US3160099A

US3160099A - Warhead projectile

Info

Publication number: US3160099A
Application number: US106424A
Authority: US
Inventors: Eugene L Nooker
Original assignee: Individual
Current assignee: Individual
Priority date: 1961-04-28
Filing date: 1961-04-28
Publication date: 1964-12-08
Anticipated expiration: 1981-12-08

Description

Dec. 8, 1964 E. NOOKER WARHEAD PROJECTILE 5 Sheets-Sheet l Filed April 28, 1961 BY WOW ATTORNEYS Dec. 8, 1964 E. NOOKER 3,160,099

- WARHEAD PROJECTILE Filed April 28, 1961 5 Sheets-Sheet 2 FIG. 3.

EUGENE L. NOOKER INVENTOR ATTORNEYS Dec. 8, 1964 E. 1.. NOOKER 3,150,099

7 WARHEAD PROJECTILE Filed April 28, 1961 s Sheets-Sheet 4 F' I G 6 a V I FIG. .7. a

ZONE 4 J ZLEi ZONE 5 ZONE I ZONE 2 omemm. sum

POSITION I E P 5 EUGENE L NOOKER INVENTOR BY QMCQ.

ATTORNEYS least three factors; the design of the hinge joint, the rod motion during unfolding, and factors affecting the prop erties of the rod materials. The rod motion will determine the severity of the hinge joint opening process, and the rod material properties in combination with the hinge joint design will determine to what degree the joint can open before rod breakage occurs for the existing conditions of rod motion. In particular, the sharpness of the rod bend and the rate at which stresses are applied to the weld regions will be critical factors. This invention is directed primarily to a hinge joint design capable of fulfilling the operational requirements of continuous rod warheads, particularly those employing steel rods of rectangular cross-section.

A hinge joint made according to the invention is shown diagrammatically in FIGS. 5 and 6, wherein is seen an inner rod 6 and an outer rod 8. The rods 6 and 8 are connected by welding, the regions where such welding occurs being indicated by the cross-hatched areas. It should be understood that the weld representatives in FIGS. 5 and 6 are only schematic, and that in an actual hinge joint there are no distinguishable boundary lines between the welded portions and the unwelded portions of the rods.

The hinge weld consists of two regions, a primary weld region, indicated by the dimension P, and a secondary weld region, indicated by the dimension S. As is best shown in FIG. 6, which view is a cross-section taken on line 6-6 of FIG. 5, the primary weld region P extends the full width of the rods, whereas the secondary weld region S is generally triangular in shape in the horizontal plane and has a progressively decreasing crosssectional area toward the central body of the rods. The weld between the rods may be made by the resistance welding method. Prior to such a welding operation a shim, of a material that may be the same as or dififerent from the material of the rods, is inserted between the rods. The shim, in addition to other important functions not herein discussed, furnishes material to the weld regions so that the size of the rods is not reduced by the welding. process. The welding process employed to make the weld is the subject matter of another invention, identified as patent application Serial Number 113,592, filed May 26, 1961, and entitled Resistance Welding Process and is capable of producing a large number of individual welds having substantially identical properties. Hence, in a continuous rod projectile the welds employed to connect each pair of rods will have substantially identical characteristics.

The primary weld region P is a region where a complete fusion and thorough diffusion exists between the material of the two rods and of the shim placed therebetween. The primary region P must be as strong as is possible, as it must Withstand the major portion of the stresses acting upon the rods during unfolding.

The secondary weld region S is a region where a weld of less strength exists than the weld of region P. The secondary weld adds strength to the total hinge joint. Additionally, it functions in a unique manner to control, to a degree, the radius about which the rod bends at the hinge joint (the bend radius), and to control the rate at which stress is applied to the primary weld during the unfolding process. By controlling the bend radius very sharp bends in the rods are avoided, and hence the possibility of the rods failing by breaking through the region of the bend is greatly reduced. By controlling the rate at which the primary weld is stress loaded, failures commonly associated with very abrupt loading are avoided. The secondary weld obtains these results because of its generally triangular shape and because it has less strength than the primary weld, whereby it fails progressively as the projectile unfolds.

