DESC:FIELD OF THE INVENTION:
This invention relates to the field of metallurgy.

Particularly, this invention relates to an improved shaped charge liner.

Specifically, this invention relates to a process for making a bimetallic shape-charged liner.

BACKGROUND OF THE INVENTION:
A shaped charge is an explosive filled cavity to focus the effect of the associated chemical energy. Different types of shaped charges are used for various purposes such as cutting and forming metal, initiating nuclear weapons, penetrating armour, or perforating wells in the oil and gas industry.

Typical modern shaped charge, with a metal liner on the charge cavity, can penetrate armour steel to a depth of seven or more times the diameter of the charge; prior art liners, used in shaped charge applications, are made of a single metal.

In prior arts, it was observed that shaped charge were, typically, associated with 20% mass in jet and 80% mass going into a slug, and hence associated with retarding penetration performance.

There is, therefore, a need to improve this performance.

In order to achieve optimum penetration, in shaped charge application, it is necessary to get high density jet mass produced from this phenomenon. For such applications, cones with high mass are desired for obtaining higher penetration or effective destruction of the target, while undergoing plastic deformation at very high temperature and pressure associated with implosion of the cone triggered by explosive.

For achieving optimum penetration, it is necessary to get high density jet mass produced from this phenomenon.

Simulation studies have forecasted that in order to get maximum penetration in a target, a frontal tip or a jet is required to be developed with solid copper after the deformation.

Also, the simulation study predicts that majority of the frontal part, of the jet, is primarily important whereas its rear portion viz., slug is undesired.

Therefore, there is a need to provide a shaped charge liner which alleviates the problems listed above.

OBJECTS OF THE INVENTION:
An object of the invention is to improve performance of applications where shaped charge liners are used.

Another object of the invention is to reduce slug mass in jet of a shaped charge.

Yet another object of the invention is to provide a shaped charge liner which performs as a slugless jet.

Still another object of the invention is to improve penetration performance of shaped charge liners.

Another object of the invention is to make a bimetallic shape-charged liner of greater effectiveness applicable to the field of metallurgy.

SUMMARY OF THE INVENTION:
According to this invention, there is provided an improved shaped charge liner, being a bimetallic conoid liner, formed of metals having different densities, said improved shaped charge liner formed by a method comprising the steps of:
- picking out two different metal disks, each disk having a different density than the other, each disk having a different flow property than the other under stress, shear-formed, separately, into separate individual cones;
- shear-forming, of said different metal disks, on to a mandrel, separately, in order to form separate cones;
- annealing of said different cones having different densities and different flow rates in order to achieve desired hardness level/s; and
- diffusion welding said annealed separate cones, together, under optimum isostatic conditions such that it provides possible positive contact of mating surfaces, of the annealed separate cones, in order to form a single conoid being an improved shaped charge liner.

In at least an embodiment, at least one metal is a light metal and at least one metal is a heavy metal.

In at least an embodiment, at least one metal is a Copper metal and at least one metal is an Aluminium metal.

In at least an embodiment, an operative front part which produces a jet being a heavier metal and an operative rear part which contributes to slug being a lighter metal.

In at least an embodiment, the conoid so formed having an outer surface material, in contact with explosives, is a relatively lighter metal and an inner surface material, not in contact with explosives, is a relatively heavier metal.

In at least an embodiment, said optimum conditions, for diffusion bonding under isostatic environment, being selected from 0.5 Mpa (pressure) to 90Mpa (pressure), 120s (holding time) to 5400s (holding time), and 510 0C (temperature) to 540 0C (temperature).

In at least an embodiment, said step of vacuum annealing comprising following parameters:
- Oven Atmosphere: <0.1 bar;
- Flushing (required only with inert gas);
- Preheat temperature: 2500 C;
- Preheat duration: < 10min;
- Annealing Temperature: 400 (-20) 0C
- Duration: 30(+5) min;
- Cooling shall be done under pressure using protective gas such as N2.

