US2429145A - Mold for casting metals - Google Patents

Description

Oct. 14, 1947" c, yv ss 2,429,145

-MOLD FOR 'CASTINGMETALS 7 Filed Dec. 26, 1942 5 Sheets-Sheet 1 a Carl zdessez 77pgaa J Oct. 14, 1947. c. WESSEL MOLD FOR CASTING METALS Filed D80. 26, 1942 5 Sheets-Sheet 2 Oct. 14 1947. c. WESSEL MOLD FOR CASTING METALS Filed Dec. 26, 1942 5 Sheets-Sheet 3 Qt! ll eagel I w? mV C. WESSEL MOLD FOR CASTING METALS Oct. 14, 1947.

Filed Dec. 26, 1942 5 Sheets-Sheet 5 .J L M Z M? Another object I... ofan improved zx zdrawn tubular methods of the prior art.

Patented Oct. 14, 19.47

2,429,145 MOLDFOR casrmc METALS Carl Wessel, Chicago, Ill

Lew W. Cleminson,

assignor to himself and Chicago, 111., as trustees Application December 26. 1942, Serial No. 470,167 4 Claims. (Cl. 22-145) The present invention relates to an improved method for making thin metal sheets or thin plates. and is particularly concerned with the provision of a method by means of which such metal sheets or plates may be formed of homogeneous large-grained structure without segregated impurities and with a minimum amount of impurities of any kind.

The present application is a continuation-inpart of my prior application which resulted in U. S. Patent No. 2,333,286, issued November 2, 1943, and application Serial No..370,344, flied December 16, 1940, for Method and apparatus for making drawn metal tubes and metal castings, which resulted in U. S. Patent No. 2,309,608, issued January 26, 1943.

One of the objects of vision of an improved the invention is the promethod of casting and means of which plates or made which have a homogeneous large-grained structure andwhich are ing to the prior art may be eliminated.

of the invention is the provisionand simpler method of making Another object of the invention is the provision of an improved method of casting by means of which the defects of the prior art methods, such as blow-holes. inclusions, segregations, faults, cracks, and other defects, are practically eliminated.

Another object of the of an-improved casting method which is adaptable to use in small or large plants and which is adapted to produce metallic members having the characteristics of high degree of uniformity of clean scrap or any other invention is the provision .and by means of which crystalline structure and a uniform smooth outer surface adapted to be polished without necessity for smoothing the surface after casting and before the polishing.

Another object of the invention is the provision of an improved method of casting by means of which tubular structures may be made having a high degree of uniformity of crystalline structure they may be constructed at a minimum cost.

Another object of the invention is the provision of an improved method of producing a superior cast metal product or a sheet metal product which is simple and which involves a minimum number of operations and the apparatus of which may be made very simple so that a minimum amountof capitaland labor is required in the production of the articles made by the process.

Other objects and advantages of the invention will be apparent from the following description and the accompanying drawings, in which similar characters of reference indicate similar parts throughout the several views.

. The drawi m ladle;

Fig. 4 is a horizontal sectional view taken on the plane of the line 46 of Fig. 3, looking in the direction of the arrows;

Fig. 5 is-a view similar to Fig. 3, with the parts of the apparatus in the position which they assume during the casting of a thin metal plate;

Fig. 6 is a fragmentary top plan view of the ladle and its cover, with the mold removed;

Fig. 7 is a diagrammatic sectional view taken on the plane of the line 7-1, looking in the direction of the arrows, of Fig. 6, with the mold shown in dotted lines, showing its position relative to the ladle; a

Fig. 8 is a diagrammatic vertical sectional view, taken on a plane passing through the axis of the ladle at right angles to the plane of the casting, showing the ladle and mold in vertical position. before the casting operation;

Fig. 9 is a similar view, with the ladle and mold tilted to such a. point that theflame of the burner is cut off from the mouth of the mold. as takes place in the beginning of the casting operation;

Fig. 10 is a similar view, with the mold and ladle tilted still farther until the free surface of the metal has begun to well up into the mold;

Fig. 11 is a similar view, showing the ladle and mold in a further tilted position, with the free surface of the metal more than half way up into the mold;

Fig. 12 is a similar view, showing the ladle and mold tilted still further until the free surface has welled up to the very top of the mold and the mold is full;

Fig. 13 is a similar view, showing the final position to which the ladle and mold are usually tilted, with the mold substantially horizontal and all parts of the mold located substantially below the main body of the metal in the ladle.

In order to illustrate the preferred means for carrying out the method, one form of apparatus or casting machine capable of practicing the method is now described in detail.

