US1212120A - Process for forming hollow forgings. - Google Patents

Description

E. H. STEEDMAN.

Patented Jan. 9, 1917.

EDWIN H. STEEDMAN, OF ST. LOUIS, MISSOURI.

PROCESS FOB FOBMING HOLLOW FOBGINGS.

Bpeoilcation of )Setters Iatent.

Patented Jan. 9, 1917.

Application filed Iarch 31, 1916. Serial No. 88,054.

To all whom t may concern Be itknown that I, EDWIN H. STEEDMAN, a citizen of the United States, residing at St. Louis, Missouri, have invented a certain new and useful Improvement in Processes for Forming JHollow Forgings, ofv which the following is a full, clear, and exact description, such 'as will enable others skilled. in the art to which it appertains tomake and use the same. v

This invention relates to a novel 4process for making hollow forgings.

Heretofore it was practically impossible to produce uniformly accurate fergings in making hollow forgings by piercing a hole or cavity in a billet or metal blank, on account of the tendency of the piercing punch to deflect from a straight line when operating on some billets or to be improperly po| sitioned with relation to the outer surface of the forgings when operating on other billets. One method that has been tried t0 overcome the objections above referred to is to arrange a guide adjacent the open end of the die, so as to try to start the piercing punch at the center of the die, but commercially this is not possible, on account of the piercing punch becoming very hot when in use and on account of the fact that it is not possible to make a 'guide that Willcompensate for the rapid wear en the end 'of the piercing punch, and thus guide the piercing punch accurately after it has been in use for a short time. Even 'when such a guide is used the irregular shape of the end of the piercing punch bearing on the 'end 'of the billet has l tendencyl to force the punch laterally during the first few inches of its travel through the billet. This, ofcourse, springs the piercing punch out 'of true axial alinement with the die. and as the punch enters farther into the billet, the spring or deflection greatly increases, frequently resulting in bending the piercing punch. As the billet is usually merely dropped into the die and not compressed prior to the piercing operation, there are voids between the outer surface of the billet'and' the inner surface of the die. Consequently, even though the piercing 'punch is accurately guided, a 'thing that is not possible com mercially, the unequal resistance caused by the voids on the side of the die cause the punch to travel out of axial alinement with the 'die es soon as it enters the billet to a reasonable extent.

The main'object of my invention is to provide a metal forging process that will insure the production of uniformly accurate hollow forgings having cavities or center openings that are accurately alined and properly positioned.

Another object is toprovide a process for making hollow forgings which makes it possible to use a billet ormetal blank of irregular form that does not even approximately fit the die, or a billet or metal blank in which the end operated upon by the piercing punch is irregular in shape, such as a sheared billet whose end yhas not been squared after coming from the rolls. To this end I have deviseda metal forging process in which the billet or blank being operated on is subjected to such treatment prior to the piercing operation that it will accurately position and guide the piercing punch that forms the cavity or center opening in the billet.

Brietiy described, my process consists in compressing a heated 4billet or metal blank and forming a depressionin said compressed portion, either in one operation or in successive operations, and thereafter forming 'a cavity, hole or opening in the billet by means of a piercing punch, or other suitable member which is guided by the metal surrounding the depression in the compressed portion4 of the billet, the outer surface of the billet being preferably shaped simultaneously with the operation of forming the cavity in same. Any suitable apparatus may be used in practicing my process, and while I have herein illustrated my process `used for making a hollow forging provided with a closed e'nd, I wish it to be understood thatmy invention is applicable -to a forging process in which a hole is punched through a billet, so as to form a tubular-shaped article.

Figure 1 of the 'drawings is a vertical sectional view of an apparatus that may be used in practising m process to compress the billet or blank an form a depression in the compressed portion of same, showing the billet prior to the compressing operation. Fig. 2 is a vertical sectional view of said apparatus, showing the billet after it has compressed and provided with a depression, the plunger in `said apparatus bein guided by -a member arranged adjacent" e open end ofthe die. `Fi 3 is a vertical sectional view, illustrating t e piercing punch enten ing the depression in the billet, preparatory to the operation of forming the cavity in the billet; and Fig. 4 is a sectional view, illustrating the billet after the piercing op: eration has been completed.

