US3813758A - Explosive welding process - Google Patents

Explosive welding process Download PDF

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Publication number
US3813758A
US3813758A US00207873A US20787371A US3813758A US 3813758 A US3813758 A US 3813758A US 00207873 A US00207873 A US 00207873A US 20787371 A US20787371 A US 20787371A US 3813758 A US3813758 A US 3813758A
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Prior art keywords
driver plate
metal sheet
sheet
explosive
layer
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US00207873A
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English (en)
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M Araki
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NOF Corp
Fats Co Ltd Japan
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Nippon Oil and Fats Co Ltd
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Priority claimed from JP11118070A external-priority patent/JPS4919993B1/ja
Priority claimed from JP11117970A external-priority patent/JPS4919992B1/ja
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
    • B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
    • B23K20/00—Non-electric welding by applying impact or other pressure, with or without the application of heat, e.g. cladding or plating
    • B23K20/06—Non-electric welding by applying impact or other pressure, with or without the application of heat, e.g. cladding or plating by means of high energy impulses, e.g. magnetic energy
    • B23K20/08—Explosive welding

Definitions

  • the collision of the driver plate is actuated by the det- [56] R f e Cit d onation of an explosive layer disposed on its surface.
  • This invention relates to a process for bonding metal sheets by high-speed projectile impact, and more particularly to a process of bonding metallic layers by high-speed projectile impact caused by detonation of an explosive layer, which explosive layer is disposed in parallel to one of said metallic layers with an intermediate driver sheet inserted between the explosive layer and the metallic layer to be driven by the impact of the explosion.
  • This Poulter Report also disclosed that, when a copper sheet is propelled at a high speed by the detonation of an explosive so as to cause the copper sheet to obliquely collide a steel member, the copper sheet is bonded to the steel member with a waved boundary surface therebetween.
  • a method was disclosed in a U.S. technical journal, Light Metal Age, April, 1962. pages 6-9, for producing a subsonic propagating velocity of the point of collision between two metallic sheets being bonded, by disposing the two sheets so as to obliquely face with each other, which propagating velocity of the point of collision depends on the detonation velocity of the explosive used, the travelling velocity of the metallic sheets relative with each other, and the angle between the two metallic sheets.
  • U.S. Pat. No. 3,137,937 which was originally applied on Feb. 4, 1960 and published on June 23, 1964, has disclosed an explosive bonding process comprising steps of supporting at least one metal layer separated from an adjacent metal layer by a space of at least 0.001 inch and in substantially parallel relationship thereto, placing a layer of a detonating explosive on the outside surface of one of the metal layers, said explosive having a detonation velocity of greater than 1,200 meters per second but less than .120 percent of the sonic velocity of the metal having the highest sonic velocity in the system, and initiating said explosive.
  • the process of this U.S. Patent will be referred to as the parallel explosive welding process or simply as the parallel process,” hereinafter, for brevity.
  • the parallel process using the explosive layer integrally adhered to the cladding metal sheet has the following disadvantages: namely, irregularity of detonation waves along the edge of the cladding metal sheet, undesirable effects of instable detonation in the proximity of the detonator, cracking and distortion of the cladding metal sheet along the edges thereof, intrusion of gaseous detonation products into the gap between the cladding metal sheet and the base metal sheet, and ineffective gond and cracks of the clad metal caused by the foregoing difficulties.
  • Japanese Patent Publication No. 1 1,231/ 1967 based on the Convention Priority of the corresponding U.S. Pat. Application Ser. No. 264,373 of March 1 l, 1963, has taught another explosive welding process, in which at least two metallic sheets are disposed so as to face with each other with an angle of not smaller than 1 degree therebetween, and an explosive layer is placed on at least one of the two metallic sheets, and detonating the explosive layer, wherein the propagating velocity of the point of collision of the metallic sheets is not greater than percent of the sonic velocity of the metallic sheets (to be referred to as the oblique explosive welding process," hereinafter, for
  • an object of the present invention is to obviate the aforesaid difficulties of conventional tech niques, by providing an improved explosive welding process.
  • an explosive welding process comprising steps of disposing at least one cladding metal sheet so as to face a base metal sheet with a spacing equivalent to one-twentieth to 25 times the thickness of that one of the two sheets which is to be driven toward the other sheet, coating a protective layer on said sheet to be driven at the surface facing away from said other sheet, placing a driver plate so as to face said protective layer with a spacing equivalent to one-twentieth to twentyfive times the thickness of said driver plate, the driver plate being at least as wide as said sheet to be driven, forming an explosive layer on said driver plate on the surface facing away from said protective layer, and igniting said explosive layer to cause said driver plate to collide and drive said sheet to be driven for generating a colliding impact large enough to bond said cladding metal sheet to said base metal
  • FIGS. I to 3 are schematic diagrams, illustrating conventional explosive welding processes
  • FIG. 4 is a schematic view of an arrangement of metallic sheets, a driver sheet, and an explosive layer, to be used in a process according to the present invention
  • FIG. 5 is a diagrammatic illustration of the manner in which the metallic sheets in the arrangement of FIG. 4 are welded by the explosive welding process according to the present invention
  • FIGS. 6 to 8 are schematic views of different arrangements, each consisting of metallic sheets, a driver sheet, and an explosive layer, for carrying out the explosive welding process according to the present invention
  • FIGS. 9 and 10 are diagrammatic illustrations of the manner in which detonation of the explosive layers of FIGS. 6 and 8 proceeds, respectively;
  • FIGS. 11 and 12 are schematic illustrations of two modifications of the arrangement of FIG. 8.
  • FIG. 13 is a schematic sectional view, illustrating the arrangement of Example I.
  • FIG. I One of the practicable explosive welding process of conventional type, i.e., the parallel explosive welding process of US Pat. No. 3,137,937, will briefly be re viewed (see FIG. I).
  • a detonator l is mounted on one end of an explosive layer 2 spread on cladding metal sheet 3, so that upon initiation of the explosive layer 2 by the detonator I, the cladding metal sheet 3 is impinged to a base metal sheet 4 so as to bond the former to the latter.
  • the explosive layer 2 should be as wide as the cladding metal sheet 3, and the detonator l is disposed outside the area facing that portion of the cladding metal sheet which is to be bonded to the base metal sheet 4.
  • the detonation of the explosive layer 2 should propagate in parallel to the cladding metal sheet 3 in a uniform fashion.
  • the actual detonation of the explosive layer 2 in the close proximity of the initiating point is somewhat instable, for instance, in an area of several tens to several hundreds millimeters from the detonator 1, depending on the type of explosives used.
  • Such instable detonation of the explosive layer in the vicinity of the initiating point results in poor quality of the bond between the cladding metal sheet 3 and the base metal sheet 4.
  • FIGS. 2 and 3 illustrate two examples of such prior suggestions.
  • a cladding metal sheet 3 is suggested to be larger than a base metal sheet, 4, to which the cladding metal sheet 3 is bonded.
  • Those edge portions of the cladding metal sheet 3 of FIG. 2, which lie outside the span of the base metal sheet 4, are cut off at the moment of the collision of the cladding metal sheet 3 to the base metal sheet 4, by the shearing force generated by the detonation of an explosive layer 2 and applied to said edge portions upon the impingement of the cladding metal sheet 3 to the base metal sheet 4.
  • those edge portions of the cladding metal sheet 3, where the bond to the base metal sheet 4 is susceptible to weakening due to the instable detonation in the proximity of the initiating point and the wave reflection at the very edges of the cladding metal sheet, can completely be separated or severed from the cladding metal sheet 3, provided that a proper marginal width is given around the peripheral edges of the starting cladding metal sheet 3 relative to the size of the base metal sheet 4. Consequently, the risk of the weak bond and the cracks around the peripheral edges of the clad metal can greatly be reduced by using a fresh cladding metal sheet which is larger than the base metal sheet tobe clad.
