US3008203A - Mold plug - Google Patents

Description

Nov. 14, 1961 J. D. DAGENHARD MOLD PLUG Filed July 2. 1959 JOHNDDAGENHARD f %In fl Ej E Big 4 United StatesPatent O MOLD PLUG John D. Dagenhard, Magnolia, Ohio, assigor to The Whitacre-Greer Fireproofing Company, Waynesbu'g, Ohio, a corporaton of Ohio Filed July 2, 1959, Ser. No. 824,702 3 Claims. (Cl. 22--148) This invention relates to mold plugs for ingot molds and moreparticularly to an improvement inthat class of mold plugs exemplfied in the United States Whitacre Patent No. Z,798 ,268, issued' Iuly 9, 1957, by virtue of which each plug shall be so securely attached to the bottom of its respective ingot that it will, without substantial exception, be withdrawn from the mold entirely with its ingot without 3,008,203 Patented Nov. 14, 1961 ice - ingress of fluid steel into the slot structure. Such a vent fracture and without sticking in whole or in part in the i bottom hole in the mold.

Although the Whitacre patent greatly improved upon all prior practices and mold plugs-for the objects and purposes stated therein, still there recurred, in my observation and experience, a small but significantly costly and aggravating pcrsistence of failure in respect 'to whole or partial detachment of plugs from ingots and/ or incomplete withdrawal from, or stickng in or fracture in the mold and/or providing an insufiicient stool or support -for the ingot when the ingot was taken from the mold and sought to -be placed in a vertical position and supported by and upon an attached mold plug as a stool or elevating support therefor. i

My study of this particular aspect of the problem, which was not entirely solved by the specific 'teaching 'of the Whitacre patent, led me to the discoverythat the desired hole is preferahly made 'big enough so that it will not be closed inadvertently in the course of manufacture or handling the wet clay plug before it is fired, and still made small enough 'to prevent any substantial or deleterious outflow of steel therethrough. In my preferred practice some molten or viscous steel enters the vent hole to insure, or be the sign of, evacuation of gases from the slot structure. 'Ihen preferably the steel freezes in the hole before filling it or flowing to any deleterious extent therethrouglr' It was my observation that the Whitacre patented plugs, lacking merely my herein improvements, were successful in the respect discussed heren in about 90% to 99% of the instances of their use, but the same plugs altered only bythe incorporation of my improvements have, as far as my present experience and observation have been-able to confirm, been entirely successful in these respects, i.e., in their whole, unbroken and unfailing attachment to and integration" with the bottom end of the mold and their unbroken withdrawal from the mold with the ingot without deleterious injury to the plug.

'Ihese and other objects and advantages of my inven tion will more fully and at large appear from the following description of prefered forms thereof, reference being had to the accompanying drawings in which:

FIGURE l is a top plan view of a mold plug embodying my invention;

FIGURE 2 is a vertical, longitudinal section of the plug shown in FIGURE 1 taken in the plane of the -line 2-2 thereof;

, FIGURE 3 is a longitudinal fragmenta'y sectional view on' a reduced scale showing the lower part of an ingot and intended casting of -fins or projections in the slots of the plug'was being irnpaired or prevented largely or entirely because air or other gases tended to be and sometimes actually was or were trapped or generated or in some way caused to be or remain in the slots, or 'bottom of the slot structure.

It is, therefore, an object of my invention to solve this problem to the extent it remained unsolved by the Whitacre plug and practice, and it is my more particular object to free the Whitacre plug -from its possibilities of and tendencies toward trapping gases in the slots or in any way to impar the casting of the intended or suflicient steel fins therein to unfailingly attach every plug to every. ingot. It is among my objects to aid in and improve upon the fulfillment of the objects of said-Whitacre patent. It is also among the objects oftmy invention to prevent generated or occluded gases from impairing the casting of fins in the slots of the plugs to their full intended depth or to no less than the depth or completeness which is or could be desired for the full intended utility of every plug and its desired best unfailing and unform attachment to the lower end of every ingot cast therewith. V

Another object is to encourage the ingress of molten steel into the slots of the plug. A more specific object is to provide avent from the slots, voids or fin-formi'ng'or projection-forming structure of mold plugs, of all 'the gases which might be trapped or =be present therein with deleterious effect against the desired attachment, between plugs and ingots, 'and however, 'to prevent deleterious or wasteful loss of steel through or from such a vent.

