US2278325A - Process for finishing forgings - Google Patents

Description

March 1942- LE ROY LAYTON PROCESS FOR FINISHING EORGINGS Filed Oct. 1 12, 1938 5 Sheets-Sheet l LE ROY LAYTON 2,278,325

Filed Oct. 12', 1938 v 5 Sheets-Sheet 2 Pawn.

' March 31, 1942.

PROCESS FOR FINISHING FORGINGS Mud! 4 LE ROY LAYTON 2,278,325-

PROCESS FOR FINISHING FORGINGS Filed Oct. 12, 1938 s Sheets-Sheet 3 March 31, 1942. LEROY LAYTON PROCESS FOR FINISHING FORGINGS 5 Sheets-Sheet 4 Filed Oct. 12, 1938 March 31, 1942. LE ROY AYTON 2,278,325

PROCESS FOR FINISHING FORGINGS Filed Oct. 12, 1938 5 Sheets-Sheet 5 punch cavities.

Patented Mar. 31, 1942 PROCESS FOR FINISHING FORGINGS Le Roy Layton, Lansdowne, Pa, assignor to Lansdowne Steel & Iron Company, Morton, Pa., a corporation of Pennsylvania Application October 12, 1938, Serial No. 234,713

" (c1. air-1.21)

2 Claims.

This invention'relates to the manufactureofhollow forgings in general and more especially to those employed as the main body portions of armament projectiles, which require accuracy in the forgin s as to balance and uniformity about the longitudinal axes thereof.

Prior to the present invention it has been customary to machine-finish, i. e. bore and/or ream, the interior surface of the cavity of each shellcase forging made by the punch or piercing tool, in addition to turning the exterior surface of the forging, in order to produce a concentrically balanced shell with truly circular, concentric inner and outer surfaces and a wall of uniform thickness therebetween. Ordnance requirements in these respects have been so stringent that it has heretofore been considered practically impossible to produce a satisfactory shell casing without machining the interior surface of the forging.

Thepresent inventioncontemplates a method and apparatus for producing hollow' forgings acceptable for use in the manufacture of shell casings and which as such will not require machine-finishing of the interior surfaces of the The process and apparatus forming the subject matter of the present invention will be fully disclosed hereinafter, reference being had to the ac companying drawings, of which:

Fig. 1 is a vertical sectional elevation of a primary forging die with a heated billet therein;

Fig. 2 is a sectional plan view taken on the line 22, Fig. 1;

Fig. 3 is a view similar to Fig. 1, with the billet consolidated in the lower part ofthe die under a elevation of the finishing machine, with the partially completed forging about the finishing tool; I Fig. 7 is a view similar to Fig. 6 showing the to be entered by finishing tool pressing the partially completed forging into the bite of a set of primary reducing rolls;

Fig. 8 is an enlarged sectional view showing the partially completed forging being contracted cross-sectionally by the primary reducing rolls;

Fig. 9 is a transverse elevation viewing the primary rolls and reduced forging from the plane.

indicated by the line 9-9, Fig. 8;

Fig. 10. is a side elevation showing the partially completed forging being reduced. elongated and finished by the primary and a secondary set of rolls;

Fig. 11 is a transverse vertical elevation showing the secondary or finishing rolls gripping the forging, as viewed from the plane indicated by the line l l-Il,Fig. 10; v

Fig. 12 is a view similar to'Figs. 6 and 7, showing the completed forging after passing through the primary and secondary rolls and making con-.

tact withamarking die;

Fig. 13' is a sectional perspective view of a finished forging} Figs. 14a and Mb'constitute aside elevation,

partly in sectionfof that portionof the apparatus I shown in Figs. 6, 7 and 12;

Fig. 15 is a plan view. partly in se'ction; of a portion of the apparatus shown in Figjli;

Fig. 16 is a transverse sectional elevation taken on the line iii-l6, Fig. 14a; i

Fig. 17 is a transverse sectional elevation taken on the line l|--l I, Fig. 14a;

Fig. 18 is a sectional plan view taken on the line l8 |8, Fig. 144:;

Fig.19 is a transverse sectional elevation taken on the line I 5-I9, Fig. 18;

Fig. 20 is a transverse sectional elevation taken on the line 20-20, Fig. 18; and

Fig. 21 is a perspective view'of a detail of the invention.

