Gradient Control Method for Microstructure Ultrafine Crystallization of Deep Cone Copper Shaped Charge Liner

Abstract

A gradient control method for a microstructure ultrafine crystallization of a deep cone copper shaped charge liner includes the steps of an extrusion forming, a recrystallization heat treatment, and a high-frequency percussion. A multi-pass extrusion is used in the extrusion forming, and in the high-frequency percussion step, a percussion speed is 30,000 to 40,000 times/min, a percussion force is 1600 N to 2000 N, and a number of percussion times is 1 to 3. The forming and surface quality control of the deep cone shaped charge liner are realized by the control technology of the present invention; the plasticity of the material is improved, and fine crystal structures are obtained; and an ultrafine grain gradient structure distributed along the thickness direction is formed in the inner surface of the shaped charge liner.

Claims

1. A gradient control method for a microstructure ultrafine crystallization of a deep cone copper shaped charge liner, comprising steps of an extrusion forming, a recrystallization heat treatment, and a high-frequency percussion gradient; wherein a multi-pass extrusion forming is used in the step of the extrusion forming, and in the step of the high-frequency percussion gradient, a percussion speed is 30,000 times/min to 40,000 times/min, a percussion force is 1600 N to 2000 N, and a number of percussion times is 1 to 3.

2. The gradient control method for the microstructure ultrafine crystallization of the deep cone copper shaped charge liner of claim 1, wherein the multi-pass extrusion forming is 4 to 8 passes of extrusion deformation under actions of a three-dimensional compressive stress and a deformation rate of 2 mm/s to 5 mm/s, a deformation amount of each pass of the 4 to 8 passes of extrusion deformation is 5% to 30%.

3. The gradient control method for the microstructure ultrafine crystallization of the deep cone copper shaped charge liner of claim 1, wherein the recrystallization heat treatment is carried out in a vacuum heat treatment furnace, a temperature of the recrystallization heat treatment is kept at 180 C. to 220 C., a holding time of the recrystallization heat treatment is 45 min to 75 min.

4. The gradient control method for the microstructure ultrafine crystallization of the deep cone copper shaped charge liner of claim 1, wherein an annealing treatment is performed before the extrusion forming, an annealing temperature is 400 C. to 450 C., an annealing time is 1.5 h to 2 h, and then cooling to below 100 C. with a vacuum heat treatment furnace is performed, a vacuum degree of the vacuum heat treatment furnace is more than or equal to 210.sup.3 Pa.

5. The gradient control method for the microstructure ultrafine crystallization of the deep cone copper shaped charge liner of claim 1, wherein the gradient control method comprises the following steps: (1) preparation of a billet: a copper rod is selected to prepare a first billet, and a diameter of the copper rod is 60 mm to 90 mm; the first billet is put into a vacuum heat treatment furnace to perform an annealing treatment, an annealing temperature is 400 C. to 450 C., annealing time is 1.5 h to 2 h, and then the first billet is cooled to below 100 C. with the vacuum heat treatment furnace to obtain the billet, the vacuum degree of the vacuum heat treatment is more than or equal to 210.sup.3 Pa; (2) the multi-pass extrusion forming: the billet obtained in the step (1) is placed in a mould cavity of an extrusion die, under action of a three-dimensional compressive stress and a deformation rate of 2 mm/s to 5 mm/s, 4 to 8 passes of extrusion deformation are performed to obtain a first deep cone copper shaped charge liner, and a deformation amount for each pass of the 4 to 8 passes of extrusion deformation is between 5% and 30%; (3) the recrystallization heat treatment: the first deep cone copper shaped charge liner obtained in the step (2) is placed in the vacuum heat treatment furnace to obtain a second deep cone copper shaped charge liner, a temperature of the recrystallization heat treatment is kept at 180 C. to 220 C., and holding time of the recrystallization heat treatment is 45 min to 75 min; (4) the high-frequency percussion gradient: an inner surface grain refining treatment is performed on the second deep cone shaped charge liner obtained in the step (3) on a high-frequency vibration percussion device to obtain a third deep cone shaped charge liner, the percussion speed is 30,000 times/min to 40,000 times/min, the percussion force is 1600 N to 2000 N, and the number of percussion times is 1 to 3; (5) fine shaping: the third deep cone shaped charge liner obtained in the step (4) is placed in the mould cavity of the extrusion die, under actions of a three-dimensional compressive stress and a deformation rate of 1 mm/s to 3 mm/s, 1 to 4 passes of the fine shaping are performed, and a deformation amount for each pass of the fine shaping is less than or equal to 2%.

