Forging stock forming method for aluminum matrix composite square thin plate

Abstract

The invention discloses a forming method of an aluminum-based composite square sheet forging stock, which mainly comprises the steps of die preheating, primary isothermal forging, intermediate blank machining, secondary isothermal forging, material distribution, surface cleaning and free forging of a square billet, can improve the deformation plasticity of an aluminum-based composite material, breaks through the limitation that the aluminum-based composite material cannot be subjected to free forging, and improves the yield of the aluminum-based composite material. The aluminum-based composite material replaces a traditional aluminum alloy free forge piece, the characteristics of high specific strength, wear resistance, fatigue resistance, good dimensional stability and the like of the aluminum-based composite material are exerted, and the problems that in the prior art, an aluminum-based composite material sheet type square billet forge piece is difficult to directly machine, and the excellent characteristics of the material cannot be exerted are solved.

Description

Technical Field

[0001] The invention relates to the field of plastic forming of aluminum-based composite materials, and in particular to a method for forming a square forging blank of an aluminum-based composite material thin plate. Background Art

[0002] The development of lightweight, high-performance and low-cost weapons and equipment has placed higher and higher requirements on components, prompting the material forming technology to develop in the direction of precision, high reliability and low cost. Compared with traditional aluminum alloy materials, aluminum-based composite materials (2009 / SiC / 15p) have excellent comprehensive properties, such as high specific strength, wear resistance, fatigue resistance, good dimensional stability, etc., and can be widely used in lightweight components of advanced aircraft. Traditional thin-plate billet forgings generally use the process of direct free forging of metal bars for plastic processing, but due to the addition of particle reinforcement phase (SiC), aluminum-based composite materials are prone to cracking during plastic deformation and are difficult to deform materials. Therefore, in actual engineering applications, due to the limitations of materials and process methods, aluminum-based composite thin-plate billet forgings are difficult to directly process and cannot give full play to the excellent characteristics of the material. Summary of the invention

[0003] In view of this, the main purpose of the present invention is to provide a method for forming a square thin plate forging billet of an aluminum-based composite material, which can solve the problem of easy cracking and difficult deformation of the aluminum-based composite material during plastic deformation in the prior art.

[0004] To achieve the above object, the technical solution of the present invention is achieved as follows:

[0005] A method for forming a square thin plate forging blank of an aluminum-based composite material, comprising:

[0006] S1. Preheat the mold. Install the open mold heating furnace and the flat mold on the large die forging hydraulic press to preheat the mold. The preheating time is ≥ 24h and the mold temperature is ≥ 450℃.

[0007] S2, isothermal forging for the first time, heating the wrapped aluminum-based composite material billet to 460-480°C and then keeping it warm, with a cold material heating insulation coefficient of 1.5-2min / mm and a hot material heating insulation coefficient of 1-1.5min / mm, and then placing it between the above-mentioned flat molds for 1-3 passes of isothermal forging, with a deformation of ≥50%, to obtain billet A;

[0008] S3, machining the intermediate billet, first using a lathe to remove the deformed sheath on the billet A, leaving the deformed aluminum-based composite material billet, and then machining the stress concentration area on the side of the billet and the connection between the deformed aluminum-based composite material billet and the deformed sheath to obtain billet B;

[0009] S4, secondary isothermal forging, first preheat the mold according to S1, then heat the blank after S3 processing to 460-480℃ and keep it warm, the cold material heating insulation coefficient is 1.5-2min / mm, the hot material heating insulation coefficient is 1-1.5min / mm, then place it between the upper and lower flat molds for the second stage 1-3 passes of low-speed isothermal forging, the material deformation is ≥20%, and the blank is cooled in air after forging to obtain the aluminum-based composite material cake blank C;

[0010] S5, dividing the aluminum-based composite material cake blank C obtained in S4 to obtain blank D;

[0011] S6, surface cleaning, using a wet shot blasting machine to clean the graphite residue on the surface of the blank D, and then polishing and cleaning the surface defects;

[0012] S7. For free forging square billet, heat the surface cleaned billet D to 460-480℃ and then keep it warm. The heating and insulation coefficient of cold material is 1.5-2min / mm, and the heating and insulation coefficient of hot material is 1-1.5min / mm. Then place it on the preheated hammer forging equipment for multiple low-speed free forging plastic processing. At the same time, the billet temperature should be monitored in real time during each forging pass to be ≥380℃. After the billet is forged, cool it in air.