In at least an embodiment, said step of diffusion welding comprising following steps and parameters:
- Pre-heating die-punch assembly to assembly to 450OC under pressure for not more than 30 minutes;
- Set the thermostat to the diffusion welding temperature;
- Once the pre-set temperature of the die-punch assembly reaches above temperature, preheat the liners at 450OC in vacuum furnace for 5 minutes;
- Apply light oil on both the mating surfaces of die-punch assembly;
- Transfer carefully coper liner from vacuum furnace to the die cavity also immediately transfer aluminium liner from furnace and place over the copper liner;
- Once both the liners are placed in die; starts pressing till the desired welding pressure is achieved;
- Pressing to continue for the desired holding time for diffusion welding; and
- Remove the Liners after 30 minutes of operation.

In at least an embodiment, said step of diffusion welding comprising following steps and parameters:
- Polishing with light (180) grit emery;
- Chemical Treatment: soaking of the liners:
(a) aqueous solution in distilled water of 2.5ml concentrated (90%) nitric acid for 20mins,
(b) 1.5 ml of dilute (50%) hydrochloric acid for 30mins,
(c) 1.0ml concentrated (65%) hydrofluoric acid) for 10mins and followed by
(d) Rinsing with distilled water.
In at least an embodiment, said method comprising a step of post-treatment of liners with the following steps and process parameters:
- Chemical Treatment done by soaking of the liners:
(a) aqueous solution in distilled water of 2.5ml concentrated (90%) nitric acid for 20mins,
(b) 1.5 ml of dilute (50%) hydrochloric acid for 30mins,
(c) 1.0ml concentrated (65%) hydrofluoric acid) for 10 mins and followed by
(d) Rinsing with distilled water;
- Wrapping the Liners into paper.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS:
The invention will now be described in relation to the accompanying drawings, in which:

Fig. 1 illustrates a process of collapse of shaped charge liner;
Fig. 2 illustrates a schematic configuration of Bimetallic lined shaped charge;
Fig. 3 illustrates a flow diagram depicting steps for shear forming;
Fig. 4 illustrates a flow diagram depicting steps for vacuum annealing of copper liners;
Fig. 5 illustrates a flow diagram depicting steps for diffusion welding of liners; and
Fig. 6 illustrates a step-wise formation of the improved shaped charge liner of this invention using the method steps of this invention.

DESCRIPTION OF THE INVENTION:
According to this invention, there is provided an improved shaped charge liner. This invention describes a method for producing a bimetallic conoid.

In some embodiments, this method uses two different metal disks, shear-formed separately into different cones, using separate tools for dimpling, flow-forming, profiling, separate pre-treatment, combined iso-static pressing. Typically, at least one metal is a light metal and at least one metal is a heavy metal.

Typically, this improved shaped charge liner is a bimetallic liner for shaped charge applications. By virtue of joining two different metals, performance of its final intended application is enhanced. By using bimetal, slug mass reduces drastically and tends to perform as nearly slugless jet; which is directly responsible for improved penetration performance of shaped charge.

It is desirable to bond these two materials’ liners, as previously discussed, in such a manner that they are able to sustain a just requirement of bonding during assembly with explosive charges and are also capable to provide high penetration performance. This requires a continuous interface between two different metal layers with good mechanical properties to sustain extreme pressures that they will experience during explosive compression. This causes the metals in a bimetallic liner to form a single directed penetrator as desired.

Presence of impurities, foreign matter, large discontinuity, voids or brittle intermetallic compound can affect the penetration performance in addition to the non-precision with regards to ovality, concentricity of the liners. These factors affect for separation of the conical liner under extreme

An exemplary method for particularly manufacturing a bimetallic, shape-charge liner consists of the steps of:
- shear-forming of dimpled blanks on to a mandrel, separately, for different materials, which has different flow properties to form separate cones;
- annealing of copper and aluminium liner to achieve desired hardness level/s;
- diffusion welding light and heavy metal cones, together, under optimum isostatic condition, using a tool (typically, die-punch assembly) that provides possible positive contact of mating surfaces in order to form a conoid.

