Heat treatment method for explosive welding composite material

Abstract

The invention discloses a heat treatment method of an explosive welding composite material, which belongs to the technical field of heat treatment, and comprises the following steps: selecting a welding base material, and performing explosive welding to obtain an explosive composite material; carrying out cold deformation on the explosive composite material; after cold deformation, pre-aging treatment is carried out at the temperature lower than the minimum recrystallization temperature of the cold deformation explosive composite material; and after the pre-aging treatment, the aging treatment temperature is selected according to the performance of the welding base metal, and the explosive composite material is subjected to aging treatment. By means of the method, it is guaranteed that all areas in the composite material have high hardness, strength and the like, and obvious weak areas do not exist. Through the combined action of the two effects, the final material shows higher comprehensive properties such as hardness, strength and conductivity.

Description

Technical Field

[0001] The invention belongs to the technical field of heat treatment and relates to a heat treatment method for explosive welding composite materials. Background Art Explosive welding is a process that uses the chemical energy of explosives to drive the flyer plate and the substrate to collide at high speed, thereby achieving the connection of the same or different materials. During the welding process, both the flyer plate and the substrate materials need to withstand high impact loads and strain hardening (especially the interface area), so the final composite material presents a non-uniform and high content of microscopic defects such as dislocations. When the composite material is composed of an aging treatment-strengthened alloy, different aging treatment response characteristics will be presented inside it during the aging treatment. Taking the composite interface with extremely high defect density as an example, some areas can undergo recrystallization during the conventional aging treatment process, which makes the microscopic defects in the corresponding area quickly and violently annihilated, while the remaining areas still retain high density defects. During the aging treatment, the precipitate phases in places with high defect density quickly nucleate and coarsen, while the precipitate phases in places with low defect density grow slowly, making the overall precipitate phases larger in size, unevenly distributed, and weak strengthening effect. The above effects cause the interface area to become a weak area with low hardness and strength after aging, reducing the comprehensive mechanical properties of the final composite material.

[0002] Therefore, it is necessary to develop a heat treatment process to achieve fine utilization of high-density microscopic defects in the welding interface area and improve the comprehensive properties of the final composite material. Summary of the invention

[0003] The purpose of the present invention is to provide a heat treatment method for explosively welded composite materials, which scientifically utilizes the regulatory effect of defects on the second phase precipitation process of the explosive composite material composed of an aging-strengthened alloy by changing the application sequence, size and duration of the aging temperature and time, and retains a certain work hardening effect, thereby improving the comprehensive mechanical properties of the composite material.

[0004] In order to achieve the above object, the present invention adopts the following technical solutions: The present invention provides a heat treatment method for explosively welded composite materials, comprising the following steps: Select welding base material and perform explosion welding to obtain explosion composite material; Cold deformation of explosive composite materials; After cold deformation, a pre-aging treatment is performed at a temperature lower than the lowest recrystallization temperature of the cold-deformed explosion composite material; After the pre-aging treatment, the aging treatment temperature is selected according to the performance of the welding base material, and the explosion composite material is subjected to aging treatment.

[0005] As a further improvement of the present invention, the welding base material is a solid solution alloy.

[0006] As a further improvement of the present invention, the explosion composite material is composed of an aging treatment strengthened alloy with a similar heat treatment process.

[0007] As a further improvement of the present invention, the cold deformation method includes cold rolling, cold forging or cold heading.

[0008] As a further improvement of the present invention, the deformation amount of the cold deformation is 0-80%.

[0009] As a further improvement of the present invention, the temperature lower than the lowest recrystallization temperature of the cold-deformed explosive composite material refers to: The temperature selected for pre-aging treatment should be lower than the lowest recrystallization temperature of each region of the cold-deformed composite material.

[0010] As a further improvement of the present invention, the temperature less than the lowest recrystallization temperature of each region of the cold-deformed composite material refers to a temperature not less than 70% of the lowest recrystallization temperature.