Referring to Figures 1 and 2, the casting apparatus which has been selected to illustrate the invention, preferably includes a movably supported ladle indicated in its entirety by the numeral l0, and a mold ll directly connected to the ladle l and adapted to be moved with it. The ladle I0 is preferably movably mounted on a pair of bearing frame members [2, I3 and is preferably so balanced with respect to the assembly ofthe mold H and ladle 10, that it will be normally held in upright position as shown in Figures 1 and 2, even when the supply of molten metal in the ladle has been exhausted.

The bearing brackets l2 and I3 may be identical in shape and construction and therefore only one of them need be described in detail. These brackets are preferably of suflicient length to permit a maximum degree of pivotal movement of the ladle and mold and may, in some embodiments of the invention, permit full rotation of the mold and ladle throughout 360. This may be accomplished by providing a pit in the fioor l4 between the frame members i2 and I3 and extending forwardly and rearwardly of them, or the frame members l2 and I3 may be supported in elevated position upon blocks I5 as shown in Figure 5. 7

Each frame member preferably has a. pair of upwardly extending columns l6, l1, integrally supported by a bottom frame member l8 which has a pair of attaching flanges i9, 20, provided with apertures for receiving the bolts or lag screws 2|. substantially T-shaped in cross-section and at the upper end of the bearing brackets 12 and I3 they are formedv with the rectangular opening 22 defined by the frame portions 23-26.

The frame portions 23-26 are preferably provided with threaded apertures for receiving the screw bolts 2l--32. Each screw bolt 21 has its inner end engaged in a socket 33 in one of the bearing blocks 34, 35, and the screws are held in fixed position by lock nuts 36.

The bearing blocks 34, 35 comprise a pair of metal members which, when assembled as shown in'Figure 2, have plane rectangular sides and are formed with a bearing aperture 31. Since the bearing blocks 34, 35 are adjustably supported by the screw bolts 21-32, they may be brought into alignment even after the frame members 12 and 13 have been secured in place, provided the frame members are also substantially in alignment.

30 portion of its outer The frame members iii-48 may be The ladle It may comprise a substantially cylindrical metal shell, such as the shell 38, having the cylindrical side walls 39 and flat bottom 40. This metal shell may be lined with a layer of suitable insulating material, such as asbestos 4|, covering the inner surface. of its side walls 33 and its bottom 40.

The asbestos lining 4| supports a second rigid lining 42 of a refractory-material, such as a ceramic product adapted to withstand the melting temperatures to which the metal is to be subiected. This ceramic lining 42 is provided with an inner chamber 43 which may be substantially cylindrical in shape except that the lower cor- 5 ners are rounded at 44, 45 and the left-hand wall 45 (Figure 3) may be tapered or may be made substantially frusto-conical at its lower .portionleading to a substantially frusto-conical cover opening 41 at the top.

The opening 41 for the cover plug 48 diverges from the cylindrical shape at the left-side where it may be provided with a flat wall surface at 43 for cooperating with the cover plug 48 to form the walls of a rectangular aperture 50 in the top of the ladle Ill.

The cover plug 48 may comprise a frustoconical member of refractory material, such as the same ceramic 42 which is formed to fit in the frusto-conical opening 41 over the major frusto-conical surface 5|. At the right-hand side, the cover plug 48 is formed with a groove 52 which is half-circular at the upper end and which increases in size frustoconically toward the bottom of the plug. When the plug 48 is assembled with the ladle ID, the

aperture 52 at the right-hand side is adapted to provide an upwardly tapered conduit for receiving the burner flame 53 which may be directed downwardly into the ladle from the gas burner 54 to apply heat to the surface .of the metal and to be reflected upwardly into the mold H.

At its left side (Figure 4) the cover plug 43 is formed with a groove 50 which is rectangular in cross-section and which at its upper end forms a discharge opening 55 of the same size as the filling opening of the mold H to which it is directly connected. The rectangular groove 54 in the cover plug 48 may increase in depth and width toward the bottom of the plug 48 (Figure 3) so as to provide a tapered conduit 56 in this side of the ladle leading from the chamber 43 to a discharge aperture which is coin cident with the filling aperture of the mold.

55 The shell 38 of the ladle ill is preferably supported in a basket-like metal frame which may consist of a metal hoop 51, and a plurality of longitudinally extending metal straps 58--6l which have inwardly turned ends 62 at their lower end for attachment to the bottom of the shell 38. A transversely extending bar 63 is carried by the bottom of the shell 38 and is adapted to be engaged by a latching lever 64 which is pivotally mounted by means of a bolt 65 on one of 5 the legs ll of the frame member l3.