6. The gradient control method for the microstructure ultrafine crystallization of the deep cone copper shaped charge liner of claim 2, wherein the recrystallization heat treatment is carried out in a vacuum heat treatment furnace, a temperature of the recrystallization heat treatment is kept at 180 C. to 220 C., a holding time of the recrystallization heat treatment is 45 min to 75 min.

7. The gradient control method for the microstructure ultrafine crystallization of the deep cone copper shaped charge liner of claim 2, wherein an annealing treatment is performed before the extrusion forming, an annealing temperature is 400 C. to 450 C., an annealing time is 1.5 h to 2 h, and then cooling to below 100 C. with a vacuum heat treatment furnace is performed, a vacuum degree of the vacuum heat treatment furnace is more than or equal to 210.sup.3 Pa.

8. The gradient control method for the microstructure ultrafine crystallization of the deep cone copper shaped charge liner of claim 3, wherein an annealing treatment is performed before the extrusion forming, an annealing temperature is 400 C. to 450 C., an annealing time is 1.5 h to 2 h, and then cooling to below 100 C. with the vacuum heat treatment furnace is performed, a vacuum degree of the vacuum heat treatment furnace is more than or equal to 210.sup.3 Pa.

9. The gradient control method for the microstructure ultrafine crystallization of the deep cone copper shaped charge liner of claim 2, wherein the gradient control method comprises the following steps: (1) preparation of a billet: a copper rod is selected to prepare a first billet, a diameter of the copper rod is 60 mm to 90 mm, and a material designation of the copper rod is chosen from the group of TU1, TU2, T2, T3; the first billet is put into a vacuum heat treatment furnace to perform an annealing treatment, an annealing temperature is 400 C. to 450 C., annealing time is 1.5 h to 2 h, and then the first billet is cooled to below 100 C. with the vacuum heat treatment furnace to obtain the billet, the vacuum degree of the vacuum heat treatment is more than or equal to 210.sup.3 Pa; (2) the multi-pass extrusion forming: the billet obtained in the step (1) is placed in a mould cavity of an extrusion die, under the actions of the three-dimensional compressive stress and the deformation rate of 2 mm/s to 5 mm/s, the 4 to 8 passes of extrusion deformation are performed to obtain a first deep cone copper shaped charge liner, and the deformation amount for each pass of the 4 to 8 passes of extrusion deformation is between 5% and 30%; (3) the recrystallization heat treatment: the first deep cone copper shaped charge liner obtained in the step (2) is placed in the vacuum heat treatment furnace to obtain a second deep cone copper shaped charge liner, a temperature of the recrystallization heat treatment is kept at 180 C. to 220 C., and holding time of the recrystallization heat treatment is 45 min to 75 min; (4) the high-frequency percussion gradient: an inner surface grain refining treatment is performed on the second deep cone shaped charge liner obtained in the step (3) on a high-frequency vibration percussion device to obtain a third deep cone shaped charge liner, the percussion speed is 30,000 times/min to 40,000 times/min, the percussion force is 1600 N to 2000 N, and the number of percussion times is 1 to 3; (5) fine shaping: the third deep cone shaped charge liner obtained in the step (4) is placed in the mould cavity of the extrusion die, under actions of a three-dimensional compressive stress and a deformation rate of 1 mm/s to 3 mm/s, 1 to 4 passes of the fine shaping are performed, and a deformation amount for each pass of the fine shaping is less than or equal to 2%.