  • clad metal is usually made by cladding a base sheet of comparatively inexpensive metal, e.g., mild steel, with a layer of comparatively expensive metal, e.g., stainless steel, Hastelloy, brass, bronze, copper, titanium, zirconium, nickel, tantalum, gold, silver, platinum, tungsten, niobium, chromium, cobalt, aluminum, molybdenum, magnesium, vanadium, zinc, tin, and their alloys. Since the material is such expensive metal, the use of excessively large cladding sheet or layer results in an unnecessary increase in the cost.
  • a base sheet of comparatively inexpensive metal e.g., mild steel
  • a layer of comparatively expensive metal e.g., stainless steel, Hastelloy, brass, bronze, copper, titanium, zirconium, nickel, tantalum, gold, silver, platinum, tungsten, niobium, chromium, cobalt, aluminum, molybdenum, magnesium, vanadium, zinc
  • edge members 3 of less expensive metal are, for instance, made of mild steel and bonded to the cladding metal sheet 3 by spot welding or by adhesive, so that the overall size of the cladding metal sheet 3 may virtually become somewhat larger than the base metal sheet 4.
  • the use of such separate edge members 3, however, has a shortcoming in that it is difficult to smoothly bond the separate edge members 3' to the cladding sheet 3, and the labor necessary for effectively bonding the separate edge members 3' to the cladding metal sheet 3 amounts to a level to make the entire explosive welding process uneconomical for practical applications.
  • the conventional explosive welding process has another shortcoming in that it is difficult to bond a metal sheet having a comparatively low ductility to a base metal sheet.
  • brittle metal sheet such tungsten sheet, is apt to be cracked by the impact of the detonation of the explosive layer.
  • the conventional oblique explosive welding process as disclosed by the aforequoted Japanese Patent Publication No. Il,23l/l967,has the following shortcoming.
  • the explosive layer is initiated at that end where the cladding metal sheet is located closest to the base metal sheet, so that the detonation proceeds towards the opposite end where the cladding metal sheet and the base metal sheet are widely separated.
  • the sheet driven by the detonation of the explosive layer tends to be distorted or cracked, due to the air resistance and the reflection of the impact waves.
  • the aforesaid maximum limit of the distance between the cladding metal sheet and the base metal sheet depends on the physical properties and the dimensions of the driven sheet.
  • the excessively large distance between the cladding metal sheet and the base metal sheet also results in a tool large acceleration of the driven sheet, so that the impact of the collision of the cladding sheet and the base sheet becomes excessively high and the bond of the two sheets becomes instable.
  • the cladding metal sheet may be disposed either in parallel to or in oblique relationship to the base sheet, and the driver plate carrying the explosive layer can be disposed at the back of either the cladding metal sheet or the base metal sheet.
  • a protective layer is secured to that surface of the metal sheet which faces the driver plate.
  • FIG. 4 an explosive layer 2 is mounted on a driver plate 5 and a detonator l is secured to the left end of the explosive layer 2, as seen in the figure.
  • a cladding metalsheet 3 is disposed in parallel with the driver plate 5 with a suitable spacing therefrom.
  • a protective layer 6 is overlaid on that surface of the cladding metal sheet 3 which faces the driver plate 5.
  • a suitable driver plate spacer means 12 is provided between the driver plate 5 and the protective layer 6 of the cladding metal sheet 3.
  • a base metal sheet 4 is placed on a work table 11 in parallel to the cladding metal sheet 3 with a suitable spacing therefrom, by inserting another spacer means 13 therebetween, such as the dimples as disclosed in the aforequoted US. Pat. No. 3,137,937.
  • the explosive layer 2 upon firing by the detonator l, detonates from the left 'tothe right, as seen in the figure, at a detonation velocity D, which depends on the type of the explosive, the shape of the explosive layer, and the loading conditions of the explosive layer on the driver sheet.
  • D detonation velocity
  • the propagating velocity of the point of collision between the driver plate 5 and the protective layer 6 of the cladding metal sheet 3 (to be referred to as the driver plate collision-propagating velocity V,,, hereinafter) is the same as the detonation velocity D of the explosive layer 2, because the explosive layer 2 is disposed in'parallel to the cladding metal sheet 3.
  • the cladding metal sheet 3 is driven downwards and collides the base metal sheet 4 at a high speed.
  • the propagating velocity of the point of collision between the cladding metal sheet 3 and the base metal sheet 4 (to be referred to as tthe base metal sheet collision-propagating velocity V, hereinafter) is identical with the aforesaid driver plate collisionpropagating velocity V and the detonation velocity D of the explosive layer 2, because the base metal sheet 4 is disposed in parallel to both the cladding metal sheet 3 and the driver plate 5.
  • the moving velocity of the cladding metal sheet 3 at the moment of its collision with the base metal sheet 4 will be referred to as the flying velocity V of the cladding metal sheet.
  • the flying velocity V of the cladding metal sheet When the base metal sheet collisionpropagating velocity V, and the flying velocity V of the cladding metal sheet are properly selected, a stable metallurgical bond can be formed between the cladding metal sheet 3 and the base metal sheet 4.
  • FIG. 5 schematically shows the manner in which the driver plate 5 of FIG. 4 is driven toward the protective layer 6 of the cladding metal sheet 3, in response to the detonation of the explosive layer 2, and the cladding metal sheet 3 strikes the base metal sheet 4 in response to the collision of the driver plate 5 with the protective layer 6 of the cladding metal sheet 3.
  • the detonation velocity D of the explosive layer 2 is directly transferred to the driver plate collision-propagating velocityV and the base metal sheet collision-propagating velocity V so that the two velocities V,, and V, are substantially identical with the detonation velocity D.
  • a metal jet 10 is generated from the colliding point between the cladding metal sheet 3 and the base metal sheet 4, as shown in FIG. 5.
  • the metal jet It acts to facilitate the metallurgical bond between the base metal sheet 4 and the cladding metal sheet 3 by exposing fresh metallic surfaces thereof.
  • the metal jet 10 also prevents the bond of the base metal sheet 4 and the cladding metal sheet 3 from being separated by the impact wave due to the collision of the two metal sheets and by its reflective wave.
  • FIG. 6 shows another arrangement suitable for carrying out the explosive welding process according to the present invention.
  • a cladding metal sheet 3 is disposed in parallel to but with a suitable spacing from a base metal sheet 4.
  • a driver plate 5 is, however, obliquely disposed relative to the cladding metal sheet 3 with an angle a between the planes of the driver plate 5 and the cladding metal sheet 3.
  • the bottom surface of the driving plate 5 faces a protective layer 6 secured to the top surface of the cladding metal sheet 3, and an explosive layer 2 is disposed on the upper surface of the driver plate 5.
  • the driver plate collision-propagating velocity V. becomes smaller than the detonation velocity D of the explosive layer 2. If the flying velocity of the driver plate 5 at the moment of its collision with the protective layer 6 on the cladding metal sheet 3 is represented by V the driver plate collisionpropagating velocity V, is given by the following equation (I).
  • the base metal sheet collision-propagating velocity V... in the case of the arrangement of FIG. 6, is substantially the same as the driver plate collision-propagating velocity V because the cladding metal sheet 3 is disposed in parallel with the base metal sheet 4.
  • FIG. 7 shows another arrangement for fulfilling the explosive welding process according to the present invention.
  • the disposition of FIG. 6 is further modified by obliquely disposing the base metal sheet 4 relative to the cladding metal sheet 3, so as to define an angle ,8 between the two metal sheets 3 and 4.
  • the two angles a and B are determined so as to generate proper flying velocity V p of the cladding metal sheet 3 at the time of its collision with the base metal sheet 4, and proper base metal sheet collisionpropagating velocity V If the flying velocity V, of the cladding metal sheet 3 at the time of its collision with the base metal sheet 4 is too low, there will not be produced a sufficiently large plastic deformation at the boundary between the base metal sheet 4 and the cladding metal sheet 3 for providing strong metallurgical bond therebetween.
