US1216282A - Method of working copper. - Google Patents

Description

F. S. CARVER & W.,H. HARMAN.

METHOD OF WORKING COPPER.

APPLICATION FILED SEPT. 2|, 1916.

1 1 2 2, Patented Feb. 20, 1917.

Lsubjected to a combined compression and FRED s. CARVER, or NEWARK, Nnw JEnsEY, AND WILLIAM H. Ham/tamer LaNsnowNE, PENNSYLVANIA.

METHOD 0]? WORKING COPPER.

release.

Specification of Letters Patent.

Patented Feb. ao', tart.

Application filed September 21, 1916. Serial No. 121,448.

To all whom it may concern."

Be it known that we, FRED S. CARVER and WILLIAM H. HARMAN, citizens of the United States, and residents of Newark, county of Essex, and State of New Jersey, and Lansdowne, county of Delaware, and State of Pennsylvania, respectively, have invented certain new' and useful Improve ments in Methods of Working Copper, of which the following is a specification.

This invention relates to an improved method of making copper tubes and rifling bands for ordnance.

The methodfis designed to provide such tubes and bands cut therefrom with com paratively littleexpense, that are solid and homogeneous throughout and that will pass the rigorous inspection invariably given'to rifling bands such as are used on projectiles to act as a seal for ordnance gases and to insure effective contact with the ,rifling of a piece of ordnance.

In the drawing forming a part of this specification, Figure 1 is a section of mechanism for forming a tube with a closed end, and Fig. 2 is a detail view of the die part of Fig. 1 and illustrating-the tube formed. Fig. 3 is a top view of the tube formed by the operation shown in Fig. 2. Figs..4, 5 and 6 illustratedrawing apparatus and the changes produced in the tube by successive drawing operations. Fig. 7 is a perspective view of a band produced by this process.

The metal, which is preferably copper, is provided in a hot state. The metal is first extrusion operation. Apparatus adapted for this purpose is illustrated in Fig. 1 consisting of a substantially cup-shaped die '10 placed in'a suitable die holder 11 and disably by molding, of a size and shape to fit closely within the lower part of the cup shaped recess 15 in the die 10 which has a I) point.

1 preferably rounded bottom 18 and substantially vertical, cylindrical side walls 18 'of ably about the height indicated by dotted .lines in Fig. 1. The side and bottom walls of the die merge gradually into one another so as to avoid all sharp corners past which the metal is to be forced and the consequent weakening or disruptingof the copper. Before placing it in the die the copper block 16 is heated to a red heat, preferably within a few hundred degrees of its melting We have found that'good results may be obtained by heating the copper blocks 16 to from about 1500, to about 1600 F., but we are not to be confined to such precise temperatures, so long ,as the copper is not melted, and isheated sufficiently to work readily in the extrusion operation to which it is subjected.

By means of the plunger 12 and head 13 the block of copper 16 is subjected to great pressure which may be as high as 25,000 to 30,000 pounds per square inch. As the plunger 12 descendsfits head 13 engages the block of copper, the first efiect of its forcible engagement therewith being to firmly settle the copper block 16 down in and give it a solid seat in the die recess 15,--forcibly bringing it into contact withthe walls thereof both at the bottom and at the sides where-- by the block of copper is firmly restrained The block of copper 16 fitting thus closely within the recess 15 in the die, the material thereof is alw'ays,,,from the first contact of the head 18 therewith, subjected to very great compressive force while being at all times restrained by the walls of the die from lateral give or expansion, and the breaking, up of the grain or fiber or weakening of the strong coherent properties of the copper, which results from the expansion thereof Without such forcible compression or restraint, or from forcing blanks down into a die which they do not fit, is avoided.

As .the punch head 13 continues its descent the copper is extrudedfrom the die and is forced upward around the punch as is. clearly shown inFig. 2, forming a tube 19 of which the interior diameter or bore is substantially the greatest diameter of the punch 13, and the outer diameter is substan- Y tially the diameter or bore of the upper substantially cylindrical surface 18 of the recess 15 in the die 10. The punch, die and copper block are preferably so proportioned that the upper end of the tube 19 so formed does not begin to emerge from the top of the die until that portion of the punch head 18 of greatest diameter has entered within the die, so that during the act of extrusion the copperv forming the sides of the tube is being forced directly upward, without lateral expansion, through the narrow annular opening between the short, straight side portion 13 of thepunch head and the sides 18' of the recess 15 in the die and the tube is formed from a block whose outer diameter .is substantially the same as the outer diameter of the extruded tube. \Vith the deep die provided with straight sides of considerable height and with a rounded bottom merging smoothly into the side walls substantially as shown, and the punch with rounded substantially mushroom shaped head the copper may be made to flow without substantial disruption of its strong coherent structure, and it is to be noted that with punches and dies formed substantially as shown the copper is forced through a passage decreasing substantially constantly in s ze until it finally passes out the narrow annular opening at the top of the die and between the die and punch head. By handling the copper in this way and preventing expansion of the copper block laterally, or in other words, away from the axis of the tube, and by making use of a block fitting substantially snugly within the lower portion of the die and against the bottom and sides thereof, whereby its shape need not be changed before the extrusion begins to take place, and by making use of the great compressive force exerted to effect the extrusion of the copper, we avoid all sponginess or lack of strong coherent structure or opening of the grain of the metal or other incipient defects which, while they may not be capable of detection in the tube as extruded, may later develop into observable defects and weaknesses and even cause breakage in the tube when subsequently drawn and in the rings themselves.