10. The gradient control method for the microstructure ultrafine crystallization of the deep cone copper shaped charge liner of claim 3, wherein the gradient control method comprises the following steps: (1) preparation of a billet: a copper rod is selected to prepare a first billet, a diameter of the copper rod is 60 mm to 90 mm, and a material designation of the copper rod is chosen from the group of TU1, TU2, T2, T3; the first billet is put into the vacuum heat treatment furnace to perform an annealing treatment, an annealing temperature is 400 C. to 450 C., annealing time is 1.5 h to 2 h, and then the first billet is cooled to below 100 C. with the vacuum heat treatment furnace to obtain the billet, the vacuum degree of the vacuum heat treatment is more than or equal to 210.sup.3 Pa; (2) the multi-pass extrusion forming: the billet obtained in the step (1) is placed in a mould cavity of an extrusion die, under the actions of the three-dimensional compressive stress and the deformation rate of 2 mm/s to 5 mm/s, the 4 to 8 passes of extrusion deformation are performed to obtain a first deep cone copper shaped charge liner, and the deformation amount for each pass of the 4 to 8 passes of extrusion deformation is between 5% and 30%; (3) the recrystallization heat treatment: the first deep cone copper shaped charge liner obtained in the step (2) is placed in the vacuum heat treatment furnace to obtain a second deep cone copper shaped charge liner, the temperature of the recrystallization heat treatment is kept at 180 C. to 220 C., and the holding time of the recrystallization heat treatment is 45 min to 75 min; (4) the high-frequency percussion gradient: an inner surface grain refining treatment is performed on the second deep cone shaped charge liner obtained in the step (3) on a high-frequency vibration percussion device to obtain a third deep cone shaped charge liner, the percussion speed is 30,000 times/min to 40,000 times/min, the percussion force is 1600 N to 2000 N, and the number of percussion times is 1 to 3; (5) fine shaping: the third deep cone shaped charge liner obtained in the step (4) is placed in the mould cavity of the extrusion die, under actions of a three-dimensional compressive stress and a deformation rate of 1 mm/s to 3 mm/s, 1 to 4 passes of the fine shaping are performed, and a deformation amount for each pass of the fine shaping is less than or equal to 2%.

11. The gradient control method for the microstructure ultrafine crystallization of the deep cone copper shaped charge liner of claim 4, wherein the gradient control method comprises the following steps: (1) preparation of a billet: a copper rod is selected to prepare a first billet, a diameter of the copper rod is 60 mm to 90 mm, and a material designation of the copper rod is chosen from the group of TU1, TU2, T2, T3; the first billet is put into the vacuum heat treatment furnace to perform the annealing treatment, the annealing temperature is 400 C. to 450 C., the annealing time is 1.5 h to 2 h, and then the first billet is cooled to below 100 C. with the vacuum heat treatment furnace to obtain the billet, the vacuum degree of the vacuum heat treatment is more than or equal to 210.sup.3 Pa; (2) the multi-pass extrusion forming: the billet obtained in the step (1) is placed in a mould cavity of an extrusion die, under the actions of the three-dimensional compressive stress and the deformation rate of 2 mm/s to 5 mm/s, the 4 to 8 passes of extrusion deformation are performed to obtain a first deep cone copper shaped charge liner, and the deformation amount for each pass of the 4 to 8 passes of extrusion deformation is between 5% and 30%; (3) the recrystallization heat treatment: the first deep cone copper shaped charge liner obtained in the step (2) is placed in the vacuum heat treatment furnace to obtain a second deep cone copper shaped charge liner, the temperature of the recrystallization heat treatment is kept at 180 C. to 220 C., and the holding time of the recrystallization heat treatment is 45 min to 75 min; (4) the high-frequency percussion gradient: an inner surface grain refining treatment is performed on the second deep cone shaped charge liner obtained in the step (3) on a high-frequency vibration percussion device to obtain a third deep cone shaped charge liner, the percussion speed is 30,000 times/min to 40,000 times/min, the percussion force is 1600 N to 2000 N, and the number of percussion times is 1 to 3; (5) fine shaping: the third deep cone shaped charge liner obtained in the step (4) is placed in the mould cavity of the extrusion die, under actions of a three-dimensional compressive stress and a deformation rate of 1 mm/s to 3 mm/s, 1 to 4 passes of the fine shaping are performed, and a deformation amount for each pass of the fine shaping is less than or equal to 2%.