[0013] Preferably, the sheath is a steel sheath with a thickness of 10-20 mm.

[0014] Preferably, the forging speed of the isothermal forging in S2 is 0.2-0.5 mm / s, and the speed decreases successively.

[0015] Preferably, during the isothermal forging process in S2, the open die heating furnace is kept powered on for heating.

[0016] Preferably, the forging speed of the low-speed isothermal forging in S4 is 0.1-0.2 mm / s, and the speed decreases successively.

[0017] Preferably, during the low-speed isothermal forging process in S4, the heating furnace is kept powered on for heating.

[0018] Preferably, the S5 material division uses water jet cutting equipment or sawing equipment.

[0019] Preferably, the forging hammer on the hammer forging equipment in S7 needs to be preheated in advance with natural gas for no less than 4 hours.

[0020] Preferably, the pressing speed of the forging hammer in S7 is not greater than 5 mm / s, and the single pressing amount is not greater than 20 mm.

[0021] The aluminum-based composite material square thin plate forging billet forming method of the present invention has the following beneficial effects:

[0022] The present invention discloses a method for forming a square thin plate forging billet of aluminum-based composite material. The method mainly includes: preheating of mold, first isothermal forging, machining of intermediate billet, secondary isothermal forging, material separation, surface cleaning, and free forging of billet, which can improve the deformation plasticity of aluminum-based composite material, break through the limitation that aluminum-based composite material cannot be free forged, and make aluminum-based composite material replace traditional aluminum alloy free forgings, give full play to the characteristics of high specific strength, wear resistance, fatigue resistance, good dimensional stability, etc. of aluminum-based composite material, and thus improve the service life of related parts. On the other hand, the high cost of aluminum-based composite material makes the aluminum-based composite square billet processed by this method can greatly save the cost of raw materials, and its material utilization rate (more than 80%) is much higher than the method of removing the material and processing it into billet after isothermal forging cake, which solves the problem that aluminum-based composite material thin plate billet forgings in the prior art are difficult to directly process and cannot give full play to the excellent characteristics of the material. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0024] Figure 1 A three-dimensional schematic diagram of a thin plate-like billet according to an embodiment of the present disclosure;

[0025] Figure 2 It is a three-dimensional schematic diagram of an aluminum-based composite material billet after being wrapped with a sheath according to an embodiment of the present disclosure;

[0026] Figure 3 It is a schematic diagram of an isothermal forging heating furnace and a die assembly for aluminum-based composite materials installed on a large die forging hydraulic press according to an embodiment of the present disclosure;

[0027] Figure 4 A blank A according to one embodiment of the present disclosure;

[0028] Figure 5 It is a schematic diagram of intermediate blank machining according to one embodiment of the present disclosure;

[0029] Figure 6 It is a schematic diagram of a material distribution method according to an embodiment of the present disclosure.

[0030]

Main component symbol description

[0031] 1. Aluminum-based composite material ingot;

[0032] 2. Package;

[0033] 3. Install the heat insulation board;

[0034] 4. Install the flat plate mold;

[0035] 5. Place the heating furnace on the stove;

[0036] 6. Lower heating furnace;

[0037] 7. Lower flat plate mold;

[0038] 8. Lower insulation board;

[0039] 9. Aluminum-based composite material ingot after deformation;

[0040] 10. The deformed cover. DETAILED DESCRIPTION

[0041] The following is a further detailed description of a method for forming a square thin plate forging blank of an aluminum-based composite material according to the present invention in conjunction with the accompanying drawings and embodiments of the present invention.