  • the cladding metal sheet 3 may resiliently be bounced at the base metal sheet 4, or may be attached to the base metal sheet 4 only very weakly.
  • the flying velocity V of the cladding metal sheet 3 at the time of collision with the base metal sheet 4 is too high, the deformation of the cladding metal sheet 3 and the base metal sheet 4 become excessively large to produce cracks and wrinkles in the final clad metal which deteriorate the commercial value of the clad metal.
  • the clad metal is cracked due to an excessively high flying velocity V of the cladding metal sheet 3.
  • the flying velocity V of the cladding metal sheet 3 at the time of collsion with the base metal sheet 4, which range depends on the physical properties of the cladding metal sheet 3 and the base metal sheet 4.
  • Those skilled in the art can easily select the proper value of the aforesaid flying velocity V,, of the cladding metal sheet 3, for instance by tests.
  • the inventors have found that satisfactory bond of the cladding metal sheet with the base metal sheet can be achieved as long as the collision-propagating velocity V is faster than 800 m/sec. but slower than the fastest sonic velocity in the cladding metal sheet 3 and the base metal sheet 4.
  • the sonic velocity here refers to the velocity of the plastic shock wave which forms when a stress which is applied just exceeds the elastic limit for unidirectional compression of the particular metal sheet.
  • the collisionpropagating velocity V may be defined in two ways; namely, the collision-propagating velocity V taken on the plane of the cladding metal sheet 3, and the collision-propagating velocity V taken on the plane of the base metal sheet 4.
  • Such velocities V,., and V can be given by the following relations.
  • Either one of the aforesaid two velocities V and V can be used as the base metal sheet collisionpropagating velocity, depending on which of the cladding metal sheet 3 and the base metal sheet 4 is to be driven by the driver plate 5.
  • suitable base metal sheet collision-propagating velocity V can be achieved for a wide range of the detonation velocity D, by properly selecting the aforesaid two angles a and B.
  • the angle between the cladding metal sheet and the base metal sheet i.e., the angle B of F IG. 7
  • this angle is the only one variable in such conventional process under these conditions.
  • FIG. 8 shows another arrangement to be used for fulfilling the explosive welding process according to the present invention, in which an initiator layer is used for initiating the explosive layer of the aforesaid embodiments. More particularly, an initiator layer 7 is spred on a detonating driver plate 8, and a detonator l is connected to the initiator layer 7 at one end thereof. Upon firing the initiator layer 7 by the detonator l, the detonating-driver plate 8 obliquely strikes the explosive layer 2 spread on a driver plate 5 similar to driver plate of the preceding embodiments.
  • FIGS. 4 to 7 having a detonator 1, or a linear wave generator, directly connected to one end of the explosive layer, a detonating wave front 9 is formed so as to face upwards, as shown in FIG. 9. Accordingly, the detonation impact is partly lost to the upper free space, and it is not fully utilized for accelerating the driver plate 5. Thus, the amount of the explosive spread on the driver plate 5 must be more than what is actually necessary for bonding the cladding metal sheet 3 to the base metal sheet 4, and hence, the explosive welding process becomes more costly.
  • the inventors have found that, if the initiator layer 7 is made wider than the explosive layer 2, the uniformity of evenness of the bond between the cladding metal sheet 3 and the base metal sheet 4 can further be improved, because such wider initiator layer 7 eliminates the irregularity of the detonating wave front 9 at the far end of the explosive layer 2 as seen from the detonator 1.
  • the detonator l, or a line wave generator, for firing the initiator layer 7 is known, According to the inventors finding, in order to orient the detonating wave front 9 downwards in the explosive layer 2 in the arrangement of FIG. 8, wherein the bottom surface of the detonating driver plate 8 is initially disposed in parallel to the top surface of the explosive layer 2, the explosion velocity d of the initiator layer 7 must be faster than the detonation velocity D of the explosive layer 2.
  • the inclination 0 of the detonating wave front 9, i.e., the angle 0 between the detonating wave front 9 and the top surface of the driver plate 5, is given by the following equation.
  • FIG. 11 shows a modification of the arrangement of FIG. 8, in which a detonating driver late 8 is obliquely disposed with respect to a driver plate 5 carrying an explosive layer 2, so as to form an angle of 1- between the plate 8 and the layer 2, and a detonator l is connected to that edge of the detonating driver plate 8 which is closest to the driver plate 5 amount various edges thereof.
  • a detonating driver late 8 is obliquely disposed with respect to a driver plate 5 carrying an explosive layer 2, so as to form an angle of 1- between the plate 8 and the layer 2, and a detonator l is connected to that edge of the detonating driver plate 8 which is closest to the driver plate 5 amount various edges thereof.
  • the velocity at which the detonating driver plate 8 initiates the explosive layer 2 on the driver plate 5 is made slower than the detonation velocity d of the initiator layer 7.
  • the inventors have found out that the aforesaid initiation velocity d must not be smaller than 1 16 percent of the detonation velocity D of the explosive layer 2.
  • FIG. 12 shows another arrangement to be used for fulfilling the explosive welding process according to the present invention, in which an initiation velocity d satisfying the conditions of the equation 9 can be achieved by using an initiator layer 7 having a detonation velocity d smaller than said initiation velocity d.
  • a detonating driver plate 8 carrying an initiator layer 7 is obliquely disposed relative to a driver plate 5 carrying an explosive layer 2, so as to form an angle Ill, and a detonator l is connected to that edge of the initiator layer 7 on the detonating driver plate 8 which is farthest from the driver plate 5 among various edges thereof.
  • the aforesaid initiation velocity d for the arrangement of FIG. 12 can be expressed as follows, in terms of the flying velocity V,,' of the detonating driver plate 8 at the moment of its collision with the explosive layer 2.
  • the value of the initiation velocity a" can be controlled by regulating the angle r11, while keeping the initiation velocity d greater than the explosion velocity d, because the term iafllll/ian(t,ll) is always positive.
  • FIGS. 11 and 12 can also be applied to the disposition including a finite'angle a between the driver plate 5 and the cladding metal sheet 3, as shown in FIG. 6, as well as to the disposition including another angle B between the cladding metal sheet 3 and the base metal 4, as shown in FIG. 7.
  • the conditions of the equations 9, l0, and ll for the arrangement of FIGS. ll and 12 must be reconsidered in view of the equations 1 to 8, if the arrangement of HG. 11 or 12 is combined with that of FIG. 6 or 7.
  • the base metal sheet collisionpropagating velocity V is identical with the dirver plate collision-propagating velocity V,, which is determined by the equation 1 while substituting the detonation velocity D with the initiation velocity d of the equation 10.
  • the base metal sheet collisionpropagating velocity velocity V is determined by the equation 3 or 4, after determining the driver plate collision-propagating velocity V in the aforesaid manner by using the equations 1 and 10.
  • the thickness of the pro tective layer 6 is assumed to be uniform, and the angle between the bottom surface of the driver plate 5 and the top surface of the protective layer 6 is identical with the angle between the bottom surface of the driver plate 5 and the cladding plate 3.
  • a protective layer 6 which is tapered, so as to provide varying time delays in the delivery of collision impact of the driver plate 5 to the cladding metal sheet 3, depending on the variation of the thickness of the protective layer 6.
  • the driver plate 5 is typically made of aluminum or steel, with or without coating of suitable metallic or resin materal.
  • the material of the driver plate 5 is, however, not restricted to aluminum and steel, and any other impact-resisting metallic material can also be used to form the driver plate 5; for instance, titanium, zirconium, stainless steel, nickel, duralmin, copper, brass, bronze, zinc, tantalum, or an alloy of elements selected from the foregoing metals. It should be noted here that the use of expensive metals for the driver plate 5 cannot be justified. unless certain properties of such expensive metals are advantageously used in the explosive welding process according to the present invention.
  • the effective area of the driver plate 5 must be as broad as the cladding metal sheet 3. What is meant by the effective area of the driver plate 5 is that of the area covered with the explosive layer 2, so that other areas covered by materials such as wooden framework for holding the explosive layer 2 are excluded from the effective area of the driver plate 5.