12. The gradient control method for the microstructure ultrafine crystallization of the deep cone copper shaped charge liner of claim 6, wherein the gradient control method comprises the following steps: (1) preparation of a billet: a copper rod is selected to prepare a first billet, a diameter of the copper rod is 60 mm to 90 mm, and a material designation of the copper rod is chosen from the group of TU1, TU2, T2, T3; the first billet is put into the vacuum heat treatment furnace to perform an annealing treatment, an annealing temperature is 400 C. to 450 C., annealing time is 1.5 h to 2 h, and then the first billet is cooled to below 100 C. with the vacuum heat treatment furnace to obtain the billet, the vacuum degree of the vacuum heat treatment is more than or equal to 210.sup.3 Pa; (2) the multi-pass extrusion forming: the billet obtained in the step (1) is placed in a mould cavity of an extrusion die, under the actions of the three-dimensional compressive stress and the deformation rate of 2 mm/s to 5 mm/s, the 4 to 8 passes of extrusion deformation are performed to obtain a first deep cone copper shaped charge liner, and the deformation amount for each pass of the 4 to 8 passes of extrusion deformation is between 5% and 30%; (3) the recrystallization heat treatment: the first deep cone copper shaped charge liner obtained in the step (2) is placed in the vacuum heat treatment furnace to obtain a second deep cone copper shaped charge liner, the temperature of the recrystallization heat treatment is kept at 180 C. to 220 C., and the holding time of the recrystallization heat treatment is 45 min to 75 min; (4) the high-frequency percussion gradient: an inner surface grain refining treatment is performed on the second deep cone shaped charge liner obtained in the step (3) on a high-frequency vibration percussion device to obtain a third deep cone shaped charge liner, the percussion speed is 30,000 times/min to 40,000 times/min, the percussion force is 1600 N to 2000 N, and the number of percussion times is 1 to 3; (5) fine shaping: the third deep cone shaped charge liner obtained in the step (4) is placed in the mould cavity of the extrusion die, under actions of a three-dimensional compressive stress and a deformation rate of 1 mm/s to 3 mm/s, 1 to 4 passes of the fine shaping are performed, and a deformation amount for each pass of the fine shaping is less than or equal to 2%.

13. The gradient control method for the microstructure ultrafine crystallization of the deep cone copper shaped charge liner of claim 7, wherein the gradient control method comprises the following steps: (1) preparation of a billet: a copper rod is selected to prepare a first billet, a diameter of the copper rod is 60 mm to 90 mm, and a material designation of the copper rod is chosen from the group of TU1, TU2, T2, T3; the first billet is put into the vacuum heat treatment furnace to perform the annealing treatment, the annealing temperature is 400 C. to 450 C., the annealing time is 1.5 h to 2 h, and then the first billet is cooled to below 100 C. with the vacuum heat treatment furnace to obtain the billet, the vacuum degree of the vacuum heat treatment is more than or equal to 210.sup.3 Pa; (2) the multi-pass extrusion forming: the billet obtained in the step (1) is placed in a mould cavity of an extrusion die, under the actions of the three-dimensional compressive stress and the deformation rate of 2 mm/s to 5 mm/s, the 4 to 8 passes of extrusion deformation are performed to obtain a first deep cone copper shaped charge liner, and the deformation amount for each pass of the 4 to 8 passes of extrusion deformation is between 5% and 30%; (3) the recrystallization heat treatment: the first deep cone copper shaped charge liner obtained in the step (2) is placed in the vacuum heat treatment furnace to obtain a second deep cone copper shaped charge liner, the temperature of the recrystallization heat treatment is kept at 180 C. to 220 C., and the holding time of the recrystallization heat treatment is 45 min to 75 min; (4) the high-frequency percussion gradient: an inner surface grain refining treatment is performed on the second deep cone shaped charge liner obtained in the step (3) on a high-frequency vibration percussion device to obtain a third deep cone shaped charge liner, the percussion speed is 30,000 times/min to 40,000 times/min, the percussion force is 1600 N to 2000 N, and the number of percussion times is 1 to 3; (5) fine shaping: the third deep cone shaped charge liner obtained in the step (4) is placed in the mould cavity of the extrusion die, under actions of a three-dimensional compressive stress and a deformation rate of 1 mm/s to 3 mm/s, 1 to 4 passes of the fine shaping are performed, and a deformation amount for each pass of the fine shaping is less than or equal to 2%.