[0042] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0043] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0044] It should be noted that the terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable where appropriate, so that the embodiments of the present application described herein can be implemented in an order other than those illustrated or described herein, for example. In addition, the terms "including" and "having" and any of their variations are intended to cover non-exclusive inclusions, for example, a process, method, system, product or device that includes a series of steps or units is not necessarily limited to those steps or units that are clearly listed, but may include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0045] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below other devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0046] See also Figure 1-Figure 6 , the present invention provides a technical solution:

[0047] A method for forming a square thin plate forging blank of an aluminum-based composite material, comprising:

[0048] S1. Preheat the mold. Install the open mold heating furnace and the flat mold on the large die forging hydraulic press to preheat the mold. The preheating time is ≥24h and the mold temperature is ≥450℃.

[0049] like Figure 1 As shown, the flat plate template includes: an upper flat plate mold 4 and a lower flat plate mold 7, and the open mold heating furnace includes: an upper heating furnace 5 and a lower heating furnace 6. The upper heating furnace 5 is located outside the upper flat plate mold 4, and the lower heating furnace 6 is located outside the lower flat plate mold 7. The upper insulation board 3 is located on the upper side of the upper heating furnace 5, and the lower insulation board 8 is located on the lower side of the lower heating furnace 6. The total height of the flat plate mold should be 20-50 mm greater than the sum of the heights of the upper heating furnace 5 and the lower heating furnace 6.

[0050] S2, the first isothermal forging, heat the aluminum-based composite material billet 1 wrapped with the sheath 2 to 460-480℃ and then keep it warm, the cold material heating insulation coefficient is 1.5-2min / mm, the hot material heating insulation coefficient is 1-1.5min / mm, and then place it between the above-mentioned flat molds for 1-3 passes of isothermal forging, the forging speed of the isothermal forging is 0.2-0.5mm / s, and the speed decreases successively. During the warm forging process, the open mold heating furnace is kept powered on for heating. The forging deformation is ≥50%, and the billet A is obtained. After the forging is completed, the billet A is cooled in the air. The first isothermal forging improves the plasticity of the billet. The cross-sectional view of the billet A after the first isothermal forging is as follows Figure 4 As shown;

[0051] The sheath 2 is a steel sheath with a thickness of 10-20 mm. Due to the presence of the particle reinforcement phase SiC, the original aluminum-based composite material ingot has extremely poor plasticity. After the aluminum-based composite material ingot 1 is treated by the wrapping sheath 2 process, the ingot is kept under certain constraints and does not crack in the initial deformation stage, and the various performance indicators of the material are enhanced through plastic deformation.

[0052] S3, machining the intermediate billet, first use a lathe to remove the deformed sheath 10 on the billet A, and the remaining deformed aluminum-based composite material billet 9, such as Figure 5 As shown in the figure, the stress concentration area on the side of the cake blank is then processed. Figure 5 In the middle A area, the deformed aluminum-based composite material billet 9 and the deformed sheath 10 are further processed, as shown in the attached Figure 5 Area B, other processing dimensions as attached Figure 5 As shown, the blank B is obtained to avoid cracking and pinching of the blank during the second stage isothermal forging, wherein the A area is the stress concentration area and the B area is the large deformation area during the secondary isothermal forging.

[0053] S4, secondary isothermal forging, first preheat the flat die according to S1, then heat the blank B to 460-480℃ and then keep it warm, the cold material heating insulation coefficient is 1.5-2min / mm, the hot material heating insulation coefficient is 1-1.5min / mm, then place it between the upper and lower flat die for 1-3 passes of low-speed isothermal forging, the forging speed of the low-speed isothermal forging is 0.1-0.2mm / s, and the speed decreases successively, the heating furnace is kept powered on for heating during the low-speed isothermal forging process, the material deformation is ≥20%, and the blank is cooled in air after forging to obtain the aluminum-based composite material cake blank C after plastic secondary reinforcement;

[0054] S5. Divide the aluminum-based composite material cake blank C by using a water jet cutting device or a sawing machine to obtain a blank D. According to the required size and shape of the square thin plate, one can divide it into two, one into three, or one into four, respectively. Figure 6 (a) Figure 6 (b) Figure 6 (c) as shown.