  • the driver plate 5 should preferably be larger than the cladding metal sheet 3 by any side thereof, because such large driver plate is effective in eliminating various undesirable phenomena involved in the explosive welding process; namely, the irregularity of detonation waves along the edge of the cladding metal sheet, the undesirable effects of the instable detonation in the proximity of the detonator, the cracking and distortion of the driver plate along the edges thereof, the intrusion of gaseous detonation products into the gap between the cladding metal sheet and the base metal sheet, and the ineffective bond and cracks of the clad metal caused by the foregoing dlfflCUltlCS.
  • the thickness of the driver plate 5 should preferably fall in a range of 0.3 to 10 times of the thickness of the cladding metal sheet 3. If the driver plate 5 is too thin, there may be generated such waves from the striking surface and the opposite surface of the driver plate at the time of its collision with the cladding metal sheet, which waves tend to reduce the collision impact of the driver plate, so that the cladding metal sheet 3 may not be accelerated sufficiently for producing strong bond between the cladding metal sheet and the base metal sheet.
  • the driver plate 5 is too thick, the amount of the explosive necessary for accelerating the cladding metal sheet 3 to a velocity required for the welding of the cladding metal sheet 3 to the base metal sheet 4 becomes too much to make the process of the invention economically feasible.
  • the suitable thickness of the driver plate 5 can easily be determined for each application by those skilled in the art, depending on the thickness and the material of the cladding metal sheet 3 and the protective layer 6.
  • the protective layer 6 is to eliminate the direct collision of the driver plate to the cladding metal sheet which direct collision might cause the bond of the driver plate 5 with the cladding metal sheet 3 and cracks and/or wrinkles on the cladding metal sheet. Accordingly, the protective layer 6 can be made of any suitable material capable of fulfilling the aforesaid functions; for instance, rubber, synthetic resin, paint, water, or gelated product of gelatine or agar or a composite mixture thereof.
  • the suitable thickness of the protective layer 6 can easily be determined by those skilled in the art, for instance, by simple tests while considering the related conditions, such as the material and the thickness of the driver plate 5 and the cladding metal sheet 3, the flying velocity V of the driver plate 5 at the moment of its collision with the protective layer 6 on the cladding metal sheet 3,the angle at which the driver plate 5 collides the protective layer 6, and the material of the protective layer 6 per se.
  • the preferable material of the protective layer 6 is a foamed layer with an apparent density of 0.01 g/cm to 0.4 g/cm which is made of rubber or synthetic resin such as vinyl chloride, vinyl acetate, polystyrene, polyethylene, epoxy resin, phenol resin, polyurethane, urea, and nylon.
  • the explosive layer 2 on the driver plate 5 should at least be as wide as the cladding metal sheet 3 to be driven by the driver plate 5.
  • the thickness of the explosive layer 2 can also readily be determined by those skilled in the art, for instance, by simple experiments, while considering related conditions, such as the thickness and material of the driver plate 5, cladding metal sheet 3, and the protective layer 6, the spacing between the driver plate 5 and the cladding metal sheet 3, and the distance between the cladding metal sheet 3 and the base metal sheet 4.
  • the suitable range of the spacing between the driver plate 5 and the protective layer 6 on the cladding metal sheet 3 is from onetwentieth to times of the thickness of the driver plate 5. If any part of the driver plate 5 is spaced from the protective layer 6 on the cladding metal sheet 3 by a distance greater than 25 times of the thickness of the driver plate 5, such portion of the driver plate is susceptible to cracking or distortion in the course of its travel to the protective layer 6, due to the compression of air at the high flying velocity of the driver plate. As a result, the bond between the cladding metal sheet 3 and the base metal sheet 4 may become inferior.
  • driver plate 5 If any portion of the driver plate 5 is disposed too close tothe protective layer 6 on the cladding metal sheet 3 by a gap smaller than the one-twentieth of the thickness of the driver plate 5, that portion of the driver plate 5 cannot be accelerated sufficiently for producing stable bond between the cladding metal sheet 3 and base metal sheet 4.
  • the suitable slanting angle a between the driver plate 5 and the cladding metal sheet 3 can be determined by the aforesaid equations 1 and 2.
  • the minimum and maximum distances between the slanted driver plate 5 and the cladding metal sheet 3 should be within the limit of the aforesaid range of one-twentieth to 25 times of the thickness of the driver plate 5.
  • the driver plate spacer means 12, for providing such spacing between the driver plate 5 and the protective I layer 6 on the cladding metal sheet 3, as illustrated in FIG. 4, preferably consists of a plurality of small pieces of foamed rubber or foamed synthetic resin.
  • the configuration and the material of the driver plate spacer means 12 are not restricted to such embodiment alone.
  • such spacer means 12 can be made of wooden or metallic blocks, provided that such blocks are so pretreated as not to cause any scratch or crack on the surface of the cladding metal sheet 3.
  • the protective layer 6 as the aforesaid driver plate spacer means, by increasing its thickness to a suitable magnitude in the aforesaid range of the one-twentieth to 25 times of the thickness of the drive plate 5.
  • the protective layer 6 should be wide enough to cover the entire effective area of the driver plate at the surface facing the cladding metal sheet 3, and it is preferably made of a foamed highmolecular compound, such as rubber or synthetic resin, because such foamed protective layer does not provide any substantial resistance to the travel of the driver plate 5 in response to the detonation of the explosive layer 2, until the protective layer 6 is so compressed as to directly transfer the kinetic energy of the driver plate 5 to the cladding metal sheet 3.
  • such expanded protective layer conveniently fulfills the two functions; namely, providing the proper spacing between driver plate 5 and the cladding metal sheet 3, and protecting the non-bonding surface of the cladding metal sheet 3.
  • an easily removable coating may be applied to that surface of the cladding metal sheet 3, which faces the, foamed material of the expanded protective layer 6, prior to the placing of the protective layer 6 thereon.
  • the use of such expanded protective layer 6 is apparently very attractive, because it eliminates the need of placingseparate driver plate spacer means 12 thereon.
  • the effective area of the detonating driver plate 8 should be at least as wide as the effective area of the driver plate 5, and preferably wider than the effective area of the driver plate 5 by more than about 5 cm at each side thereof. If the effective area of the driver plate 5 itself isconsiderably wider than the cladding metal sheet 3, the excess size ofthe effective area of the detonating driver plate 8 over the effective area of the driver plate 5 is not so pressing. What is meant by the effective area of the detonating driver plate 8 is that portion of the plate 8 which is covered by the initiator layer 7, but areas under the framework for holding the initiator layer 7 is excluded from the effective area of the detonating driver plate 8. The inventors have found out that the preferable thckness of the detonating driver plate 8 is 0.3 mm to 3 mm.
  • the spacing from the bottom surface of the detonating driver plate 8 to the top surface of the explosive layer 2 carried by the driver plate 5 should not be smaller than one-twentieth of the thickness of the detonating driver plate 8 but should not exceed 25 times of the thickness of the detonating driver plate 8.
  • the detonating driver plate 8 may be placed in parallel to the driver plate 5, as shown in H0. 8, or slanted by a suitable angle, such as the angle ill as shown in PK]. 12 and as given by the equation 10.
  • the aforesaid preferable range of the spacing between the detonating driver plate 8 and the driver plate 5 is valid regardless of the angular relation between the two plates 5 and 8, because an excessively large spacing results in an over-acceleration of the detonating driver plate 8 so as to cause uneven bond of the cladding metal sheet 3 to the base metalsheet 4, while a too narrow spacing results in an insufficient acceleration of the detonating driver plate 8 which may in turn cause ineffective bond of the cladding metal sheet 3 to the base metal sheet 4.
