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2,46,165 C. J. BURCH PROCESS OF SPINNING HOLLOW ARTICLES Flled June 10, 1943 ‘ Auxiliary name ' iNVENTOR CHARLE J. URCH Patented Aug. 20, 1946 2,406,059 UNITED STATES PATENT OFFICE 2,406,059 PROCESS OF SPINNING HOLLOW ARTICLES Charles J. Burch, Plain?eld, N. J ., assignor to The Linde Air Products Company, a corporation of . Ohio Application June 10, 1943, Serial No. 490,295 1 2 Claims. (Cl. 29-1482) This invention relates to the art of metal work ing and more particularly to spinning end clo sures in hollow articles. In spining the open end portion of a, metal tube or cylinder, the end of the blank is closed at the center. The central portion of the closure, however, is non-homogeneous, being traversed by a hair-line pipe or valley, which is highly un desirable especially in chemical bombs and the 2 ' perature ?ame against the work so as to melt the metal in the closure immediately prior to the completion of the spinning operation, and ex truding the melted meta1 and all oxide inclusions from the resulting closure, so that the metal is homogeneous throughout. Referring to the drawing: ‘ . Fig. l is a fragmentary view partly in cross section and partly in side elevation of a rotat like. To overcome this in the past it has been 10 ing tube having its end portion heated by th proposed to drill out the defective central por ?ames of a multi?ame heating head; ‘ tion of the spun closure and ?ll the resulting Fig. 2 is a similar view of the tube at the begin hole with a plug. It has also been proposed, in ning of the spinning operation, an auxiliary the case of brass parts, to put a drop of'solder ?ame being directed against the work so as to on the formed closure as a precaution against 15 melt the metal at the zone of closure; leaks. Such proposals involve additional mate Fig. 3 is a similar view showing the auxiliary rial and added steps in making the ?nished prod ?ame directed against the work at the zone of uct and are not entirely satisfactory in avoid closure during the completion of the spinning ing leaks in the case of gas containers in which the gas is under a minimum pressure of the order 20 Fig. 4 is a similar view of the completed clo of 100 pounds per square inch, for example. sure without oxide inclusions; ‘ Therefore, themain object of this invention Fig. 5 is a fragmentary view in cross section is to provide an improved spinning process of of a cylinder having a semi-spherical end clo operation; closing the open end of a metal cylinder or tube, - , ’ sure made according to the invention; - which overcomes difficulties and disadvantages 25 Fig. 6 is a similar view with the auxiliary ?ame of the prior art and results in an end closure directed against the inside of the closure; and that is entirely free of oxide inclusions and is . Fig. 7 is a similar view of the resulting closure homogeneous throughout. Another object of the which is entirely free of oxide inclusions. invention is to provide a tube end closure spin— Referring to Figs. 1,. 2, 3 and 4 of the draw ning process which eliminates the hair-line pipe 30 ing, the end portion Ill of a tube or cylinder C from the resulting end wall. A further object is heated by the group of ?ames ll extending of the invention is to provide an improved prod longitudinally of the end portion In and directed uct. perpendicularly against the same from a multi In a hot spinning operation where the tube end is to be closed, it has been the practice to 35 ?ame heating head H which is mounted in proper lateral position with respect to the tube C‘, the heat such end prior to, or during forming, to a latter being rotated about its longitudinal axis temperature that would allow the metal to be by any suitable machine (not shown). The easily spun inwardly. The center of the end ?ames ll are preferably produced by burning closure would thus be formed shut, and a forge weld simulated. However, the formation of oxide 40 amixture of oxygen and acetylene which may be mixed either externally or internally of the on the metal surface thus forced together, led head H. Post-mixed oxy-acetylene ?ames are to oxide inclusions and a doubtful closure at preferred as the heating means, although the end the end. According to the present invention, by portion It of the tube C may be heated in a fur means of an auxiliary ?ame, directed at the center'of the end just as the edge is being forced 45 nace or by induction or in any suitableway in cluding friction. After the end portion ID of closed, a true fusion weld is made, thus assuring the tube C has been suitably heated, a tool T that the oxides will be melted and forced out, applies pressure inwardly against such heated and solid metal result. portion l? as the tube C rotates about its longi More particularly, according to the present invention, there is provided the process of form 50 tudinal axis, and the heated portion i9 is spun or turned inwardly, as shown by Fig. 2. In order ing hollow articles, which comprises closing the open end of a metal cylinder by a spinning oper to prevent hair-line cracks or oxide occlusions . ation, the ?nal closure being incidentally sub at the center of the resulting closure, according ject to a hair-line of oxide inclusions, and pre to the invention, an auxiliary ?ame l2, prefer venting such hair-line by directing a high-tem 55 ably an oxyacetylene ?ame from a blowpipe "2,406,659 .