It will be understood that the forgings manufactured in accordance with the principles of the present inventionmay be produced from round billets of substantially the same diameter as the opening in the die in which the preliminary steps of the process of the present invention are carried out; or the billets may be squareor of other cross-sectionalshape, with the transverse diagonal or other greatest cross-sectional measurement substantially equal to the diameter of the open mouth of the die; or the-billets may be of the type disclosed in my 'tw o prio'r United States 'Patents No. 2,057,580 and No. 2,059,124, dated October 13, 1936, and October 27, 1936, respectively, wherein the cornersof a square billet having normal diagonal measurements greater than the mouth opening of the die are reduced diago-' nally and the sides of the billet intermediate the corners bulged. by lwhich the billet receives a peculiar, substantially circular cross sectional shape having its greatest measurement slightly I less'than the diameter of the mouth opening of the die, as shown in In Fig. 1 of the present drawings a primary die D is shown as having received a heated billet B of the above noted peculiarly circular or other suitable shape. In the present instance the bot tom of the die D, which may be fixed or movable, preferably the latter, is provided with a circular depression d.

In Fig. 3, a"dumping" or consolidating tool I, having a collar 2 which more or less snugly fits the circular or other shaped bore of the die D and which, beneath the collar 2, is provided with a tapered, circular, or other shaped initial piercing lug or boss 3, has been lowered into the die D and pressed against the hot metal of the billet B under hydraulic or other power, suflicient to compress the billet B between the bottom of the i die cavity and the underside of the collar 2. Under and by such compression the still-hot metal of the billet B is upset or caused to flow and become consolidated in the die D, around the boss}, in the depression d, and into full contact with the side walls of the die D, as shown in Figs. 3 and 4.

The billet B is thus transformed into an initial forging blank BI, with a nose pad 1) formed on one end by the depression (1 in the bottom of the die D, a centralized initial piercing cavity CI formed in the opposite end by the boss 3 of the tool I, and with initial side walls WI, WI, of

predetermined length and thickness formed around the centralized cavity CI.

, The ,tool I after effecting the above noted consolidation of the hot metal in the lower part of the die D is withdrawn and a secondary piercing tool or punch 5 is lowered into the die D under hydraulic or other suitable power. 7

The secondary piercing tool 5 is of a substantially cylindrical form, in the present instance,

although it may conform to any cross seetionalj shape that it may be desired to have in the cavity formed thereby in the forging.

The lower portion 6 of the secondary piercing tool 5 is tapered in accordance with the taper of the initial piercing boss 3 on the tool I. The

, extreme end I of the tool 5 is of substantially the same size and shape as the initial piercing ele- -ment 3 and consequently corresponds in .shape and size to the initial cavity CI formed in the initial blank BI by the element 3.

The end I of the piercing tool 5 first makes snug contact with substantially the entire surface of the cavity CI in the initial blank BI and is then forced by hydraulic or other suitable power down deeper into the hot metal of the initial forging blank BI, causing the heated metal to flow upwardly in the die D around the tapered end 6 of the tool 5, then up around the body portion 8 of said tool, at all times making and maintaining complete contact with both the exterior surface of the tool 5 and the interior surface of the die D; whereby the walls WI, WI of the blank BI shown in Fig. 4 are thinned and elongated, as

shown at W2, W2 in Fig. 5, with said walls ex ployed in addition to those disclosed above and by which the interior of the forging is finished accurately without machining.

The preliminary steps disclosed above, and by which the primary forging B2 is produced, are all carried on in a single heat. The steps by which the primary forging B2 is finished are likewise carried on in the same heat with the preliminary steps, whereby reheating and, consequently, formation of excessive scale on the interior wall of the forging are eliminated.

The secondary piercing tool 5 isthen removed .from the hot metal in the die D and the primary forging B2 is kicked out of or otherwise removed from the die D, as by raising the movable bottom DI of the die. The still-hot primary forging B2, after its removal from the die D, is placed in a horizontally disposed trough 9 (see Figs. 14a and 16), which supports said primary forging with its longitudinal axis coaxially aligned with the longitudinal axis of a finishing tool I0. As shown in Figs. 6, 7 and 8 the diameter of the finishing tool III is less than the diameter of the piercing C2 as made in the primary forging B2 by the second piercing tool 5.