  • the aforesaid desirable spacing between the detonating driver plate 8 and the driver plate 5 can be provided in the same manner as the spacing between the driver plate 5 and the protective layer 6 on the clad ding metal sheet 3, e.g., by using wooden or metallic blocks, foamed rubber or synthetic resin pieces.
  • only one cladding metal sheet is bonded to the base metal sheet.
  • the present invention is not restricted to the explosion welding of only two metal sheets.
  • two separate metal sheets may be bonded to a base metal sheet, simply by disposing the two metal sheets between the driver plate 5 of FIG. 4 and the base metal sheet 4 of the figure.
  • the driver plate 5 may be used for driving the base plate 4, instead of driving the cladding metal sheet 3, as shown in FIG. 4. Furthermore, it is also possible to drive both the cladding metal sheet 3 and the base metal sheet 4 toward each other by using a pair of driver plates for actuating the two metal sheets from opposite surface thereof.
  • the spacing between the cladding metal sheet 3 and the base metal sheet 4 can be selected, depending on the type of the metal sheets to be bonded and the thickness thereof.
  • the spacing between the cladding metal sheet and the base metal sheet, according to the present invention, is somewhat different from the teaching of the aforequoted US. Pat. NO. 3,137,937 specifying such spacing not smaller than 0.00] inch.
  • a driver plate is used for actuating a cladding metal sheet toward a base metal sheet, so that various difficulties of conventional explosive welding processes can easily be mitigated.
  • the direct drive of the cladding'metal sheet or the base metal sheet with the detonation of an explosive layer, according to the aforesaid conventional explosive welding processes tends to produce cracks in the clad metal produced thereby, and the reflection of the detonating pressure directly applied to the cladding metal sheet tends to weaken the bond of the cladding metal sheet to the base metal sheet along the peripheral edges of the clad metal produced thereby. Accordingly, the yield of conventional processes of making clad metal by explosive welding has been fairly low.
  • driver plate according to the present invention behaves somewhat like a lining of such porous metal sheet. so that excellent bond can be produced between a metal sheet having holes and a base metal sheet by the explo' sive welding process according to the present invention.
  • EXAMPLE 1 A lOO( width) X 200( length) 9(thickness) mm (this width-length-thickness order will be followed in the subsequent description of sheet dimensions in all Examples) base sheet 4 made of 4] Kglmm tensilc strength class steel. was placed on ground prepared to act as a worktable 11, and six aluminum cubes l3 of lXlXl mm were disposed on the top surface of the steel sheet so as to support a IOOXZOOXZ mm cladding metal sheet 3 of 50 Kg/mm strength class titanium, in alignment with the steel sheet with 1 mm spacing therefrom, as shown in PK]. 13. A 1 mm thick protective layer 6 consisting of a pressed black rubber sheet of regular class was secured to the top surface of the titanium sheet 3 by a synthetic rubber adhesive, so as to cover the entire span of the top surface of the titanium sheet 6.
  • a driver plate 5 consisting of a 270 l mm mild steel sheet was placed above the protective layer 6 with a spacing of 10 mm, by supporting it on the worktable 11 by wooden blocks 12.
  • the lengthwise edges and the widthwise edges of the driver plate 5 were disposed in parallel with the corresponding edges of the cladding and base metal sheets 3 and 4, so that the driver plate widthwise extended 15 mm beyond the cladding and base metal sheets on each side edge thereof, while lengthwise extended 50 mm on one longitudinal edge and 20 mm on the longitudinally opposite edge beyond the corresponding edges of the cladding and base metal sheets.
  • H0. 13 schematically shows a longitudinal sectional view of such arrangement of the driver plate 5 relative to the cladding and base metal sheets 3, 4.
  • a wooden rectangular frame 14 with an outside dimension of l30(width) X 270(length) mm was placed on the top surface of the driver plate 5, which wooden frame was made of wooden blocks having a cross section of mm width and mm height.
  • the outer edge of the wooden frame 14 was aligned with the corresponding four side edges of the driver plate 5 and secured thereto by a suitable adhesive.
  • An explosive layer 2 was disposed on the top surface of the drive plate 5 within the area defined by the wooden frame 14, by uniformly spreading 310 grams of explosive powder consisting of 10 parts by weight of tetranitromethylaniline and 90 parts by weight of ammonium perchlorate.
  • the explosive layer thus formed was initiated by detonator (as represented by a heavey dotted line in FIG. 13) from its edge farthest from the cladding metal sheet 3.
  • the detonation velocity D of this explosive layer 2 proved to be 2,100 m/sec.
  • the flying velocity V, of the cladding metal sheet 6 at the time of collision with the base metal sheet 4 proved to be 2,100 m/sec., and hence, the titanium sheet was firmly bonded to the steel sheet, so as to produce a clad metal.
  • Combustion and heat de composition compounds of the protective rubber layer 6 were left on the outer surface of the cladding titanium sheet, but such compounds were completely removed by wiping with a solvent. Consequently, a clean fresh surface of the titanium sheet was exposed.
  • the clad metal thus prepared was excellent for practical applications. Peeling tests and tensile strength tests showed that the peeling strength and the tensile strength of the clad metal were not smaller than 50 Kg/mm and 35 Kg/mm respectively.
  • the spacing between the cladding metal sheet 3 and the base metal sheet 4 was provided by supporting the cladding metal in the same way as the Example 1 by using aluminum cubes of suitable size inserted therebetween.
  • EXAMPLE 2 An arrangement similar to that of HO. 6 was formed, by using the folowing elements.
  • Base metal sheet 4 l00 200Xl5 mm steel plate of 41 Kg/mm tensile strength class Cladding metal sheet 3: lO0X200 2 mm stainless steel sheet of SUS-27 Spacing between the base and cladding metal sheets:
  • Protective layer 6 0.05 mm thick peelable synthetic resin coating plus 5 mm thick agar layer overlaid thereon
  • Driver plate 5 lX250 2 mm aluminum sheet
  • Explosive layer 2 l20X250 3 mm explosive sheet secured to the aluminum drive plate, consisting of 75 parts by weight of trinitrotrimethylenetriamine and parts by weight of a synthetic resin paste, with a detonation velocity D of 7,000 m/sec.
  • the driver plate 5 was supported by wooden blocks on the ground, where the base metal sheet 4 was also placed, so that the lower portion of the driver plate 5 was in contact with a lOO mm edge of the agar protective layer 6 while the dirver plate 5 being further extended downwards by 30 mm, as gnerally indicated in FIG. 6.
  • the explosive layer 2 was initiated at its lowermost edge by a linear wave generating means.
  • the drive plate 5 collided with the cladding metal sheet 3 through the protective layer 6, so as to cause the stainless steel sheet 3 to collide the steel base metal sheet 4 at a base sheet collision-propagating velocity of 3,480 m/sec.
  • a clad metal sheet consisting of a base steel sheet covered with a stainless steel sheet was produced.
  • EXAMPLE 3 An arrangement of FIG. 8 was formed by using the following materials.
  • Base metal sheet 4 l00 200X9 mm steel sheet of 815C
  • Cladding metal sheet 3 l00 200 l mm Hastelloy C Spacing between the sheets 3 and 4: 0.3 mm
  • the assembly of the parallel spaced sheets 3 and 4 was placed in a 15OX250 mm bag made of 0.1 mm thick polyethylene sheet, and the bag was sealed by a high-frequency sealing machine after de-aerating it.
  • the package thus made was placed in a water vessel of 300X300X50 mm cardboard box, so as to place the Hastelloy sheet upwards in parallel with the water surface in the vessel at a depth of 5 mm from the water surface.
  • driver plate 5 and a detonating driver plate 8 of the following dimensions were prepared.