[0011] As a further improvement of the present invention, the pre-aging treatment at a temperature lower than the lowest recrystallization temperature of the cold-deformed explosion composite material utilizes microscopic defects to promote the nucleation of the second phase and consumes part of the strain energy stored in the composite material so that recrystallization does not occur.

[0012] As a further improvement of the present invention, the aging treatment of the explosive composite material utilizes the residual microscopic defects obtained from the pre-aging treatment and the aging treatment temperature to continue the nucleation and growth of the second phase.

[0013] As a further improvement of the present invention, the temperature of the aging treatment should be determined according to the "Heat Treatment Process Specification Data Manual".

[0014] Compared with the prior art, the present invention has the following beneficial effects: The present invention scientifically designs the conditions such as the application order, size and duration of the aging temperature and time of the cold-deformed explosive composite material. On the one hand, the regulating effect of high-density defects on the nucleation and growth of the precipitate phase can be fully utilized in multiple levels, and a greater precipitation degree and a smaller precipitation phase size (large nucleation density and reduced average size of the precipitate phase) can be obtained at the same temperature and time, and the aging process of each region inside the composite material can be effectively coordinated. On the other hand, the method can inhibit the recrystallization process, so that a certain degree of dislocation strengthening can still be maintained in the interface region of the composite material after aging, ensuring that each region inside the composite material has higher hardness, strength, etc. without obvious weak areas. Through the combined effect of the above two effects, the final material will show higher comprehensive properties such as hardness, strength and conductivity. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 is the hardness distribution of each area inside the composite plate under the conventional aging method; Figure 2 This is the grain orientation scatter diagram of each region inside the composite plate under the conventional aging method; Figure 3 To change the hardness distribution of each area inside the composite plate during the primary aging time under the patented method; Figure 4 To change the hardness distribution of each area inside the composite plate during the secondary aging time under the patented method; DETAILED DESCRIPTION In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0016] In the present invention, the term "and / or" describes the association relationship of associated objects, indicating that there may be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. A and B can be singular or plural. The character " / " generally indicates that the associated objects before and after are in an "or" relationship.

[0017] In the present invention, "at least one" means one or more, and "plurality" means two or more. "At least one of the following" or similar expressions refers to any combination of these items, including any combination of single items or plural items. For example, "at least one of a, b, or c", or "at least one of a, b, and c", can all mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be single or multiple.

[0018] It should be understood that in various embodiments of the present invention, the size of the serial numbers of the above-mentioned processes does not mean the order of execution, some or all of the steps can be executed in parallel or sequentially, and the execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present invention.

[0019] The terms used in the embodiments of the present invention are only for the purpose of describing specific embodiments, and are not intended to limit the present invention. The singular forms "a", "said" and "the" used in the embodiments of the present invention and the appended claims are also intended to include plural forms, unless the context clearly indicates other meanings.

[0020] The weight of the relevant components mentioned in the description of the embodiments of the present invention may not only refer to the specific content of each component, but also indicate the weight ratio between the components. Therefore, as long as the content of the relevant components is proportionally enlarged or reduced according to the description of the embodiments of the present invention, it is within the scope disclosed in the description of the embodiments of the present invention. Specifically, the mass described in the description of the embodiments of the present invention may be a mass unit known in the chemical industry such as µg, mg, g, kg, etc.

[0021] Under the conventional single-stage aging treatment process at the same temperature, due to the uneven distribution of defect density inside the explosion composite material, the aging treatment processes in various regions vary greatly and are difficult to coordinate. For example, the composite interface with a very high dislocation density exhibits differentiated defect evolution behaviors in different regions at high temperatures. The precipitation phase in the region where recrystallization occurs and the defects are sharply reduced grows slowly, while the precipitation phase in the region with residual high-density defects coarsens rapidly. The precipitation process of each part and its corresponding precipitation phase size, content and precipitation degree are difficult to coordinate, resulting in the interface becoming a weak area with low hardness and strength after aging treatment, reducing the mechanical and electrical properties of the composite material.