With the primary forging B2 and the finishing tool In in the relativepositions shown in Fig. 6, said finishing tool is advanced axially into the cavity C2 of said primary forging freely and substantially without contacting the side walls of the cavity until the blunt end II of said tool makes contact with the flat bottom end c3 of the cavity C2. Continued axial movementof the tool I0 advances the primary forging B2 into the bite of a series of rolls RI. 1

Each of the rolls RI is provided with a concave face I-2 and said concave faces are arranged about a common axis coinciding with the axis of the tool I0 and the primary forging B2 and collectively form a substantially complete circle through which the primary forging is passed by further axial movement of the finishing tool lll.

It will be noted upon reference to Fig. '7 that the outside diameter of the finishing tool I0 is less than the inside diameter of the cavity or bore C2 of the forging B2; and that theangle of taper of the end I3 of the tool I0 is less than the angle of taper of the inner end of the cavity C2 of the forging B2. Consequently, as the tool I0 moves from the position shown in Fig. 6 to the position shown in Fig. 7 it makes no contact whatsoever with the side walls of the cavity C2. The only contact made between the tool and the forging until such time as said forging passes I into the bite of the rolls RI is that made between the flat blunt end II and rounded corners I4 of the tool In and the fiat end c3 and correspondingly rounded corners of the cavity C2 in the forging.

Preferably, the diameter of the flat surface C3 and that of the blunt end I I are substantially the same, .whereby a snug fit between the two is ac complished. and consequent centering of the tool II) with respect to the cavity C2 in the forging is effected. Continued movement of the tool In forces the forging B2 into the bite of the rolls RI, as shown in Figs. 8 and 9.

The circle or throat described by the combined concave faces I2 of the rolls RI, RI is loss in diameter than the outside diameter of the forging B2 and as the forging is passed through the throat formed by said rolls it is reduced in diameter or contracted cross-sectionally, causing a corresponding reduction in the diameter of the cavity C2 and effecting contact between the out- ,er surface of the tool I and the inner wall of the cavity G2 at the same time. As the passage B2 progressively contracts the forging cross-sectionally and produces a further elongation of the wallsW2 of said forging, along the length of the tool I0.

The side edges of the concave faces I2 of the rolls RI are outwardly filleted, as indicated at I5 in Fig. 9, whereby, as the forging B2 passes through said rolls, longitudinal fins f are formed along the forging B2 and act to relieve the extremely high pressure produced by the reduction in the diameter of the forging as the same passes through the rolls RI.

From the rolls RI the forging passes into the bite of a second series .of rolls R2, as shown in Figs. 6, '7, 8, l0 and 11. The faces of the rolls R2 are concave, as illustrated at I8 in Fig. 11, and

together with the edgesof the concave faces in laterally abutting relation to each other forming a complete circle or throat of progressively smaller diameter than the throat formed by the rolls slightly less in diameter than the throat described by the concave surfaces I2 of the rolls RI, whereby. as the tool I 0 continuesto move axially, the primary forging B2 is advanced through the rolls RI into the bite of the rolls R2 and through said rolls, which progressively reduces the outside diameter of the forging B2 with a relatively large reduction made by the rolls RI and a relatively slight further reduction made by the rolls R2. The roll R2 also, due to the position of the fins j with respect to the concave faces I6 of the roll R2, eliminate said fins and produce a substantially complete plain cylindrical surface on the outside of the forgin B2. 1

Reduction in the outside diameter of the forging molds said forging around the finishing tool I0, whereby the diameter of the cavity C2 is reduced to that of the outside diameter of the finishing tool In and a finished surfaceC3 is formed in the finished forging B3 shown in Fig. 13, the walls W3 of said finished forging being elongated as a result of reduction in diameter of the primary forging B2 about the finishing tool I0.

As the finished forging B3 passes out of the bite of the rolls R2, continued axial movement of the tool IIl causes the fiat face of the pad b on the closed end X of the forging B3 to be brought into contact with a marking die I1, and, a illustrated in Fig. 12, the marking die I1 is arranged to apply any desired identification to the end of the completed forging.