14. The gradient control method for the microstructure ultrafine crystallization of the deep cone copper shaped charge liner of claim 8, wherein the gradient control method comprises the following steps: (1) preparation of a billet: a copper rod is selected to prepare a first billet, a diameter of the copper rod is 4) 60 mm to 90 mm, and a material designation of the copper rod is chosen from the group of TU1, TU2, T2, T3; the first billet is put into the vacuum heat treatment furnace to perform the annealing treatment, the annealing temperature is 400 C. to 450 C., the annealing time is 1.5 h to 2 h, and then the first billet is cooled to below 100 C. with the vacuum heat treatment furnace to obtain the billet, the vacuum degree of the vacuum heat treatment is more than or equal to 210.sup.3 Pa; (2) the multi-pass extrusion forming: the billet obtained in the step (1) is placed in a mould cavity of an extrusion die, under the actions of the three-dimensional compressive stress and the deformation rate of 2 mm/s to 5 mm/s, the 4 to 8 passes of extrusion deformation are performed to obtain a first deep cone copper shaped charge liner, and the deformation amount for each pass of the 4 to 8 passes of extrusion deformation is between 5% and 30%; (3) the recrystallization heat treatment: the first deep cone copper shaped charge liner obtained in the step (2) is placed in the vacuum heat treatment furnace to obtain a second deep cone copper shaped charge liner, the temperature of the recrystallization heat treatment is kept at 180 C. to 220 C., and the holding time of the recrystallization heat treatment is 45 min to 75 min; (4) the high-frequency percussion gradient: an inner surface grain refining treatment is performed on the second deep cone shaped charge liner obtained in the step (3) on a high-frequency vibration percussion device to obtain a third deep cone shaped charge liner, the percussion speed is 30,000 times/min to 40,000 times/min, the percussion force is 1600 N to 2000 N, and the number of percussion times is 1 to 3; (5) fine shaping: the third deep cone shaped charge liner obtained in the step (4) is placed in the mould cavity of the extrusion die, under actions of a three-dimensional compressive stress and a deformation rate of 1 mm/s to 3 mm/s, 1 to 4 passes of the fine shaping are performed, and a deformation amount for each pass of the fine shaping is less than or equal to 2%.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The patent or application file contains at least one drawing executed in color.

[0036] Copies of this patent or patent application publication with color drawing(s) will be provided by the Office upon request and payment of the necessary fee.

[0037] FIG. 1 is a flow chart of a preparation process of a shaped charge liner;

[0038] FIG. 2 is a diagram showing a grain structure of a red copper billet (metallographic microscope is magnified 50 times, and average grain size is about 210 m);

[0039] FIG. 3 is a diagram showing a multi-pass extrusion forming process of a double cone shaped charge liner;

[0040] FIG. 4 is a diagram showing a microstructure of a cone shaped charge liner after a recrystallization treatment (metallographic microscope is magnified 500 times, and average grain size is about 6 m);

[0041] FIG. 5a is a diagram showing a gradient structure distribution of a gradient grain structure of a shaped charge liner along a thickness direction;

[0042] FIG. 5b is a diagram showing a size of a grain structure 0.8 mm away from an inner wall in a gradient grain structure of a shaped charge liner along a thickness direction is about 3 m; and

[0043] FIG. 5c is a diagram showing a size of a grain structure 0.2 mm away from an inner wall in a gradient grain structure of a shaped charge liner along a thickness direction is about 0.6 m.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0044] The present invention is further described below with reference to the specific embodiments.