[0055] S6. Surface cleaning: Use a wet shot blasting machine to clean the graphite residue on the surface of the blank D, and then polish and clean the surface defects, such as microcracks, pinch marks, folds, and saw cut surfaces;

[0056] S7. Free forging square billet. Heat the surface-cleaned billet D to 460-480℃ and then keep it warm. The heating and insulation coefficient of cold material is 1.5-2min / mm, and the heating and insulation coefficient of hot material is 1-1.5min / mm. Then place it on the preheated hammer forging equipment for multiple low-speed free forging plastic processing, which depends on the size of the forging billet. Generally, it is 3-5 times. The pressing speed of the forging hammer is not more than 5mm / s, and the single pressing amount is not more than 20mm. The forging hammer on the hammer forging equipment needs to be preheated with natural gas for not less than 4h in advance, and the preheating temperature is ≥200℃. At the same time, the billet temperature should be monitored in real time during each forging, and it should be ≥380℃. After the billet is forged, it is cooled in the air to obtain aluminum-based composite material thin plate billet forgings with dimensions that meet the requirements.

[0057] The splitting methods in S5 are divided into: one-to-two, one-to-three, and one-to-four. When the length and width of the final square thin plate are similar, the one-to-four splitting method can be used; when the length and width of the square thin plate are relatively large, the one-to-three splitting method is used. In the one-to-three method, except for the 2# blank with a relatively regular size, the remaining blanks after the splitting all contain fan-shaped features. When implementing step seven, it is necessary to add 1-2 width reduction steps for shaping. When the length-to-width ratio of the square thin plate is between 1.5-2.5, the one-to-two splitting method can be used.

[0058] Example

[0059] In order to make the purpose, technical solutions and advantages of the present invention more clear, the forging method mentioned above will be described below in conjunction with specific embodiments.

[0060] Take the preparation of a certain aluminum-based composite material sheet-like billet forging as an example. Forging size: 60×250×1230mm, weight: 52kg, material grade: 2009 / SiC / 15p.

[0061] Firstly, an aluminum-based composite material billet 1 with a size of φ420×500 mm is selected and wrapped with a sheath 2 .

[0062] Then, the initial billet of the aluminum-based composite material was subjected to the first isothermal forging upsetting process for two times according to the S2 method on a large die forging hydraulic press. The die was preheated according to step 1, with a preheating time of 24 h and a preheating temperature of 450°C. The billet height was initially upset to 200 mm and cooled in air after forging to obtain billet A. The specific heating and forging process parameters are shown in Table 1 below.

[0063] Table 1

[0064]

[0065] Next, the ingot with a thickness of 200 mm obtained above is processed according to the requirements of S3 to obtain billet B.

[0066] Then, the initial billet of the aluminum-based composite material was subjected to two secondary isothermal forging upsetting processes according to the S4 method on a large die forging hydraulic press. The die was also preheated according to the S1 method, with a preheating time of 24 h and a preheating temperature of 450 ° C. The billet height was finally upset to 120 mm and cooled in air after forging to obtain an aluminum-based composite material billet C. The specific heating and forging process parameters are shown in Table 2 below.

[0067] Table 2

[0068]

[0069]

[0070] Then, the obtained aluminum-based composite material cake blank C is divided into materials according to S5, such as Figure 6 As shown, the cake blank is divided into three on the water jet cutting equipment to obtain three blanks D, numbered 1#, 2#, and 3#, with the width of 2# blank being 220±5mm, and the surface of blank D is cleaned and polished according to the method shown in step S6.

[0071] Finally, the billet D with a cleaned and smooth surface is preheated for a sufficient time and then placed on a hammer forging device for 2-3 passes (3 passes for the middle billet and 2 passes for the billets on both sides) of low-speed free forging to obtain a thin square slab with good surface quality and a size of 250±5×60±5×1230±10mm. After forging, it is cooled in air. The specific free forging process parameters are shown in Table 3 below.

