US2997774A

US2997774A - Method of making steel shells

Info

Publication number: US2997774A
Application number: US636007A
Authority: US
Inventors: Lyon George Albert
Original assignee: Individual
Current assignee: Individual
Priority date: 1957-01-24
Filing date: 1957-01-24
Publication date: 1961-08-29
Anticipated expiration: 1978-08-29

Description

29, 1961 G. A. LYON 2,997,774

METHOD OF MAKING STEEL SHELLS Filed Jan. 24, 1957 4 Sheets-Sheet 1 Aug. 9, 9 G. A. LYON 2,997,774

METHOD OF MAKING STEEL SHELLS Filed Jan. 24, 1957 4 Sheets-Sheet 2 E17 7 Eg. 8

ZEYVEH far 650265 /416E7 Zro/v Aug. 29, 1961 e. A. LYON METHOD OF MAKING STEEL SHELLS 4 Sheets-Sheet 3 Filed Jan. 24, 1957 FJg.//

7 2 I 3 P w N Z N E N 9 n m 2 E 4 v. a W I n 6A x I AM m 0 Aug. 29, 1961 cs. A. LYON METHOD OF MAKING STEEL SHELLS Filed Jan. 24, 1957 4 "Sheets Sheet 4 INF-EH fUF 050,06: A5627 [ram United States Patent Z,997,7 74 METHOD OF MAKING STEEL SHELLS George Albert Lyon, 13881 W. Chicago Blvd., Detroit 28, Mich. Filed Jan. 24, 1957, Ser. No. 636,007 4 Claims. (Cl. 29-1.21)

The present invention relates to the making of large size shells and more particularly steel shells.

An important object of the present invention is to improve the making of large size steel shells starting with ingot pieces and ending with the completed shells.

Another object of the invention is to provide improvements in the making of large bomb head shells.

A further object of the invention is to reduce the cost and increase the quality and accuracy of bomb shells of the low drag type.

It is a further object of the invention to provide an improved method of making steel shells directly from ingot pieces and without requiring rolling, and whereby the grain structure of the material is maintained in the most efiicient orientation throughout the working of the material from the ingot piece to the completed drawn shell.

It is yet another object of the invention to provide improvements in the treating of the material or blank in the various steps from raw material to the final drawing or Working operation.

It is also an object of the invention to provide an improved method of making steel shells with a minimum of heating and handling steps.

Other objects, features and advantages of the present invention will be readily apparent from the following detailed description of a preferred embodiment of the invention taken in conjunction with the accompanying drawings, in which:

FIGURE 1 is a fragmental side elevational view of a steel ingot showing how pieces thereof are prepared for further working according to the present method;

FIGURE 2 is a sectional elevational view of a more or less schematic showing of a dial type press setup for pancaking the ingot pieces;

FIGURE 3 is an enlarged fragmentary sectional detail view taken substantially along the line IIIIII of FIG- URE 2;

FIGURE 4 is an edge elevational view partially in section of the metal blank after it has been center punched;

FIGURE 5 is a vertical sectional view through the metal blank after it has been cupped;

FIGURE 6 shows the metal blank after the first draw;

FIGURE 7 shows the blank after a further draw;

FIGURE 8 shows the blank following an additional draw;

FIGURE 9 shows the shell blank after a heading operation;

FIGURE 10 shows the shell after the final elongation drawing operation;

FIGURE 11 shows the shell after a base end portion has been removed;

FIGURE 12 shows the shell after drop ring sockets have been assembled therewith;

FIGURE 13 shows the shell after back tapering and first nosing; and

FIGURE 14 shows the shell after the final nosing.

In the making of large steel shells such as may be used for the head shell portions of low drag bombs of 500 to 1,000 lb. size, speed of manufacture, low cost, uniformity of quality and accuracy in dimension are important factors.

Cost of material is an important consideration. Ac-

' cording to the present invention instead of using rolled 2,997,774 Patented Aug. 29, 1961 slab or stock, pieces of steel ingot of appropriate size are used. To this end, a steel ingot 15 as it comes from the ingot mold is turned down to remove scale and other usual surface impurities and imperfections. Then, the ingot 15 is cut into pieces of proper length to afford the desired weight of material. One such piece 17 is shown at the large end of the ingot separated from the remainder of the ingot by a saw slot or kerf 18. Where the ingot is of the tapering type as shown, the pieces 17 will, of course, be of graduated length to compensate for smaller diameters, so that all of the pieces will have the same weight or mass, as separated from the ingot.

In a preferred form, steel of SAE 1330 grade is used. The ingot pieces are heated in a salt bath to a temperature of 2300" F. to 2400 F. The salt bath heating has the advantage that it protects the ingot piece against corrosion or scaling and also it requires a minimum of heating time and heats uniformly throughout the piece. Such uniform heating is highly advantageous in that when the uniformly heated piece is pressed to flatten the same, less pressure can be used than where the heating is less uniform.