Embodiment 1

[0045] (1) Preparation of billet: taking a shaped charge liner having an inner chamber with a shape of a double cone structure and a tapered wall thickness as an example, the shaped charge liner has an aperture of 165 mm, a height of 178 mm, an inner cone depth of 142 mm, a wall thickness of 2.4 mm to 3.2 mm, a top small cone angle of 36, a large cone angle of 64, and a transition arc R between the large and small cone angle of 220 mm. According to plastic forming theory and near-uniform plastic deformation principle, a machining allowance of 0.3 mm is left on the outer surface of the shaped charge liner, and a forming process boss of 25 mm is designed on the top of the cone shaped charge liner; the forming process is simulated and optimized by UG and DEFORM software, and the volume of the billet is calculated. The extruded T2 copper rod of 90 mm is selected as the raw material, and the outer surface of the rod was cut to make a billet having a diameter of 88 mm and a height of 55 mm. The content of the impurity element of the T2 red copper rod is as shown in Table 1.

TABLE-US-00001 TABLE 1 Content of impurity element of T2 copper rod Brand Bi Sb As Fe Ni Sn S O Zn Total T2 0.001 0.002 0.002 0.005 0.002 0.002 0.004 0.005 0.004 0.1

[0046] The billet is kept in a VQG-2500 intelligent temperature-controlled vacuum heat treatment furnace at 4201 C. for 1.5 h, and the degree of vacuum is 1.510.sup.3 Pa. After the heat preservation treatment, the billet is cooled to 80 C. with the furnace to obtain a billet with uniform composition and structure. The hardness is from HB35 to HB38, and the average grain size is about 210 m, as shown in FIG. 2.

[0047] (2) Multi-pass extrusion forming: the billet obtained in step (2) is placed in the mould cavity of the extrusion die, under the actions of the three-dimensional compressive stress and a certain deformation rate, 7 passes of the extrusion deformation are performed to obtain the cone shaped charge liner, and its forming process is shown in FIG. 3. The deformation amount arrangement for each pass is shown in Table 2. The multi-pass extrusion die includes die system, punch system, and ejection system. The multi-pass extrusion forming equipment is 1600 t hydraulic press, and deformation rate of the hydraulic machine is 2 mm/s to 5 mm/s. The die system of the extrusion die is installed on the work surface of the hydraulic press. The ejection system is connected with the ejector mechanism of the hydraulic press. The punch system is connected with the working slider of the hydraulic press and the extrusion punch is driven by the working slider of the hydraulic press to perform extrusion. The extrusion punch cooperates with the extrusion concave die to make the billet in a three-dimensional stress state. The first pass is a large deformation cogging process to obtain a cone billet. The subsequent 2 to 6 passes are reaming extrusion (the deformation amount is less than 30%), so that the wall thickness of the shaped charge liner is gradually thinned. As the extrusion pass increases, the work hardening effect is enhanced and the deformation amount gradually decreases. The last pass is the final shaping, which improves the dimensional accuracy and dimensional stability of the formed component, and the deformation amount is generally less than 10%. After the multi-pass extrusion forming, a shaped charge liner having the required shape, size, surface quality, and a certain mechanical property is obtained.

TABLE-US-00002 TABLE 2 Process parameters of the extrusion deformation Deformation Deformation Amount Deformation Deformation Pass Arrangement Rate Temperature Lubricant 1 28% 4 mm/s 25-30 C. Tea oil 2 28% 3 25% 4 25% 5 20% 6 16% 7 6%

[0048] (3) Recrystallization heat treatment: the cone shaped charge liner obtained in step (2) is placed in a vacuum heat treatment furnace, and is kept at 210 C. for 60 min, then the grain boundary optimization, and the dislocation slip and dislocation climbing are performed by recrystallization treatment, causing the change of the local lattice and the interface orientation of grain boundary, promoting the formation of dynamic recrystallization and twinning during annealing, and reducing the work hardening effect. The average grain size of the shaped charge liner is about 6 m, as shown in FIG. 4.