The manner in which the continuous rod projectile unfolds after explosion of its associated high explosive charge is shown schematically, in idealized form, in

FIGS. 8 and 9. In FIG. 8 the projectile is partially unfolded. As the inner and outer rods 6 and 8 separate, they bend about the hinge joint 10. During such opening of the hinge joint, the secondary weld S will fail, or tear, progressively, the triangular configuration of the weld region acting to control the rate at which the tearing progresses. This progressive failure allows the bend radius of the rods to increase slowly as the rods unfold, thereby avoiding very sharp bends. Additionally, the stresses associated with the rod unfolding process are applied progressively to the primary weld region. In FIG. 9, the unfolding operation has continued, and it will progress until the inner and outer rods are substantially in axial alignment when the projectile is fully expanded. Further expansion of the projectile will then cause one or more of the hinge joints to fail, resulting in breakup of the projectile.

A hinge joint is shown in perspective in FIG. 10 after the projectile has reached its maximum expansion. The secondary weld S is shown at 14- in its failed condition, the primary weld P still being substantially intact and holding the rods together.

It is thus seen that a hinge joint consisting of a primary weld region and a secondary weld region, constructed as herein described, will provide a connection between the rods of a continuous rod projectile that will allow for controlled bending of the rods, and that will control the rate of application of stresses to the primary weld.

The particular dimensions and the materials employed in a projectile are determined by a number of factors, such as the overall warhead design, its geometry, the high explosive employed, etc. In a typical warhead, the dimensions of the rods 6 and 8 may be, by way of example, one-fourth inch on a side, and about eighteen inches in length, and the material of the rods may be S.A.E. 1008 steel. In such a projectile, the primary weld region P would be about three-eighths inch in length, and the secondary weld region S would be about five-eighths inch in length.

As has been indicated, the physical properties of the primary weld region and the secondary weld region are very important to the successful operation of the hinge joint. In particular, there must be a complete fusion and a thorough diffusion of the material in the primary weld region, and the properties of both the primary and the secondary weld regions must meet at least a minimum standard in each of the hinge joints employed in the projectile. If one hinge joint were to be below such a minimum standard, it would provide a point at which a fracture could occur during the early stages of unfolding, hence destroying the necessary continuity of the projectile. The geometry of the secondary weld must be so designed as to properly control the bend radius, such design being dependent upon the dimensions and materials of the rods employed, as well as other factors.

An example of the metallurgical structure desirable in a typical hinge joint is shown schematically in FIG. 7, said view representing an axial cross-section taken through the rod centers. For purposes of the example, it is assumed that the rods measure one-fourth inch on a side, are of S.A.E. 1008 steel, have a Rockwell B scale hardness of about 75, and that they are welded by the resistance method with the use of a shim. The shim is assumed to be of S.A.E. 1008 steel having a Rockwell B hardness of -85 and is elliptical in cross-section, the major and minor axis of the ellipse measuring about 0.142 inch and 0.055 inch, respectively.

For such materials, the metallurgical structure of the Weld region, after welding, but before the welded rods have been annealed, should be substantially as follows:

Zone 1: Completely recrystallized ferrite. Grain size 3-4. Zone 2: Completely recrystallized ferrite. Grain size 46.' Zone 3: Completely recrystallized ferrite. Grain size 5-6. Zone 4: Completely recrystallized ferrite. Grain size 5-6. Zone 5: Partially recrystallized ferrite. Grain size 67.

After annealing of the welded rods, the structure of the Weld region should be:-

ZOne 1: Completely recrystallized ferrite. Grain size 3-5. Zone 2: Completely recrystallized ferrite. Grain size 3-4. Zone 3: Completely recrystallized ferrite. Grain size 34. Zone 4: Completely recrystallized ferrite. Grain size 3-4. Zone 5: Completely recrystallized territe. Grain size 3-4.

The hardness of the hinge Weld should be substantially uniform throughout, and complete fusion exists in the primary weld region.

