US2452974A

US2452974A - Electric upsetting and forming

Info

Publication number: US2452974A
Application number: US543230A
Authority: US
Inventors: Westin Sven; Westin Axel
Original assignee: Fed Machine & Welder Co
Current assignee: Fed Machine & Welder Co; Federal Machine & Welder Co
Priority date: 1944-07-03
Filing date: 1944-07-03
Publication date: 1948-11-02
Anticipated expiration: 1965-11-02

Description

, N 1943- s.-wEs'r 1N ETAL ELECTRIC UPSETTING AND FORMING 3 Sheets-Sheet 1 Filed July 3, 1944 S a llkiil .H

V Em

Sven Westz'n Axel Weszz'n INVENTORj 1 AT TORNEX 7 BY W [5% S. WESTIN ET AL ELECTRIC UPSETTING AND FORMING Nov. 2, 1948.

3 Sheets-Sheet 2 Filed July 3, 1944 fiven Wesfzn Axel Wesfin INVENTORJ'.

, ATTORNEY.

1948- s. WESTIN ETA]. 2,452,974

ELECTRIC UPSETTING AND FORMING ,Filed July 3,1944 s Sheets-Sheet a Sven Westm I Axel Wesfzn INVENTOR5 543M ATTORNEY Patented Nov. 2, 1948 2,452,974 ELECTRIC UPSETTING AND FORMING Sven Westin.

West Allis, and Axel Westin, Milwaukee, Wis.. assignors, by mesne assignments,

to Federal Machine & Welder 00., Warren,

Ohio, a corporation of Ohio Application July 3, 1944, Serial No. 543,230

16 Claims.

lhis invention relates to electric upsetting and forming, as in upsetting the ends of tubes, pipe and the like. In general it relates to a method and apparatus similar to that described in United States Letters Patent No. 2,340,784 granted to the present inventors on February 1, 1944.

In apparatus of this type the end of the pipe is forced into an upsetting die cavity in a pair of electrodes which supply heating current to the pipe during relative rotation between the pipe and die, and the pipe is first formed along an inclined surface of the die during heating of the metal and then upset in thickness as the pipe is pressed against the closed end of the die cavity. An entrance die is provided for straightening the heated end of the pipe as it is withdrawn from the forming die.

One of the principal objects of the present invention is to provide a more accurate straighten ing of the heated end of the blank as it is withdrawn from the forming die.

Another object of the invention is to prevent scoring of the blank during forming.

Another object is to more readily initiate the upsetting of the metal at the end of the blank and to eliminate the tendency for the blank to buckle when the end reaches the closed end of the die cavity.

Another object is to provide for the accurate offsetting of the thickened portion either toward the inside or toward the outside of the blank with the metal concentric with the blank.

Another object is to provide a slight thickening of the blank opposite the major offset thickened portion to furnish metal for subsequent machining operations.

According to the invention the entrance die which effects the straightening operation upon withdrawal of the blank is constructed with one of its members fitting closely to the cold blank as the latter moves therethrough and adapted to rotate with the blank to prevent scoring of the blank. Upon withdrawal of the blank after upsetting of its end in the forming die the upset thicker portion is offset opposite to the tight fitting portion of the entrance die. 7

According to another feature of the invention the portion of the entrance die fitting close to the blank is made of a length sufficient to insure that a portion of the cold blank will engage the same at all times during the straightening of the upset end of the blan This means that the straightening portion of the entrance die should be longer than the heated upset portion of the blank in order to obtain the desired concentricity of the heated end and the body of the blank.

Where it is desired to provide excess metal for machining on the side of the tightly fitting entrance die a cooperating die is provided to throw a certain amount of the upset metal back to the opposite side of the upset.

For the purpose of facilitating upsetting of the blank end and eliminating buckling of the blank, the closed end of the forming cavity has a plurality of risers in its surface which serve to spread the end edge of the rotating blank as it engages the bottom of the die and to initiate upsetting of the blank at the end edge.

