US3740993A

US3740993A - Process for producing hollow forging with frusto conical exterior andinterior surfaces

Info

Publication number: US3740993A
Application number: US00198239A
Authority: US
Inventors: C Moore
Original assignee: Individual
Current assignee: MOORE CHARLES H JR
Priority date: 1971-11-12
Filing date: 1971-11-12
Publication date: 1973-06-26
Anticipated expiration: 1990-06-26

Abstract

A hollow open-ended frusto-conical forging having substantially uniform wall-thickness from end-to-end, for use as a reducer in pipe lines and the like, is made by first obtaining a hollow work-piece having a frusto-conical exterior surface and substantially cylindrical interior surface. This work-piece is heated to forging temperature and placed around a horizontally disposed cylindrical mandrel which is supported on the bed of a power press and the platen of the power press is pressed against the major portion of the work-piece which is internally supported by the mandrel to obtain a tapering reduction in the major portion of the work-piece thereat. The platen is then raised and the work-piece is partially rotated to position an immediately adjacent segment of the work-piece between the platen and mandrel. These steps are continued, with the intermediate raising of the platen and partial rotation of the work-piece until the inside and outside diameters of the work-piece are of acceptable dimensions throughout a 360* arc. The power press is then adjusted to increase the lowermost position of the platen with respect to the mandrel, and the steps described are repeated throughout a 360* arc as before. This is continued until the final hollow product with frusto-conical exterior and interior surfaces of the desired dimensions has been obtained.

Description

iluited States Patent 1191 Moore, Sr.

[ June 26, 1973 22] Filed: Nov. 12, 1 971 [21] Appl. No.: 198,239

[52] US. Cl 72/370, 72/375, 72/377 [51] Int. Cl B21k 21/10 [58] Field of Search 72/375, 376, 377,

' [56] References Cited UNITED STATES PATENTS I 6/1972 Muller et al. 72/421 7/1926 Larkin 72/340 Primary Examiner-Lowell A. Larson Attorney-Robert U. Geib, Jr.

[5 7] ABSTRACT A hollow open-ended frusto-conical forging having substantially uniform wall-thickness from end-to-end,

for use as a reducer in pipe lines and the like, is made by first obtaining a hollow work-piece having a frustoconical exterior surface and substantially cylindrical interior surface. This work-piece is heated to forging temperature and placed around a horizontally disposed cylindrical mandrel which is supported on the bed of a power press and the platen of the power press is pressed against the major portion of the work-piece which is internally supported by the mandrel to obtain a tapering reduction in the major portion of the workpiece thereat. The platen is then raised and the workpiece is partially rotated to position an immediately adjacent segment of the work-piece between the platen and mandrel. These steps are continued, with the intermediate raising of the platen and partial rotation of the work-piece until the inside and outside diameters of the work-piece are of acceptable dimensions throughout a 360 arc. The power press is then adjusted to increase the lowermost position of the platen with respect to the mandrel, and the steps described are repeated throughout a 360 are as before. This is continued until the final hollow product with frusto-conical exterior and interior surfaces of the desired dimensions has been obtained.

3 Claims, 4 DrawingFigures PATENIEB M26 I975 Char/e3 H. Moore IN VENTOR ATTORNEY PROCESS FOR PRODUCING HOLLOW FORGING WITH FRUSTO-CONICAL EXTERIOR AND INTERIOR SURFACES There is considerable demand, for many industrial applications for frusto-conical reducers for pipe lines, such, for example, as reducing a 24 inch pipe to a inch pipe, or even 18 inches, a 20 inch pipe to an 18 inch pipe or even 16 inch pipe to a 14 inch, etc.

As pipe wall thicknesses vary from low schedules to high schedules from 108 to Schedule 160 (the wallthickness of 24 inch pipe in Schedule 108 is .258 inch and in Schedule 160 the wall thickness of 24 inch pipe is 2.343 inches) it will be observed that in the larger schedules these reducers become massive forgings, and heretofore have been very expensive to produce.

Prior to the present invention such frusto-conical articles (reducers and the like) were mostly produced either by l. pressing a round bar into a conical die so as to upset the metal downwardly into the die, then center punching a cylindrical bore to the small end of the work-piece, and finally machining the interior of thework-piece to produce the desired frustoconical shape and size 2. machining a cylindrical work-piece on both the interior and exterior to produce frusto-conical surfaces thereon which is prohibitively expensive 3. pressing a tapered plug into a necessarily heavy (due to the wall-thinning on the big end) cylindri cal work-piece which is disposed in a special and expensive frusto-conical die which is very limited as to the shape and size of the product it will produce, i.e., only feasible in the event of a sizeable run" of the desired product. Even so, there remains considerable metal to be machined from the outside.