Each successive heated ingot piece 17 is subjected to longitudinal flattening pressure, that is to pressure applied to the axis of the piece in order to flatten the same laterally. This may be accomplished in a press structure as shown in FIGURES 2 and 3. In order to gain as much speed with minimum cooling, a dial bed press may be used wherein a dial bed 19 is provided with a plurality of

stations

20, 20a and 20b which may be separated by dividing lines or markers or members 21 and adapted to be successively brought into position under a flattening punch 22 (FIG. 3) by turning of the dial bed or turntable 19 (see directional arrow in FIG. 2) about an axis 23, which may be provided by a shaft or spindle.

In the first or loading station 20, one of the severed, heated ingot pieces 17 is generally centered in upright position on the bed 19 within a confining, thickness gauging ring member 24 which may be placed loosely and thereby freely laterally adjustably upon the face of the bed 19 and is provided with a central sizing opening defined by a sizing internal periphery 25' that is preferably at least slightly tapered to facilitate blank removal and in the present instance is shown as circular in outline. The diameter of the sizing opening and the thickness of the confining plate 24 are predetermined to afford a disk blank or pancake of the required dimensions related to the mass of material in the ingot piece 17 so that in the pressing of the ingot piece in the station 20a by ap-' plication of axial flattening pressure by the punch 22 a flattened metal blank B is attained which is of the desired thickness as gauged by the confining and gauging ring 24 and is of the proper diameter as determined by the confining wall or perimeter 25. Since the confining ring 24 is self-adjustable or floating on the bed 19, it can readily adjust itself to any initial eccentricity of the ingot piece 17 to the confining perimeter 2.5 as the ingot piece is squeezed and flattened by the flattening punch 22, the perimeter of the blank B then assuming the shape deterrnined by the confining perimeter 25 in the final portion of the flattening stroke and until the punch 22. comes to a gauged stop against the confining ring member 24, in this instance a substantially perfectly circular perimeter.

Immediately after completion of the pressing stroke, the flattening punch 22 is backed off and the dial press bed 19 indexed so that the now flattened blank B can be removed at the unloading station 20b. This may be accomplished by engaging the confining and gauging ring 24 in or by suitable apparatus for transporting the blank to the next working station which is preferably equipped to punch a central hole 27 in the blank (FIG. 4) to serve not only as a carrying hold aperture but also as an indexing hole or socket for subsequent drawing operations. If preferred, of course, the dial press bed may be equipped with a punching station for providing the central hole 27.

It is preferred to cup and draw the blank B into shell form immediately after flattening and while the same is still possessed of as much residual heat as practicable. While the central portion of the blank B gains some heat due to the severe displacement of material, the peripheral area of the blank by making contact with the confining ring 24 loses some of its heat. It is therefore preferable to normalize the blank B after stripping from the confining ring 24, in a salt bath furnace to a temperature of from 1500 F. to 1800 F. Thereby the central portion of the blank and the peripheral portion of the blank and throughout the thickness of the blank attains the same temperature. The thus temperatureequalized blank is ready for cupping and drawing which may, if preferred, be accomplished in automatic dial feed and fast acting presses so as to accomplish a plurality of successive operations before the blank has cooled to the point where it requires reheating or annealing.

As the first drawing operation upon the heat stabilized blank B, it is cupped to provide, as shown in FIGURE 5, a bottom wall 28 and a cylindrical side wall 29, with both of the walls about the same thickness and with the material contracted into the cylindrical wall 29 present in the elongation of such wall. Immediately thereafter and while the cupped blank is still at drawing heat, the side wall is subjected to a first full drawing in which its diameter is reduced and the thickness reduced while the length of the cylindrical wall is substantially increased, as shown in FIGURE 6.

Before the next or second full draw of the cylindrical wall 29, the temperature of the partially drawn shell is heat stabilized to preferably 1500 to 1800 F. The second full draw is then completed to substantially the shape shown in FIGURE 7. Then the shell blank is annealed at a temperature of about 1260 F., quenched, pickled, and phoscoated. This prepares the shell for further drawing thereof by cold working the same.

In the third draw which is effected cold, the cylindrical shell wall 29 is substantially elongated but the open or mouth or nose end is left undrawn and thus thicker and of larger outside diameter than the remaining major extent of the cylindrical wall. The result of this third draw is depicted in FIGURE 8, showing a thickened external mouth end collar 30.

In the next step in the proces, the base wall 23 which throughout the several elongation draws of the cylindrical wall has remained of the same thickness, is headed as shown in FIGURE 9 to substantially enlarge the central opening 27 and provide an annular substantially thickened portion 31 about the enlarged aperture 27. The partially drawn shell is then annealed, pickled and phoscoated and the cylindrical wall 29 subjected to the final elongation draw to the form as substantially shown in FIGURE 10. This final elongation draw is facilitated by the shaping during the heading operation of the outside diameter of the base wall 28 to a tapering smaller diameter which at its minimum is about the same as the final outside diameter of the cylindrical wall 29 at completion of the last elongation drawing thereof.

