Process for preparing high-strength and high-toughness metal material with multi-scale gradient composite structure through explosion processing

Abstract

The invention discloses a process for preparing a high-strength and high-toughness metal material with a multi-scale gradient composite structure through explosive processing, and relates to the field of high-strength and high-toughness metal material processes, the process comprises the following steps: 1, preparing a sand base, a base plate, a cover plate and an explosive, and polishing the outer surfaces of the base plate and the cover plate; the supporting object is placed at the top end of the base plate, the covering plate is placed at the top end of the supporting object, the explosive is placed on the covering plate, and the composite plate with a good metallurgical bonding interface can still be prepared by adjusting the detonation velocity of the explosive and the interval between the plates under the conditions that the tensile strength of the base plate of the welding plate reaches up to 1.4 GPa and the fracture strain of the covering plate is higher than 25%. In addition, by increasing the detonation velocity, the composite plate material is subjected to surface hardening, a grain size gradient layer is generated on the surface of the material, the explosive hardening and explosive welding machining processes are optimized, and meanwhile one-time forming of machining of the high-strength multi-scale gradient structure composite metal plate is achieved.

Description

Technical Field

[0001] The present invention relates to the field of high-strength and high-toughness metal material processes, and particularly relates to a process for preparing a multi-scale gradient composite structure high-strength and high-toughness metal material by explosive processing. Background Art

[0002] The multi-scale gradient structure means that both macroscopic and microscopic gradient structures exist simultaneously in the overall material. The macroscopic gradient is mainly a laminated structure, and the microscopic gradient is mainly a grain size gradient. The laminated structure can be prepared by explosive welding, and the grain size gradient can be prepared by explosive hardening.

[0003] Explosive hardening can rely on a relatively high detonation velocity to refine the grains on the surface of the material, thereby preparing a hardened layer with a grain size gradient. However, a relatively high detonation velocity means that this process can only harden a single-layer plate and cannot perform welding on the basis of hardening.

[0004] When explosive welding is faced with high-strength metals, there are often some problems, such as a small welding area, which easily leads to the fracture of the welded plate, etc. When welding plates with relatively high strength, the process still needs to be optimized.

[0005] Therefore, it is necessary to propose a process for preparing a multi-scale gradient composite structure high-strength and high-toughness metal material by explosive processing to solve the above problems. Summary of the Invention

[0006] The purpose of the present invention is to provide a process for preparing a multi-scale gradient composite structure high-strength and high-toughness metal material by explosive processing to solve the problems that when explosive welding is faced with high-strength metals, there are often some problems, such as a small welding area, which easily leads to the fracture of the welded plate, etc. When welding plates with relatively high strength, the process still needs to be optimized.

[0007] To achieve the above purpose, the present invention provides the following technical solution: A process for preparing a multi-scale gradient composite structure high-strength and high-toughness metal material by explosive processing, comprising the following steps:

[0008] First step, prepare a sand base, a base plate, a clad plate and explosives, and polish the outer surfaces of the base plate and the clad plate;

[0009] Second step, after polishing, place the base plate on the sand base, place a support on the top of the base plate, place the clad plate on the top of the support, and place the explosives on the clad plate;

[0010] Third step, detonate the explosives through a detonator, and use the explosive welding method to form a composite plate by welding the base plate and the clad plate in one step;

[0011] Step 4: After welding, the composite plate is heat-treated. The composite plate is placed in a heating furnace, heated to 650 °C, held for 2 h, then cooled with the heating furnace to 150 °C, taken out, and air-cooled. After air-cooling, cold rolling is carried out.

[0012] Among them, the explosive used is ammonium nitrate explosive, with a detonation velocity of 3200 m / s and a density of 1.05 g / cm 3 , the thickness of the explosive is 60 mm, the strength of the clad plate is 700 MPa, the strength of the substrate is 1.4 GPa, and the interval between the substrate and the clad plate (2) is 5 mm, that is, the height of the support is 5 mm;

[0013] The substrate is made of 30CrMnSiNi2MoVE material, the clad plate is made of 10CrNi3MoV material, the thickness of the substrate is 14 mm, and the thickness of the clad plate is 6 mm.