It is to be understood that this invention is not limited to rods of any particular dimensions, nor of any particular material. Hinge joints-constructed according to the invention are useable in projectiles of any of a number of possible dimensions and materials, and they function in all cases to maintain the continuity of the expanding continuous rod projectile.

Obviously, many modifications and variations of the present invention are possible in the light of the above teachings. It is therefore to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically descirbed.

What is claimed is:- e

1. In a warhead projectile including a plurality of rods, said rods being arranged in layers, corresponding end portions of the rods of one layer being juxtaposed with respectto corresponding end portions of the rods of another layer, a hinge weld for rigidly connecting said juxtaposed end portions, including a primary weld region at the end portions of the rods wherein substantially complete fusion exists between the material of the juxtaposed cross-sectional area from said primary weld region toward the central portions of said rods.

4. A continuous rod warhead projectile including a plurality of rods, said rods being arranged in layers, corresponding end portions of the rods of one layer being juxtaposed with respect to corresponding end portions of the rods of another layer, a hinge weld rigidly connecting the juxtaposed end portions of the rods, said hinge weld including a primary weld region of relatively great strength at the end portions of the rods and a secondary weld region of comparatively less strength than said primary weld region, said secondary weld region being positioned longitudinally inwardly of said primary weld region and away from the outer ends of the rods, said hinge weld being confined entirely between the end portions of the rods.

rod portions, and a secondary weld region of relatively less strengththan said primary weld region, said secondary Y weld region being positioned longitudinally inwardly of tionally said primary weld region and said secondary weld region are coterminious.

3. A hinge weld as claimed in claim 2, wherein additionally said secondary weld progressively decreases in 5. A continuous rod warhead projectile including a plurality of rods, said rods being arranged in layers, corresponding end portions of the rods of one layer being juxtaposed with respect to corresponding end portions of the rods of another layer, a hinge weld rigidly connecting the juxtaposed end portions of the rods, said hinge weld including a primary Weld region at the end portions of the rods wherein substantially complete fusion and thorough difiusion exists between the material of the juxtaposed rod portions, and a secondary weld region of relatively less strength than said primary weld region, said secondary weld region being contiguous to said primary weld region and being spaced longitudinally inwardly from the outer ends of the rods, said hinge weld being confined entirely between the end portions of the rods.

6. A continuous rod warhead projectile as claimed in claim 5, wherein the cross-sectional area of said secondary weld region progressively decreases from said primary weld region toward the central portions of said rods.

References Cited in the file of this patent UNITED STATES PATENTS 1,211,001 Steinmetz Jan. 2, 1917 1,247,331 Robinson Nov. 20, 1917 2,452,659 Huldt Nov. 2, 1948 2,662,277 Stone Dec. 15, 1953 2,972,950 Wclanetz Feb. 28, 1961

Claims

1. IN A WARHEAD PROJECTILE INCLUDING A PLURALITY OF RODS, SAID RODS BEING ARRANGED IN LAYERS, CORRESPONDING END PORTIONS OF THE RODS OF ONE LAYER BEING JUXTAPOSED WITH RESPECT TO CORRESPONDING END PORTIONS OF THE RODS OF ANOTHER LAYER, A HINGE WELD FOR RIGIDLY CONNECTING SAID JUXTAPOSED END PORTIONS, INCLUDING A PRIMARY WELD REGION AT THE END PORTIONS OF THE RODS WHEREIN SUBSTANTIALLY COMPLETE FUSION EXIST BETWEEN THE MATERIAL OF THE JUXTAPOSED ROD PORTIONS, AND A SECONDARY WELD REGION OF RELATIVELY LESS STRENGTH THAN SAID PRIMARY WELD REGION, SAID SECONDARY WELD REGION BEING POSITIONED LONGITUDINALLY INWARDLY OF SAID PRIMARY WELD REGION AND AWAY FROM THE OUTER ENDS OF THE RODS, SAID HINGE WELD BEING CONFINED ENTIRELY BETWEEN THE END PORTIONS OF THE RODS.