[0022] The purpose of the present invention is to scientifically utilize the regulatory effect of defects on the second phase precipitation process of an explosion composite material composed of an aging-strengthened alloy by changing the application sequence, size and duration of aging temperature, time, etc., while retaining a certain work hardening effect, thereby improving the comprehensive mechanical properties of the final composite material.

[0023] The present invention provides a heat treatment method for explosively welded composite materials. Specifically, it includes: Step 1, cold deformation of the explosive composite material; Step 2, performing a pre-aging treatment on the explosive composite material; Step 3, performing aging treatment on the explosive composite material.

[0024] Among them, the explosive composite materials are composed of aging-treated strengthened alloys with similar heat treatment processes, and the alloys are all in a solid solution state. The cold deformation methods include cold rolling, cold forging or cold heading, and the deformation amount is 0-80%.

[0025] The temperature selected for pre-aging treatment should be lower than the minimum recrystallization temperature of the cold-deformed composite material.

[0026] The temperature of aging treatment should be determined according to the "Heat Treatment Process Specification Data Manual".

[0027] The deformation amount between 0-80% can be selected according to the specific deformation mode, for example, 10-80%, 30-80%, 10-70%, 20-60%, 30-50%, 11%, 22%, 23%, 35%, 46%, 54%, 63%, 78%, 80%. Optimally, it is not less than 70% of the temperature.

[0028] The principle of the present invention is: Cold deformation treatment: The explosive composite material is subjected to cold deformation such as cold rolling, cold forging or cold heading, with the deformation amount controlled between 0-80% to introduce high-density microscopic defects (such as dislocations) and store strain energy.

[0029] Pre-aging treatment: Pre-aging treatment is carried out at a temperature below the minimum recrystallization temperature of the cold-deformed composite material. The purpose of this step is to promote the massive nucleation of the second phase by utilizing the high-density micro-defects and reasonably consume part of the strain energy stored in the composite material to prevent recrystallization during the subsequent high-temperature aging treatment.

[0030] Aging treatment: After the pre-aging treatment, a higher temperature is selected for aging treatment. This step utilizes the residual high-density defects and high temperature conditions to continue to promote the large-scale nucleation and growth of the second phase, continue to make the second phase nucleation and growth, achieve a more uniform distribution of hardness in the composite plate, prevent the generation of weak areas with significantly lower hardness, and improve the comprehensive precipitation effect. At the same time, a good level of work hardening is retained in the interface area so that the interface area of ​​the final composite material will not become a weak area with lower hardness and obtain better comprehensive performance. The temperature of the aging treatment should be determined according to the "Heat Treatment Process Specification Data Manual".

[0031] These three core steps effectively utilize the regulatory effect of internal defects of explosion composites on the second phase precipitation process by regulating the aging treatment temperature, time and sequence, while retaining the work hardening effect, thereby significantly improving the comprehensive mechanical properties of the composites.

[0032] The present invention first performs a pre-aging treatment at a temperature lower than the lower limit of the recrystallization temperature of the deformed composite material, utilizes the high microscopic defect density in each region to promote the large-scale nucleation of the second phase, and reasonably consumes the strain energy stored in part of the composite material, so that it cannot be recrystallized during the aging treatment at high temperature. Furthermore, the composite material after the pre-aging treatment is continuously aged at a higher temperature to prevent the ineffective low-quality consumption of microscopic defects due to the recovery process during the low-temperature aging treatment (low temperature, slow element diffusion, and the precipitation phase cannot grow effectively), and fully utilizes the residual high-density defects and high temperature conditions to continue to promote the large-scale nucleation and growth of the second phase, improve the comprehensive precipitation effect, and retain a good work hardening level in the interface area, so that the interface area of ​​the final composite material will not become a weak area with low hardness, thereby obtaining better comprehensive performance.