  • Driver plate 5 l30X260 l mm mild steel sheet
  • Explosive layer 2 190 grams of explosive powder consisting of 2 parts by weight of tertranitromethylaniline and 98 parts by weight of ammonium perchlorate, being disposed on the driver plate'5 in the same manner as Example 1 in the form of l20X25OX6 mm layer
  • Detonating driver plate 8 l40 270 0.6 mm mild steel sheet
  • Initiator layer 7 95 grams of initiator powder consisting of 20 parts by weight of tetranitromethylamine' and parts by weight of ammonium perchlorate, being disposed on the detonating driver plate 8 in the same manner as Example 1 in the form of l30X26OX3 mm layer
  • Spacing between the detonating driver plate 8 and explosive layer 2 5 mm Five parallel cotton threads were stretched on the top opening of the cardboard box with a spacing of 10 mm between adjacent threads, so that the assembly of the aforesaid driver plate 5 and the de
  • the 260 mm edges of the driver plate 5 extended beyond the 200 mm edge of the cladding metal sheet 3 by 15 mm on either side thereof, while one of 130 mm edges of the driver plate 5 extended beyond the corresponding 100 mm edge of the cladding metal sheet 3 by 50 mm.
  • the center of the detonating driver plate 8 was vertically aligned with the center of the dirver plate 5, so that each edge of the former extended beyond the corresponding edge of the latter by 5 mm.
  • the initiator layer 7 of the aforesaid arrangement was fired at the edge farthest from the cladding metal sheet 3 by a No.- 6 electric detonator.
  • the initiator layer 7 was detonated at a detonation velocity d of 1,800 m/sec., so as to fire the explosive layer 2 at an initiating velocity of 1,800 m/sec. Consequently, the 6 mm thick explosive layer 2 was detonated at a detonation velocity D of 1,150 m/sec., with a detonating wave front 9 slanted 40 relative to the bottom surface of the explosive layer 2.
  • the driver plate 5 was driven through the water in the cardboard box, so as to cause the cladding Hastelloy C sheet to the base steel sheet st a base plate collision-propagating velocity V of 1,800 m/sec.
  • V base plate collision-propagating velocity
  • the Hastelloy sheet thus clad on the base steel sheet had an attractive fresh surface, as if it had not been sujbected to the explosion welding process.
  • As a result of cutting tests of the clad metal thus formed only one imperfect bond of about 15 mm length and 2-3 mm width was found at a portion corresponding to one edge of the initiator layer 8. Otherwise, the bond of the cladding metal to the base metal was perfect, without any cracks. Bending tests were made on specimens formed by cutting the clad metal, by bending each specimen with a radius equivalent to the specimen thickness. Neither peeling nor cracking was noticed in both of the bendings from the front surface and from the back surface of the clad metal.
  • EXAMPLE 4 An arrangement similar to that of FIG. 12 was formed by usingthe following materials, in which two cladding metal sheets 3 were used so as to sandwich one base metal sheet 4.
  • Base metal sheet 4 100 200 1 mm copper sheet
  • Two cladding metalsheets 3 each being 100X200 1 mm nickel sheet Spacing between the sheets 3 and 4: each being 0.2
  • the base metal sheet 4 was sandwiched by the two cladding metal sheets 3, while keeping all the edges of the sheets 3 and 4 in alignment with each other.
  • the assembly of the parallel spaced sheets 3 and 4 was placed on the ground acting as a worktable l1.
  • driver plate 5 and detonating driver plate 8 were prepared.
  • Driver plate 5 l50X280Xl mm steel sheet Explosive layer 2: the same explosive powder consisting of parts by weight of tetranitromethylaniline and 90 parts by weight of ammonium perchlorate, with an apparent density of 1.0 g/cm, being disposed on the driver plate 5 in the same manner as Example 1 in the form of 140 270X6 mm layer
  • Detonating driver plate 8 150 280 1 mm steel sheet
  • Initiator layer 7 same as the last mentioned explosive layer 2
  • the driver plate 5 carrying the explosive layer 2 was placed in parallel with the aforesaid assembly of the base and cladding metal sheets 3 and 4, while inserting the foamed resin spacer 12 between the assembly and the driver plate 5.
  • the 280 mm edges of the driver plate 5 extended beyond the corresponding 200 mm edge of the cladding metal sheet 3 by 25 mm on either side thereof, while one of 150 mm edges of the driver plate 5 extended beyond the corresponding mm edge of the cladding metal sheet 3 by 50 mm.
  • One of the mm edges of the detonating driver plate 8 was placed vertically 25 mm above the top surface of the explosive layer 2 in parallel with corresponding 150 mm edge of the wooden frame of the driver plate 5, at the side where the driver plate 5 extended beond the cladding sheet 3 by 50 mm.
  • the opposite 150 mm edge of the detonating driver plate 8 was placed vertically 10 mm above the top surface of the explosive layer 2. As a re sult, the detonating driver plate 8 was inclined by about 3, relative to the top surface of the explosive layer 2.
  • the initiator layer 7 of the aforesaid arrangement was fired at the edge farthest from the cladding metal sheet 3 by a linear wave generator.
  • the initiator layer 7 was detonated at a detonation velocity d of 1,800 m/sec, so as to fire the explosive layer 2 at an initiating velocity of 2,200 m/sec. Consequently, the 6 mm thick explosive layer 2 was detonated at a detonation velocity D of 1,800 m/sec., with a detonating wave front 9 slanted 55 relative to the bottom surface of the explosive layer 2.
  • the driver plate 5 was driven through the foamed urethane spacer 15 at a high speed, so as to collide with the assembly of the base and cladding sheets 3 and 4, for causing the cladding sheets 3 and the base steel sheet 4 to collide at a base plate collision-propagating velocity V of 2,200 m/sec.
  • V base plate collision-propagating velocity
  • Base metal sheet 4 20 50X3 mm tantalum sheet
  • Cladding metal sheet 3 20X50 3 mm tungsten sheet Spacing between the base and cladding metal sheets:
  • Spacer l2 foamed styrene member, with a 50x80 mm horizontal and a right-angled triangular cross section having a 10 angle facing the vertical edge, apparent density being 0.002 g/cm
  • Driver plate 5 2 mm thick aluminum sheet of similar size with the inclined surface of the spacer 15
  • Expolsive layer 2 3 mm thick explosive sheet secured to the aluminum driver plate, with apparent density of 1172 gjcm and a detonation velocity D of 4,000 m/sec.
  • the parallel combination of the base sheet 4 and the cladding sheet 3 was placed on the ground with the cladding sheet facing upwards.
  • the horizontal surface of the spacer 15 was placed on the cladding sheet 3, so that the each edge of the horizontal surface of the spacer extends beyond the corresponding paralleldisposed edges of the cladding sheet 3 by 15 mm.
  • the driver plate 5 was placed on the inclined top surface of the spacer 15 so as to be inclined by 10 relative to the cladding tungesten sheet 3.
  • the explosive layer 2 was initiated at the central portion of its lowermost edge by a No. 6 electric detonator.
  • the driver plate 5 collided with the cladding tungsten sheet 3 after flying through the spacer 15, so as to cause the cladding tungsten sheet 3 to collide the base tantalum sheet 4 at a base sheet collisionpropagating velocity V, of 2,500 m/sec.
  • V base sheet collisionpropagating velocity
  • the bond between the base tantalum sheet 4 and the cladding tungsten sheet 3 proved to be satisfactory except two imperfections of about 3 mm width and about 5-10 mm length on edges of the cladding tungsten sheet 3. Otherwise the bond was perfect, without any cracks.
  • Base metal sheet 4 lX200Xl5 mm steel plate of 4] Kg/mm tensile strength class Cladding metal sheet 3: l00 200X6 mm titanium sheet of KS-50 Angle [3 between the base and cladding metal sheets:
  • Protective layer 6 l mm thick pressed black rubber of regular grade Driver plate l50 300X3 mm mild steel sheet Explosive layer 2: 30 mm thick explosive powder layer held by a cardboard frame secured to the mild steel driver plate, consisting of 10 parts by weight of tetranitromethylaniline and 90 parts by weight of ammonium perchlorate, with an apparent density of 1.1 g/cm"
  • Angle a between the driver plate 5 andthe protective layer 6 2
  • the angle ,8 between base steel sheet and the cladding titanium sheet was formed by keeping the 100 mm edges thereof in contact with each other while inserting an L-shaped spacer between the opposite l00 mm edges of the two sheets at a suitably inclined posture.