The difficulty with respect to this third prior art method is quite apparent, while the problem with respect to the first two is, of course, the very high cost of machining to remove or hog large areas of metal as distinguished from the displacement thereof by forging.

It is among the objects of the present invention to provide a highly efficient and relatively simple and inexpensive process for producing frusto-conical forgings of the type referred to. v

Another object is the provision of a process of the type described which may be effectively and inexpensively utilized for a single product as well as for a large run.

Still another object is the attainment of the foregoing advantages with the use of equipment of existing design.

The foregoing and other objects and advantages will become more readily understood from the following description and annexed drawings, wherein like reference characters designate like parts, and wherein:

FIG. 1 is a perspective of an example of a cylindrical work-piece which is obtained as a preliminary to prac ticing the process of the invention, and showing its dimensions for comparative purposes.

FIG. 2 is a schematic view illustrating a conventional heavy duty press, with stationary horizontal bed and vertically movable platen shown in the raised position, together with a pair of mandrel supportswhich rest on the bed and between them support a round elongate mandrel, and the work-piece as mounted on the mandrel prior to the commencement of the forging operation.

FIG. 3 is another schematic view, but illustrating the work-piece both prior to the forging operation (in dotted lines) and as completely forged (solid lines and cross-hatched).

FIG. 4 is a sectional elevation of the work-piece after it has been subjected to the process of the invention, and illustrating the respective dimensions.

Referring more particularly to the drawings, the numeral 2 designates the bed or bottom of a heavy duty press, while the platen thereof is shown at 3, being in the raised position.

Disposed upon the bed or bottom 2 of the press is a pair of spaced parallel mandrel supports 4, which between them support a round mandrel 5 of substantially uniform diameter, and which, for purposes of enhanced strength, is shown as having a solid interior.

In the manner well-known in the art the distance the platen 3 may be moved downwardly toward the bed or bottom of the press is determined by a plurality of superposed blocks which act as shims, the same being schematically illustrated in FIG. 2, it being understood, however, that they may be disposed anywhere between the platen and the bed which will achieve the desired result.

As indicated earlier herein, there is first obtained, as by pipe-punching, a cylindrical work-piece A of roughly predetermined height and inside and outside diameter, which is machined on the outside so as to provide a frusto-conical exterior, and which is heated to forging temperature; or is forged to this exterior contour in a die and is then center-hole punched. In either event the inner wall of the work-piece A is cylindrical.

In FIG. 1 an example of the immediate foregoing is given as:

Height 26" Inside Diameter 15.5" Outside Diameter Large End 25.75" Outside Diameter Small End 22.625" (machined) Weight 3417.00 lbs.

Referring to FIG. 2, the cylindrical work-pieceA machined or forged to an outside taper in diameter, as described hereinbefore, and as heated to forging temperature, is moved into position between the spaced parallel mandrel supports 4 with the round mandrel 5 inserted through it, whereby it is supported by the mandrel above the bed or bottom 2 of the press.

As will be observed, the diameter of the round mandrel 5 is slightly less than the inside diameter of the cylindrical work-piece A, and for the example given herein was 15 inches.

With the work-piece A supported in the position described, tlne platen 3 of the heavy duty press is lowered to a suitable extent by utilizing the controls for such positioning which are conventional equipment on apparatus of this type. As an alternative, spacer blocks or large shims (not shown) may be disposed on the upper extremities of the U-shaped vertically extending mandrel supports 4 operating against the internal support of the round mandrel 5, to make an appreciable reduction in the wall thickness of the work-piece at that point.

The platen 3 is then raised, and the work-piece A is partially rotated, either by hand (as with pikes which are standard foundry equipment) or by one of several types of machines which are adapted to such purposes.

After the partial rotation of the work-piece A, the platen 3 is again lowered into contact therewith, making an adjoining reduction in the wall-thickness which is similar to the one previously made.

This forging operation with the raising of the platen and intermittent partial rotation of the work-piece is repeated until the work-piece has been rotated throughout a 360 arc.

