US451900A - Process of casting - Google Patents

Description

(No Model.)

W. G. RICHARDS.

PROCESS OF GASTING.

No. 451,900. Patented May 5; 1891.

1n: NORRIS PETERS 0a., murmurnm, WASHINGYUN, n c,

UNITED STATES PATENT OFFICE.

\VILLIAM G. RICHARDS, OF BOSTON, MASSACHUSETTS.

PROCESS OF.CAST|NG.

SPECIFICATION forming part of Letters Patent No. 451,900, dated May 5, 1891. Application filed October 25,1890- Serial No. 369,296- (No model.)

To all whom it may concern.-

Be it known that I, WILLIAM G. RICHARDS, a citizen of the United States, residing at Boston, in the countyof Suffolk and State of Massachusetts, have invented certain new and useful Improvements in Processes of Making Steel Castings, of which the following is a specification.

This invention relates to the manufacture of plate and flange castings, the object being to furnish a method whereby this class of castings may be made in steel without breakage.

In the drawings accompanying and forming a part of this specification, Figure 1 is a plan View of the lower part or nowel of a mold suitable for use in making one form of plate and flange steel castings by my newly-invented process. Fig.2 is a vertical section in line a a, Fig. 1,of the complete mold, showing the mold space filled and illustrating the operation. Fig. 3 is a plan view similar to Fig. 1 of the nowel of a mold for making circular plate and flange castings. Fig. 4 is a section in line b b, Fig. 3, of the complete mold and illustrates the operation of making the casting. Fig. 5 is a diagrammatic View shown in connection with Fig. 2 and illustrates the nature of the invention.

Similar characters designate like parts in all the figures.

The flask for containing the mold proper consists, or may in its general features consist, of the nowel-frame 18 and the cope-frame 19, constructed and combined substantially as in ordinary practice. The mold proper consists of the nowel 8 and the cope 9 set thereon, substantially as indicated in the drawings.

A suitable pouring-head, designated in a general Way by O, is attached to one side of the mold at or near the base thereof and extends to a point at some elevation above the top of the mold, substantially as indicated in Fig. 4. v

The main runner 12, through which the metal is conductedto a point adjacent to the under side of the mold, is formed in the nowel immediately under the mold-surface and is supplied by the channel of the pouring-head, which extends downward and connects with said horizontal runner, as indicated by dotted lines in Figs. 3 and 4. The particular mode, however, of supplying the molten metal to the main runner is not essential. The main runner 12 communicates with the moldspace through one or more mold-filling pas-- sages, as 13, which branch cit from the main runner at suitable distances apart. Said mold-filling passage or passages are preferably of relatively small cross-sectional area.

In the cope of the mold are formed a series of vents or overflow-passages, those over one flange-space being designated by 32 while those over the other flange-space of the mold are designated by 30; also, the usual center core 52 is or may be provided for making the central opening when the casting is circular,

as in Figs. 3 and 4.

The casting in the mold shown in Figs. 1 and 2 consists of a flat plate 20, having at opposite edges thereof the opposing flanges 14' and 16. The casting shown in Fig. 4 consists, likewise, of a flat plate 20, having opposing flanges 14 and 16; but in this case said plate is circular and the opposing flanges are concentric, the inner flange 16 constituting the hub and the outer flange 14 the rim of a plate and rim wheel. When a mold of the construction shown in Figs. 1 and 2 is filled with molten steel, the said flanges 14 and 16 are drawn by the shrinkage of the plate 20 forcibly against the shoulders 3 and 4 of the mold, thereby causing a longitudinal tension in the plate, tending to rupture the same at the weakest point thereof, which point will naturally be the point where the plate retains its heat the longest. In the making of steel castings the molds employed, in order to resist the intense cutting action of the white-hot metal, are necessarily formed of firm material, while, on the other hand, thesteel, owing to its peculiar physical character, is without much strength at the moment of its greatest shrinkage, so that on the solidifying of the plate 20 said plate is naturally ruptured, as indicated in Fig. 5, leaving a considerable space, as 6, at the normal line of separation, which line most naturally comes at the juncture of the plate with one of the flanges. To overcome thisbreakage, I fill the mold and feed the casting by a method in which the plate and flange j unctureis flooded or throughflowed during the contraction of the plate,