[0033] The "Heat Treatment Process Specification Data Manual" is an important reference book on heat treatment process specifications and data. It records in detail the heat treatment process specifications and related data of various metal materials. The manual mainly compiles the heat treatment process specifications of metal materials such as steel, non-ferrous metals, and high-temperature alloys, and is divided into multiple subcategories according to material types and delivery status, which is easy to find. The content of the book is mainly taken from the latest data in the national standards GB / T and YB / T, which can be used as a reference for heat treatment production staff in designing process flows and improving management work, and can also be used as a reference for scientific researchers in product design and development.

[0034] The present invention is described in detail below with reference to specific embodiments: Example 1 (1) Selecting solid solution CuNiSiCr alloy as welding base material and performing explosive welding to obtain composite materials; (2) Cold rolling the composite material by 20%; (3) The recrystallization temperature of the cold-rolled composite material is 400°C, so the cold-rolled composite material is pre-aged at 380°C for 0.5h; (4) According to the Heat Treatment Process Specification Data Manual, the recommended aging temperature range of the alloy is 450-600℃. The aging temperature is 470℃, and the cold-rolled composite material is aged for 3h. The results are as follows: Figure 3 As shown, Figure 1 Compared with the traditional method, the hardness at the interface is increased by HV 30.

[0035] Figure 1 Hardness distribution of each area inside the composite plate, CRC0-welded, CRC20-welded + cold rolled 20%, CRC60-welded + cold rolled 60%: (a) CRC0, CRC20 and CRC60; hardness after aging at different temperatures for 3h; (b) CRC0, (c) CRC20 and (d) CRC60.

[0036] Figure 2 Grain orientation distribution (GOS) diagram of the composite plate after peak aging at 470℃, CRC0 (a1-3), CRC20 (b1-3), CRC60 (c1-3), serial numbers 1-3 are substrate, flying plate and interface respectively, the degree of recrystallization in the interface area is 48.1%, 63.3% and 60.9%, which seriously weakens the work hardening.

[0037] Figure 3 According to the method of the present invention, the hardness distribution of each internal region of CRC20 is obtained after pre-aging at 380°C for 0.5h and 1h and aging at 470°C for 3h.

[0038] Figure 4 According to the method of the present invention, the hardness distribution of each internal region of CRC20 is measured after pre-aging at 380°C for 0.5h and aging at 470°C for 1h and 5h respectively.

[0039] from Figure 3-4 It can be seen that after pre-aging treatment, the hardness difference between the sample interface and the original flyer plate or substrate area is rapidly reduced (from HV 60-80 of direct aging to HV 30-40), the hardness distribution is more uniform, and there is no obvious weak area inside the composite material. Figure 1 Compared with the process with similar aging time, the hardness of other areas of the composite material has not decreased, which means that the overall strength of the material is improved. At the same time, the relatively longer aging time can make full use of the promotion effect of defects on precipitation, increase the degree of precipitation, reduce the defect density, and ultimately improve plasticity and conductivity at the same time.

[0040] Example 2 (1) Selecting solid solution CuNiSiCr alloy as welding base material and performing explosive welding to obtain composite materials; (2) Cold rolling the composite material by 20%; (3) The recrystallization temperature of the cold-rolled composite material is 400°C, so the cold-rolled composite material is pre-aged at 380°C for 1h; (4) According to the Heat Treatment Process Specification Data Manual, the recommended aging temperature range of the alloy is 450-600℃. The aging temperature is 470℃, and the cold-rolled composite material is aged for 3h. The results are as follows: Figure 3 As shown, Figure 1 Compared with the traditional method, the hardness at the interface is increased by HV 30.