In pursuit of theseobjects of my invention, I found that a centrally located vent hole formed in the middle'bottom of the slot structure of the plug and of relatively small size serves to guarantee the exhaustion of allgases-in -front of and below the downward flow of steel into the slots upon the first pourings of steel at the beginning of the pouring of the ingot. This appears to be especially the case when the slot structure is mouthed or beveled upwardly and outwardly at the top of the plug to invite the mold with an ingot cast therein and engaging my improved plug; and

FIGURE 4 is a top plan view of an illustrative modified formof mold plug embodying my improvement..

The mold plug P is preferably made of ceramic material such as fire clay and otherwise as taught in the Whitacre' patent, and takes the form ofa truncated cone adapted to fit into the taperecl hole H, FIG. 3, in the bottom of the ingot mold M to close the same against the egress of molten steel as is understood in the art and more tully explained in the Whitacre patent. The plug in its truncated form has a flat circular upper face 21 and a flat circular lower face 23 and is characterized by narrow intersectng slots 25 which open into the upper face 21 of the plug and extend downwardly into the body of the plug about two-thirds or three-quarters of the whole depth thereof to .their bottoms 26. Preferably theslots in this form have 'enlarged e'nds 26, and, improving and departing from the specific teachings of the Whitacre patent, I prefer that the upper ends of the slotted structure he a'red outwardly as at 27 to invite the more ready reception and intake of molten steel into the, intersecting slots orslotted structure 25.`

To assure the egress of air and gas from the whole slotted structure when the hot steel is poured into the mold and flows into the slotted structure 25, 'I provide in the middle of the bottom of the plug, the vent hole 30 out of which air and gas may escape at the bottom of the slotted structure when the steel flows into the slots at the top thereo'fi As suggested in FIGURE 3 in the preferred practice of my invention, the size of the hole 30-is large enough to exhaust quickly all the gases from the slotted structure 2'5 and small enough to nhibt the substantial outflow of steel through the hole 30 before the steel freezes therein. In a preferred functioning of my invention a small tit 31 of steel will penetrate the hole perhaps half of its length before it freezes or :becomes too viscous to flow any further; this, as 'l observed, insuring that the gases will have been exhausted out of slot structure ahead of steel flowing thereinto and insuring the casting of the steel fins therein according to the intention and objects of the Whitacre patent. In FIGURE 3 the section is taken through fins F lying transve'sely of the plug and integrally onne ted wi h, t 'bosx t ei q here *a d .w h the tit 31- -in-th e;vent holep below. As taught and in tended in the -Whitacrepatent awell formed-fin structure F, of which the slot'structure 25is the matrix, should satisfactorly and securely attach every plug to every ingot. Now my improvement provides and insures this desired and desirable result, t t

For a specific example of a preferred form of my ina other form of'slt structure as also suggestedin-the venton, the plugof FIGS. 1-3 'may 'oe 4" deep, 7" maximum diameter and 6" minimum diameter with'the-slots 25 intersecting in the central vertical axis of the plug and symmetrically disposed and having an overall width, i.e., maximum horizontal dimension, FIGS *l and ,3, of about 3" to 4", a thickness (corresponding to fin thickness) throughout the rectangular portions of about /8 to about and the Slots having enlarged cylindrical terminal ends 26 struck on about a %"to A'radius and symmetrically disposed in relation to the interveningstraight rectangular parts of the slots. 'In this form `I;prefer that URES 1-3.

the slots have a depth of 3'? to 3 /2". In 'such a plug I prefer to make the vent hole about A" in diameter when it is a's short as about /2"in,lengtl 1 and not greater than about /2 in diameter if the hole isto ;be as much as about 1" long. It may also be kept; in' mind that since the main' function of the vent hole isto permit the outflow of gas, .my purpose is merely to -:have the hole large enough to assure a free rapid outflow of gas 'at the moment of casting the fins,.and any making of 'the holelar'ger than this necessary minimum is merely to perserve .a'n adequate orfice against the hazard of the partial closing .thereof as .by wiping .over or squeezing the bottom 'endlof it while the clay of the plugis wet and/orbeng'worked, dried or fired.

