US2029800A - Method of preparing metal stock and apparatus therefor - Google Patents

Description

Feb.-4, 1 936. TEMPUN 2,029,800

METHOD OF PREPARING METAL STOCK AND APPARATUS THEREFOR 'Filed June 22, 1954 2- Sheets-Sheet 1 Z A j 24 if; Z6 20 2/ 25 /7 VENTOR Rm Limp/m Feb. 4, 1936. R. 1.. TEMPLIN- 2,029,800

METHOD OF PREPARING METAL STOCK AND APPARATUS THEREFOR Filed June 22, 1 934 2 Sheets-Sheet 2 IN VENT OR Ema/d A imp/m Patented Feb'. 4, 1936 METHOD OF PREPARING METAL STOCK AND APPARATUS THEREFOR Richard L. 'lcmplin, New Kensington, Pa, as-

signor to Aluminum Company of America, Pittsburgh, Pa, a corporation of Pennsylvania Application June 22, 1934, Serial No. 1313'" Claims. (01.78-63) The invention relates to metal working and in particular concerns the preparation or improvement of forging stock or of metal stock in genera 5 l In the metal working arts recognition has been accorded to the beneficial effects of working in relation to grain refinement and improvement in mechanical properties of metal. Inseparable from the advantages which may be said to result from the working methods commonly employed,

as in rolling or drawing, are certain inherent disadvantages. Perhaps one of the most important of these is represented by the phenomenon generally referred to as the production of directional 5 properties in the metal. Thus it is well known that in the case of rolled shapes, for example, the tensile strength willbe greater in the direction of rolling than transversely thereto. Many attempts have been made to avoid or minimize the directional eflect of rolling and kindred working operations but, so far as I am aware, none of the methods now known to the art are completely effective; and in some cases they are of doubtful value.

The designs of roll passes and of forging dies are illustrative of the means commonly employed to work the metal in such a way as to tend toward refinement of the grain structure and the elimination of directional properties. The improvement obtainable by such expedients is quite limited, however, and is largely dependent on size and shape of the metalstock which is used, in relation to the size and shape of the product or intermediate product which is to be fabricated.

It is an object of the present invention to provide a method and apparatus for preparing metal stock which is characterized by substantial freedom from directional properties and which show in this respect a far greater improvement than is obtainable by any of the methods which heretofore have been employed. Another object is to provide apparatus for preparing metal stock characterized by an improvement in mechanical properties and, more particularly, by an increased fatigue limit. I

A more specific object of my invention is to provide apparatus for preparing special aluminum stock characterized by freedom from directional properties and by an attendant improvement in physical properties in all directions, with a marked improvement in fatigue limit.

A further object of the invention is to provide apparatus for preparing metal stock which apparatus comprises an attachment which can be used in connection with conventional extrusion presses, and a method of preparing metal stock by a combination of die expressing and die forging steps which can be performed with ordinary extrusion machinery used in conjunction with my special attachment. Other objects and advan- 5 tages will appear from the following description in which reference will be had to the accompanying drawings.

In the drawings, Fig. 1 represents a cylindrical extrusion billet adapted to be processed in the 10 apparatus and by the method which is to be described. Fig. 2 is a vertical sectional view taken through the longitudinal axis of the cylinder of an extrusion press and associated structure, with the parts shown in the position which they occupy 15 at the end of the first step of the method. Fig. 3 is a vertical sectional view also taken on the longitudinal axis of an extrusion press and showing a fragment of the cylinder of the press and associated structure. The parts are shown in the 20 position which they occupy after the extruded billet formed in the first step of the method hasv been ejected from the die assembly, with the die assembly withdrawn to permit ready removal of the billet.

Fig. 4 is a fragmentary vertical sectional view of the extrusion press cylinder and a portion of the die assembly in which, however, the die has been replaced by a solid block. The parts are. shown in the position which they occupy at the 30 beginning of the second step of the method. Fig.

5 is a view similar to Fig. 4 butshowing the plunger of the press partially advanced and with the other parts in the position occupied durin an intermediate stage of the second step of the 35 method. Fig. 6 is a view similar to Figs. 4 and 5 but with the parts in the position occupied after the completion of the second step and during removal of the processed billet and the sleeve from the cylinder of the press. Throughout the de- 40 scrlption of the drawings similar reference numerals will be used to indicate the same parts.

The apparatus and method which I have devised are adapted to work or knead the metal by first efiecting a reduction in the cross sectional 5 area of the starting billet by extrusion, and thereafterupsetting the extruded billet by what will be referred to as a die forging operation which brings the billet back to substantially its original form. The method broadly relates to that de- M scribed in my copending'application, Serial No. 731,876, and the present invention is concerned with a novel apparatus and method for carrying out the general process described in connection with Figs. 4 and 5 of the copending case.

