US2328742A

US2328742A - Method of making flanged tubing

Info

Publication number: US2328742A
Application number: US379180A
Authority: US
Inventors: Rupert M Rogers; Paul D Hileman
Original assignee: Thompson Products Inc
Current assignee: Northrop Grumman Space and Mission Systems Corp
Priority date: 1941-02-17
Filing date: 1941-02-17
Publication date: 1943-09-07
Anticipated expiration: 1960-09-07

Description

p 1943- R. u npsas ET m. 2,328,742

METHOD OF HIKING FLANGED TUBING 2 Sheets-Sheet 1 Filed Feb. 17, 1941 FEW :7? Ruper'f' M. Rogers Pauf D. Hileman Sept. 7, 1943;

OGERS ET AL Filed Feb. 17', 1941 2 Sheets-Sheet 2 Paul D. jleman Patented Sept. 7, 1943 Thompson al lln otl Incorporated, Cleveland, Ohio, a cor- Frodn poration of Ohio Application February 11, 1 941, sens! iv. 31am 3 Claims. era-s) Our invention covers anlmp'roved method of forming flanges at the ends of tubing, our invention being of particular advantage and importance where the tubing is comparatively thin walled and of metal as, for example, stainless steel, which makes the formation of a flange in a punch press or a heading machine exceedingly difflcult due to the rapid variation of temperature and the high expansion coeflicient of the metal itself. For efiicient formation of flanges certain temperatures must be reached before proper forging can be done, and with prior methods the tubing, after reaching the proper forging temperature, usually distorts and presents numerous difflculties. In view of these difllculties, the process heretofore resorted to for making flanged tubing has been to take a tube of outer diameter equal to the large diameter of the flange to be formed and to turn down the tube to form the flange and the tube body of the desired wall thickness. Obviously. such, prior procedure is costly both in material and labor. Furthermore, the internal structure resulting from this method of manufacture is not altogether desirable, as all the flow lines are parallel to the axis of the tube thereby providing a structural weakness at the junction between the flange and the tube proper, and flanged tubes thus manufactured have failed in service due to cracks developing at the junction of the fiance and tube body.

The important object of our invention is to provide a method for makingflanged' tubing in which the structural conditions are more ideal, in that the flow lines, instead of beingparallel to the axis of the tube, will follow the circumferential contour of the flange and the adjacent portion of the tube body, so that the finished structure will be less susceptible to the development of cracks from the fatigue stresses set up during service.

A further important object of the invention is to provide a method of making flanged tubing which will achieve the ideal conditions referred to more economically and will produce a better article at a much lower cost.

In accordance with our invention, the tubular article to be flanged is a length of, tubing stock of the wall thickness or gauge desired for the service for which the article is to be adapted, and the flange is formed thereon in a suitable electric gathering or upsetting machine under a uniform heating range which can be very carefully controlled, so that pressing or forging operations, subsequent to the gathering or upsetting operation, may readily effect the metal flow for the formation of the flanged end to produce the greatest strength where most needed.

On the accompanying drawings, we have shown various stages of formation of a flange on a tube and parts of an electric gathering machine for producing these various stage formations. 0n the drawings:

Figure 1 is an end view of a finished flanged tube;

Figure 2 is a longitudinal cross section of the finished flanged tube;

Figure 3 more or less diagrammatically illustrates the clamping jaw structure for a tube blank to be flanged and the forming elements engageable with the blank;

Figure 4 is a vertical cross section of a portion of the forming mechanism with the tube blank therein about to be electrically upset at one end for flange formation;

Figure 5 shows the apparatus in Figure 4 operating to forge the gathered metal into a flange;

Figure 6 is a longitudinal section of the tube blank:

Figure 7 is a longitudinal section of the blank with the end thereof upset after it has been formed in the machine; and

Figure 8 is a section showing the gathered material after forging thereof to form the flange.

Any suitable type of cliectrical upsetting machine may be employed, for example, a type of machine such as is disclosed in Drake Patent No. 1,870,987, dated August 9, 1932. The machine parts shown on the drawings in this application have been modified to receive a tubular blank, but electrical and hydraulic controls such as are disclosed in the Drake patent may be employed for the heating and the upsetting and forging where the article is tubular.

The finished article, shown in Figures 1 and 2, comprises the tube body B with the flange F at one end, the inner diameter along the flanged portion being the same as the inner diameter of the tube body. For forming the flange, the electrical gathering or upsetting apparatus such as shown on Figures 3, 4, and 5 may be used. The blank A, Figure 6, is inserted between the bushing halves Ii and H in the laws if and II supported from the carriage It, the jaws being operated to clamp the blank with its lower end projecting below the bushings a distance necessary for the desired amount of metal for the flange to be formed. The

law structure is connected with a suitable electrio circuit by a conductor ii.

Below the carriage is the stationary electrode IS in whichis a die block IT, a conductor l8 connecting this electrode with the current supply circuit.

