Method of making a composite forged-metal article

A composite metal article having a massive portion connected to a plate portion in a connecting plane is formed by die forging the massive portion between dies so as to produce a flash fin in this plane on the massive portion and welding the plate directly to the fin in this plane.

FIELD OF THE INVENTION 
My present invention relates to a composite metal article made at least in 
part by forging and, more particularly, to a machine element having a 
forged part and a plate-like part secured to the forged part. Specifically 
the invention relates to a method of making such an article and to the 
article made by the method. 
BACKGROUND OF THE INVENTION 
In many applications in machine tools or for ground working tools or for 
the fabrication of machine, vehicle and structural parts, it is desirable 
to make use of a composite construction of which a relatively massive 
member is constituted by a forging, especially a steel or alloy steel drop 
or die forging, and a metal plate which is welded to this forging. 
For the most part, such elements have been fabricated by forging the 
massive part from a blank, billet or bloom of steel, removing any forging 
flash or fins which may be produced by the pressing of the material 
between the forging dies, positioning a surface of the forging with an 
edge of the plate, and welding the two together. 
The welding operation may effect the contours of the forging in this case 
and the plate finishing of the forging prior to welding represents an 
expensive and time-consuming operation, especially where grinding is 
required for the removal of the flash or fin. 
Furthermore, when the plate is welded directly to the body of the forging, 
significant stresses develop at the weld joint which cannot be absorbed by 
any resilience in the massive body of the forging so that premature 
rupture may be a danger. In any event, the connection between the plate 
and the forging has only limited ability to withstand stress, and 
especially alternate bending stress, which may lead to early fatigue. 
Finally, because of the nature of the differences in the contours of the 
plate and the body of the forging at which the weld seam is to be 
produced, difficulties have been encountered in the automated production 
of the weld seam using welding robots and like automatons. 
OBJECTS OF THE INVENTION 
It is, therefore, the principal object of the present invention to provide 
an improved method of making a composite article of the type described 
whereby the fabrication and weld seam is simplified and more readily 
accomplished utilizing automatic means and welding robots, in particular. 
Another object of this invention is to provide a method of making a 
composite body in which a plate is welded to a forging wherein the weld 
junction is capable of withstanding greater stresses and suffers less 
fatigue than is the case with earlier devices. 
Another object of the invention is to reduce the fabrication costs in the 
making of such composite articles, yet obtaining articles with improved 
properties. 
It is also an object of this invention to provide an improved composite 
article having the properties enumerated. 
SUMMARY OF THE INVENTION 
These objects and others, which will become apparent hereinafter are 
attained, in accordance with the present invention which provides a method 
of making a composite body, especially a steel body which comprises the 
steps of die forging a relatively massive part of this body between a pair 
of dies while pressing a flashing fin of the material of this part between 
the dies to form a fin, and welding a plate section to the fin preferably 
so that the fin and the plate lie in a common plane. 
According to this invention, therefore, an edge of the fin is welded to an 
edge of the plate section and advantageously, the forging fin is produced 
in a thickness which corresponds substantially to the thickness of the 
plate which is welded thereto. 
The fin can converge in thickness toward its edge which is welded to the 
plate and, in the latter case, therefore, the fin will taper outwardly to 
the thickness of the plate. 
The edges of the plate and the fin which are joined by welding to one 
another, can be machined to allow the desired type of weld to be obtained. 
If a nondeposited butt weld is desired, the two surfaces can be machined 
so as to be flat and lie in surface contact with one another. However, if 
deposit welds are used, either with an X weld joint or a V weld joint, 
these edges are beveled accordingly and in the crevices between the 
beveled or chamfered surfaces, a weldment is deposited, e.g. by electric 
arc welding. 
The invention is based upon my discovery that, when a flash of the forging 
is permitted to remain in this resulting fin as a thickness corresponding 
substantially to the thickness of the plate, a plate welded thereto can 
lie in a plane corresponding to the junction plane between the dies and 
any stresses which are then applied in this region can be taken up not 
only by the weld seam which is formed, but also by the fin on one side and 
the plate on the opposite side. 
Since standard deposit welds can be formed without such precautions because 
the weld is removed from the massive portions and contours of the body of 
the forging, welding robots can be readily employed. 
The stress distribution can be improved still further when, as previously 
noted, the fin tapers to the weld seam. In the latter construction, the 
fin forms a high-strength stiffening member for the machine element to 
greatly improve the polar moment of inertia and hence reduce the fatigue 
tendency of the article. 
An important aspect of the invention is that it allows affixing a plate to 
a forged body along a predetermined connection line by forging that body 
so that the fin or flash formed between the two dies projects at this 
line, and then welding the plate to the fin.

SPECIFIC DESCRIPTION 
In FIG. 1 I have shown a fragment of a composite article, e.g. a propeller 
or screw for driving a ship and which comprises a hub 1 forged from metal 
and which can be provided with a bore (not shown) allowing this hub to be 
mounted upon a shaft carrying the screw. 
According to the invention, the forged part 1 is forged between a pair of 
dies which, with respect to this part, will be understood to have engaged 
the right and left sides thereof so that a portion or fin 5 of this 
material will be forced between these dies to produce the flash. 
In the embodiment shown, the fin 5 has converging flanks 5a and 5b which 
are connected by fillets 5c and 5d to the rounded contour 5e of the body 
of the forging 1. A butt weld 4 connects the plate 2 to this fin, the 
thickness of this plate corresponding to the thickness of the fin 5 at the 
surface F of the latter. The plate is connected to the fin so that both 
the fin and plate lie in a connecting plane 3. 
The fin 5 is of course the usual flash-produced fin generated in the die 
forging and which is not removed. 
As can be seen from FIG. 2, both the edge of the fin as represented at 5' 
and the edge 2' of the plate can be beveled to form a pair of symmetrical 
V-shaped grooves in which weldment 4a is deposited to form an X-type weld 
seam. 
In FIG. 3, the end faces of the fin and the plate are shown to be chamfered 
at 5' and 2', respectively, to form a single V-section groove in which the 
weld 4b is deposited.