Heretofore the finishing of the inside wall of the cavity of the shell casing and other, hollow forgings by the piercing tool has been considered to be impossible, becauseof marring or other changing of the surface of the piercing tool as a result of successive piercing operations by said tool in each of which the piercing tool has remained in contact with the hot metal of the forging throughout the entire piercing and elongation of each forging, which resulted in overheating. I

In the present instance, finishing of the interior surface of the forging cavities is made possible by employing the initial and/or secondary piercing tools. as above described, to produce the primary cavity C2 in the primary forging B2 by utilizing a finishing tool to complete the forging operations by making the finishing tool of a diameter less than that of the primary piercing tool and th primary cavity and contracting the primary forging cross-'sectionally around the finishing tool, and by reducing the time of contact of the finishing tool with the hot metal of the forging, whereby the finishing tool does not absorb as great an amount, of heat from the forging as the piercing tool heretofore, making the finishing tool less susceptible to marring.

As a further means of keeping the finishing tool from being marred or damaged, the tool is kept as cool as possible by being periodically submerged in water or other coolingliquid after each primary forging has been completed.

Furthermore, a variable stroke is provided for the finishing tool to cut down'the time ,of its contact with the hot metal and wherebyfsaid tool is moved rapidly from the position shown in Fig. 6 to the position shown in Fig; 7, then slower as said tool advancesthe forging through thereducing rolls RI and R2, then rapidly from the rolls R2 until the forging makes contact with the marking die I1, and then rapidly in a reverse direction from the position shown in Fig. -12 to one end of a piston rod or ram rod 20. The rod fluid for moving the ram 25 relative to the cylinder' 26 in the direction causing the finishing tool ID to pass the primary forging B2 through the reducing rolls RI, R2, is admitted from a suitable ,source, such as a hydraulic accumulator, through a pipe 21, tapped into a cylinder head 28 which closes the one end of a--ram cylinder 26. Escape of the operating fluid from the opposite end of the cylinder 26 around the ram 25 is prevented by a suitable packing gland 29.

In a like mar iner one end 30 of the piston bore 22 formed in the ram 25 is closed, as shown in Fig. 18, by the metal of the'ram, thus preventing escape of operating fluid therefrom. The opposite end of the piston bore 22 is closed by a threaded plug 3I in which is mounted a suitable packing gland 32 which prevents escape of operating fiuid from said end of said bore around the piston or rain rod 20.

The ram cylinder 26 is provided with a flange 33 which acts as a. supporting frame for the one end of the cylinder. The flange 33 is provided with feet 34 which rest on a solid foundation 35 and which are secured thereto by bolts 36. The opposite end of the cylinder 26 is supported by a frame 31 which rests on the foundation 35 and is provided with feet 38 which are secured to said foundation by bolts 39.

Supported by the frame members 33 and 31 at each of the opposite sides of the ram cylinder 26 is a ram returning cylinder 46. In each of the cylinders 40 is a piston H which is connected by a piston rod 42 to a flange 43 formed on or secured to the outer end of the ram 25. Pipes 44, 44 adjacent the frame 33 communicate with the interiors of the cylinders 46 between the fixed heads 45 thereof and the pistons 4|. Motive fluid admitted through the pipes 44, 44 acting against the pistons H and through the rods 42, 42 returns the ram 25 to its initial position after the completion of each finished forging B3.

The-reducing rolls RI are rotatably mounted in a frame 46 which is provided with feet 41 secured to the foundation 35 by bolts 48. The rolls R2 are rotatably mounted in a framework 49 which is secured to or forms a part of framework 46 in which the rolls RI are rotatably mounted. The roll sup-porting frames 46-49 are tied to the framework 33 which supports the ram cylinder 26, by means of tie rods 56, 56, said tie rods passing throughthe flange 43 on the ram 25 and functioning asa guide-way for the ram when the ram is projected from the cylinder 26.

The trough 9 which supports the primary forging B2 prior to its being engaged by the finishing tool I is secured to the roll frame 46, as shown in Figs. 14a and 16.

The stripper I8 by which the finished forgings B3 are removed from the finishing tool III is slidably mounted in guide-Ways i, 5I carried by the roll frame 49. The stripper I8 is provided with a slot 52 of a width slightly greater than the diameter of the tool til and less than the outside diameter of the finishedforging B3. After the finished forging is moved to the position shown in Fig. 12 the stripper I8 is moved by an operating handle 53 from the position shown in Fig. 1'7 to a position wherein the slot 52 of the stripper fits around the tool I6 behind the finished forging B3 and whereby, as the tool It! is retracted by reverse movement of the piston 2|, the end of the finished forging B3 in which the finished cavity C3 is formed engages the stripper I8 which removes the said forging from the tool Ill.