In the operation of my invention the..first rrush .oi i molten steel to thebottom of the mold strikes', Washes over or floods over the upper surface of the plugtending to flow i into 'the slotstructure 25 and being direted 'and guided into theslots by thebeveled' and chamfered upper open ings27 thereof whereuponto, flow downwardly into and fill the Slots-with presentnew freedom and-'certaintyby virtue of the free 'egress of ?the air and gases 'through the vent; bole 30. As presently informed, I' believe that 'the manner inwhich the molten steel flows into the slotted structure of my improved plug is probably difleren't from its manner of flow into any prior plug by virtue of its speed and fluidity. According to prio'r practice, as I believe, air and gases trapped in the` slot structure tended to prevent the full' casting of the desired fins `therein, not

` merely by gas displacing steel, but rather'by slowing the flow of steel in the slots sufficiently to let it lose heat rapidly and gain viscosity and tend to freeze before filling the Slots, and, possibly, before'greatly compressing the trapped air or gases. The rapid filling ofthe Slots with hot fluid steel permits the advantageous en'ploynent 'of narrower slots and a thinner fin structure while still gaining my better attachment of the plug tothe lingot. The

smallness of my vent hole and the relative lengththereof Will transfer heat quickly to the plug structure adjacent the vent hole and preferablyfreeze the steel before it fills the whole depth of the hole. "Thereupon the wholefin structure will have been poured, and the casting thereof in the slot structure of theplug 'willybe well initiated wherewith to guarantee thedesired`successful attachment to and coaction between the plug and the ingot. i

The environment of my invention in FIGURE4 is that of a plug P' thesame as the plug P having, however, an-

Whitacre patent and forthe purposes thereof with, however, my same vent hole 30 located in relatively the same place to do the same work in the same way and get the same results as in the slot structure 25 of FIGURES 1-3. 'In the form od? =FIGURE i the upper open ends of the slots 35 may be beveled and outwiardly" chamered as at 37 corre'ponding to the 'similar constructions27.. .`As taught in the Whitacrepatentlhecurved slotte'd structure s of FIGURE 4 may do muchthe' same work inja somewhat different way Compared with the straight. sltted structure 25 and get about mesme results? The Slots 35 have preferably thesame propgrtions and occupy about the sam sp e nrth pl g .a u h n x spe t l E 1 and n f r ame t e s he neki aton and advantages of my improvementitsg'environj ment ofF IGURE 4 will be ubstantially and es entially the same as that desctibedabqvewithrespect; o

ments in, of and for my invention and impriernent occur to those skilled in the whqcome to :appreciate d u de t n t s A dldpao az t lm s in the scope and effect of my patent to the preferred forms and enrbodinents of my invention hereinpecifia lly illusra d n d cri ed n i d .i atu ;Q D PPP sistent with the' progress by which `my invnton has promoted the art. i 5

1. Inthe combination of a big-ndup ingot moldand a plug for the lower opening thereof, an iniprove d plug closing the lower opening of said ingot mold whilst the ingot is being cast and being disposed to become attachd to the ngot ri g e a in ,sa d m i y l u a ing spaced'upper and lower` faces and l javing a yoidd` por o p g hr pp r-fa wh bxt be re e tive of fluid ingot material from the bottom of the ingot tending to attach, the p1ug to theingot and having a vent leading downwardly' awaytrom sidvoided portion and through which gas but, not ingot material may ,escapeto tmosp j h n .s d ngo ma er al nt s, d voided portion whereby to tend to assure the ing :of said voided portion with ingot material,

References Cited in thefile of .this patent r UNITED srarsj PATENTS Carbon & Graphite catalog, Section M-SO0 ANational .Carbon Co. Inc., p. 13, received in.U,S. Patent Oflice Jan. 19,194&

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