwardly and downwardly sloped periphery with the slope extending from the plane of the bottom of the mat.

2. An ingot mold insert mat comprising a generally disk-like metallic body having a bottom surface to contact the bottom of a mold comprised of coiled strip metal and with grooves in its top surface, and a downwardly and outwardly sloped peripheral portion on the body extending from the top of the mat to the plane of the bottom.

3. An ingot mold insert as defined in claim 2 wherein the body is comprised of coiled metal strip of different widths.

4; Aningot mold insert as defined in claim 2wherein the peripheral portion comprises an annulus into which the coiled body is fitted.

5. An ingotmold insert comprising a body formed of spiral convolutions of strip metal adapted to be received in the bottom of an ingot mold and rest on the bottom of the mold characterized by a peripheral portion that is sloped downwardly to the plane of the bottom and outwardly whereby the insert has a greater projected area at the bottom than at the top and the sloped edge serves to deflect metal flowing against the insert upwardly, the bottom edges of the convolutions of the strip forming the bottom surface of the mat and being free of any obstruction which precludes contact of the bottom of the mat with the bottom of the ingot mold in which it is placed.

6., An ingot mold insert mat comprised of coiled metal strip, a pin with its upper'end bifurcated at the center of the coil in which the ends of the strip are secured, and a ceramic plug. of less diameter than the mat at the bottom of the'rnat into which one end of the pin is secured, and through which rotation for winding the coil is imparted to the mat when it is being formed, said plug projecting below the bottom of the mat and being tap- References Cited in the file of this patent UNITED STATES PATENTS Grosjeau July 8, 1873 Cooley June 26, 1888 15 Wolfe: Nov. 16, 1915 6 Anderson Ian. 27, 1920 Bell Aug. 15, 1922 Otterbein Apr.- 10, 1923 Gathmann June 27, 1933 Estep Apr. 5, 1938 Barton June 8, 1948' Schmartz Nov. 9, 1948 Patterson Oct. 23, 1951 Baldwin Ian. 5, 1954 Schmartz May 1, 1956 Sterick et a1. Oct. 1, 1957 FOREIGN PATENTS Canada Oct. 23, 1951 France Mar. 26, 1952