  • the angle a between the driver plate 5 and the protec- 'tive layer was also made by using a similar L-shaped spacer.
  • One of the ISO mm edges of the driver plate 5 extended slantly downwards beyond the 100 mm edge of the cladding titanium sheet 3, while extending the two 300 mm edges of the driver plate 5 beyond the 200 mm sides of the cladding titanium sheet by 25 mm on either side thereof.
  • the explosive layer 2 was initiated at its lowermost edge by a No. 6 detonator.
  • the detonation velocity D of the explosive layer 2 was 2,800 m/sec.
  • the driver plate 5 collided with the cladding metal sheet 3 through the protective layer 6 at a driver plate collision-propagating velocity of 2,550 m/sec., so as to cause the titanium sheet 3 to collide the steel base metal sheet 4 at a base sheet collision-propagating velocity of 2,330 m/sec.
  • a clad metal sheet consisting of a base steel sheet covered with a titanium sheet was produced.
  • EXAMPLE 7 An arrangement similar to that of FIG. 7 was formed, by using the following elements.
  • Base metal sheet 4 l00 200X9 mm steel plate of 41 Kg/mm tensile strength class Cladding metal sheet 3: l00 200X2 mm stainles steel sheet of SUS-27 Angle B between the base and cladding metal sheets:
  • Protective layer 6 2 mm thick agar layer overlaid on the cladding metal sheet
  • Driver plate 5 120X250 2 mm aluminum sheet
  • Explosive layer 2 l20 250X3 mm explosive sheet secured to the aluminum driver plate, consisting of parts by weight of triminitrotrimethylenetriamine and 25 parts by weight of a synthetic resin paste, with a detonation velocity D of 7,000 m/sec.
  • the driver plate 5 was supported by wooden blocks on the ground, where the base metal sheet 4 slantly carrying the cladding stainless steel sheet at 5 was placed, so that the lower portion of the driver plate 5 was supported from the ground by wooden blocks so as to keep the lower surface of the driver plate 5 in contact with a I00 mm edge of the agar protective layer 6 while the a driver plate 5 being further extended downwards by 30 mm, as generally indicated in FIG. 7.
  • the explosive layer 2 was initiated at its lowermost edge by a linear wave generating means.
  • the driver plate 5 was impinged to the cladding metal sheet 3 at a high speed through the protective layer 6 at a flying velocity of 3,500 m/sec., so as to cause the stainless steel sheet 3 to collide the steel base metal sheet 4 at a base sheet collision-propagating velocity V, of 2,160
  • the protective layer 6 consisting of the agar layer was replaced with a peelable synthetic resin coating on the top surface of the cladding stainless steel sheet.
  • the means for angularly supporting the driver plate 5 consisting of an L-shaped member was replaced with a foamed styrene resin member having a wedge-like cross section with a tip angle of 12 and an apparent density of 0.04 g/cm.
  • the size of the inclined surface of the foamed styrene resin member was substantially identical with the size of the aluminum drive plate 5.
  • EXAMPLE 9 An arrangement of FIG. 8 was formed by using the following materials.
  • Base metal sheet 4 lOX200 9 mm steel sheet of 41 Kg/mm tensile strength class Cladding metal sheet 3: l00 200 2 mm titanium sheet Spacing between the sheets 3 and 4: 1 mm
  • Driver plate 5 l30 270 l mm mild steel sheet
  • Explosive layer 2 20 mm thick explosive layer consisting of 2 parts by weight of tetranitromethylaniline and 98 parts by weight of ammonium perchlorate, being disposed on the driver plate 5 in the same manner as Example 1
  • Protective sheet 6 l00X200 l mm pressed black rubber sheet, secured to the cladding titanium sheet 3 by a synthetic resin adhesive
  • Detonating driver plate 8 l70 300 0.8 mm mild steel sheet lnitiator layer 7: 1 mm thick initiator powder layer,
  • Example I The detohating driver plate 8 was disposed in parallel with the driver plate 5, while keeping all the edges of the two plates 5 and 8 in parallel with each other. One of the 170 mm edges of the detonating driver plate 8 extended beyond the corresponding edge of the driver plate 5 by 30 mm.
  • the initiator layer 7 of the aforesaid arrangement was fired at the center of the edge farthest from the cladding metal sheet 3 by a No. 6 electric detonator.
  • the initiator layer 7 was detonated at detonation velocity d of 2,500 m/sec, so as to fire the explosive layer 2 at an initiating velocity of 2,500 m/sec. Consequently, the 6 mm thick explosive layer 2 was detonated, with a detonating wave front 9 slanted by 23,6 relative to the bottom surface of the explosive layer 2.
  • the driver plate 5 was driven through the protective rubber layer 6 to the cladding titanium sheet 3 at a driver plate collision-propagating velocity V of 2,120 m/sec., so as to cause the cladding titanium sheet 3 to collide with the base steel sheet at a base sheet collision-propagating velocity V of 1,820 m/sec.
  • V driver plate collision-propagating velocity
  • Example II The same tests as Example I were made on the clad metal thus obtained in this Example 9, and excellent properties of the clad metal were proved by such tests.
  • EXAMPLE l0 An arrangement similar to FIG. 12, as modified by the disposition of FIG. 7, was formed by using the fol' lowing materials.
  • Base metal sheet 4 l00 150Xl5 mm steel plate of SPC 15 class Cladding metal sheet 3: 100x l50 6.4 mm Hastelloy C sheet Angle B between base metal sheet 4 and cladding metal sheet 3: 15
  • Driver plate 5 120 170 3 mm mild steel sheet Explosive layer 2: l20 l70 8 mm explosive layer.
  • the base steel sheet 4 was placed on the ground, and one of the two mm edges of the cladding metal sheet 3 was kept in contact with the corresponding 100 mm edge of the base steel sheet 4, so as to let the cladding metal sheet 3 extend over the base steel sheet 4 at an angle of 15.
  • Each edge of the driver plate 5 extended beyond the corresponding edges of the cladding Hastelloy sheet 3 by 10 mm, while the minimum vertical distance between the lower surface of the driver plate 5 and the protective layer 6 was 10 mm.
  • the angle ill between the bottom surface of the detonating l00 l50X2 mm vinyl acetate driver sheet 8 and the top surface of the explosive layer 2 was defined at the uppermost edge of explosive layer 2, i.e., at the opposite edge to the edge where the angle a of 15 was defined between the bottom surface of the driver plate 5 and the protective layer 6.
  • the initiator layer 7 was fired by a line wave generator, at its edge opposite to the edge where the angle ill of was defined.
  • the initiator layer 7 expolded at a detonation velocity 0' of 7,000 m/sec., so as to cause the detonating driver plate 8 to collide with the explosive layer 2 at initiating velocity of 24,300 m/sec., with a detonating wave front 9 slanted by l6.7 relative to the top surface of the driver plate 5.
  • the driver plate 5 was driven through the protective vinyl acetate layer 6 to the cladding metal sheet 3 at a driver plate collisionpropagating velocity V of l,870 m/sec., so as to cause the cladding Hastelloy sheet 3 to collide with the base steel sheet 4 at a base sheet collision-propagating velocity V, of 1,290 m/sec.
  • V driver plate collisionpropagating velocity
  • the weakly bonded portion was located close to the position of the linear wave generator.
  • the 100 mm edge of the cladding Hastelloy sheet 3 was in contact with the corresponding 100 mm edge of the base steel sheet 4 in this Example 10. An extra test was made, while separating the 100 mm edge of the Hastelloy sheet from the corresponding 100 mm edge of the base steel sheet by 0.5 mm, and in this case no weakly bonded portion was generated.