At the limit of movement of the plunger head 13 suflicient material is preferably left between the preferably rounded end 17 of the punch head 13 and the correspondingly rounded bottom 18 of the die to form a closed end'20 for the tube 19 of a thickness sufficient to permit the use of such closed end as a means whereby the tube may be manipulated in subsequent operations.

The straight sided portion 13 of the head 13 being relatively very short, the tube 19 may be readily stripped from the head 13 when the latter is withdrawn from the die.

The tube thus formed being subjected to very great compressive force during its extrusion, and being formed from a block whose diameter is substantially the same as that of the tube formed by the extrusion process, and which fits substantially closely against the sides and bottom of the die, whereby any unrestrained lateral expansion or other change of shape prior to extrusion and consequent weakening is avoided, is of strong, solid coherent structure throughout and is adapted for subsequent treatment as by drawing operations, the character of the material of the tube so provided being such that subsequently no flaws, weakness or sponginess, such as would be inadmissible in copper rifling bands formed therefrom, are developed by the subsequent operation of drawing.

The tube shown in Figs. 2 and 3, after being stripped from the punch, can now be subjected to the required number of drawing steps, whereby it may be given correct dimensions. In the drawing we show the tube illustrated in Fig. 2 placed in the drawing die 22 (Fig. 1) and it is pushed through the die by reason of the drawing punch 23 having the end 20 of the tube 19 to bear against. The die 22 and punch 23 are properly proportioned to change the shape and thickness of .the tube, the form shown changing the tube 19 in Fig. 1- to the shape shown at 19 in Fig. 5. If required, this tube 19 is pressed through the drawing die '24: by the plunger 25 which bears on the end 20. The tubes are preferably drawn cold. They may be pickled and annealed from time to time as before and between the steps of drawing.

These operations result-in the production of a tube which may have substantially the form shown at 19" in Fig. 6. Tubes of practically any desired length may be obtained.

Having produced the tube 19" of the required diameter and thickness, the said tube can be cut 01f as at 26, such cuts resulting in the formation of bands as 27 shown in Fig. 7, the extreme end 26 of the drawn tube, which may be slightly imperfect and is generally more or less irregular in shape, being usually trimmed off and discarded. Such trimmed oif end 26 and the bottom part 20 left after the rings are cut ofi", may, of course, be remelted and used over so that no part of the expensive copper is lost. Vith our improved process a very considerable economy results from the fact that there is no need for rolling the copper as is required when bands are made from copper sheets and all scrap and trimmings, which are greatly less than in the case of cutting blanks from rolled sheets, are immediately available for reuse on being simply melted up. All of the operations of making bands according to our improved process may be very readily and inexpensively carried out,

Lemma the cost of thereby producing bands so perfect that the proportion of rejections on most rigid inspection is substantially negligible, being but a few cents per pound.

The compression, extrusion and drawing steps herein shown and described closely knit and compress all parts of the side walls of the tubes, and bands cut from such tube are of substantially uniformly good density and firmness throughout, which is the most necessary qualification of the bands. While the tubes formed by extrusion as described are preferably cylindrical they may be of any cross-sectional form.

llaving thus described our invention, we claim:

1. The process of working copper which includes introducing into a substantially cupshaped die, a heated copper block of substantially the same shape as the die and fitting closely in the lower part thereof and extruding the copper from the die in the form of a tube.

2. The method of working copper which includes introducing a heated copper block into a die in which the block fits substantial] y closely against the sides and bottom of the die and extruding the copper to form a tube by means of a punch having a lesser diameter than the diameter of the die and of the copper block fitting therein.

3. The method of working copper which includes introducing a heated copper block into a die provided with substantially cylin- (lrical sides and a rounded bottom in the lower portion of which die the block fits closely, and extruding the copper to form a firmly coherent tube with a closed end by means of a punch having a lesser diameter than the diameter of the die and block.

4. The process of working copper, which includes introducing into a die having its bottom walls merging gradually into its side walls, a heated copper block of substantially the same shape as the die and fitting substantially closely into the lower part thereof, and extruding the copper from the die to form a strong coherent tube whose outer giameter is substantially the diameter of the 5. The process of making copper rifling bands, whichincludes introducing into a substantially cup-shaped die, a heated copper block of substantially the same shape as the die and fitting in the lower part thereof, extruding the copper from the die in the form of a tube, drawing the tube thus formed, and cutting it into rings.

6. The method of making copper rifiing bands which includes introducing a heated copper block into a die into and against the sides and bottom of which the block fits substantially closely and extruding the copper to form a tube by means of a punch having a lesser diameter than the diameter of the die and of the copper block fitting therein, drawing the tube so formed and cutting it into rings.

7. The method of making copper rifiing bands which includes introducing a heated copper block into a die provided with substantially cylindrical sides and a rounded bottom in the lower portion of which die the block fits closely, and extruding the copper to form a firmly coherent tube with a closed end by means of a punch having a lesser diameter than the diameter of the die and block, drawing the tube so formed by force exerted against the closed end and cutting it into rings.

8. The process of making copper rifiing bands, which includes introducing into a die having its bottom walls merging gradually into its side walls a heated copper block of substantially the same shape as the die, and.

fitting substantially closely into the lower part thereof, extruding the copper from the die to form a strong coherent tube, whose outer diameter is the same as the diameter of the bore of the die, drawing the tube so formed, and cutting it into rings.

' In testimony that we claim the foregoing, we hereto set our hands, this 18th day of Sept, 1916.

FRED S. CARVER. W. H. HARMAN.

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