Referring more particularly to Fig. 2, cylinder may be of conventional construction and are .merely representative of typical extrusion press design. It is usual to provide means for heating the cylinder of the press and, as shown, this means is afforded by an outer casing 4 which is recessed at 5 to provide heatln': chambers. The casing 4 in the construction shown forms part of the frame 6which carries the die assembly bed plate I, and the die assembly which is indicated generally by the reference numeral 8.

The die assembly 8 may also be of conventional construction and, in the design shown, comprises the tool container 9 with an integral die holder I0 provided with a conical recess to receive the die II. The die II is held in place by a back-up piece I2 which, in turn, is locked in place by the die block I3. The forward face of the die I I fits into a conical recess I4 formed in the end of the cylinder I, and the entire die assembly 8 is locked in position by means of a wedge block I5 which is shaped in the form of an inverted U through the center of which the extruded billet may pass. An actuating rod I6 is attached to the wedge block I5 and forms a part of mechanical means (not shown) for raising and lowering the wedge block. A movable portion I I of the usual run-out table is secured, as at I8, to the container 9 of die assembly 8. I prefer that the movable table ll be arranged for mechanical operation by a cylinder and plunger arrangement, such as customarily provided in connection with extrusion press equipment, so as to provide a convenient means for withdrawing the die assembly into the position shown in Fig. 3.

In order that the metal, after passing through the die II, may be further processed in accordance with the second step of my method, it is quite essential that the extruded billet be straight and true. I have provided for this by means of a run-out guide in the form of a tube or pipe I9 which passes through concentric apertures 20 in the tool container 9, die block I3 and back-up member I 2. At its inner end the tube I9 is seated in the counter-boredportion 2I of the die II, abutting a shoulder at the end of the counterbore. Tube I9 is aligned with the axis of the extruded billet and supported at its outer end by any convenient means, as by the bracket 22, which may be secured to the table I! by screws 23. The end of the extrusion plunger is shown at 24. A follower 25 is provided, which has a diameter substantially equal to that of the inside of the cylinder, and the end 'of the plunger 24 is arranged to bear against the follower 25.

The extruded billet is shown at 26 and will have a collar 21 formed by the end metal which does not pass through the die. At the end of the extruding operation the wedge block I5 is raised into the position shown in Fig. 3, and the die assembly 8 is withdrawn to permit removal of the extruded billet 26. It will be found convenient to provide an auxiliary plunger 28 which can be rigidly mounted in the position shown in Fig. 3 or may be arranged to be swung out of the way as desired. As the die assembly 8 is withdrawn from the end of the cylinder I the extruded billet 26 is brought into abutting relationship with the end of the plunger 28 and pushed back through the die I I, after which it drops down or is lowered onto the transverse rails 29 in position to be rolled or lifted out of the way. During or after the initial movement of die assembly 8 away from the end of cylinder I, the plunger 24 may I during the upsetting operation.

be further advanced into the position shown in Fig. 3 to push follower 25 out of the cylinder I.

In the next step of the process, which will be described with reference to Figs. 4 and 5, the end of the cylinder I is closed by means of a solid block 30 which is held in the tool container 9 in lieu of the die II and which is provided with a conical portion 3I seating against the conical end I4 of cylinder I. A sleeve 32, the interior diameter of which conforms to the diameter of the extruded stock 26 and the exterior diameter of which corresponds to the interior diameter of the extrusion press cylinder I, is slipped over the extruded stock 26 and the sleeve, with the stock therein, is slid into the cylinder I from the right, as viewed in Fig. 4. I prefer that the extruded billet 26 be turned end for end so that the collar 21 thereof will abut the block 30 which closes the end of the cylinder I. A follower 25', similar to the follower 25 described in connection with Fig. 2 but smaller in diameter so that it will conform with the interior diameter of sleeve 32, is placed in the end of the sleeve behind the billet 26- and the plunger 24 brought to bear against this follower 25'. It will be observed that by using the separate followers 25 and 25' it is possible to use the same plunger 24 in both steps of the method which is of advantage where both steps are to be performed in the same extrusion press.

-As pressure is applied by means of the plunger 24 acting against the follower 25', the extruded billet 26 is caused to conform with the walls of the cylinder I. The sleeve 32 is allowed to be pushed to the right, as viewed in Figs. 4 and 5, as the metal flows'around the inner end 33 of said sleeve. forging, the billet 26 is brought back to the original form shown in Fig. 1, or to substantially that form. Fig. 5 illustrates the die forging operation and shows the parts in the position occupied during an intermediate stage of this operation. At the completion thereof the upset or die forged billet will appear as indicated by the dotted lines 34 in Fig. 5 and the full lines in Fig. 6.

The die assembly 8 is again withdrawn to open the end of cylinder I and coincidentally with this movement of the die assembly or following such movement, plunger 24 is further advanced into the cylinder to eject the upset billet 34, allowing it to drop down on the die assembly bed plate I. The sleeve 32 may also be ejected from the cylinder I in the same direction by withdrawing the In this operation of upsetting or die.

plunger 24 to the right sufficiently to allow the follower 25' o be replaced again by follower 25 so that when the plunger 24 is again advanced to the left the sleeve 32 will be pushed out of the cylinder I and will in turn engage the end of the upset billet 34 and push it farther to the left, as indicated in Fig. 6, to allow its ready removal.

