US2109528A - Apparatus for vibrating ingot molds - Google Patents

Description

March 1, 193s. B M, FINE. 2,109,528

APPARATUS FOR VIBRATING INGOT MOLI-DS Filed April 28,- 19:57

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Patented Mar. l, 1938 UNITED STATES PATENT OFFICE Bernard M. Fine, Philadelphia, Pa., assgnor to The Midvale Company, Philadelphia, Pa., a corporation of Delaware Application April 28, 1937, Serial No. 139,404

3 Claims.

The invention relates to the art of jarring or vibratingingot molds for the purpose of avoiding certain defects incident to the casting of steel and steel alloys in stationary molds. Solidication in 6 such molds is begun by the chillV of the mold Walls and proceeds at a gradually reducing rate inward.

This variation in the rate of freezing produces a coarse, columnar crystalline structure adjacent the exterior of the ingot extending inward a 10 certain distance, changing into a finer structure of heterogeneous crystals in the interior. Another incident to the casting of steel in stationany molds is a tendency towards the formation of a deep central cavity at the top of the ingot,

l5 necessitating the subsequent removal of a considerable weight of metal from that end of the ingot in order to insure solidity of the remaining part.

In the casting of certain alloy steels these phenomena are exhibited in a very serious degree.

The long columnar crystals tend to slide upon each other producing rupture of the surface when the ingot is forged. The large amount of top scrap involves a serious economic waste.

While it is well known to subject molds to a jarring action, particularly in a vertical direction, and sometimes in a lateral direction or in both directions, such operations have been successful only to a limited degree in minimizing the development of the defects above specified.

' 'Ihe object of my invention is to effect vibration of such character and rapidity as to produce ingots more nearly vfree of all defects incident to the casting of ingots in stationary molds or in molds that have been subjected to jarring actions such as have been heretfore practiced.

The invention has proved satisfactory in practice, greatly reducing the extent of columnar crystallization and flattening the pipe to the form 40 of a shallow bowl. It has been found especially applicable to the casting of ingots of certain alloy steels, although its advantages are not limited thereto.

- Different embodiments of the invention are illustrated in the accompanying drawing, in

which- Fig. 1 is an elevation, mainly in section, of an apparatus for vibrating either a single mold or several molds simultaneously if they are accommodated and symmetrically secured upon Vthe vibrating cover of the operating cylinder. Fig. 2

is a vertical section of a modication that is adapted to vibrate through a greater distance and at a lower speed than that for which vthe construction of Fig. 1 is especiallyadapted. Fig.

3 is an inverted plan view of the head of the cylinder of Fig. 2. Fig. 4 is a side view, vpartly in section, and Fig. 5 an end view, of an apparatus for vibrating a series of molds.

In Fig. 1, h. is a cylinder of very small volume compared with its diameter. A cover e coacts with the end wall of the cylinder to close the latter, the lower surface of the cover e and the upper face of the cylinder h being true planes. A suitable elastic pressure medium, preferably compressed air, or less preferably steam or other suitable gas, reaches the cavity of the cylinder through the channel r and pipe s, the latter being connected with a suitable source o'f elastic pressure, such as an air compressor (not shown). The head e is provided with a depending circumferential flange or skirt g, spaced apart from' the exterior walls of the cylinder, which serves to keep the cover in place and to protect the seat f from injury, as, for example, by deposit of grit. In the construction shown the cover e is of the considerable thickness required to accommodate a plug a'extended beyond the bottom of the ingot mold a.

Upon the head e is set and secured, by any suitable means, the mold or molds a which it is the object of the invention to vibrate during filling and/or after being filled with molten metal.

When the elastic pressure medium, such as compressed air or steam, preferably the former, is admitted to the cylinder through channel r, the head e of the cylinder is lifted, thus lifting the mold or molds upon its upper surface. As soon as the head e is thus lifted a very short distance, the pressure uid begins to escape over the wall f of the cylinder, thus increasing the effective pressure area, and accelerating the rise of the head and its burden until the lift is suiiicient to permitthe escape of air faster than its supply, when the head falls by gravity and the ingot mold receives a jolt. The pressure within the cylinder rapidly builds up, repeating the cycle and producing a rapid vertical vibration. A

The rapidity of the vibration depends upon a number offactors, including the elastic pressure in the cylinder, the volume of the cylinder, the relation between the superimposed load and the area of the cylinder, the thickness of the cylinder walls as affording an increased effective pressure area, and the clearance between the pendant skirt and the cylinder wall.

It is particularly to be noted that the described cylinder operates without any valve, properly speaking, the cover acting both as valve and cylinder head. It is not uncommon for a piston to act as a valve but not to have the cylinder head so operate.

As an example of one embodiment of the invention, a vibrating apparatus constructed like that of Fig.` 1 and adapted to support and vibrate a 9" mold weighing 1,845 pounds and containing a uid ingotweighing 540 pounds, comprised a cylinder cover weighing 450 pounds. The air admitted to the cylinder had a pressure of 70 pounds to the square inch and was effective to produce vibrations of about 720 per minute having an amplitude of about one-sixteenth of aninch.

It is practicable and desirable to impart to the metal cooling in the ingot mold not only vibrations of the order of that specified, but even much more rapid vibrations; andI prefer that the rate of vibration should not be less than about 400 or 500 vibrations per minute. Even, however, Where the rate of vibration is reduced to about 200 vibrations per minute, substantially better results, both in degree and in kind, are produced as compared with vibrating mechanism heretofore used. In fact the production of vibrations by means of a gaseous elastic pressure medium applied as described is of decided advantage independent of the number of vibrations. n the other hand, a rapid vibrating rate within the range above specified possesses decided advantages independent of the means for producing such rapid vibrations.