Referring to the drawin s, 1 deslgnates the billet or metal blank rom which the article is to be formed. Said billet is arranged in a die. A while in a heated condition. the billet being so shaped and proportioned that it can be dropped into the die A easily, even though the. outer surface of the billet is irregular and has slight projections thereon. Thereafter, the billet is compressed and a depression is formed in said compressed portion hy means of a forming plunger B provided with a projection B that is arranged or accurately guided in longitudinal alxnement with the center axis of the die A, so that the cavity or center opening in the completed article will be concentric with theI outer surface of the article, the projection B of the forming plunger preferably being of substantially conical Shape, although it might be cylindrical, square, or of any deA sired shape without departing from the spirit of my invention. The die A conforms to the shape of the outer surface of the article being formed, and when the forming plunger B acts on the billet, as shown in Fig. Q, it forms a depression 2 in the upper end of the billet. distorts the metal in the billet and forces the metal in the upper end portion of the billet laterally toward the side walls of the die A, causing the billet to fill the die suliiciently to oll'er an equal resistance en all sides to the piercing punch or member used in the succeeding operation. While I prefer to form a depression in the billet and compress the metal into the die to the desired extent in one operation, it will, of course, be obvious that the billet could be compressed and a depression formed in said compressed portion by two separate and distinct operations. The forming plunger B is guided accurately, either by the upper end portion of the die A, or by a suitable guiding member A', shown at Fig. 2, arranged adjacent the open end of the die A, so as to prevent said forming plunger from being forced sidewise when it strikes a. billet with an irregular upper end, as shown in Fig. l, it beingr an easy matter to secure a good mechanical guide for the forming plunger B, on account of the fact that said plunger does not become heated to any appreciable extent and because the large lat eral surface of the plunger can he readily lubricated.

The final step in the forging operation consists in forming a cavity or hole in the billet and distortin the metal sufficiently to cause the outer su ace of the billet to con form accuratelyY to the shape of the die A, this final step being preferably effected by a piercing punch or member C which is forced into the metal contained by the die A after the forming plunger B has been withdrawn. When the piercing punch C moves toward the die A, the end of said punch, which is tapered or substantially conical-shaped, enters the depression 2 in the upper end of the billet, thus causing the punch C to be centered accurately with relation to the die A. In view of the fact that the metal in the upper end portion of the billet is compressed until it practically fills the upper portion of the die A and is of substantially equal density surrounding the depreion Q, the uplper end portion of the billet will oler su cient resistance on all sides to the punch C, to hold said punch straight when it starts to dlstortthe metal in the billet. As the punch C continues to more through the billet, it is held perfectly straight and is prevented from deflecting from a straight line by means of the compressed metal surrounding the depression 2 in the billet and by the metal that is compressed progressively and equally as the punch (l travels through the billet. The result is that the completed forging will be commercially accurate, as the metal is distributed evenly throughout all portions of same, and the center cavity is concentric with the outside of the forging.

As previously stated, any suitable apparatas may be used in practising my process, and while I have referred to the forming plunger B and the punch C as being moved toward the die A, it wili of course be obvious that the die in which the billet is arranged could he moved with relation to the members that act upon the billet.

The process above described makes it possible to produce hollow forgings of uniform shape and size in which the center openings are accurately formed and in which the metal in all portions of the side walls of each article is of uniform density.

Having thus described my invention, what I claim, and desire to secure by Letters Patent, is:

1. A process for forming a hollow forging, characterized by forming a depression or recess in a billet. and also compressing the metal surrounding said depression prior td the operation of forming a cavity or center opening in the billet.

2. A process for forming a hollow forging, characterized by forming a depression or recess in a billet and also subjecting the billet to longitudinal pressure in a die so as to compress the metal surrounding said depression in the billet and thus cause the metal to substantially fill the adjacent portion of the die, prior to the operation of forming a cavity or center opening in the billet. i

3. A process for forming a hollow article,

which consists in compressing a billet or metal blank in a die and also simultaneously forming a depression in said billet by a` member that exerts longitudinal pressure on the billet, and thereafter forming a cavity or opening in the billet by means of a member that is centered by the depression in the billet and guided by the compressed metal in the billet that surrounds said depression.

4. A process for formingr a hollow forging, which consists in forming a depression in a heated billet or metal blank and also compressing the metal around said depression so that it is of substantially uniform density, and thereafter forging said billet into the shape of a hollow article by a mem ber that enters the depression formed in the billet during the first part of the forging operation.

5. A process for forming a hollow forging, which consists in forming a depression in a heated billet arranged in a die and also compressing the billet so as to fill the die to the desired extent around said depression,

and thereafter forging said billet into a hollow article by a member that enters the depression in the billet during the first part of the forging operation;

6. A process for forming a hollow forging, which consists in arranging a billet or metalblank in a die, subjecting the billet to endwise pressure so as to compress one end portion of same forming a depression in the compressed portion of said billet concentric with the side walls of said die, and thereafter forming a cavity or center opening in the billet in a single operation by means of a piercing punch that is centered and guided by the depression in the billet.

7. A process for forming a hollow forging, which consists in compressin a billet or metal blank in a die and also orming a depression in said billet concentric with the side walls of said die, and thereafter forming a cavity or center opening in the billet by means of a piercing punch that is centered by said depression and guided by the metal in the billet surrounding said depression.

8. A process for forming a hollow forging, characterized by compressing a billet or metal blank in a die and also simultaneously forming a depression in said billet concentric with the side walls of said die, the billet being compressed to a sufficient extent so that when the piercing punch used in the subsequent operation is started into said depression a substantially equal resistance will be offered on all sides to the piercing punch while it is traveling through the billet to form the center opening or cavity in the billet.

In testimony whereof I hereunto aflix my signature in the presence of two witnesses, this twenty-eighth da of March, 1916.

DWI H. STEEDMAN.

Witnesses:

W. A. YAEGER, A. P. Fox.

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