It will readily be appreciated by those skilled in the metal working art to which the present invention appertains, that many variations can be made, both in the apparatus which has been described and in the suggested manipulation of such apparatus, while continuing to utilize the general teaching afforded by my novel method and apparatus as herein published. For example, it may be found desirable to remove the collar 21 after the first step of the method and I have found it sometimes to be of advantage as otherwise the edge of the collar may be detached and follow the sleeve 32 in its movement to the right Likewise it would be possible to remove the extruded billet 26 by pushing it back through the cylinder I instead of out to the left, or, after the upsetting through a die to reduce its diameter, placing the extruded stock within a sleeve conforming with the interior of the cylinder and the exterior of the extruded stock. andapplying pressure to the end of the extruded stock to upset it and cause it to conform with the walls of the cylinder while allowing the sleeve to be pushed out as the metal flows around the inner end thereof; and the essential steps in such method comprise providing a cylinder with a closed end, placing therein a sleeve, and within the sleeve 2. billet, and applying pressure to the end of the billet to upset it and cause it to conform to the walls of the cylinder whileallowing the sleeve to be pushed out as the metal flows around the inner end thereof. The essential feature of the apparatus resides in. the slidable sleeve and its arrangement in a cylinder with a closed end and a plunger slidable within the cylinder and within the sleeve, providing means for die forging a cylindrical billet to increase the cross sectional area thereof. I

The cycle of extrusion and upsetting may be repeated any number of'times in accordance with the method described in my copending applica= tion hereinabove referred to. After removal of the sleeve 32 in the manner which'has been described in connection with Fig. 6 it is only necessary to replace the solid block 30 with the die II and repeat the operations described. I

*prefer to produce a number of extruded billets 26 at one time and thereafter conduct a series of upsetting operations, in orderto avoid the necessity for interchanging the die II and block 30 and the followers 25 and 25' any more often than is necessary. Obviously the first step might be performed on one press and the second step on another, although in the foregoing description it hasbeen assumed that the same press would be usedfor all operations.

In order to enable those skilled in the art to readily practice the invention I have described specific embodiments and employed specific lan-- guage, but I have no intention of excluding equivalents or minor variations of the invention set forth.

I claim: v I 1. In the method of preparing metal stock the step which comprises upsetting a metal billet by forces acting parallel to the longitudinal axis 'of the billet until it has assumed an upset form of increased cross sectional area throughout substantially its entire length.

2. Method of preparlng metal stock which comprises extruding a metal billet through a die to reduce the cross sectional area thereof, guiding the extruded stock as it issues from the die to preserve its alignment, upsetting the extruded stock by forces acting parallel to the longitudinal axis thereof while restricting the flow of metal in a lateral direction to cause the said extruded stock initially to assume at one end a form of increased cross sectional area while initially retaining the form of reduced cross sectional area throughout the major portion of its length, and

'allowing the initial increase in cross sectional area to progress throughout the length of the extruded stock until it has assumed an upset form of increased cross sectional. area throughout subreduce the cross sectional area thereof, guiding the extruded stock as it issues from the die to preserve its alignment, upsetting the extruded stock by forces acting parallel to the longitudinal axis thereof while restricting the flow of metal in a lateral direction to cause the said extruded stock initially to assume at one end a form substantially equal in cross sectional area to that of the original metal billet while initially retaining the form of reduced cross sectional area throughout the major portion of its length,- and allowing the initial increase in cross sectional area to progress throughout the length of the extruded stock until it has assumed an upset form of cross sectional area substantially equal to that of the original billet throughout substantially its entire length. v

4. Apparatus for preparing metal stock com-' prising a cylinder for limiting the upsetting flow of a metal billet, one end of said cylinder being closed, an elongated sleeve arranged within the cylinder, said ,sleeve adapted for receiving a metal billet therewithin with one end abutting the closed end of said cylinder, the inner end of said sleeve being initially closely adjacent said closed end of the cylinder, and means for applying pressure to the other end of said billet to cause it to conform with the walls of the cylinder while allowing the sleeve to be pushed out of the cylinder as the metal flows around the inner end of the sleeve.

5. Apparatus for preparing metal stock which comprises a cylinder for limiting the upsetting flow of a metal billet, one end of said cylinder being closed, a sleeve slidably arranged within the cylinder, said sleeve adapted for receiving a metal billet therewithin with one end abutting the closed end of said cylinder, the inner end of said sleeve being initially closely adjacent said closed end of the cylinder, and means including a substantially fiat-ended plunger slidable within said sleeve for applying pressure to the other end of said billet to cause it to conform with the walls of the cylinder while allowing the sleeve to be pushed out of thecylinder as the metal flows around the inner end of the sleeve.

- RICHARD L. TEMPLIN.

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