Fig. 3 illustrates a flow diagram depicting steps for shear forming.
Fig. 4 illustrates a flow diagram depicting steps for vacuum annealing of copper liners.
Fig. 5 illustrates a flow diagram depicting steps for diffusion welding of liners.

In at least an embodiment, of this invention, it is postulated to use dissimilar layered copper-aluminium combination for developing shaped charge cones, that can produce higher mass frontal tip mainly consisting of copper and aluminium at rear on deformation.

In the simplest form, the method of manufacturing bimetallic conoids, according to the principles of the present invention, consists of, first, forming individual cones from the metal disks and, second, diffusion welding of these cones under optimised isostatic condition.

In at least an embodiment, a bimetallic liner is provided, in that the bimetallic liner is made of a first liner component, preferably made of Aluminium and a second liner component, preferably, made of copper; the two liner components being diffusion bonded. Optimum process parameters for diffusion bonding of Aluminium liner component with and Copper liner component, to form the bimetallic liner, of this invention, is 0.5 Mpa (pressure) to 90Mpa (pressure), 120s (holding time) to 5400s (holding time), and 510 0C (temperature) to 540 0C (temperature). It was observed that diffusion bonding, of two different liners components, imparts about 40% increase in penetration depth compared to similar dimensions of monolithic liner (preferably, made of copper).

An exemplary method for particularly manufacturing a bimetallic, shape-charge liner consists of the steps of:
(a) Punching out circular blanks from metallic sheet/s (at least one being light metal and at least one being heavy metal);
(b) Dimpling of the punched out circular blanks separately to provide a basic tip radius (tip radius and tip thickness achieved during this process is the final one as difficult to achieve in shear forming particularly inside tip radius whereas the outside tip radius is achievable during final sixing operation);
(c) Shear forming of the dimpled blanks on to a mandrel designed separately for different materials, which has different flow properties to form separate cones (Mandrel with accurate tip radius provides firm hold to the dimpled circular blanks during shear forming. Tip radius for both the overlapping liners designed differently in order to provide the positive contact during diffusion bonding; thereby different mandrels are designed for fabricating the light and heavy material cones having desired tip radius but same slant angle. Further Roller (nose radii R3, diameter 300mm incident angle 5o) and Mandrels (conical base diameter 250mm slant angle 60o each with tip radii of 5.2mm and 6.2mm) made from ASTM A681-D2 (50-60HRC 0.8µm surface finish) ;
(d) Parting of excess material, with different tooling, in order to achieve final dimensions for different cones;
(e) Vacuum annealing of copper liner to achieve desired hardness level;
(f) Roughing mating surfaces with light-grit (180) emery for ease in diffusion welding;
(g) Pre-treatment of cones based on the metallurgy, separately:
(i) Aluminum cones are soaked into: 10% Na2CO3 (sodium carbonate) solution for 15 minutes followed by 50% dilute HCl (hydrochloric acid) for 15 minutes subsequently with 5% dilute HNO3 (nitric acid) solution for 20 minutes and rinsing with distilled water for 10 minutes;
(ii) Copper cones are soaked into: 28% HNO3 (nitric acid) solution for 15 minutes followed by 50% dilute HCl (hydrochloric acid) for 15 minutes, subsequently 1% dilute HF (hydrofluoric acid) for 20 minutes and rinsing with distilled water for 10 minutes
Diffusion welding light metal cones and heavy metal cones, together, under optimum isostatic condition using a tool that provides possible positive contact of the mating surfaces to form a conoid;
(h) Post-treatment of the bonded conical liner before using it into an explosive filling operating.