After a complete series of reductions or bites have been taken in the wall of the work-piece throughout a 360 arc, the power press is so adjusted as to increase the lower limit to which the platen will be moved. Such power press controls are entirely conventional, but power presses without the same may be utilized by simply adopting the expedient of providing spacer blocks for disposition atop the upper extremities of the U- shaped upper ends of the mandrel supports 4.

According to the foregoing, the wall-thickness of the small end of the work-piece need undergo no change, and the entire operation concluded when the wallthickness at both the small end and the big end are the same.

As an example, each individual reduction in the thickness of the wall of the work-piece A may be approximately l inch and extend over an area in width of approximately 6 inches until all 26 inches have been covered throughout a 360 arc.

It has been found practical to effect the desired total reduction in the wall-thickness of the work-piece A without resort to the expense and delay of re-heating.

The work-piece A, after being completely forged in accordance with the teachings of the present invention, is represented at B in FIG. 4. As will be observed in this Figure, the dimensions of the frusto-conical forging B, for the example given, are as follows:

Prior to Finish Machining Height 26" Inside Diameter Large End 31.5

Inside Diameter Small End 19.5" Outside Diameter Large End 375" Outside Diameter Small End 25.5" Weight 3417 pounds To Finish 32" ID. X 20" LD. X

2.5" Wall as a cone.

As will be observed from the foregoing, a single setup of mandrel supports 4 and round mandrel 5 may be effectively utilized to obtain frusto-conical forgings or varying sizes and tapers.

It is interesting to note that the weight loss due to the initial machining was only 456 pounds (the difference between 3,873 pounds and 3,417 pounds) to get workbetween 5,796 pounds and 3,417 pounds).

In producing the completed frusto-conical forging of the example given herein, the following calculations are taken into consideration in order to develop the dimension of work-piece A, as shown in FIG. 1.

CD. at Big End 1.0. at Big End CD. at Small End ID. at Small End Pipe Punching 15.5" X

Plus 1" at Big End (see 7 V V ,7.

above) 94.42 1b plus 60.07 1h (1 at Big End) 147.88 I 25.75" diameter (FIG.

113.58 lb 22.675 diameter (small end of work-piece A in FIG. 1)

Having thus described the invention what I claim as new and desire to secure by letters patent is:

I claim:

1. The process for making an open-ended; frustoconical hollow-forging having substantially uniform wall-thickness from end-to-end for use as reducers in pipe lines and the like; which consists essentially of obtaining a work-piece of frusto-conical exterior and substantially uniform inside diameter from end-toend heating the said work-piece to forging temperature placing the work-piece while heated to forging temperature on a horizontally extending cylindrical mandrel which is of smaller outside diameter than the inside diameter of the work-piece and while the mandrel is supported on the bed of a press pressing the platen of the press against the exterior of that portion of the work-piece which is internally supported by the mandrel raising the platen partially rotating the work-piece repeating the application of pressure and the raising of the platen while intermittently partially rotating the work-piece through 360 until the inside and outside diameters are of acceptable dimensions extending the adjustment of the platen toward the mandrel;

and

continuing the foregoing operational steps until the desired internal and external dimensions have been obtained.

2. The process of claim 1 wherein the exterior surface of the starting work-piece is machined on the outside to provide a frusto-c'onical surface prior to heating to forging temperature.

would have required a starting weight of 5,796 pounds, 6

and a resultant weight loss of 1,379 pounds (difference 3. The process of claim 1 wherein the initial workpiece is forrned in a die.

II I. I l t

Claims

1. The process for making an open-ended; frusto-conical hollowforging having substantially uniform wall-thickness from end-toend for use as reducers in pipe lines and the like; which consists essentially of obtaining a work-piece of frusto-conical exterior and substantially uniform inside diameter from end-to-end heating the said work-piece to forging temperature placing the work-piece while heated to forging temperature on a horizontally extending cylindrical mandrel which is of smaller outside diameter than the inside diameter of the work-piece and while the mandrel is supported on the bed of a press pressing the platen of the press against the exterior of that portion of the work-piece which is internally supported by the mandrel raising the platen partially rotating the work-piece repeating the application of pressure and the raising of the platen while intermittently partially rotating the work-piece through 360* until the inside and outside diameters are of acceptable dimensions extending the adjustment of the platen toward the mandrel; and continuing the foregoing operational steps until the desired internal and external dimensions have been obtained.

2. The process of claim 1 wherein the exterior surface of the starting work-piece is machined on the outside to provide a frusto-conical surface prior to heating to forging temperature.

3. The process of claim 1 wherein the initial work-piece is formed in a die.