[0014] Preferably, the explosive clad plate evenly covers the upper surface.

[0015] Preferably, a wooden strip surrounds the outer edge of the top of the clad plate. The explosive is filled in the surrounded wooden strip, and the explosive is leveled. The detonator is placed in the explosive.

[0016] Preferably, the support is made of wooden blocks and multiple supports are provided.

[0017] The technical effects and advantages of the present invention:

[0018] 1. Through theoretical analysis of the explosion window and combined with the actual welding process, the detonation velocity of the used explosive and the interval between plates are adjusted. When the strength of the welded plate is as high as 1.4 GPa, a composite plate with a good metallurgical bonding interface can still be prepared. In addition, by increasing the detonation velocity, surface hardening occurs in the composite plate material, and a grain size gradient layer is generated on the material surface. While optimizing the explosion hardening and explosion welding processing technology, one-time forming of high-strength multi-scale gradient structure composite metal plates is realized.

[0019] 2. High metallurgical bonding strength and high surface nanocrystallization are achieved by adjusting the detonation velocity of the explosive and the interval between plates.

[0020] 3. Through the one-time forming process, a microscopic grain size gradient structure is generated on the surface of the clad plate, and a macroscopic laminated gradient structure is generated in the overall material. Through the combined action of macro-micro multi-scale gradients, the strength and toughness of the overall material are regulated, and the strengthening and toughening effects of the laminated material are realized, broadening the application of the explosion welding process in the composite of high-strength - high-toughness steel / steel. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of the position structure of the clad plate and the substrate of the present invention.

[0022] Figure 2 This is a schematic structural diagram of the process flow for preparing a multi-scale gradient composite structure high-strength and high-toughness metal material by explosive processing according to the present invention.

[0023] Figure 3 This is a metallographic diagram of the weld structure of the present invention.

[0024] Figure 4 This is a metallographic diagram of the surface layer of the material of the present invention.

[0025] In the figure: 1, explosive; 2, cladding plate; 3, support; 4, substrate; 5, sand base. Specific embodiments

[0026] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present invention.

[0027] The present invention provides a process for preparing a multi-scale gradient composite structure high-strength and high-toughness metal material by explosive processing as shown in Figures 1 to 4 and includes the following steps:

[0028] S1. Prepare the sand base 5, the substrate 4, the cladding plate 2 and the explosive 1, and polish the outer surfaces of the substrate 4 and the cladding plate 2 to ensure that the outer surfaces of the substrate 4 and the cladding plate 2 are smooth and free of foreign matter adhesion before explosive welding.

[0029] After polishing, place the substrate 4 on the sand base 5. A groove for placing the substrate 4 can be opened in the sand base 5 to fix the substrate 4 and prevent the substrate 4 from moving during welding. At the same time, other methods can also be used to fix the substrate 4.

[0030] A support 3 is placed on the top of the substrate 4, the cladding plate 2 is placed on the top of the support 3, and the explosive 1 is placed on the cladding plate 2. Specifically, the installation method of the explosive 1 is that a circle of wooden strips surrounds the outer edge of the top of the cladding plate 2, the explosive 1 is filled in the surrounding wooden strips, and the explosive 1 is leveled. The detonator is placed in the explosive 1, and the thickness of the explosive 1 and the height of the wooden strips are both 60 mm.

[0031] S3. Detonate the explosive 1 through the detonator and use explosive welding to form the substrate 4 and the cladding plate 2 into a composite plate in one step;

[0032] S4. After welding, the composite plate is heat-treated. The composite plate is placed in a heating furnace and heated to 650 °C. After holding for 2 h, it is cooled with the heating furnace to 150 °C, then the composite plate is taken out and air-cooled. After air-cooling, cold rolling is carried out. The purpose is to flatten the bent steel plate after explosion welding, and finally a regular and flat composite plate can be obtained;

[0033] Among them, the explosive 1 uses ammonium nitrate explosive, with a detonation velocity of 3200 m / s and a density of 1.05 g / cm3. The strength of the cladding plate 2 is 700 MPa, the strength of the base plate 4 is 1.4 GPa, and the interval between the base plate 4 and the cladding plate 2 is 5 mm, that is, the height of the support 3 is 5 mm;

[0034] The base plate 4 is made of 30CrMnSiNi2MoVE material, the cladding plate 2 is made of 10CrNi3MoV material, the thickness of the base plate 4 is 14 mm, and the thickness of the cladding plate 2 is 6 mm.