Above the carriage H is the ram structure R whose lower end is surrounded by an annular die member [9 whose outer diameter is the same as the inner diameter of the tube blank A to be flanged. An abutment ring 20 of angular cross section engages the upper outer corner of the die member IS, the radial leg of this abutment ring being engaged by a spring 21 within the pocket 22 in the body of the ram R. Upon downward movement of the ram, the axial leg of the abutment ring will engage the upper end of the blank for engagement of its lower end with the electrode 16 for completion of the electrical circuit and heating of the blank end for upsetting thereof.

The bushing halves l and II are axially shiftable in the jaws l2 and I3, this shift being limited by the engagement of pins 23 extending from the bushings into slots 24 in the jaws. The bushings are normally held in their upper position with the pins at the upper ends of the slots 24 by springs 25. An abutment ring -26 surrounds the abutment ring and is movable in a pocket 21 against a spring 21', this movement being limited by pins 28 extending from the ring and engaging in slots 29 in the ram, the spring normally holding the abutment ring 26 in its outer position shown on Figure 4. When the ram is shifted downwardly, the blank A engaged by the spring pressed ring 20 moves downwardly against the die block I! in the stationary electrode I6, and the projecting lower end of the blank is heated and upset to gather the metal 1 for the flange, as shown in dotted lines in Figure 4. While the blank is held pressed against the electrode by the spring pressed abutment ring 20 for the upsetting of the flange end, the ram body with the die ring l9 continues, and when the lower end of the die ring reaches the gathered metal f, the abutment ring will engage with the bushings i0 and l l and these bushings will be shifted down until stopped by the pins 23. The inner lower corners of the bushings are bevelled, as indicated at 30, for the desired shape of the outside of the flange. Before this bevelled end engages with the gathered metal 1, the ram will have moved downwardly for movement of the die ring l9 past the gathered metal and into the recess 3| in the die block I! of the lower electrode, movement of the die ring past the gathered metal forcing this-metal outwardly into position below the bushings I0 and H, so that during final downward movement of the ram structure these bushings will be carried therewith to forge the gathered metal 1 to form the flange as shown on Figure 5. Thus, the blank A is first electrically heated and gathered or upset at its end to the embryo stage shown in Figure 7, and then while the gathered metal is st ll hot it is forged to form the flange, the structure being then as shown on Figure 8.

Suflicient metal is gathered or upset so that a perfect solid flange is formed. Any excess metal 32 will be forced out between the bushings and the electrode l6 as shown on Figure 5, and this excess metal may be readily removed in a lathe sulting flanged tube is preferably sand blasted to remove dirt, scale, or other foreign matter, and it is then treated between inner and outer die members to take out any distortions and to bring it to finished shape and size. After his cold finish treatment, the excess metal 32 is turned off, and we then have the finished product shown on Figures 1 and 2.

It is evident that, instead of performing the upsetting step and the forging step by the same apparatus, the hot forging could be accomplished by separate apparatus.

We have thus produced an improved method by which tubing can be economically and efficiently flanged by upsetting under proper and uniform heat conditions, and forging for the desired flange form with the flow lines directioned to give maximum strength to the flanged end of the tubing, our method producing much better articles than the type referred to and at a much lower cost.

We claim as our invention:

1. The method of flanging metal tubing during a single pressure stroke which comprises slidably supporting a metal tube while holding the tube against inward collapse and outward bulging except at the portion thereof to be flanged, resiliently urging the tube in an axial direction against an abutment, passing electrical current through the portion of the tube to be flanged for heating the same to forging temperatures, continuing the urging and heating steps until a thickened inwardly and outwardly extending bead portion is formed on the tube portion to be flanged, positively expanding by a force applied axially of the tube, the inner portion of the bead to move the same in an outward direction for increasing the outwardly extending bead portion, and pressing in a direction axially of the tube the thus increased outwardly extending bead portion into a flange of desired shape while holding the bead portion against inward collapse.

2. The method of flanging metal tubing during a single pressure strok which comprises slidably clamping inner and outer portions of a tube, urging the tube in an axial direction to thrust a free end portion thereof against an abutment, passing electrical current from the abutment through the free end portion of the tube to heat the end portion to forging temperatures, continuing the urging step'until a thickened bead portion is formed on the free end portion of the tube, moving an expanding member axially in the tube to force the bead portion outwardly, and moving a pressing member axially on the tube to shape the bead into a flange.

3. The method of flanging tubing during a single pressure stroke which comprises slidably clamping inner and outer portions of a tube, urging the tube in an axial direction to thrust a free end portion thereof against an abutment, heating said free end portion of the tube to temperatures at which the same may be worked, continuing the urging step until a thickened bead portion is formed on the free end portion of the tube, moving an expanding member axially in the tube to force the head portion outwardly, and moving a pressing member axially on the tube to shap the bead into a flange of desired configuration.

RUPERT M. ROGERS. PAUL D. HILEMAN.