[0041] Example 3 (1) Selecting solid solution CuNiSiCr alloy as welding base material and performing explosive welding to obtain composite materials; (2) Cold rolling the composite material by 20%; (3) The recrystallization temperature of the cold-rolled composite material is 400°C, so the cold-rolled composite material is pre-aged at 380°C for 0.5h; (4) According to the Heat Treatment Process Specification Data Manual, the recommended aging temperature range of the alloy is 450-600℃. The aging temperature is 470℃, and the cold-rolled composite material is aged for 1h. Figure 1 Compared with the traditional method, the hardness at the interface is increased by HV40. At the same time, it can be seen that the hardness fluctuations in various areas of the entire plate are very small.

[0042] Example 4 (1) Selecting solid solution CuNiSiCr alloy as welding base material and performing explosive welding to obtain composite materials; (2) Cold rolling the composite material by 20%; (3) The recrystallization temperature of the cold-rolled composite material is 400°C, so the cold-rolled composite material is pre-aged at 380°C for 0.5h; (4) According to the Heat Treatment Process Specification Data Manual, the recommended aging temperature range of the alloy is 450-600℃. The aging temperature is 470℃, and the cold-rolled composite material is aged for 5h. Figure 1 Compared with the traditional method, the hardness at the interface is increased by HV34, and the hardness fluctuation in each area of ​​the whole plate is relatively small.

[0043] Example 5 (1) Selecting solid solution CuNiSiCr alloy as welding base material and performing explosive welding to obtain composite materials; (2) Cold forging of composite materials 0%; (3) The recrystallization temperature of the composite material is 400 °C, so the cold-rolled composite material is pre-aged at 380 °C for 1 h; (4) According to the Heat Treatment Process Specification Data Manual, the recommended aging temperature range of the alloy is 450-600℃. The aging temperature is selected as 600℃, and the cold-rolled composite material is aged with 0.5h as the starting point and 0.5h as the interval. The condition corresponding to the maximum average hardness of the whole plate is taken as the optimal heat treatment process.

[0044] Example 6 (1) Selecting solid solution CuNiSiCr alloy as welding base material and performing explosive welding to obtain composite materials; (2) Cold forging of composite materials by 80%; (3) The recrystallization temperature of the composite material is 400 °C, so the cold-rolled composite material is pre-aged at 280 °C for 4 h; (4) According to the Heat Treatment Process Specification Data Manual, the recommended aging temperature range of the alloy is 450-600℃. The aging temperature of 450℃ was selected, with 0.5h as the starting point and 0.5h as the interval. The cold-rolled composite material was aged. The condition corresponding to the larger average hardness of the whole plate but the smallest square difference was taken as the optimal heat treatment process.

[0045] Example 7 (1) Select the same solid solution maraging steel as the welding base material and obtain the composite material by explosive welding; (2) Cold forging of composite materials by 50%; (3) The recrystallization temperature of the composite material is 450°C, so the cold forged composite material is pre-aged at 300°C for 2h; (4) According to the Heat Treatment Process Specification Data Manual, the recommended aging temperature range for the alloy is generally 480-510°C. The aging temperature of 480°C is selected, with 0.5h as the starting point and 0.5h as the interval. The cold-rolled composite material is aged, and the condition corresponding to the maximum average hardness of the whole plate is taken as the optimal heat treatment process.

[0046] Example 8 (1) Select Ti-5322 alloy as welding base material and perform explosive welding to obtain composite materials; (2) Cold rolling the composite material by 20%; (3) The recrystallization temperature of the composite material is 550°C, and the cold-rolled composite material is pre-aged at 500°C for 0.5h; (4) According to the Heat Treatment Process Specification Data Manual, the conventional aging temperature range of the alloy is 500-600℃. The aging temperature of 550℃ is selected, and the cold-rolled composite material is aged with 0.5h as the starting point and 0.5h as the interval. The condition corresponding to the larger average hardness of the whole plate but the smallest square difference is taken as the optimal heat treatment process.