[0035] The welded composite plate material has a good metallurgical bonding interface, and the interface metallographic structure is as Figure 3 shown.

[0036] For the composite plate formed by explosion welding, on the basis of having a good interface, a microstructure with a grain size gradient is also prepared on the surface layer of the material. The thickness of the gradient layer is greater than 100 μm, as Figure 4 shown. The results show that through the process designed by the present invention, while ensuring the welding effect and hardening effect, the one-time forming of a high-strength and high-toughness metal material with a multi-scale gradient composite structure can be realized, which has high engineering significance.

[0037] The present invention can achieve high metallurgical bonding strength and high surface nanocrystallization by adjusting the detonation velocity of the explosive and the interval between plates. Through theoretical analysis of the explosion window and combined with the actual welding process, the present invention adjusts the detonation velocity of the used explosive and the interval between plates. When the strength of the welded plate is as high as 1.4 GPa, a composite plate with a good metallurgical bonding interface can still be prepared. In addition, by increasing the detonation velocity, the flyer plate material undergoes surface hardening, and a grain size gradient layer is generated on the material surface. While optimizing the processing technologies of explosion hardening and explosion welding, the one-time forming of a high-strength multi-scale gradient structure composite metal plate is realized.

[0038] The explosive cladding plate 1 is evenly covered on the upper surface of the cladding plate 2. The support 3 is supported by wooden blocks, and multiple supports 3 are provided.

Claims

1. A process for preparing high-strength and high-toughness metal materials with multi-scale gradient composite structures by explosive processing, characterized in that: The following steps are involved: S1, preparing a sand base (5), a base plate (4), a cover plate (2) and an explosive (1), and polishing the outer surfaces of the base plate (4) and the cover plate (2); S2. After polishing is completed, the substrate (4) is placed on the sand base (5), a support (3) is placed on the top of the substrate (4), the cover plate (2) is placed on the top of the support (3), and the explosive (1) is placed on the cover plate (2); S3, detonating the explosive (1) by means of a detonator, and using an explosion welding method to weld the base plate (4) and the cover plate (2) into a composite plate at one time; S4. After welding, the composite plate is heat treated by placing the composite plate in a heating furnace, heating it to 650°C, keeping it warm for 2 hours, cooling it to 150°C with the heating furnace, taking out the composite plate, and air cooling it, followed by cold rolling; Among them, the explosive (1) uses ammonium nitrate explosive, with a detonation velocity of 3200m / s and a density of 1.05g / cm 3 , the thickness of the explosive (1) is 60 mm, the strength of the cover plate (2) is 700 MPa, the strength of the base plate (4) is 1.4 GPa, the interval between the base plate (4) and the cover plate (2) is 5 mm, that is, the height of the support (3) is 5 mm; The substrate (4) is made of 30CrMnSiNi2MoVE material, the cover plate (2) is made of 10CrNi3MoV material, the substrate (4) is 14 mm thick, and the cover plate (2) is 6 mm thick.

2. The process for preparing a high-strength and high-toughness metal material with a multi-scale gradient composite structure by explosive processing according to claim 1, characterized in that: The explosive covering plate (1) is evenly covered on the upper surface of the covering plate (2).

3. The process for preparing a multi-scale gradient composite structure high-strength and high-toughness metal material by explosive processing according to claim 1, characterized in that: The outer edge of the top of the covering plate (2) is surrounded by wooden strips, the explosive (1) is filled in the surrounding wooden strips, and the explosive (1) is leveled, and the detonator is placed in the explosive (1).

4. The process for preparing a multi-scale gradient composite structure high-strength and high-toughness metal material by explosive processing according to claim 1, characterized in that: The support (3) is supported by a wooden block, and a plurality of supports (3) are provided.

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