[0049] (4) High-frequency percussion gradient: an inner surface grain refining treatment is performed on the cone shaped charge liner obtained in step (3) on a high-frequency vibration percussion device, the percussion speed is 32,000 times/min, the percussion force is 1500 N, and the number of percussion times is 2.

[0050] (5) Fine shaping: the component obtained in step (4) is placed in the mould cavity of the extrusion die, under the actions of three-dimensional compressive stress and deformation rate of 1 mm/s, 2 passes of fine shaping are performed, and the deformation amount for each pass is about 1%.

[0051] The difference of circumferential wall thickness of the cone shaped charge liner is 0.02 mm to 0.07 mm, and the roughness of inner surface is Ra 0.03 m to Ra 0.1 m, and the deviation value of the taper angle is less than or equal to 2.

[0052] The grain size distribution of the above-mentioned shaped charge liner is analyzed by using the metallographic microscopic method (Table 3). The gradient fine grain structure is formed along the wall thickness of the shaped charge liner (FIG. 5a).

[0053] The average grain size of the grain structure 0.8 mm away from the inner wall is about 3 m (FIG. 5b) and the average grain size of the grain structure 0.2 mm away from the inner wall is about 0.6 m (FIG. 5c).

TABLE-US-00003 TABLE 3 Grain structure distribution of shaped charge liner along thickness direction and generatrix direction Distance from inner surface 0.2 mm 0.4 mm 0.6 mm 0.8 mm 1 mm 1-small cone 0.61 1.0 1.9 2.7 4.5 2-circular arc 0.56 1.2 1.8 3.1 5.1 3-big cone 0.68 1.3 2.1 3.2 4.8 4-opening 0.75 1.1 1.9 2.8 5.2 Average value 0.65 1.15 1.93 2.95 4.9

Embodiment 2

[0054] (1) Preparation of billet: taking a shaped charge liner having an inner chamber with a shape of single cone structure and an equal wall thickness as an example, the shaped charge liner has an aperture of 156 mm, a height of 162 mm, an inner cone depth of 148 mm, a maximum wall thickness of 3.2 mm, and an inner taper angle of 60. According to plastic forming theory and near-uniform plastic deformation principle, a machining allowance of 0.4 mm is left on the outer surface of the shaped charge liner formed by multi-pass extrusion forming, and a forming process boss of 20 mm is designed on the top of the shaped charge liner. The forming process is simulated and optimized by UG and DEFORM software and the volume of the billet is calculated. The stretched T2 copper rod of 60 mm is selected as the raw material and the outer surface of the rod was cut to make a billet having a diameter of 58 mm and a height of 80 mm. The billet is kept in a VQG-2500 intelligent temperature-controlled vacuum heat treatment furnace at 4001 C. for 2 h, and the degree of vacuum is 1.510.sup.3 Pa. After the heat preservation treatment, the billet is cooled to 80 C. with the furnace to obtain a billet having uniform composition and structure. The hardness is from HB32 to HB35, and the grain size of the copper is about 70 m.

[0055] (2) Multi-pass extrusion forming: the billet obtained in step (1) is placed in the mould cavity of the extrusion die, under the actions of the three-dimensional compressive stress and a certain deformation rate, 6 passes of the extrusion deformation are performed, and the deformation amount arrangement for each pass is shown in Table 4. The multi-pass extrusion die includes a die system, a punch system, and an ejection system. The multi-pass extrusion equipment is 1600 t hydraulic press, and the deformation rate of the hydraulic machine is 2 mm/s to 5 mm/s. The die system of the extrusion die is installed on the work surface of the hydraulic press. The ejection system is connected with the ejector mechanism of the hydraulic press. The punch system is connected with the working slider of the hydraulic press, and the extrusion punch is driven by the working slider of the hydraulic press to perform extrusion. The extrusion punch cooperates with the extrusion concave die to make the billet in a three-dimensional stress state. The first pass is a large deformation cogging to obtain a cone billet. The subsequent 2 to 5 passes are reaming extrusion (the deformation amount is less than 30%), so that the wall thickness of the shaped charge liner is gradually thinned. As the extrusion pass increases, the work hardening effect is enhanced, and the deformation amount gradually decreases. The last pass is the final shaping, which improves the dimensional accuracy and dimensional stability of the formed component, and the deformation amount is generally less than 10%. After the multi-pass extrusion forming, a shaped charge liner having the required shape, size, surface quality, and a certain mechanical property is obtained.