The latching bar 34 has a slot 66 which engages the bar 63 when the ladle is in vertical position as shown in Figure 2, to retain it in this position against any possibility of moving or tipping. A

tension coil spring 61 has one end secured to the frame member 13 at the bolt 30 and the other end pivotally secured to the latching lever 64 by means of a block 88 secured to the end of the spring and pivotally mounted by means of the pivot pin 69. The latching lever is thus urged upper ends and secured by 2 but may be moved out of engagement with its keeper 88 by pressing downward on the latching lever 84 with the foe I The hoop I! is secured to the vertical frame members 88'8| at their intersection by suitable bolts or by welding, and the vertical frame members 88-8I may be turned outwardly at their means of bolts to a cover plate I8 which may project beyond the outer wall of the shell 88 sufilciently to engage the laterally turned ends II of the frame mem-: bers 58-8 I. The cover plate I8 is provided with a rectangular aperture 12 located to register with the discharge aperture 88 in the ladle l8 and plu 48 and the conduit extending through the cover plate I8 is made continuous and smooth-from the conduit 58 into the filling opening of the mold II, the aperture I2 being of the same size as the filling opening of the mold I I. I

The cover plate 18 holds the Plug 48 firmly in place and it is also provided with an aperture I8 (Figure for passing the gas burner nozzle 54. The bolts I4 which secure the frame members 58-6I to the cover plate 18 may also be used to secure to the top of the cover plate a plurality of metal bars f|5-I8. of rectangular section and they are a. part of the structure utilized with other bars for securing the mold directly to the top of the ladle.

For example, the metal bar 18 may be secured to the cover plate 18 by a plurality of bolts passing through the bar and threaded into the cover plate and the bar I6 is preferably located with its inner face 88 substantially parallel to both of the edges of the discharge aperture 12 as it is intended to hold one-half of the mold II in proper position in registry with the aperture I2 at itslower end. 1

. 4 The mold comprises a pair of parts 8| 82 and the lower and left corner 83 of the mold half 8| engages the face 88 of the bar lb. The bars I8 and 11 carried by the .cover plate 18 are preferably elongated and extend forwardly from the ladle I8 ,over a length which is sufllcient to support the half mold member 8| when it is in the position of Figure 2. For this purpose, the bar members 16 and ll may be braced by having an upwardly extending frame member 88 at the end of each bar member 7-8, ll, the upper end of which is secured to another horizontally extending bar 85 by means of screw. bolts 88. The bar members 16, Il may be secured together at regularly spaced points by transversely extending bars 81, 88, 88 and the inner ends of the bars85 may be secured to the fixed mold member 82 by a rivet or bolt 83.

The bars I6, 1'! and the bars 85 are spaced from each other laterally sufiiciently so that the mold member 8| may lie between them and the vertical frame members 84 project above the bars 88 to provide a stop surface 88 for engagement with the laterally projecting pipe 8| carried by mold member 8!. Thus, the mold member 8| is prevented from sliding endwise toward the left oif the supporting frame which comprises the bars 18, TI, 85, 84 and others.

The horizontal supporting frame for the mold member 8| may be indicated in its entirety by the numeral 82. The mold member 82 is preferably fixedly supported on the ladle I8 by means of a vertically extending frame on each side. This frame may consist of the vertically extending frame members 8388 (Figured) which are These metal bars may be on the cover plate 18.

The bars 88, 84 are secured together at regularly spaced points and the bars 85, 88 are secured together at regularly spaced points by means of screw bolts and horizontal frame members 88-|8I The frames at together by the transversely extending frame member I82.

The uppermost transverse frame members 88 (Fig. 3) are joined by a frame member I83 which may have a beveled surface I84 on the side which engages the fixed mold member 82. The fixed mold member is preferably substantially rectanular in elevation and comprises a metal member provided with a plane, smooth and polished surface I88 forming one of the sides of the mold cavity I88.

The two mold members 8| and 82 are made of metal having a higher melting point than the metal which is to be cast into plates. For example, when casting aluminum and certain other alloys. cast steel molds may be used. The mold member 82 is preferably provided with a rearwardly extending reenforcing border flange I81 extending on all the four edges of the body plate I88 and it is also preferably provided with a plu- I88. Vertically extending reenforcing ribs may also be employed for the purpose of preventing the warping of the mold, and the lower edge of the fixed mold so that it will fit against the cover plate 18 when the mold is disposed at an angle as shown.

The face I85 of this mold 82 registers with the opening I2 in the cover plate I8 which in turn registers with the discharge opening 55 from the chamber 43 of the ladle. The width of the mold members 8|, 82 is such that the mold cavity I 88 0 is as wide as-the discharge openings 12 and 58 are long. The thickness of the mold cavity I 86 is the same from top to bottom and is of such thickness that the lower open end of the mold has the walls of its cavity in registry with the edges of the opening 12 in the cover plate I0.

- The fixed mold 82 rests againstthe frame mem ber I83 at the top and against the cover plate 18 at the bottom and is preferably secured in place by a plurality of screw bolts II| extending through the frame members 89 and threaded into the flange of screw bolts II2 (Fig. 7) may pass through the lateral frame-members l1 and may be threaded into the flange I81 (Fig. 5) of the mold 82 ad- Jacent its lower end.