  • the surfaces of the metal sheets to be bonded were polished, mechanically or chemically, so as to remove any oxide film therefrom. ln the case of those anti-corrosion metal whose oxide is negligible, the surfaces to be bonded were cleansed by a suitable solvent for removing foreign matters therefrom, prior to the explosion welding tests.
  • An explosive welding process comprising the steps of disposing at least one cladding metal sheet so as to face a base metal sheet with a spacing equivalent to one-twentieth to times the thickness of that one of the two sheets which is to be driven toward the other sheet.
  • a protective layer on the sheet to be driven at the surface of the latter facing away from the other sheet placing a driver plate so as to face the protective layer with a spacing equivalent to one-twentieth to twenty-five times the thickness of the driver plate, the latter being at least as wide as the sheet to be driven, forming an explosive layer on the driver plate on the surface of the latter facing away from the protective layer, and igniting the explosive layer to cause the driver plate to collide with and drive the sheet to be driven, for generating a colliding impact large enough to bond the cladding metal sheet to the base metal, the explosive layer being so related with the spacing between the driver plate and the protective layer that the driver plate collides with the protective layer at a velocity which is fast enough to cause the sheet to be driven to collide with the other metal sheet at a velocity faster than 800 m/sec. but slower than the highest sonic velocity in the cladding and the base metal sheets.
  • the cladding metal sheet consists of a metal selected from the group consisting of titanium, stainless steel, Hastelloy, brass, bronze, copper zirconium, nickel, tantalum, silver, gold, platinum, tungsten, niobium, chronium, cobalt, aluminum, molybdenum, magnesium, vanadium, zinc, tin and their alloys.
  • the thickness of the protective layer is tapered so as to provide varying time delays in the delivery of the collision impact of the driver plate to the cladding metal sheet.

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US00207873A 1970-12-15 1971-12-14 Explosive welding process Expired - Lifetime US3813758A (en)

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USRE29879E (en) * 1975-07-11 1979-01-16 Western Electric Company, Inc. Method of forming a laminate
US4333597A (en) * 1980-05-27 1982-06-08 Explosive Fabricators Method of explosively forming bi-metal tubeplate joints
US4887761A (en) * 1987-12-16 1989-12-19 Imperial Chemical Industries Plc Method of making explosively bunded multi-laminar composite metal plate
US5138114A (en) * 1990-09-27 1992-08-11 Texas Instruments Incorporated Hybrid/microwave enclosures and method of making same
US5318213A (en) * 1990-11-30 1994-06-07 British Aerospace Public Limited Company Explosive bonding
CN100408247C (zh) * 2006-03-13 2008-08-06 洛阳双瑞金属复合材料有限公司 Hastelloy B-3-钢金属复合材料的制造方法
US20110127020A1 (en) * 2008-06-30 2011-06-02 Outotec Oyj Method for manufacturing a cooling element and a cooling element
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US8336180B2 (en) 2010-09-29 2012-12-25 Flsmidth A/S Method of forming or repairing devices configured to comminute material
US8484824B2 (en) 2010-09-01 2013-07-16 Flsmidth A/S Method of forming a wearable surface of a body
CN103495840A (zh) * 2013-09-27 2014-01-08 新兴铸管股份有限公司 双层合金复合板的生产方法
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CN105643127A (zh) * 2016-02-29 2016-06-08 西安天力金属复合材料有限公司 一种多晶硅提炼设备用大幅面银/钢复合板的制备方法
CN106624328A (zh) * 2015-11-03 2017-05-10 南京和畅新材料有限公司 爆炸焊接铌钢复合板的方法
CN108145303A (zh) * 2017-12-21 2018-06-12 安徽宝泰特种材料有限公司 大面积全贴合率锆/钛/钢爆炸复合板的制备方法
WO2019063010A1 (zh) * 2018-03-05 2019-04-04 中国矿业大学 一种锆基金属玻璃与轻质金属板的爆炸焊接方法
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US11084122B2 (en) 2017-07-13 2021-08-10 Ohio State Innovation Foundation Joining of dissimilar materials using impact welding
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CN103586574B (zh) * 2013-10-16 2015-10-21 太原理工大学 一种镁铝合金复合板的爆炸焊接成型方法
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US4333597A (en) * 1980-05-27 1982-06-08 Explosive Fabricators Method of explosively forming bi-metal tubeplate joints
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US5318213A (en) * 1990-11-30 1994-06-07 British Aerospace Public Limited Company Explosive bonding
CN100408247C (zh) * 2006-03-13 2008-08-06 洛阳双瑞金属复合材料有限公司 Hastelloy B-3-钢金属复合材料的制造方法
US20110127020A1 (en) * 2008-06-30 2011-06-02 Outotec Oyj Method for manufacturing a cooling element and a cooling element
US8701967B2 (en) * 2008-06-30 2014-04-22 Outotec Oyj Method for manufacturing a cooling element and a cooling element
WO2011133269A1 (en) * 2010-04-23 2011-10-27 Flsmidth A/S Wearable surface for a device configured for material comminution
US8281473B2 (en) 2010-04-23 2012-10-09 Flsmidth A/S Wearable surface for a device configured for material comminution
CN102858457A (zh) * 2010-04-23 2013-01-02 Fl史密斯公司 用于材料粉碎装置的耐磨表面
US8484824B2 (en) 2010-09-01 2013-07-16 Flsmidth A/S Method of forming a wearable surface of a body
US8336180B2 (en) 2010-09-29 2012-12-25 Flsmidth A/S Method of forming or repairing devices configured to comminute material
CN102430900B (zh) * 2011-10-30 2014-02-26 太原钢铁(集团)有限公司 一种复合钢板的制造方法
CN102430900A (zh) * 2011-10-30 2012-05-02 太原钢铁(集团)有限公司 一种复合钢板及其制造方法
CN103495840B (zh) * 2013-09-27 2016-06-29 新兴铸管股份有限公司 双层合金复合板的生产方法
CN103495840A (zh) * 2013-09-27 2014-01-08 新兴铸管股份有限公司 双层合金复合板的生产方法
CN103639585A (zh) * 2013-12-21 2014-03-19 西安天力金属复合材料有限公司 厚复层锆/钛/钢复合板爆炸复合中雷管区的控制方法
CN103639585B (zh) * 2013-12-21 2016-05-25 西安天力金属复合材料有限公司 厚复层锆/钛/钢复合板爆炸复合中雷管区的控制方法
CN106624328A (zh) * 2015-11-03 2017-05-10 南京和畅新材料有限公司 爆炸焊接铌钢复合板的方法
CN105643127A (zh) * 2016-02-29 2016-06-08 西安天力金属复合材料有限公司 一种多晶硅提炼设备用大幅面银/钢复合板的制备方法
US11084122B2 (en) 2017-07-13 2021-08-10 Ohio State Innovation Foundation Joining of dissimilar materials using impact welding
US11759884B2 (en) 2017-07-13 2023-09-19 Ohio State Innovation Foundation Joining of dissimilar materials using impact welding
CN108145303A (zh) * 2017-12-21 2018-06-12 安徽宝泰特种材料有限公司 大面积全贴合率锆/钛/钢爆炸复合板的制备方法
WO2019063010A1 (zh) * 2018-03-05 2019-04-04 中国矿业大学 一种锆基金属玻璃与轻质金属板的爆炸焊接方法
CN110064835A (zh) * 2019-04-11 2019-07-30 洛阳双瑞金属复合材料有限公司 一种tmcp型桥梁钢不锈钢复合板爆炸焊接制造方法
CN110948109A (zh) * 2019-11-28 2020-04-03 西部金属材料股份有限公司 一种镁基与铝基异种金属板材的焊接方法
CN114599163A (zh) * 2021-04-15 2022-06-07 河南科技大学 一种铜基复合板材的制备方法
CN114599163B (zh) * 2021-04-15 2023-10-31 河南科技大学 一种铜基复合板材的制备方法

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DE2161414B2 (de) 1973-06-20
SE381202C (sv) 1977-05-09
SE381202B (sv) 1975-12-01

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