The piston or ram rod is provided with a pair of segmental lugs 55. 55 which normally are slidably mounted in a correspondingly shaped pair of grooves 56, 56. The grooves 56 are formed in a sleeve 51 which is rotatably mounted in an extension 58 of and on the forward end of the ram 25. Securedto the sleeve ii! is a split collar 59 which is provided with an annular rib 60. The annular rib 60 is mounted in a correspondingly shaped groove 6! formed in the ram extension. 58. The collar 59 is provided with suitable handles 62, 62 by which the collar 53 and consequently the sleeve 5? may be rotated to bring the solid portions 63 of the sleeve ii'l. which lie between the grooves 56, 56 of said sleeve, behind the segmental lugs 55 on the ram rod 26 when such lugs'are in the position shown in Fig. 21.

After each forging operation the finishing tool HI as it passes beyond the rear end of the trough the container 64 by the underside of the tool I6 coming into contact with a block of wood 65 or'other suitable material resiliently supported in any suitable manner as by a spring 66 shown in Fig. 14a.

The finishing tool I0 is raised from its inactive full lineposition shown in Fig. 14a to its oper-' ating position shown in broken lines in said figure by an air hoist or similar mechanism comprising a cylinder 61, a rod 68, chains 63 and yoke or loop I0 through which'the tool I0 loosely extends.

When the primary forging B2 is placed in the receiving trough 9 the converging sides of said trough center said forging with respect to the axis of the ram rod 26 and the coinciding axis of the opening formed by and between the concave faces of the rolls RI, RI, and R2, R2. The tool I0 is then raised from its full line to its broken line position, as shown in Fig. 14a, which brings the axis of said tool into alignment with the axis of the primary forging B2. Fluid pressure admitted to the cylinder 22 through the port 23 quickly advances the ram rod 26 and tool I0 and causes the tool to move from the position shown in Fig. 6 into the cavity C2 of the forging B2, until the end II of said tool engages the base 03 of the cavity C2 and advances said forging along said trough into the bite of the rolls RI, in the position shown in Fig. '7.

In order to effect rapid movement of the tool into the cavity of the forging and the forging into contact with the rolls RI it is'preferable that air under pressure be used as the motivating fluid in the cylinder bore 22.

When the forward end of the forging B2 engages the rolls RI the lugs on the ram rod 20 have moved from the position shown in Fig. 18

'to the position shown in Fig. 21 with respect to said ram. The collar 56 is then rotated to bring the solid abutments 63 into line with and behind the lugs 55. Motivating fluid, preferably water under high pressure from a hydraulic accumulator is then admitted to the rear end of theram cylinder 26 through the pipe 21.

The slower moving hydraulic pressure then advances the ram 25 until the abutments 63 engage the lugs 55 on the ram rod 20. The ram rod 26 and the finishing tool I0 connected thereto are then looked to and move with the ram 25 as an integral part thereof and pass the forging B2 through the primary reducing rolls RI and the secondary rolls R2, I

As soon as the rear end D2 of the forging B2 passes the axis of the secondary rolls R2 the'air pressure built up in the cylinder 22 between the piston 2I and the solid end 30 of said cylinder bore projects the ram rod 20 and finishing tool III rapidly, causing the fiat face of the ad b on the forward .end bI of the finished forging B3 the piston 2i and the closure-plug 3|, while the port 23 is opened to exhaust, the collar 59 having previously been turned to realign the grooves 56 with the lugs 55 on the ram rod 20. The application of the air pressure to the cylinder -22 through the port 24 rapidly moves the ram rod in a reverse direction, the first result of which is that the rear end b2 of the forging B2 strikes the stripper I8 and strips the forging B3 from the finishing tool ID as the ram rod and finishing tool continue to move rearwardly, the lugs 55 in the meantime passing into and along the grooves 56 in the sleeve 51 into the position shown in Fig. 18.