The movable mold member 8| preferably has a body portion which is similar in construction, body plate H3, a

ever, is preferably provided which extends across the top of the mold member 8| and down both sides of the mold member 8|, but is open at the bottom, thereby defining a mold filling opening I. This mold member has its lower border fiange H8 provided with an oppositely beveled surface 8 so that it may fit against the cover surface H8 is such that when the toe 88 of the mold 8| engages the bar the filling opening Ill is in registry with the opening I2 in the cover plate 18. Thus, the mold II is adapted to have a filling opening which is of substantially the 75 same size as the discharge opening in the ladle,

82 is preferably beveled as at IIIl plate 18. The width of this secured to the horizontally extending bars 81, 88

each side are secured rality of transversely extending reenforcing ribs I81 of the mold 82. Another pair the reasons for which will be described hereinafter.

The movable mold 8i may be provided with a handle III which is of sufficient length to pro- :Iect laterally from may comprise a metal pipe which is secured to the vertically extending reenforcing flanges II4 (Fig. 1) by a plurality of screw bolts I20 which pass through apertures of the pipe and are threaded into the flanges I I4. The handle also serves the purpose of providing a support for the mold 8| when it is moved into the dotted line position of Fig. 2, resting on the frame members by means of handle 9|.

The fixed mold 02 is preferably provided with means for holding the movable mold Si in tight engagement with it as follows: At the upper end of the fixed mold 02, there is secured to its rear side on each of the reenforcing ribs II4, an upwardly extending metal bar I13. Each of these bars and its assembled parts are identical so that only one need be described. Each bar H3 is secured by means of screw bolts I2I passing through the bar and threaded in ribs I I4 of mold member 02. At its upper end the bar IIS pivotally supports a lever I22 by means of screw bolt I23. Lever I22 carries a pivoted wedging member I24 by means of screw bolt I25. Wedging lever I24 has its lower inner end beveled at I20 and the lever I22 may have a fiber extension I21 for grasp by the hands of the operator.

The upper flange I01 of the fixed mold 02 also supports a. pair of forwardly extending keeper frame members I28 spaced from it by a spacer I29. Keeper frame members I28 are joined by a keeper bar I30 which may be secured thereto y The operation of the securing means is as follows:

The wedging lever I24 engages the rib II4 of movable mold member 0|. When the lever I22 is pulled downward by its handle I21, its outer side engages the bar I30 and its beveled surface I26 engages the mold. The proportions of the parts are such that wedging lever I24 is driven in between the mold 8| and bar I30 as a wedge to hold the mold members 01 and 02 together. The wedging action thus provided is sufllcient to hold the two halves of the mold tightly together, but it is also adapted to take care of the expansion of the mold when the hot metal is poured into the mold.

The supporting framework for the ladle I0 also includes a pair of upwardly extending frame members I3I, I32, secured by means of screw bolts to the ladle shell 38 at the bottom and to the band 51. The frame members I3I, I32, preferably extend upward beyond the cover plate where they may be bent outwardly slightly as indicated at I33, I34. and provided with the horizontal handle portions I35, I36.

Thus, the ladle and mold assembly has a handle I35, I35 at each end which may be grasped by a pair of operators or either of them in tilting the ladle and mold from the position of Fig. 3 to Fig. 5.

The mold II is also preferably provided with a pair of.similar wedging members, one located at each side of the mold. In this case, the fixed mold is provided with a pair of forwardly extending strap members I31, I30, joined by a transverse strap I39 to form a keeper similar to I20, I20, I30, previously described.

A pivoted lever I40 comprising a pair of straps I4 I, I42 spaced and secured to a handlebar I43 both sides of the mold II. It 1 welding or any convenient fastening means.

is pivotally mounted on a f-rame'member; I44 by means of a screw bolt I45. A similar wedging member I45 extends between the straps I31, I30 and inside the strap I39 to engage the mold BI and this wedging member I40 is pivotally mounted on lever I40 by screw bolt I41. A

The frame member I44 may be a fixed member carried by the vertically extending bars 06. In this case the action of the wedging members is the same as described with respect to the wedging members I24 at the top, there being sufficient space between the mold to permit the necessary pivotal movement of the levers I40.

The interior of the mold cavity I00 in the mold member 8i likewise has its surface I40 in a substantially plane, smooth and polished condition, and the same is true of the inner surface I49 of the border flanges H5 at the end and both sides. Thus, the mold cavity I06 is of uniform crosssection from top to bottom and of uniform size.

The angular tilt of the mold cavity I06 with respect to the top of the ladle I0 is preferably such that when the ladle and mold are tilted, the free surface I50 of the molten metal I5! is adapted to well upward into the mold as the tilting progresses. The metal does not, therefore, run down to the end I49 0f the mold cavity I00, but it moves upward into the cavity in a solid stream of uniform cross-section until the cavity is entirely filled and thereafter the continued tilting of the mold to the position of Fig. 5 permits a pressure to be placed on the metal in the mold which is determined by the head of metal above the mold cavity in the ladle in Fig. 5.