The accompanying drawings illustrate the invention and the views Figure 1 is a longitudinal central section through the apparatus and showing a pipe blank ready for the upsetting operation;

Fig. 2 is a transverse section taken on line 22 of Fig. 1 showing the front of the entrance dies; Fig. 3 is a similar transverse section taken on line 3-3 of Fig. 1 showing the front of the forming dies; 7

Fig. 4 is a similar transverse section taken on line 4-4 of Fig. 1 cutting through the forming dies and showing in plan view the bottom of the closed end of the die cavity; v

Fig. 5 is a detail perspective view of the forming die plug showing the risers at the closed end of the forming die cavity; I

Fig. 6 is an enlarged longitudinal central section showing the forming dies and a portion of the entrance dies with the end of the blank about halfway in the forming dies during an upsetting operation;

Fig. 7 is similar to Fig. 6 showing the end of the blank engaging the risers in the closed end of the forming die and spreading for the initial upset;

Fig. 8 is similar to Fig. 6 showing the blank with its end. completely upset in the forming die;

Fig 9 is an enlarged longitudinal central section showing the entrance dies and a portion of the forming dies with the formed blank partially drawn over the entrance die plug;

Fig. 10 is similar to Fig. 9 showing the final straightening of the blank with the inside sur' faces in alignment and the upset ofiset radially outward of the blank; y

Fig. 11 is similar to Fig. 9 showing the inward coining of the upset portion in the outer entrance die which serves to slightly reduce .the inside therein are as follows:

diameter to provide metal for machining on the inside of the blank; and

Fig. 12 is a View similar to Fig. 11 showing a modification. of the apparatus for throwing the upset portion to the inside of the blank after it is straightened.

The tubular blank i being formed is supported. for rotation and longitudinal movement by a rotary chuck gripping the blank at one end. The chuck 2 is driven by an electric motor and is reciprocated axially by a. hydraulic cylinder and piston arrangement, not shown.

The forming apparatus of the present invention is mounted on a base 3 and comprises in general an entrance die t for a forming die The entrance die comprises a central plug 6 which may be mounted for free rotation on a spindle l secured axially in the forming die 5. An outer die member a; which may be stationary and mounted on the base 3 has a central open ing for cooperating with the plug :2 in the final shaping of the end of the blank during withdrawal of the same.

In the mounting of the central plug 5 a substantial clearance is provided between it and spindle 1 to allow for centering of the same in the blank and for tolerances in blank shape. Likewise the outer die member 3 is mounted in a rubber cushion ring 9 secured in a fixed ring l supported on the base a. his provides ,fcr lateral adjustment of member 3 required. It can be said that both the plug and member are mounted for limited floating movement to compensate for tolerances in the blank and the like.

The forming die 5 is stationary and comprises an inner plug H and an outer die member l2 fitted thereon and having cooperating circumferential die faces shaped to form a circular cavity l3 of the thickness of the final upset end of the blank and of gradually reduced diameter so that as the end of the blank 4 moves into the cavity it first engages the outer wall thereof, i. e.. the face of the outer die member l2, inwardly along the inclined die gages the bottom or closed end illustrated in Figs. 6 and 7.

The inner plug it is held in an outer die body M by means of a shoulder l5 on spin. l and which presses against the outer end of plug. The spindle passes axially through the plug and body l4 and is secured therein by the real nut IS on the end of the spindle. The spindle is removable from the front of the die 5 upon removal .of nut l6 at the rear.

The plug Ii, outer die member l2 and die body 14 are made in two halves separated on a vertical plane passing longitudinally through the axis of the die and a plate of electrical insulation ll is disposed between the two halves of the structure.

A power transformer iii disposed behind [1e die 5 has its pimar leads is connected to source 26 of electric energy, and its secondary leads 2| connected respectively the opposite halves of the die body !4. In this manner heating current is supplied to the end of blank 5 as it engages the two halves of the outer die member IZ, the current passing circumferentiaily through the blank between the two halves which constl tute electrodes. As the blank l is rotated in contact with the electrodes the heating current is passed through successive adjacent regions of the blank progressively around its circumference thereby softening a circumferential portion of face until it of the cavity as and then moves 4 the blank at the end." This allows forming of the softened portion as the blank moves into the die cavity, and colder metal of the blank en gages the electrodes to be similarly softened thereby and formed.