[0047] Example 9 (1) Mg-3Nd-1Zn alloy was selected as the welding base material and explosively welded into a composite material; (2) Cold heading of composite materials 0%; (3) The recrystallization temperature of the composite material is 200 °C, so the cold-forged composite material is pre-aged at 150 °C for 5 h; (4) According to the Heat Treatment Process Specification Data Manual, the recommended aging temperature range of the alloy is 195-205°C. The aging temperature is selected as 200°C, and the cold-rolled composite material is aged with 0.5h as the starting point and 0.5h as the interval. The condition corresponding to the maximum hardness is taken as the optimal heat treatment process.

[0048] The above contents are only for explaining the technical idea of ​​the present invention and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution in accordance with the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

[0049] The present invention scientifically designs the conditions such as the application order, size and duration of the aging treatment temperature and time of the cold-deformed explosive composite material. On the one hand, it can fully utilize the regulatory effect of high-density defects on the nucleation and growth of the precipitate phase at multiple levels, obtain a greater precipitation degree and a smaller precipitate phase size (large nucleation density and reduced average size of the precipitate phase) at the same temperature and time, and effectively coordinate the aging treatment process of each region inside the composite material. On the other hand, this method can inhibit the recrystallization process, thereby maintaining a certain degree of dislocation strengthening in the interface region of the composite material after aging treatment, ensuring that each region inside the composite material has higher hardness, strength, etc. without obvious weak areas. Through the combined effect of the above two effects, the final peak aging treatment state material will show higher comprehensive properties such as hardness, strength and conductivity.

[0050] The above contents are only for explaining the technical idea of ​​the present invention and cannot be used to limit the protection scope of the present invention. Any changes made on the basis of the technical solution in accordance with the technical idea proposed by the present invention shall fall within the protection scope of the claims of the present invention.

Claims

1. A heat treatment method for explosively welded composite materials, characterized in that: The following steps are involved: Select welding base material and perform explosion welding to obtain explosion composite material; Cold deformation of explosive composite materials; After cold deformation, a pre-aging treatment is performed at a temperature lower than the lowest recrystallization temperature of the cold-deformed explosion composite material; After the pre-aging treatment, the aging treatment temperature is selected according to the performance of the welding base material, and the explosion composite material is subjected to aging treatment.

2. A heat treatment method for explosively welded composite materials according to claim 1, characterized in that: The welding base material is a solid solution alloy.

3. A heat treatment method for explosively welded composite materials according to claim 1, characterized in that: The explosive composite material is composed of an aging-treated strengthened alloy with similar heat treatment processes.

4. A heat treatment method for explosively welded composite materials according to claim 1, characterized in that: The cold deformation method includes cold rolling, cold forging or cold heading.

5. A heat treatment method for explosively welded composite materials according to claim 1, characterized in that: The deformation amount of the cold deformation is 0-80%.

6. A heat treatment method for explosively welded composite materials according to claim 1, characterized in that: The minimum recrystallization temperature of the composite material lower than the cold deformation explosion temperature is: The temperature selected for pre-aging treatment should be lower than the lowest recrystallization temperature of each region of the cold-deformed composite material.

7. A heat treatment method for explosively welded composite materials according to claim 1, characterized in that: The temperature less than the lowest recrystallization temperature of each region of the cold-deformed composite material refers to a temperature not less than 70% of the lowest recrystallization temperature.

8. A heat treatment method for explosively welded composite materials according to claim 1, characterized in that: The pre-aging treatment at a temperature lower than the lowest recrystallization temperature of the cold-deformed explosive composite material utilizes microscopic defects to promote the nucleation of the second phase and consumes part of the strain energy stored in the composite material so that recrystallization does not occur.

9. A heat treatment method for explosively welded composite materials according to claim 8, characterized in that: The aging treatment of the explosive composite material utilizes the residual microscopic defects obtained from the pre-aging treatment and the aging treatment temperature to continue the nucleation and growth of the second phase.

10. A heat treatment method for explosively welded composite materials according to claim 1, characterized in that: The temperature of the aging treatment should be determined according to the "Heat Treatment Process Specification Data Manual".

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