The cover plate I0 may be provided with a sliding cover I52 slidably mounted in guides I53 and provided with a slot I54 for engaging the gas burner pipe. The cover plate I52 may be provided with a handle I55 so that it may he slid to the open or the closed position by means of the handle. Thus, the burner opening may be closed, if desired, or, if necessary, to prevent the spilling of the metal out of the burner opening when the mold is tilted to the position of Fig. 5.

The method and operation of the apparatus is as follows: The ladle I0 is preferably preheated by means of the gas burner 54, the flame 53 of which plays into the cavity 43. Metal may be melted in one or more separate furnaces and a suitable supply of clean molten metal such as that provided by clean scrap or by ingots, may be placed in the cavity 43 after which the cover plug 48 and cover plate 10 may be secured in place. The burner 54 is then again directed into the ladle cavity 43 and the flame is reflected from the free surface I50 of the molten metal into the mold cavity I06. This drives out the air and maintains a constant supply of neutral atmosphere, comprising exhaust gases. The pressure in the ladle is maintained slightly above atmospheric pressure so gas flows out crevices and air or oxygen cannot enter.

The apparatus may be preheated by means of this flame and by casting a few plates to bring it to the proper temperature. Thereafter, the casting operation may be carried out as follows: The mold having been closed and secured by means of 0 the wedges, the ladle and mold are tilted gradually from the position of Fig. 3 in a counterclockwise direction. As the ladle is tilted, the free surface of the molten metal I5I is, of course, maintained in horizontal position, and as the mold is lowered, this free surface rises in the mold the handlebars I33, I34 and "filled. The air or gas between the mold halves by the pressure ofthe v or gas.

. adjacent the walls of cavity I 08 due to the tilted position of the mold on the ladle.

The rising continues during the tilting operamold at the bottom and moves uniformly up throughthe mold until the mold is completely molten metal which is'sumcient to expel the air As the tilting is continued downward to the position of Fig. 5, after the mold has been filled,

a predetermined pressureis placed upon the metal in the mold and while-the metal pressure is continued until the pletely taken up by the head of sure applied to the mold.

The casting in the mold freezes from the flat surfaces of the mold inward toward the center, and ii the mold is tilted backward quickly enough, a hollow plate may be formed or a hollow tube may be formed by the metal which has congealed the mold, the molten metal running out of the inside to leave the casting hollow. Thus, the present invention may be used for making hollow castings or hollow tubes of any cross-section.

It should be understood that the cross-section of the mold may be circular for the making of hollow round'pipes or it may be square or hexagonal or triangular or rectangular or any known or desired geometric form, the filling opening of the mold being of the same size and shape. The casting also congeals from the outer end of the mold, that is, the upper end in Fig. 3, toward the filling opening, the lastto congeal being that portion adjacent the filling opening, so that additional metal is supplied to the casting as'it congeals and all shrinkage is taken up.

In order to permit sufficient time for this congealing. the tilting action of the mold is so carried out that a predetermined number of seconds or counts are employed, or the mold may be held-for a short time in the position of Fig. before it is tilted back into the position of Fig. 3.

As soon as the mold is tilted back to the uppermost position the wedges are released and the movable mold member BI is moved away from the fixed mold 82 and the movable mold is laid upon the horizontal supports 85. The casting will then be lying against the fixed mold member 82 and a very short sprue may extend'into the discharge opening 55 of the ladle, but a minimum amount of sprue is present and there is a minimum amount of metal wasted by sprue action.

The result is a cast metal plate of homogeneous uniform grained structure without any segregations of impurities and without any pipe or cavity in the case of a solid casting. The present metal has been found to have an increased tensile strength and an increased purity over the metals cast according to the methods of the prior art, and the metals are particularly adapted to be used for drawing out metal cans or tubular containers such as the cans that are used for shields covering radio tubes of radio receivers.

The superlative product resulting from the use of this apparatus is attributed to the method of casting which may the present or other apparatus and which is summarized as follows:

The method is preferably carried out by means a, closed insulated ladle having a mold directly in the mold cools, shrinkage is commetal. under presattached to the discharge opening of the ladle so is expelled from the crack that there is practicallyno sprue attached to the The mold is of metal of a higher meltished on all sides.

The cross-section of the mold is preferably uniform from one end to the other for the casting of plates or other articles of uniform cross-section, and the filling opening of the mold, which is in registry with thedischarge opening of the ladle, is of the same size as the cross-section of the mold. The discharge opening from the ladle is The ladle is filled to a clean molten metal,

tained in the ladle to keep air out.