In order to prevent shorting of the electrodes by spindle l, insulation 22 is secured around the spindle and between it and the two electrodes.

When the end of the blank reaches the end of the die cavity as illustrated in Fig. 7 it engages risers 23 in the end wall of the die cavity. The risers E3 constitute merely raised portions in the end of the cavity as illustrated in perspective in Fig. 5, and they serve to facilitate initial spreading of the metal at the end of the blank to start the thickening action which then progresses from the end of the blank outwardly toward the mouth of the die cavity.

If no risers 23 were provided the ent're end of the blank would abut the end wall of the die cavity and tend to resist lateral spreading so that there would be danger of buckling or wrinkling of the blank as it continues to move into the die.

The number of risers 23 will vary with the diameter of the blank, it bein preferable that a sufiicient number be employed to prevent the blank from engaging the bottommost portion of the end of the die. By providing the risers 23 the metal at the end of the blank which rotates relative to the die would be initially spread, thereby absorbing the inward movement of the blank, and after starting of the thickening action at the end this action continues uniformly and progressively back along the blank toward the mouth of the die cavity, until the blank is upset as shown in Fig. 8.

After upsetting of the blank in the forming die 5 the heating current is discontinued and the blank is withdrawn through the entrance die 4.

In this operation the end of the blank which is initially of somewhat smaller diameter is ex panded as it comes out of the die cavity. It is further eXpanded as it passes over the plug ii.

For this purpose the plug 5 is constructed with a central cylindrical body section 26 of a diam eter approximating that of the inside of the cold blank 1. The length of section should be greater than the length of the heated portion of the formed blank, so that as the blank is with drawn over the plug there will always be cold metal engaging the section 24 as the heated metal is straightened out, and the inside diameter of the straightened heated portion will be in alignment with that of the cold portion of the blank.

This insures that the formed end of the pipe is aligned with and concentric of the remainder of the pipe blank with the added thickness offset outwardly.

Should it be desired to have some thickening toward the inside for later machining operations, the outer die member 8 constitutes a threat or bell with an internal diameter slightly less than the outside diameter of the thickened end of the blank so that as the upset blank leaves the section 26 of plug a it passes through the throat of member 3 and is reduced slightly in diameter. This reduction of the heated pipe end throws a slight amount of metal inwardly of the blank as illustrated in Fig. 11.

If it is desired to have the upset offset radially inward of the blank, instead of outwardly, the apparatus is modified as indicated in Fig. 12. The plug 6' is made smaller so that it does not enlarge the upset portion of the blank but merely straightens it internally. The throat of the outer die member 8 is cylindrical and has a diameter approximating the outside diameter of the cold portion of the blank I and a length in excess of the length of the heated portion of the blank. In passing through the throat the upset portion of the blank is straightened and made concentric with the outside surface of the blank, the outside surfaces being in alignment.

If, after straightening the upset as described above and illustrated in Fig. 12, it is desired to have a slight amount of metal on the outside for machining, the plug 6 is provided with a second raised cylindrical section 25 of slightly greater diameter than that of the inside of the upset portion so that it enlarges the latter portion and draws the metal thereof between it and a relieved portion 26 of the outer die member 8'.

In the apparatus shown in Fig. 12 the outer die member 8' is mounted for free rotation in a fixed bearing member 21. In this way the member 8 can rotate with blank I as the latter is fed theret-hrough during upsetting of the blank end, the throat of the member 8 closely gripping the cold blank in this operation. It is not necessary to mount the plug 6' for rotation although it is so shown in Fig. 12.

The invention provides a straightening die construction that does not score the workpiece and that may be utilized first to straighten the upset portion of the blank while offsetting it either radially inward or outward, and then to re-offset the portion to any desired radial location relative to the blank. In doing this the invention provides a straightening die member that closely engages the surface of the cold blank and rotates therewith, and that supports the blank centered by continual engagement with a cold portion of it While straightening the hot and upset portion of the blank.