In preferred embodiments, the process parameters for vacuum annealing of copper liners are as follows:
- Oven Atmosphere: <0.1 bar
- Flushing (required only with inert gas)
- Preheat temperature: 2500C
- Preheat duration: < 10min
- Annealing Temperature: 400 (-20) 0C
- Duration: 30(+5) min
- Cooling done under pressure using protective gas such as N2

In preferred embodiments, the process parameters for preparation of diffusion welding setup are as follows:
- Preheat the Die-Punch assembly to 450OC under pressure for not more than 30 minutes;
- Set the thermostat to the diffusion welding temperature;
- Once the pre-set temperature of the die-punch assembly reaches above temperature- Preheat the Liners at 450OC in vacuum furnace for 5minustes;
- Apply light oil on both the mating surfaces of die-punch assembly;
- Transfer carefully coper liner from vacuum furnace to the die cavity also immediately transfer aluminium liner from furnace and place over the copper liner;
- Once both the liners are placed in die; starts pressing till the desired welding pressure is achieved;
- Pressing to continue for the desired holding time for diffusion welding;
- Remove the Liners after 30 minutes of operation.

In preferred embodiments, the process parameters for diffusion welding of liners are as follows:
- Polishing with light (180) grit emery;
- Chemical Treatment: soaking of the liners:
(a) Aluminum cones are soaked into:
10% Na2CO3 (sodium carbonate) solution for 15 minutes;
50% dilute HCl (hydrochloric acid) for 15 minutes;
5% dilute HNO3 (nitric acid) solution for 20 minutes; and
rinsing with distilled water for 10 minutes.
(ii) Copper cones are soaked into:
28% HNO3 (nitric acid) solution for 15 minutes;
50% dilute HCl (hydrochloric acid) for 15 minutes;
1% dilute HF (hydrofluoric acid) for 20 minutes; and
rinsing with distilled water for 10 minutes.

In preferred embodiments, the process parameters for post-treatment of liners are as follows:
- Chemical Treatment: soaking of the liners:
(a) aqueous solution in distilled water of 2.5ml concentrated (90%) nitric acid for 20mins,
(b) 1.5 ml of dilute (50%) hydrochloric acid for 30mins,
(c) 1.0ml concentrated (65%) hydrofluoric acid) for 10 mins and followed by
(d) Rinsing with distilled water
- Wrapping the Liners into paper.

In preferred embodiments, Aluminium is used as the lighter metal sheet to form the outer cone in contact with an explosive whereas Copper is used as the heavier metal sheet for the inner cone. The aluminium, being pyrophoric in nature, on sufficient combustion, produces oxide vapours with exothermicity. This aluminium oxide being vaporised does not form part of the slug / jet and further reduces the slug mass leading to nearly-slugless penetration.

The conical liners, when individually formed, as cones, by shear-forming, provides apt grain flow and grain direction along the axis of cones. Further, adhesion of these distinct cones by isostatic diffusion welding provides a uniform thickness of intermetallic compound. The properties of intermetallic compound are controlled by diffusion welding parameters such as pressure, temperature, and holding time. Optimum process parameters provide optimum lap shear strength (15N to 50N) to the diffusion welded liners. In case of lesser strength, there is always scope of detachment / delamination of the cones before subjecting the bimetallic liners for explosive filling.

Some major disadvantage of the bimetallic liners formed using explosion welding are:
(a) the rippled interface formed from the molten metal;
(b) larger interface thickness which cannot be reduced and thus not useful particularly in smaller caliber of the shaped charges.
Contrarily, the diffusion welding process leads to tiny level interface due to atomic level mass transfer, with marginal bond shear strength that is just sufficient to hold both the liners together in assembly with explosive charge.

The cones, when separately shear formed, maintain accurate dimensions that can provide positive contacts during diffusion welding with under optimum isostatic conditions; with the pyrophoric liner on the exterior side (to be in contact with explosive) provides an improved liner for shaped charge application.

Collapse of bimetallic liner is similar to monolithic liner. When this invention’s bimetallic liner collapses onto itself, under extremely high pressures, exerted by the shaped-charge explosion, these materials form a long, thin, continuous, rod like penetrator directed along a conical axis of the charge liner.