The casting operation is then carried out with the mold in direct connection with the ladle and by tilting the mold until the metal wells upward into the mold in a solid unbroken stream without any agitation or churning. The congelation of the metal may begin as it enters the mold, but nevertheless the solid plug of the metal in the ladle. The sliding engagement with the polished sides of the mold has a burnishing action on the finished casting.

The method of casting preferably includes the application to the mold of a gaseous flame, which is so adjusted that it produces a certain amount of soot in every fine condition. This may be done by using an excess of gaseous fuel, suchas illuminating gas, over other words, the gaseous fuel predominates over 5 the oxygen supply which would be required for perfect combustion, flame.

This-soot may uniformly coat the conduit leading from the ladle to the mold, and may coat the thereby producing a red 0 metal surfaces of the mold with a thin, fine layer of pure carbon. This carbon reduces the surface tension of the aluminum alloy filling the mold, and causes it to fill the mold more perfectly, but is sufliciently thin and-fine so that it does not affect the surface of the casting, which conforms quite exactly to the cavity of the mold and provides a smooth and finished casting.

In addition to this, the carbon coating facilitates the separation of the mold from the casting, making the removal of the casting from the mold, or vice versa, easier than it would otherwise be.

Where the article to be cast is of uniform crosssection, so that congelation may start as the metal enters the mold. the carbon coating acts as a the supply of oxygen. In

lubricant for the entering metal and aids in producing a more finished surface.

Before the casting operation is begun, the flame impinges on the free surface of the metal, and-is reflected into the mold to preheat the mold, and

especially to heat the filling aperture.

As the tilting progresses and the free surface covers the filling opening of the mold, the flame continues to heat the metal in the ladle, and when the mold and ladle have reached their extreme position the flame impinges against the wall of the ladle to continue the supply of heat for maintenance of the temperature of the molten metal in the ladle.

Thus the flame is automatically cut off from the filling aperture of the mold by the tilting action, and automatically re-applied to the metal when the ladle and mold return to their original position.

The temperature of the metal in the ladle is preferably maintained as close as possible to the melting temperature of the metal used in casting, that is, slightly above the solidifying temperature, so that'when cast it solidifies quickly in the mold.

. Less time is thus required for casting, and any tendency toward segregation is minimized by quicker congelation. The tendency toward segregaticn is greatest during congelation, and quicker congelation reduces or substantially eliminates segregation of impurities and segregation of ingre ients of an alloy.

This close to congelation maintained by frequent measurement and constant observation of the indicated temperature of the molten metal in the furnace, by adiustment of the furnace and ladle'temperature, by adjusting the heating arrangements of the ladle and of the furnace and by replenishing the ladle supply at proper time and temperature.

The ladle gas burner can. be adjusted to higher or lower heat; or, if the metal in the ladle or furnace is too hot, 9. small solid piece of clean metal can be thrown into the molten metal to absorb heat by reason of its being heated and melted. The heat of fusion is taken from the surrounding molten metal, thereby reducing the tem erature o a'l of the metal when molten.

For example, the silicon aluminum alloy 356 of the Aluminum Company of America has a a composition of 7% the rest aluminum. a range of solidificat on of from silicon, 0.3% magnesium, and

1130 degrees F.

to 1075 degrees F. Using this alloy, the molten metal in the furnace may be maintained at a. temperature not over 1300 degrees F. and not less than 1250 degrees F.

Under the same conditions, with small castings of irregular shape, the temperature of the metal in the ladle may be maintained at from 1175 degrees F. to 1200 degrees F.; but, if the machine is used for casting thin plates, the temperature of the molten metal in the ladle may be maintained at a temperature between 1225 degrees F. and

1250 degrees F.

Under these conditions the mold might be maintained, for example, at a temperature of from 600 degrees F. to 700 degrees F., preferably at about. 650 degrees F.

It is also found that the proper temperatures for the molten metal in the ladle decrease during operation from the proper temperature which should be used in the beginning. For example, in the beginning, when the ladle is bringing the mold and other parts up to proper temperature, one

the ladle and of that in may start with a temperature of 1250 degrees F. with this alloy, and a half hour later reduce the operating temperature of the metal in the ladle to 1200 degrees F., and still later to 1175 degrees F. in the ladle, which may be then used for the substantially constant operating temperature.

The mold being attached directly to the ladle, with only one part detachable, keeps the mold hotter than it would otherwise be, but the mold is maintained at a temperature lower than that of the molten metal in the ladle, as indicated above, in order that it may cool the molten metal when the mold has been filled, and effect a quicker congelation.

In order that the mold may be cooler than the ladle parts, it is provided with some heat insulation between it and the ladle.

temperature is While in some embodiments of the invention artificial cooling by liquid or gas might be used, the temperature differential between the mold and the ladle andbetween the respective parts of the mold is preferably so regulated by the construction of the mold and ladle that no artificial cooling is needed for most castings.