The modification shown in Figs. 2 and 3 comprisesv an open top box or cylinder t and a head comprising a solid body or block u of nearly the height of the cylinder, having a top peripheral ange v normally resting on the top of the cylinder and provided with a rib w surrounding the upper end of the cylinder. The ingot or ingots may be supported directly on the head. A channel r for admission of compressed air is formed in the base of the cylinder. The block u has formed in its periphery vertically extending grooves a: open at their lower ends and extending nearly to the flange v.

In the operation of the device of Fig. 2 the head of the cylinderis lifted to a predetermined height, namely, until the upper ends of the grooves :r rise just above the top of the cylinder, whereupon the air rapidly is exhausted from the cylinder, followed by an immediate drop by gravity of the head to the position shown in Fig. 2. 'I'he drop of the head closes the cylinder so that the incoming compressed air is quickly effective to again lift the head, and the described operation is repeated. In this modification the rapidity of the vibrations may be controlled by the intensity of the air pressure and by the dimensions of the grooves x. i

The apparatus shown in Figs. 4 and 5 is one adapted to vibrateA a row of molds.

Removably mounted on a pair of longitudinally extending I beamsv b, bis a series of molds a, a, a, a. Cross braces d, d, d connect the I beams and secure them together in fixed relationship. The I beams are supported, midway of their length, upon a central cross-bar c, which rests on the cover or head of a cylinder h, which may be assumed to be a side elevation of the cylinder shown in Fig. 1.

Mounted on the foundation plate i, at each end thereof, is a pair of bolsters k, k, carrying bearings m, m for a pair of shafts n, n. 'I'he shafts extend along opposite sides, and just below the level, of the I beams. Secured to the feet of the I beams, at opposite ends thereof, are laterally extending angle bars o, o. Secured to the shafts n, ateach end, are arms p, p pivotally attached respectively to the corresponding angle bar o.

Normally, when the connection to the air compressor is closed, the molds and their supporting structure are stationary in the position shownv in Fig. 4. When, however, compressed air is admitted to the cylinder through channel r, the head e of the cylinder is lifted, thus lifting the entire mold-supporting structure and the molds mounted thereon.

When several ingots are to be vibrated simultaneously, it is important to insure that the vibrating apparatus shall be raised to a uniform height throughout its length, and that the reaction of the mold weight be delivered to the center of the head e; that is, that the mold support, during its vibrations and when in its upper and lower positions, shall be maintained, longitudinally, in a perfectly horizontal position. This is effected by the described parallel motion device, since an equal arcuate movement must be imparted to the two arms p at opposite ends of each shaft, thereby insuring absolute coordina'- tion in the lifting and dropping motion of the I beams.

It will be understood that the invention is not limited to the specific embodiments shown. It is intended to include within the scope of the invention any structural variations from such specific embodiments that comprise the essential elements of the invention as defined in the appended claims.

In claiming the vibrating apparatus I intend to cover all the uses to which it may be found adapted.

'Ihe process of vibrating an ingot support mold herein described may be practiced by means of mold vibrating devices other than those herein described, but such devices are especially well adapted to practice the process. The process forms the subject-matter of a divisional application led August 4, 1937, Serial No. 157,270.

What I claim and desire to protect by Letters Patent is:

1. A vibrator vfor ingot molds comprising an open top cylinder, a head resting upon and adapted by its own weight to close the cylinder, an elastic pressure fluid inlet in constant communication with the cylinder whereby there is provided an uninterrupted ow of an elastic pressure fluid to the cylinder thereby to build up pressure Within the cylinder and lift the head and open communication from the pressure fluid inlet through the cylinder to between the head and the top wall of the cylinder thereby to relieve the pressure within the cylinder and allow the head to drop by gravity and thereby allow pressure to again build up thereon, whereby the vibrator may be made eiective to impart to the ingot mold rapid vibrations of small amplitude.

2. A vibrator for ingot molds comprising an open top cylinder of relatively great diameter but of relatively small height and volume, a head' resting upon and adapted by its own weight to close the cylinder, an elastic uid inlet in constant communication with the cylinder throughout its height and thereby constantly pressing against the head thereby to build up pressure within the cylinder and lift the .head and open communication circurnferentially between the head and top wall of the cylinder thereby to quickly thereafter so relieve the pressure within the cylinder as to allow the head to drop after it has effected a lifting movement of the ingot y 9,109,523 mold of small amplitude, the dropping of thehead again allowing pressure to again quickly build up within thecylinder.

3. A vibrator for ingot molds comprising an open top cylinder, a head slidable in the cylinder and having a flange overlying the top wall of the cylinder,v the head thereby adapted by its own weight to close the cylinder, an elastic pressure fluid inlet in constant communication with the bottom of the cylinder whereby there is provided an uninterrupted ow of an elastic pressure uid to the cylinder thereby to build up pressure within the cylinder and litt the head, the body of the head being grooved from its lower end to near its top to allow pressure iluid outflow therethrough and thence between the ange of the head and the top wall of the cylinder to thereby relieve the pressure below the head and allow the head to drop by gravity and thereby again close the cylinder and again allow the `pressure to again build up therein.

BERNARD M. FINE.

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