- 3 l . . nozzle N, is directed against the extreme annular end !3 of the rotating work?. _ As the spinning operationjcontinues, ‘as shown by Fig. 3, the .auxiliary?anie i2 is kept directed against the edge ['3 of the tube C, so that a 4 Fig. 6 shows a modi?cation 'wherein the ?ame [2 is directed continuously against the work E at the zone 28 of closure from the inside of the cylinder E, during the completion of the hot spinning operation to eliminate oxide inclusions entirely from the closed end 2| of the cylinder. The. resulting product is like that shown in Fig.7. A featured the invention is the actual melt closing operations is. completed, some of the ing of the ‘metal at the edge before the opening melted metal and all of the oxide inclusions are axially displaced, leaving an end wall 15 the in-J 10 .is completely closed, to form a real fusion weld, as distinguished from a simulated forge weld of terior of which is entirely free of oxide inclusions, the prior art inwhich the metal is said to “weld” the metal being solid and homogeneous through itself together at the line or point of closure. out such interior. . I The‘ latterproduces an inferior weld that in ‘ By way of example, a tube ‘(Lhaving an‘ out cludes objectionable, oxides which are eliminated side diameter of 1.35 inches, ‘and‘a wall ‘thick by the present invention. ness of 16 gauge, was heated by the multi?ame lnfthezm'odi?ca'tion of the invention shown in oxy-acetylene heating head I-Land‘ arscmarelendaL closure l5 formed by the flat faced tool TV While, - Fig. 6, it will be understood that the internally disposed auxiliary ?ame l2 may be directed the end was being closed, a single auxiliary ?ame i2, burning about 9 cubic feet per hour of 20 against the end closure in accordance with the invention whilea forming tool is being applied oxygen and a like amount of acetylene; was di to the outside of the semi-spherical end portion rected manually ‘at’ the point of the closing cone of the tube or cylinder E. just. before it was completely ‘closed. A true Practice of the present invention entirely fusionweldthusrwas produced at the center of theclbsure, which closure ‘was gas tight under 25 eliminates the hair-line crack or oxide inclusions which'was present in all closures formed by spin 100 pounds per square ‘inch of" hydrogen. ning operations known prior to- the invention. Hair-line cracks .7 or’ oxide‘ inclusions at the Thus, the invention reduces the cost and im center'and all doubts as to whether the tubes are proves the resulting product to such an extent perfectly sealed'are 'eliminatedby-the use of an auxiliary ?ame according to the present inven 301 that it has gone into commercialuse on a large ‘puddle or appreciable amount M of molten metal ‘formed atthecenter of the closure. .As the tion. . ' ' " ' In,.the' example given above, a No. 6 tip at tached to a W'—17. oxweld blowpipe was used to obtain the auxiliary ?ame l2.‘ After the main heating head H was shut o?, the forming oper ation ‘was started’. The auxiliary-flame l2rwas direotedagainst'the,edge |3*of\ the‘tube C in a substantially axial direction; As the forming progressed, this edge it moved toward-the cen ter ‘somewhat like a- shutter,» decreasing the di- . ameter of the opening at the smaller end of the conical portion. When such diameter reached % inch to 1;; inch, the edge l3 was visibly molten and ran together’ forming“ a puddle M at the center. ~ Thus‘,v while the end portion was still in the form of a» cone, the ‘end orthe tube was per fectly-'sea'ledf.-i' Further forming pushed in the cone, leavin'g4a é?at» end 15 and a substantially square annular corner 16.,’ , ReferringltoFig. 5,.the.open'end of a metal cylinder. D is shown. beingzclosed by a hot spin ningLOper-ation. Oxide inclusions in the ?nal clo sure: are :entirelyeprevented,according to the in ventionnjby directing the-‘?ame 12 against the worked as to melt the metal; at H in the closure I 8,-immediately prior-to the completion of the hot spinning ‘operation which closes'the end wall IQ of. the cylinder. D, as shown by Fig. 7. In this example, the end wall I9 of the cylinder is semi spherical, and is entirely free of oxide inclusions, the metal being solidandhomogeneous through out. scale in the manufacture of chemical I bomb burster tubes and the like. ' What is claimed is: ‘ l. A method of closing an end of a tubular metal article which comprises rotating said ar ticle about its longitudinal axis while initially applying a group of heating ?ames longitudinal ly to a portion of the article extending back from the open end to be closed; applying pressure in wardly against such heated end‘ portion while the article is rotating, to spin inwardly said heat ed portion and the periphery of its end edge and thereby progressively close said end of said ar ticle; and, beforehsaid end is completely closed and while continuing such rotation and such ap plication of inward pressure, directing an aux iliary flame, separate from said group of ?ames, against said end ecEe-and the part adjacent thereto, to provide suil’icient additional heat to melt metal along said edge at the‘ ?nal closing zone, whereby oxide inclusion is eliminated from said'clo‘sing zone as said end is completely closed during the continuance of such rotation and such application of ‘inward pressure. 2.1A method. of closing an endiof a tubular metal article as claimed in claim 1, wherein said‘ auxiliary ?ame is disposed within said tubular metal article‘ and is directed against the inte rior side of said end edge and the interior sur face. of the part adjacent tozsaid edge. CHARLES J. BURCH.