However, it was observed in simulation studies, according to one non-limiting exemplary embodiment, that every section of a liner contributes to all along length of jet and slug. The explosive shock outside liner walls causes deforming liner to move inwardly to their surfaces at collapse velocities (implosion). The movement due to collapse being converging, the inner part moves faster than the outer part due to continuity of mass. The velocity increases rapidly as it converges more towards the centre and the outer surface lags in velocity. The inner part of the cone forms a jet which is squeezed out from inner-apex of the lining while the outer part which is moving slower to the inner forms the residue in the form of slug. Thus, metal in the conical lining divides into two parts of gradient velocity based on the position, with the dividing surface between these two liner components being a cone lying somewhere within the inner and outer surfaces of the original hollow cone.

According to non-limiting exemplary embodiments, conical, bimetal, shaped-charge liners of approximately 60mm caliber (and 600 angle) were formed in accordance with the method of the present invention by shear forming aluminium and copper liners out of 100mm diameter 2mm in thickness circular disks. The circular disks were dimpled, separately, to provide the tip radius separately so that:
(a) tip radius is maintained for overlapping the formed cones; and
(b) concentricity before shear forming is available.

These dimpled disks were subjected to shear forming for transforming into the cones on a separate mandrel which has major difference of tip radius while the angle is uniform. The cones so produced have a final thickness of 1.05mm. The formed cones, were then subjected to parting operation to get a desired height and
dimensions of the base. The formed and parted cones owing different metals accrue higher hardness and thereby subjected to annealing process (vacuum annealing for copper and solution annealing for aluminium cones).

In order to accelerate the diffusion welding, mating surfaces of the annealed cones (outer surface of copper cone and inner surface of aluminium cone) were prepared by polishing with light grit emery and followed by pre-treatment with chemicals such as:
- aqueous solution in distilled water of 2.5ml concentrated (90%) nitric acid,
- 1.5 ml of dilute (50%) hydrochloric acid, and
- 1.0ml concentrated (65%) hydrofluoric acid)
in order to remove any grit, oil, dust or foreign matter.

For diffusion welding, the setup placed under hydraulic press is kept pre-heated at the temperature of about 450oC. The temperature of bonding selected below the solvus line in Al-Cu phase diagram. The isostatic condition for diffusion welding includes constant pressure, controlled temperature, and holding time. The tool for diffusion welding is a die-punch assembly designed to provide positive contacts between the mating surfaces of the different metal cones. In order to get best results, for shaped charge application, the optimum conditions for diffusion welding of aluminium-copper copper liners are 0.5MPa, Temperature 5100C, and holding time of 5400s. Post treatment of the diffusion welded bimetallic cones include:
- chemical treatment with aqueous solution in distilled water of 2.5ml concentrated (90%) nitric acid,
- 1.5 ml of dilute (50%) hydrochloric acid, and
- 1.0ml concentrated (65%) hydrofluoric acid.
The final wall thickness of the cone measured 2.mm and was equally divided between copper and aluminium.

Metallographic and mechanical investigations confirmed intermetallic compound responsible to achieve higher penetration performance. The recovered slug on penetration confirms the slugless jet phenomena with improved penetration performance.

Upon examination of bimetallic liners formed with diffusion welding at optimised isostatic conditions, it observed no tangible change in the hardness, grain flow, grain orientation. The intermetallic compound formed (s, ?, ?1, ?1, d, ?, ?2, a1, a2) responsible for better mechanical strength of the bond, which is just sufficient to hold both the liners in welded form. No separation occurs during detonation and

Tip radius (outer radii 7.2 mm and 6.2mm for Alumnium while inner radii 6.2mm and 5.2mm respectively for Copper and 6.2mm for Alumnium), angle (60o) and basic height (6mm) provides a starting point for the shear forming operation. A computer numerically controlled 3-axis shear forming operation gives better control in forming the high-precision liners. Handling of the malleable, ductile formed cones is significant at every stage of manufacture.

It can be seen that this method provides a very effective and efficient method of producing a bimetallic, shape-charged liner.

As compared to monolithic shaped charge when constructed with single metal (copper), according to prior art, a gradient is created with the use of different metals; the inner layer, being relatively lighter, being responsible to amplify jet velocity.