[0072] Table 3

[0073]

[0074] After heat treatment, the aluminum-based composite material thin plate forging billet was tested for its various mechanical properties. The room temperature tensile strength was ≥500MPa, the elongation was ≥8%, and the high cycle (cycle number 10 7 ) Stress fatigue limit ≥200MPa, the strength performance of forgings is greatly improved while retaining a certain deformation plasticity.

[0075] The above description is only a preferred embodiment of the present invention and is not intended to limit the protection scope of the present invention.

Claims

1. A method for forming a square thin plate forging blank of an aluminum-based composite material, characterized in that: include: S1. Preheat the mold. Install the open mold heating furnace and the flat mold on the large die forging hydraulic press to preheat the mold. The preheating time is ≥24h and the mold temperature is ≥450℃. S2, isothermal forging for the first time, heating the aluminum-based composite material billet (1) wrapped with the sheath (2) to 460-480°C and then keeping it warm, with a cold material heating insulation coefficient of 1.5-2min / mm and a hot material heating insulation coefficient of 1-1.5min / mm, and then placing it between the above-mentioned flat molds for 1-3 passes of isothermal forging, with a deformation of ≥50%, to obtain billet A; S3, machining the intermediate blank, first using a lathe to remove the deformed sheath (10) on the blank A, leaving the deformed aluminum-based composite material billet (9), and then machining the stress concentration area on the side of the blank and the connection between the deformed aluminum-based composite material billet (9) and the deformed sheath (10), to obtain a blank B; S4, secondary isothermal forging, first preheat the mold according to S1, then heat the blank after S3 processing to 460-480℃ and keep it warm, the cold material heating insulation coefficient is 1.5-2min / mm, the hot material heating insulation coefficient is 1-1.5min / mm, then place it between the upper and lower flat molds for the second stage 1-3 passes of low-speed isothermal forging, the material deformation is ≥20%, and the blank is cooled in air after forging to obtain the aluminum-based composite material cake blank C; S5, dividing the aluminum-based composite material cake blank C to obtain blank D; S6. Surface cleaning: using a wet shot blasting machine to clean the graphite residue on the surface of the blank D, and then grinding and cleaning the surface defects; S7. For free forging square billet, heat the surface cleaned billet D to 460-480℃ and then keep it warm. The heating and insulation coefficient of cold material is 1.5-2min / mm, and the heating and insulation coefficient of hot material is 1-1.5min / mm. Then place it on the preheated hammer forging equipment for multiple low-speed free forging plastic processing. At the same time, the billet temperature should be monitored in real time during each forging pass to be ≥380℃. After the billet is forged, cool it in air.

2. The method for forming a square thin plate forging billet of aluminum-based composite material according to claim 1, characterized in that: The sheath is a steel sheath with a thickness of 10-20 mm.

3. The method for forming a square thin plate forging billet of aluminum-based composite material according to claim 1, characterized in that: The forging speed of the isothermal forging in S2 is 0.2-0.5 mm / s, and the speed decreases successively.

4. The method for forming a square thin plate forging billet of aluminum-based composite material according to claim 1, characterized in that: During the isothermal forging process in S2, the open die heating furnace is kept powered on for heating.

5. The method for forming a square thin plate forging billet of aluminum-based composite material according to claim 1, characterized in that: The forging speed of the low-speed isothermal forging in S4 is 0.1-0.2 mm / s, and the speed decreases successively.

6. The method for forming a square thin plate forging billet of aluminum-based composite material according to claim 1, characterized in that: During the S4 low-speed isothermal forging process, the heating furnace is kept powered on for heating.

7. The method for forming a square thin plate forging billet of aluminum-based composite material according to claim 1, characterized in that: The S5 material division uses water jet cutting equipment or sawing equipment.

8. The method for forming a square thin plate forging billet of aluminum-based composite material according to claim 1, characterized in that: The forging hammer on the hammer forging equipment in S7 needs to be preheated with natural gas for no less than 4 hours in advance.

9. The method for forming a square thin plate forging billet of aluminum-based composite material according to claim 1, characterized in that: In the forging hammer in S7, the pressing speed is not greater than 5 mm / s, and the single pressing amount is not greater than 20 mm.

Images