whereby the space or separation 6 (indicated in Fig. 5) is refilled as fast as formed, thus in effect lengthening the plate to counteract the shrinkage thereof during its suddenshrinkage period. This operation of flooding the plate-juncture, and thereby overflowing the rim during the sudden shrinkage of the plate 20, is indicated in Fig. 2 by the shading at 25, whereby is indicated the stream of metal which passes from the main runner 12 through the mold-filling channel 13, traverses the plate and flange juncture at the dotted line 7, passes through the interior of the flange, and escapes by an overflow through the cope-vents 30. In passing from the plate into the upper part of the flange said current reaches to the pipe-forming region of the flange, and thus prevents piping in the overflowed flange.

Referring to Figs. 3 and t, it will be seen the operation there shown is similar to that above described in connection with Figs. 1 and 2, excepting that in making the circular plate and flange casting the through-flowing of the plate and flange juncture is performed at frequent intervals throughout the circumference of said juncture, so that in practice the feed-currents will spread to form a substantially continuous line. In this form of casting it is most natural for the plate to contract toward the center of itself, which of course is toward the inner flange or hub 16.

Consequently the overflow described should be made through the peripheral flange, as indicated in the drawings. In the mold for making circular or wheel-shaped castings of the kind described the main runner (shown in plan view by dotted lines in Fig. 3) enters the nowel tangential to the line of the series of mold-filling channels 13, thus conducting the metal to all of said channels by an easy curve not materially obstructing the flow of the metal.

The operation of filling the mold and of feeding the casting being similar to the operation described in connection with Fig. 2, the minor features are designated by like reference-characters in both cases.

The combined operation of flooding or through-flowing the plate and flange juncture and overflowing the flange by a current through said juncture and flange I designate as overflowing the rim through the plate and flange juncture.

The practical importance of this improvement will be recognized when it is remembered that the sudden shrinkage of the molten steel occurs before the metal acquires any material degree of tenacity, taking place simultaneously, or substantially so, with the setting in of congelation. Consequently by the old methods of making the described kinds of castings the plate would be broken or materially weakened at the juncture there of with one of the flanges, said imperfection not unfrequently extending to a complete separation of the casting at that point.

While my present invention is especially valuable for the making of plate and rim wheels, it is equally well adapted to the making of some other kinds of plate and flange castings, whether with two flanges, as in Fig. 2, or with only one, since in some cases the length and weight of the plate offer sufficient resistance to the shrinkage movement to normally separate the casting at the plate and flange juncture.

The direction of the feed-current through the plate-juncture is more effective when toward the flange; but in some cases said current may be run in the opposite direction, as indicated at the left hand of Fig. 5, where the passage 13 connects with the lower edge of the flange, the feed-current 25 passing from the flange through the plate juncture and through a vent extending from the plate to the top of the cope.

In pouring the mold the mold-filling current may be continued to feed the casting, the final overflow being, according to the wellknown law of the flow of fluids, in the direction of least resistance. For this reason the moldfilling passage is made contiguous to the platejuncture to be flooded, since at the later stages of the operation this arrangement eifectually prevents overflowing the opposite flange.

The improved molds herein shown and described constitute the subject-matter of separate applications, Serial Nos. 388,4l1 and 388,438, filed April 11, 1891.

Having thus described my invention, I claim The process herein described of making plate and flange steel castings, which consists in filling the mold and through-flowing the plate and flange juncture during the contraction of the plate.

WILLIAM G. RICHARDS.

\Vitnesses:

FRANCIS I-I. RICHARDS, HENRY L. RECKARD.

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