In the apparatus illustrated the amount of metal used in the mold and the proportions of the mold and the amount of heat radiating surface provided are adapted to effects. proper cooling without necessity for artificial means, and these proportions are shown in the drawings.

The tilting is preferably carried out slowly so that the mold is filled slowly, and when the mold is filled the tilting is continued until the full pressure of the remaining metal in the ladle is placed on the metal in the mold.

Referring to Figs. 8 to 13, these figures show progressively the action of the flame and the molten metal during the casting operation.

In Fig. 8 the ladle is in upright position, and the.

flame is playing on the free surface of the metal, and is deflected into the mold.

Assuming that the dross on the surface has been skimmed off, the casting operation may then gun to well up into the sprue or filling conduit.

This alloy is stated to have as shown in Fig.

As the tilting proceeds, it will be seen in Fig. 10 that the metal wells up into the mold. In this figure it has just begun to enter the mold. Further tilting causes the free surface of the metal to well up farther into the mold.

In Fig. 11 the mold is more than half way full.

In Fig. 12 the tilting has progressed to such a point that the mold is entirely full. This position is such that the free surface of the metal is above every part of the mold cavity.

The tilting is then continued to the position 7 of Fig. 13, in which substantially every part of the mold cavity is below the main body of molten metal in the ladle. When a plate is being cast, 13, the mold cavity may be in substantially horizontal positio In this position the pressure 01 the head of metal in the ladle is applied to the metal in the U mold.

For some embodiments of the invention it is only necessary to proceed to the position of Fig. 13, but in others the tilting may be continued until the mold is substantially or entirely inverted, the mold'being in vertical position, with the opening for the burner closed.

There are advantages in this additional step of inverting the mold and casting after the filling it at of the mold, as the natural h'eat gradient is then established from the lowermost and coldest part of the mold to the uppermost and hottest part of the mold near the ladle.

For example, at the temperatures mentioned, varying from 1250 degrees R, beginning, down to a stated temperature of 1175 degrees F., one hundred and twenty casting might be made per hour;

and of course the major part of this time is spent in removing the casting from the mold and reassembling the mold.

The exact amount of time which should be taken up in tilting the mold and the speed of tilting may be determined best by trial. For example, between five and ten seconds might be used in the timing of the down movement of the mold; but this may be varied by reason of the following conditions.

The thinner the cavity, the faster the filling and the freezing should be; and therefore the thinner castings must be made b .tilting at a faster speed. The heavier the casting, the slower the filling may be, and in such case the mold may be brought down slowly, consuming as much as thirty seconds. The speed of the down movement is important; and if the downwardmovement is properly timed, the casting will be well formed.

In some cases, after the down movement has been completed, the mold may be lifted at once;

but if the castings are heavier, the mold must be held down in the lower position for a certain number of seconds, until the congealing is accomplished inward from both sides of the mold, and back from the end of the mold to the filling aperture.

One advantage of holding the major axis 01' the mold in substantially horizontal position during congelation, or of merely moving it to the substantially horizontal position to fill the mold, is that all parts of the cavity will be subjected to substantially the same head of pressure by the metal in the ladle, because they are at the same level, and the pressure should be the same in a plane parallel to the free surface and at a predetermined distance below the free surface.

The tilting is preferably carried outslowly so that the mold is filled slowly and when the mold is filled, the tilting is continued until the full pressure of the remaining metal in the ladle is 5 placed on the metal in the mold.

The metal in the mold then congeals from the large plane fiat surfaces of the mold inward toardthe center and from that end of the mold remote from the filling opening back to the filling opening. As the cooling of the casting takes tion and full metal pressure applied for a short time until congelation takes place. The timing depends upon the metals which are being cast and upon the characteristics and thickness of the mold and the temperatures employed.

When hollow castings, such as tubes or hollow lates, are to be made, the ladle and mold are tilted backward to the uppermost position immediately without any delay and the thickness depends upon the temperatures and the speed of tilting and re-tilting. This may quickly be determined by trial, and it is not possible to specify any given time except with a given apparatusat a given temperature. L

There is no spurting otthe metal out of a nozzle into the 'mold, no forming of drops or separate oxidised particles, and the only part of the casting which is subjected to air is that small area at the end or the solid advancing stream or metal in the mold and that end portion becomes the end oi the casting.

The present method may be used for casting various types of metals and alloys, and it is only necessary to use suitable molds of metal of a melting point higher than the metal to be used in casting. I

As soon as theassemblyis tilted back to the upper position, the wedges are released and the movable mold members withdrawn and the castcooling influences.

When the metal is to be used for drawing metal I containers, the plates may be taken to a punching prior art.

It an improved method of making castings and grained homogeneous structure without any segregated impurities or cavities or other defects.