Various embodiments of the invention may be employed within the scope of the accompanying claims.

We claim:

1. In a device of the class described for upsetting and forming the hot end of an otherwise cold tubular blank, an upsettin die adapted to receive and upset the end of the blank, means to effect relative rotation between the blank and die during the upsetting operation, and a straightening die mounted at the mouth of the upsetting die and free to rotate with the blank relative to the upsetting die during upsetting of the blank, said straightening die being adapted to engage the upset end of the blank as the latter is withdrawn from the die and to straighten the same.

2. In a device of the class described for upsetting and forming the hot end of an otherwise cold tubular blank, an upsetting die adapted to receive and upset the end of the blank, means to effect relative rotation between the blank and die during the upsetting operation, and a straightening die mounted at the mouth of the upsetting die and free to rotate with the blank relative to the upsetting die during upsetting of the blank, said straightening die having a die face for tightly engaging a cold surface of the blank as the heated end is withdrawn from the die and shaping the corresponding surface of the heated portion of the blank in alignment with said cold surface.

3. In a device of the class described having an upsetting die for forming the hot end of an otherwise cold tubular blank, a straightening die disposed at the mouth of the upsetting die and tree to rotate with the blank relative to the upiii setting die, said straightening die having a die face for tightly engaging a surface of the cold blank and shaping the corresponding surface of the heated portion of the blank in alignment with said cold surface as the blank is withdrawn from the upsettin die, and a cooperating die member for altering the offset of the upset portion of the blank after straightening of the same.

4. In a device of the class described for upsetting the heated end of a tubular blank by forcing the end of the blank into a die cavity while relatively rotating the blank and die and.- the-re after withdrawing the end of the blank from the die, an apparatus for straightening the upset portion of the blank as the same is withdrawn from the upsetting die, comprising a straightening die at the mouth of the upsettin die and supported for free rotation with the blank relative to said upsetting die as the blank moves forwardly into the die cavity and disposed to engage the upset portion of the blank and to straighten the same as the end of the blank is withdrawn from the die.

5. In a device of the class described for upsetting the ends of tubular blanks, an apparatus for straightening the heated upset portion of the otherwise cold blank as the same is withdrawn from the upsetting die, comprising a straightening die at the mouth of the upsetting die and supported for free rotation with the blank relative to said upsetting die as the blank is moved forwardly into the upsetting die, said straightening die having a cylindrical surface of a diameter to engage a surface of the cold blank and shape the corresponding surface of the heated upset portion of the blank in alignment with said cold surface and of a length substantially greater than the length of the heated portion of the blank.

6. In a device of the class described for upsetting the ends of tubular blanks, an apparatus for straightening the heated upset portion of the otherwise cold blank as the same is withdrawn from the upsetting die, comprising a straightening die at the mouth of the upsetting die and sup ported for free rotation with the blank relative to said upsetting die as the blank is moved forwardly into the upsetting die, said straightening die having a cylindrical surface of a diameter to engage a surface of the cold blank and shape the corresponding surface of the heated upset portion of the blank in alignment with said cold surface and of a length substantially greater than the length of the heated portion of the blank, and a cooperating die member for reforming the radial offset of the upset portion of the blank after straightening of the same.

7. In a device of the class described for up setting an end of a cylndrical tubular blank, an apparatus for straightening the heated upset portion of the otherwise cold blank as the same is withdrawn from the upsetting die, comprising an inner plug mounted for free rotation with the blank as the latter enters the upsetting die and having a cylindrical body portion of a diameter closely approximating the inside diameter of the blank and a length substantially greater than the length of the heated portion of the blank providing for engagement with the cold blank surface to guide the blank during straig tening of the heated upset end of the blank as the latter is withdrawn from the upsetting die and passes over the plug.

8. In a device of the class described for upsetting an end of a cylindrical tubular blank, an apparatus for straightening the heated upset 7 portion of the otherwise cold blank as the same is Withdrawn from the upsetting die, comprising an inner plug mounted for free rotation with the blank as the latter enters the upsetting die and having a cylindrical body portion of a diameter closely approximating the inside diameter of the blank and a length substantially greater than the length of the heated portion of the blank providing for engagement with the cold blank surface to guide the blank during straightening of the heated upset end of the blank as the latter is withdrawn from the upsetting die and passes over the plug, and a cooperating outer die member having a throat of a diameter tending to draw the upset portion of the blank to a smaller outer diameter.