TABLE-US-00004 TABLE 4 Parameters of deformation pass Deformation Deformation Amount Deformation Deformation Pass Arrangement Rate Temperature Lubricant 1 28% 3 mm/s 25-30 C. Rapeseed oil 2 25% 3 23% 4 22% 5 16% 6 8%

[0056] (3) Recrystallization heat treatment: the cone shaped charge liner obtained in step (2) is placed in a vacuum heat treatment furnace, and kept at 200 C. for 60 min, then the grain boundary optimization, the dislocation slip and dislocation climbing are performed by recrystallization treatment, causing the change of local lattice and the interface orientation of grain boundary, promoting the formation of dynamic recrystallization and twinning during annealing, and reducing the work hardening effect. The average grain size of the shaped charge liner is 4 m.

[0057] (4) High-frequency percussion gradient: an inner surface grain refining treatment is performed on the cone shaped charge liner obtained in step (3) on a high-frequency vibration percussion device, the percussion speed is 35,000 times/min, the percussion force is 2000 N, and the number of percussion times is 3.

[0058] (5) Fine shaping: the component obtained in step (4) is placed in the mould cavity of the extrusion die, under the actions of three-dimensional compressive stress and deformation rate of 2 mm/s, 1 pass of fine shaping is performed, and the deformation amount for the pass is about 1%.

[0059] The difference of circumferential wall thickness of the cone shaped charge liner is 0.02 mm to 0.05 mm, and the roughness of inner surface is Ra 0.01 m to Ra 0.08 m, and the deviation value of the taper angle is less than or equal to 1.

[0060] The grain size distribution of the above-mentioned shaped charge liner is analyzed by using the metallographic microscopic method (Table 5). The gradient fine grain structure is formed along the wall thickness of the shaped charge liner. The average grain size of the grain structure 0.8 mm away from the inner wall is about 2 m, and the average grain size of the grain structure 0.2 mm away from the inner wall is about 0.2 m.

TABLE-US-00005 TABLE 5 Grain structure distribution of shaped charge liner along thickness direction and generatrix direction Distance from inner surface 0.2 mm 0.4 mm 0.6 mm 0.8 mm 1 mm 1-small cone 0.15 0.47 1.1 1.7 2.4 2-circular arc 0.20 0.54 1.4 1.8 2.8 3-big cone 0.18 0.72 1.2 2.1 2.7 4-opening 0.24 0.58 1.5 1.9 2.9 Average value 0.19 0.58 1.30 1.88 2.7

[0061] The results show that the forming and the surface quality control of the deep cone shaped charge liner are achieved by using a control technology of a severe deformation accumulated by multi-pass extrusion forming; the plasticity of the material is improved by static recrystallization treatment, and fine grain structure is obtained. The high-frequency percussion grain refining technology is used to form an ultrafine grain gradient structure distributed along thickness direction on the inner surface of the shaped charge liner. By this method, the difference of circumferential wall thickness of the shaped charge liner is 0.02 mm to 0.07 mm, the roughness of inner surface is Ra 0.01 m to Ra 0.1 m, the deviation value of the taper angle is less than or equal to 2, and the internal structure has ultrafine grain gradient, effectively and fully utilizing the physical properties of the fine crystalline material. X-ray photography shows that rupture time of the jet of the shaped charge liner prepared by the method of the present invention is extended by about 6% compared to that prepared by the conventional process. The effective length of the jet is increased by about 10%, and the collimation is better. The static high-explosive anti-tank test is performed on the shaped charge liner prepared by Embodiment 1, uniform steel target having a thickness of 1450 mm can be effectively penetrated, and the penetration depth thereof is increased by more than 200 mm compared to the shaped charge liner formed by conventional forming process.