As the mold opening is of the same size as the ladle discharge opening, the metal may well up into the mold without any agitation or spurting or splashing, and there are no small particles or, drops formed which may harden first and be oxidizedon their outside and then incorporated 65 in the casting. The casting comprises one uni-' 70 gauge and width, but the amount of rolling that is necessary is very small because of the initial thin character of the plate castings. amount of rolling is eliminated, and the cost of the metal sheets is greatly reduced.

75 According to my method, no part of the melted the invention,

- cavity and also metal is ever separated from the compact stream of melted metal walling up into the mold. If any part of the metal becomes separated from the stream, it wouldbe surrounded with oxygen and become oxidized, and would not fuse again in the mold to make such a homogeneous structure as I am able to secure.

While I have illustrated a preferred embodiment of my invention, many modifications may be made without departing from the spirit of and I do not wish to be limited to the precise details of constructionset forth, but desire to avail myself of the scope of the appended claims.

Having thus describedmmy invention, what I claim as new and desire to secure by Letters Patent of the United States is:

all changes within 1. A permanent mold assembly comprising a metal plate having a mold filling opening therein, a pair of longitudinally extending metal frame members carried by said plate, and a pair of transversely extending frame members projecting transversely from said plate and secured to said longitudinal frame members, a mold member comprising two halves, one of said halves fitting between said longitudinally extending frame members adjacent said filling opening and having its inner surface in registry with the edge of said filling opening, said transversely extending frame members having a cross head adapted to support said one half of the mold, the second half of said mold member being provided with a cavity and also fitting between said'longittudinal and transverse frame members against the first half of the mold, said cavity being formed with an opening at its lower end in registry with said filling opening in said plate, and means for securing said mold halves together, said latter means comprising a pivoted lever carried by the first mold half, and a cross bar carried by said first mold half, a wedging member pivoted on said lever, and adapted to be engaged between the cross bar and the second mold half.

metal plate having a mold filling opening therein,

a pair of longitudinally extending metal frame members carried by said plate, and a pair of transversely extending frame members projecting transversely from said plate and secured to said longitudinal frame members, a mold member comprising two halves, one of said halves fittin between .said longitudinally extending frame members adjacent said filling opening and having its inner surface in registry. with the edge of said filling opening, said transversely extending frame members having a cross-head adapted to support said one half of the mold, the second half of said mold member being provided with a cavity and also fitting between said longitudinal and transverse frame members against the first half of the mold, said cavity being formed with an opening at its lower end in registry with said filling opening in said plate, and means for securing said mold halves together, said plate also having longitudinally extending frame members pro- 2. A permanent mold assembly comprising a metal platehaving a mold filling opening therein, a pair of longitudinally extending metal frame members carried by said plate, and a pair of transversely extending frame members projecting transversely from said plate and secured to said longitudinal frame members, a mold membercomprising two halves, one of said halves fitting between said longitudinally extending frame members adjacent said filling opening and having its inner surface in registry with the edge of said filling opening, said transversely extending frame members having a cross head adapted to support said one half of the mold, the second half of said mold member being provided with a fitting between said longitudinal and transverse frame members against the first half of the mold, said cavity being formed with an opening at its lower end in registry with said filling opening in said plate, and means for securing said mold halves together, said plate also having a transverse shoulder member secured on the plate to engage the outer surface of the second half of the mold to hold the parts of the mold together at said plate.

3. A permanent mold assembly comprising a vided with a cross-bar and of sufllcient length to support the second half of the mold when it has been separated from the first half.

4. A permanent mold assembly comprising a metal plate having a mold filling opening therein, a pair of longitudinally extending metal frame members carried by said plate, and a pair of transversely extending frame members projecting transversely from said plate and secured to said longitudinal frame members, a mold member comprising two halves, one of said halves fittin between said longitudinally extending frame members adjacent said filling opening and having its inner surface in registry with the edge of said filling opening, said transversely extending frame members having a cross-head adapted to support said one half of the mold, the second half of said mold member being provided with a cavity and also fitting between said longitudinal and transverse frame members against the first half of the versely and longitudinally extending spaced rein forcing ribs.

CARL WESSEL.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,333,286 Wessel Nov. 2, 1943 440,801 Adams Nov. 18, 1890 r 954,368 Allison Apr. 5, 1910 1,533,734 Gotze Apr. '14, 1925 2,106,614 Lindner Jan. 25, 1938 94,170 Pedder Aug. 31, 1869 1,138,443 Bie'rbaum May 4, 1915 1,368,445 Little Feb. 15, 1921 48,215 Sexton June 13, 1865 905,287 Chipman Dec. 1, 1908, 2,134,829 McWane Nov, 1, 1938 2,223,617 Johnston Dec. 3, 1940 2,209,519 Halbrock July 30, 1940

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