Fig. 1 illustrates a process of collapse of shaped charge liner.

The metal from the outer-cone traverses into a slug that travels to the left at relatively slow speeds (500 to 1000 m/s) while that from inner-cone traverses into a jet that travels to the right along the axis at very high speeds (2000 to 10000 m/s) depicted in process of liner collapse in bimetallic jet, as shown in fig 1.

Kinetic energy comprising components of mass and velocity. For a finite duration interaction process, an element gets more velocity, if mass is reduced. Therefore, by using a liner of relatively lighter mass / density, it will produce relatively higher velocity jet. On the contrary, a low-density jet will be less effective for penetration {P=Lv(?j/?t), P - penetration, L- length of jet, ?j- density of jet & ?t - density of target material}. Thus, for optimum penetration, it is desired to have high velocity and high-density jet.

While accomplishing this type of arrangement, mass of slug also reduces substantially. The massive slug formed in collapse of monolithic-liner, of the prior art, can have tendency to plug a hole formed by the jet; thus, defeating the purpose of Chemical Energy warheads to penetrate an armour or inhibiting / preventing flow of oil in oil well.

To achieve this objective, in accordance with at least an embodiment of this invention, the liner is, now, a bimetallic liner, having metals of different densities, in that, an operative front part which produces a jet is made, preferably, of copper and an operative rear part which mainly contributes to slug is made, preferably, of Aluminium.

The resulting bimetallic, shape-charged liner is ductile, and this method is best in manufacturing technology.

The advantages of a bimetallic liner in shaped charge application are:
(i) Diagnosing jet formation;
(ii) Overcoming limitations imposed by mechanical response, i.e., shock velocity, coherency;
(iii) Increasing jet ductility from exothermic intermetallic reaction between metals during jet formation; and
(iv) Reducing cost of high density or high valued materials (e.g. gold, platinum, rhenium, tantalum)

According to a non-limiting exemplary embodiment, a study was conducted in which 60 caliber shaped charges were formulated with Aluminium and Copper as the Aluminium material as liner material (3%), head height of explosive maintained as one calibre, the charge was point detonated at base and filled with HMX based main composition and Booster of RDX based composition, as shown in fig.2.

Fig. 2 illustrates a schematic configuration of Bimetallic lined shaped charge.

The Liners had been flow-formed, individually, and diffusion-bonded under isostatic condition. The parameters of the bonding were optimised, as mentioned above, and the shaped charge, using such liners, were tested for penetration performance.

As compared to monolithic shaped charge when constructed with single metal (preferably, Copper), according to prior art, a gradient is created with use of different metals; the inner layer, being relatively lighter, being responsible to amplify jet velocity.

Fig. 1 also depicts a scheme of collapse of bimetallic liner wherein the inner liner collides onto the axis.

Fig. 6 illustrates a step-wise formation of the improved shaped charge liner of this invention using the method steps of this invention.

According to a non-limiting exemplary embodiment, it was, further, observed that bimetallic liner, of this invention, filled with high explosive produces jet velocity which is about 28% higher than that with monolithic liner.

According to a non-limiting exemplary embodiment, it was, further, observed that with bimetallic liner, of this invention, slug mass is 35% of the original liner mass compared to 80% in monolithic liner (of the prior art).

The TECHNICAL ADVANCEMENT of this invention lies in providing an improved shaped charge liner such that by using bimetal, its slug mass reduces drastically and tends to perform as slugless jet.; this is responsible for improved penetration performance of shaped charge which is its TECHNICAL ADVANTAGE.

While this detailed description has disclosed certain specific embodiments for illustrative purposes, various modifications will be apparent to those skilled in the art which do not constitute departures from the spirit and scope of the invention as defined in the following claims, and it is to be distinctly understood that the foregoing descriptive matter is to be interpreted merely as illustrative of the invention and not as a limitation.