It may be observed that as a result of the several hot and succeeding cold working steps, substantially increased speed is attained and nevertheless a smoothly surfaced product is produced. By effecting the cupping, and first two draws hot and in rapid succession, time delay in heating is reduced to a bare minimum because reheating is minimized if not eliminated and any stabilizing to cool down or raise temperature in the partially drawn shell can be effected quickly. While the hot working may leave the surface in a rougher condition than ultimately desired, the cold working operations result in a highly desirable smooth surface. While two cold work drawing operations have been described, additional one or more cold elongation drawing operations may be added where the size of the shell requires.

Following the final cold draw, the annular central base portion 31 is cut out, and before or after such cutting out of the base portion, the collar 30 is subjected to a restrike forming operation wherein an annular tapered mouth surface 32 is provided. The shell now appears as shown in FIGURE 11.

While the opposite ends of the shell are still open to their maximum extent, the cylindrical wall 29 of the shell may be provided with such openings therethrough and structural additions thereto as may be required, for bomb head purposes comprising drop ring or hanger boss sockets 33 as shown in FIGURE 12. Machining for and assembly of the boss or socket members or inserts 33 is substantially facilitated by the relatively free access enabled through the opposite open ends of the tubular shell member.

Thereafter, the shell is subjected to a cleaning operation, the mouth end portion 30 thereof is annealed at 1250 to 1260 F. and then pickled, and phoscoated. The mouth portion 30 is now redrawn to bring the same into an outside diameter cylindrically in line with the cylindrical wall 29 and to contract the thickened mouth collar to the inside of the shell, as shown in dash outline in FIG- URE 12.

At its nose end portion, the shell is then cold worked to partially nose the same toward a desired nose ogive as shown in FIGURE 13. Also, the base end of the shell is back tapered by cold Working the same to the desired form. This substantially contracts the base end portion 28.

For the final nosing of the shell, substantially the ogive nose end portion of the shell is heated to about 1600 to l800 F. in a salt bath and the final nosing accomplished hot. This results in the finished shell form shown in FIGURE 14.

Finally, the finished shell is hardened by subjecting the same to heating to about 1600 F. and quenching the same in oil of about F. The hardened shell may then be tempered or drawn back by heating to 1100 to 1150 F. Any finish machining in the nose and base portions of the shell can then be effected, the shell painted and packed or sent to the assembly lines.

From the foregoing it will be appreciated that the present invention provides a shell of uniform grain struc ture since the untrimmed, sized blank from which it is drawn is derived from an ingot piece that has been fiattened axially to produce a radial grain structure which carries over into the tubular shell wall as a straight uniform grain from the base to the tip of the shell and throughout the cross-section thereof. The economy of material thus attained is also important since there are no scrap losses that have usually been attendant upon trimming of a blank to the proper size. Economy is also attained in the high speed cupping and drawing of the blank into the shell form with minimum treatment intervals for heating or annealing.

It will be understood that modifications and variations may be effected without departing from the scope of the novel concepts of the present invention.

I claim as my invention:

1. In a method of making a bomb head shell, drawing a steel blank into elongated shell form with a base wall and a tubular wall, shaping the tubular wall at the month end portion thereof into an externally thickened collar, cutting out a portion of the base wall so that access into the shell can be had from both ends thereof, securing hanger socket bosses to said tubular wall intermediate the ends thereof, and thereafter back tapering and nosing the shell to substantially reduce the openings at the nose end and at the base end of the shell.

2. A method as defined in claim 1 wherein the nosing is effected in two steps including 'a first nosing effected substantially coincident with back tapering, then heating the nose end portion of the shell in a salt bath, and final nosing the shell to provide thereon a predetermined ogive.

3. A method according to claim 2, including the further step of hardening the finally nosed shell, then tempering and final machining and finishing the shell.

4. In a method of making shells, drawing a metal blank into elongated tubular wall form with a substantially thicker base wall, heading the base wall and tapering the periphery of the base wall inwardly from juncture with the tubular wall, and then drawing the larger diameter portion of the taper and the tubular wall to an outside diameter substantially the same as the smaller diameter of the base wall periphery taper.

6 References Cited in the file of this patent UNITED STATES PATENTS 224,765 Bennett Feb. 24, 1880 848,927 Schoen Apr. 2, 1907 1,242,127 Bell Oct. 9, 1917 2,028,996 Sautier Jan. 28, 1936 2,245,642 Bell Aug. 26, 1938 2,286,064 CoXe June 9, 1942 2,350,491 Butler June 6, 1944 2,357,110 Heineman Aug. 29, 1944 2,371,716 Snell Mar. 20, 1945 2,404,304 Layton July 16, 1946 2,515,841 Stuart July 18, 1950 2,755,543 Dunn July 24, 1956 2,805,466 Lyon Sept. 10, 1957 ,840,884 Biginelli July 1, 1958 OTHER REFERENCES Metals Handbook, 1948 edition published by American Soc. of Metals, Cleveland, Ohio.