Fluid under pressure, either pneumatic or hydraulic is then admitted by the pipes 44 into the retracting cylinders 40, said fiuid operating against the pistons 4| to retract the piston rods 42 which, being connected to the cross head 43 of the ram 25, moves said cross head and said ram in a reverse direction to retract the tool It fully from the rolls RI and R2. Continued rearward movement of the ram withdraws the finishing tool Into a position where the end ll thereof passes beyond the rear end of the trough 9 and permits the tool III to drop into the cooling liquid within the container 64, it being understood that in the meantime the tool raising loop (0 has been lowered to permit said tool to drop into contact with the shock absorbing block 65 on the spring 56.

If for any reason the forging does not freely strip from the tool l0 when the air pressure is applied to the piston 2| through the port 24, as above descr1 ed, the stripping will be effected when the ram 25 is retracted by hydraulic pressure applied to pull-back cylinders 40, through the inlets M, which will cause the plug 3| in the ram 25 to engage the piston 2| and move the piston rod 20 and tool I0 rearwardly with sufficient force to strip the finished forging from the tool.

Obviously, the various fluid conducting pipes are provided with suitable valves whereby inlet and exhaust of motive fluid to and from the various cylinders may be readily controlled.

The method of the present invention, as described above, constitutes a decided improvement over the methods of the prior art in which the forgings are reduced diametrically and elongated longitudinally by passing them though one or more rings, in that, by the present method a greater reduction in a single pass through the rolls can be made than could be accomplished by any single pass through a draw ring, because in attempting to make a great. reduction with a draw ring or in progress steps through a series of draw rings axially aligned and simultaneously engaging the forging, the friction of the ring or rings opposing the force exerted on the end of the piercing by the tool exceeds the tensile strength of the metal between the end of the tool and the ring and causes the metal to thin out in what is termed necking, which draws the metal out of contact with the surface of the tool and produces an uneven inner surface in the forging and a consequent non-uniform thickness in the wall of the forging: whereas, .under the present method the rolls by reason of their rolling contact with the exterior surface of the forging reduces the opposition to the passage of the forging through the throat of the rolls and compresses the metal radially at the same time as the wall of the forging is elongated, whereby the physical character or properties of the metal are increased to an appreciable extent over the resulting product of the old method, and whereby the metal being pressed with such great force against the exterior surface of the finishing tool produces a decided improvement in the character of the finish of the interior wall of the forging, the surface of the wall being extremely smoother with decidedly less scale formation than under the old method.

In the present instance the first set of rolls makes the reduction and in so doing raises fins on the outer surface of the forging while the second set of rolls primarily eradicates the fins and effects little or no reduction in the diameter of the forging.

I claim:

1. The method of making hollow forgings which consists in forming a cavity with a closed end and a cross-section of predetermined shape and dimensions to a predetermined depth inwardly from one end of a heated billet to form a primary forging, insertinga finishing tool of the same shape but of slightly lesser cross-sectional dimensions into the open end of said cavity free from contact with the walls of said cavity to provide an air space between the exterior surface of the tool and the interior surface of the cavity at a relatively high speed until the end surface of the tool engages the closed end surface of said cavity, advancing the tool and the forging through a throat of lesser dimensions than the outside cross-sectional measurements of the billet at a. relatively low speed to contact and compress the forging cross-sectionally into contact with the outside surfaces of the finishing tool to finish the forging by reducing the cross-sectional dimensions of the cavity to the cross-sectional dimensions of the tool, and retracting the tool from the finished forging substantially at said relatively high speed.

2, The method of making hollow forgings which consists in forming a cavity with a closed end and a cross-section of predetermined shape and dimensions to a predetermined depth inwardly from one end of a heated billet toform a primary forging, inserting a finishing tool of the same shape but of slightly lesser cross-sectional dimensions into the open end of said cavity free from contact with the walls of said cavity to provide an air space between the ex-:-

terior surface of the tool and the interior surface of the cavity at a relatively high speed until the end surface of the tool engages the closed end surface of said cavity, advancing the tool and the forging through a throat of lesser dimensions than the outside cross-sectional measurements of the forging at a relatively low speed to contract and compress the forging crosssectionally into contact with the outside surfaces of the finishing tool to complete the forging by reducing the cross-sectional dimensions of 'the cavity to the cross-sectional dimensions of the tool, retracting the tool from the finished forging substantially at said relatively high speed and cooling said tool preparatory to its entrance into the cavity of another of said billets.

LE ROY LAYTON.

Images