,CLAIMS:WE CLAIM,

1. An improved shaped charge liner, being a bimetallic conoid liner, formed of metals having different densities, said improved shaped charge liner formed by a method comprising the steps of:
- picking out two different metal disks, each disk having a different density than the other, each disk having a different flow property than the other under stress, shear-formed, separately, into separate individual cones;
- shear-forming, of said different metal disks, on to a mandrel, separately, in order to form separate cones;
- annealing of said different cones having different densities and different flow rates in order to achieve desired hardness level/s; and
- diffusion welding said annealed separate cones, together, under optimum isostatic conditions such that it provides possible positive contact of mating surfaces, of the annealed separate cones, in order to form a single conoid being an improved shaped charge liner.

2. The improved shaped charge liner as claimed in claim 1 wherein, at least one metal is a light metal and at least one metal is a heavy metal.

3. The improved shaped charge liner as claimed in claim 1 wherein, at least one metal is a Copper metal and at least one metal is an Aluminium metal.

4. The improved shaped charge liner as claimed in claim 1 wherein, an operative front part which produces a jet being a heavier metal and an operative rear part which contributes to slug being a lighter metal.

5. The improved shaped charge liner as claimed in claim 1 wherein, the conoid so formed having an outer surface material, in contact with explosives, is a relatively lighter metal and an inner surface material, not in contact with explosives, is a relatively heavier metal.

6. The improved shaped charge liner as claimed in claim 1 wherein, said optimum conditions, for diffusion bonding under isostatic environment, being selected from 0.5 Mpa (pressure) to 90Mpa (pressure), 120s (holding time) to 5400s (holding time), and 510 0C (temperature) to 540 0C (temperature).

7. The improved shaped charge liner as claimed in claim 1 wherein, said step of vacuum annealing comprising following parameters:
- Oven Atmosphere: <0.1 bar;
- Flushing (required only with inert gas);
- Preheat temperature: 2500 C;
- Preheat duration: < 10min;
- Annealing Temperature: 400 (-20) 0C
- Duration: 30(+5) min;
- Cooling shall be done under pressure using protective gas such as N2.

8. The improved shaped charge liner as claimed in claim 1 wherein, said step of diffusion welding comprising following steps and parameters:
- Pre-heating die-punch assembly to assembly to 450OC under pressure for not more than 30 minutes;
- Set the thermostat to the diffusion welding temperature;
- Once the pre-set temperature of the die-punch assembly reaches above temperature, preheat the liners at 450OC in vacuum furnace for 5 minutes;
- Apply light oil on both the mating surfaces of die-punch assembly;
- Transfer carefully coper liner from vacuum furnace to the die cavity also immediately transfer aluminium liner from furnace and place over the copper liner;
- Once both the liners are placed in die; starts pressing till the desired welding pressure is achieved;
- Pressing to continue for the desired holding time for diffusion welding; and
- Remove the Liners after 30 minutes of operation.

9. The improved shaped charge liner as claimed in claim 1 wherein, said step of diffusion welding comprising following steps and parameters:
- Polishing with light (180) grit emery;
- Chemical Treatment: soaking of the liners:
(a) aqueous solution in distilled water of 2.5ml concentrated (90%) nitric acid for 20mins,
(b) 1.5 ml of dilute (50%) hydrochloric acid for 30mins,
(c) 1.0ml concentrated (65%) hydrofluoric acid) for 10mins and followed by
(d) Rinsing with distilled water.

10. The improved shaped charge liner as claimed in claim 1 wherein, said method comprising a step of post-treatment of liners with the following steps and process parameters:
- Chemical Treatmentdone by soaking of the liners:
(a) aqueous solution in distilled water of 2.5ml concentrated (90%) nitric acid for 20mins,
(b) 1.5 ml of dilute (50%) hydrochloric acid for 30mins,
(c) 1.0ml concentrated (65%) hydrofluoric acid) for 10 mins and followed by
(d) Rinsing with distilled water;
- Wrapping the Liners into paper.

Dated this 09th day of March, 2023

CHIRAG TANNA
of INK IDEE
APPLICANT’S PATENT AGENT
REGN. NO. IN/PA – 1785