9. In a device of the class described for upsetting an end of a cylindrical tubular blank, an apparatus for straightening the heated upset portion of the otherwise cold blank as the same is withdrawn from the upsetting die, comprising an outer die member mounted for free rotation With the blank as the latter enters the upsetting die and having a cylindrical throat portion of a diameter closely approximating the outside diameter of the blank and a length substantially greater than the length of the heated portion of the blank providing engagement with the cold blank surface to guide the blank during straightening of the heated upset end of the blank as the latter is withdrawn therethrough from the upsetting die.

10. In a device of the class described for upsetting an end of a cylindrical tubular blank, an apparatus for straightening the heated upset portion of the otherwise cold blank as the same is withdrawn from the upsetting die, comprising an outer die member mounted for free rotation with the blank as the latter enters the upsetting die and having a cylindrical throat portion of a diameter closely approximating the outside diameter of the blank and a length substantially greater than the length of the heated portion of the blank providing engagement with the cold lank surface to guide the blank during straightening of the heated upset end of the blank as the latter is withdrawn therethrough from the upsetting die, and a cooperating inner plug having a raised section of a diameter tending to expand the upset portion of the blank to control the oifsetting of the upset on the blank.

11. In the upsetting of the heated end of an otherwise cold tubular blank, the straightening of the blank after upsetting by first drawing the heated upset portion of the blank against a die maintained in alignment with a cold surface of the blank and thereby offsetting the upset wholly to one side of the thickness of the blank, and thereafter drawing the upset portion against an opposing die to effect a radial relocation of the upset.

12. In the upsetting of the end of a cylindrical tubular blank wherein the heated upset portion of the blank is formed inwardly during the upsetting operation, the straightening of the blank by drawing the same over a plug in contact with the cold inside surface of the blank to thereby align the inside surface of the heated upset portion with the cold inside surface of the remainder of the blank and expand the upset radially outward from the blank, and thereafter readjusting the offsetting of the upset by drawing the same through a die throat of smaller diameter than the outside diameter of the upset.

13. In the upsetting of the end of a cylindrical tubular blank wherein the heated upset portion of the blank is formed with a radial offset during the upsetting operation, the straightening of the blank by drawing the same through a long die throat in contact with the cold outer surface of the blank to thereby align the outside surface of the heated upset-portion with the cold outside surface of the remainder of the blank and contract the upset radially inward frorn the blank.

14. In the upsetting of the end of a cylindrical tubular blank wherein the heated upset portion of the blank is formed with a radial offset during the upsetting operation, the straighteningof the blank by drawing the same through a long die throat in contact with the cold outer surface of the blank to thereby align the outside surface of the heated upset portion with the cold outside surface of the remainder of the blank and contract the upset radially inward from the blank, and thereafter readjusting the offsetting of the upset by drawing the same over a plug which expands the same to a predetermined inside dimension.

15. In the upsetting of the end of a tubular blank in electrode forming dies of the class described, the initial spreading of the heated metal at the end of the blank as the same rotates relative to the upsetting die by reducing the frictional engagement of the end edge of the blank with the bottom end of the die cavity and engaging said end edge with die faces of limited circumferential extent to effect a progressive forming of the metal in spaced areas traveling circumferentially of the blank.

16. In apparatus for upsetting the end of a tubular blank wherein electrode forming dies provide a circular die cavity with a closed bottom end into which the blank is fed during relative rotation between the blank and dies, a plurality of risers spaced circumferentially in the bottom end of the die cavity to engage successive limited circumferentially spaced portions of the end of the blank and thereby effect an initial spreading of the end of the blank as it engages the same.

SVEN WESTIN, AXEL WESTIN.

EEEFERENCES CITED The following references are of record in the Westin et a1. Feb. 1, 1944