Uniform forming process method for composite rotary extrusion

Abstract

The invention belongs to the technical field of metal plastic deformation, and particularly relates to a composite rotary extrusion uniform forming process method. Comprising the following steps: step 1, blanking and chamfering to obtain a blank; secondly, a die forging oil press is adopted for sequentially conducting die forging on the blank in a rotary backward extrusion mode and a rotary forward extrusion mode to obtain a die forging piece; and thirdly, the die forging is subjected to heat treatment.

Description

Technical Field

[0001] The invention belongs to the technical field of metal plastic deformation, and in particular relates to a uniform forming process method of composite rotary extrusion. Background Art

[0002] Titanium alloys, with their low density and high specific strength, are widely used in aviation, aerospace, and weaponry. While their strength is comparable to that of typical high-strength structural steels and superalloys, their density is only approximately 57% of steel and 55% of superalloys, resulting in a higher specific strength. Aluminum and magnesium alloys have lower densities, only approximately 60% and 40% of titanium, respectively, but their tensile strength is generally less than one-third that of titanium. This is the primary reason for the gradual decline in the use of aluminum and steel in advanced fighter jets and engines, while the use of titanium alloys continues to rise. In recent years, the rapid development of the global aviation industry has placed higher demands on the function and performance of aircraft, leading to the widespread use of high-strength titanium alloys, particularly in aircraft structural components. Superalloys also offer excellent high-temperature strength, good oxidation and hot corrosion resistance, and excellent fatigue performance and fracture toughness, among other properties, leading to their primary applications in the aerospace and energy sectors.

[0003] Due to the excellent high-temperature mechanical properties of titanium alloys and high-temperature alloys, they play an important role in the field of aerospace. With the vigorous development of aerospace, the demand for high-temperature alloys and titanium alloys is also increasing, which has prompted the vigorous development of new technologies and processes.

[0004] In the aviation field, high-temperature alloy and titanium alloy forgings formed by a single extrusion process such as forward extrusion or reverse extrusion have incomplete grain crushing in the core due to the difference in structure between the edge and the core, and the large grains are elongated along the axial direction, resulting in hardness and brittleness under radial force. The edge has a uniform and fine structure, resulting in unevenness between the inner and outer parts of the forging, and the designed forging process is not ideal. In addition, from a mechanical point of view, the single extrusion process is formed under the action of three-dimensional compressive stress. For high-temperature alloys and titanium alloys, the equipment load is too large, time-consuming and labor-intensive, and the forming process is relatively difficult, affecting factory production efficiency. Therefore, the single extrusion process is currently rarely used on large high-temperature alloy and titanium alloy forgings, and has certain limitations in the aviation field.

[0005] Therefore, in view of the unevenness of the core and edge, forming load, and degree of microstructure refinement of extruded high-temperature alloys and titanium alloys, a new technical solution is urgently needed to forge such forgings. Summary of the Invention

[0006] Purpose of the invention: To provide a uniform forming process method of composite rotary extrusion, which can effectively reduce the equipment load while improving the strain uniformity and organizational uniformity of the core and edge, and improve the comprehensive mechanical properties of the forging.

[0007] Technical solution: A composite rotary extrusion uniform forming process method, comprising: Step 1: Cutting and chamfering to obtain the blank; Step 2: Using a die forging hydraulic press to perform rotary reverse extrusion and rotary forward extrusion on the blank in sequence to obtain a die forging; Step 3: Heat treatment of die forgings.

[0008] Preferably, in step 2, before die forging, the process further includes: Heat the blank and mold: the blank is heated in an electric furnace to 40°C below the phase change point, and the heating and thermal insulation coefficient is calculated as 0.6min / mm; the mold is heated to 450°C with the furnace, and the heating and thermal insulation coefficient is calculated as 0.5min / mm; the mold includes a die, a punch and a mandrel.

[0009] Preferably, in step 2, the forging process is specifically as follows: Assemble the punch and mandrel together. The mandrel is T-shaped with a rounded convex end. The punch is then bolted to the upper platform, which is equipped with an upper hydraulic ejector cylinder. The upper ejector cylinder presses the mandrel to the bottom of the punch cavity, maintaining the position of the upper ejector cylinder and mandrel. Next, the base is fixed to the lower platform with a U-shaped key block and bolts. The lower platform is equipped with a rotating device, and the die is fixed to the base with a U-shaped key block. Finally, by adjusting the upper and lower platforms, the punch and die are vertically aligned on the same axis. Place the blank into the die, move the upper platform downward, wait for the mandrel to enter the inner cavity of the die, and then the lower platform drives the die to rotate clockwise for reverse extrusion. When the mandrel end and the upper opening of the extrusion ratio in the die are at the same horizontal line, the mandrel stops moving and the reverse extrusion process is completed. The rotary forward extrusion method is determined according to the flow pattern of the billet and rotary forward extrusion is performed.

[0010] Preferably, during the rotary reverse extrusion process, the rotation speed of the lower platform is 0.5 to 1.2 rad / s.

[0011] Preferably, during the rotary reverse extrusion process, the pressing speed of the mandrel is 1 to 5 mm / s.

[0012] Preferably, when the billet flow mode is bidirectional flow, the rotary forward extrusion mode is: The die is kept rotating clockwise at the same rate, and the upper ejector cylinder is retracted to the position where it coincides with the bottom of the upper platform. The punch continues to press down under the action of the upper platform. After contacting the billet, the pressing speed is 1 to 5 mm / s, and the rotary forward extrusion process is carried out. At this time, due to the reaction force of the billet, the core shaft moves upward at a certain rate. When the position of the punch and the inner cavity of the die coincide, the upper platform stops pressurizing. At this time, the upper ejector cylinder ejects the core shaft, and the core shaft pushes the extruded forging from the die into the base, and the rotary forward extrusion process is completed.

[0013] Preferably, when the billet flow mode is unidirectional flow, the rotary forward extrusion mode is: The die is kept rotating clockwise at the same rate at all times, and the upper ejector cylinder is used to apply pressure to fix the mandrel in the position of rotary reverse extrusion. During the entire forging process, the mandrel position remains unchanged, and the punch begins to press down. After contacting the billet, the pressing speed is 1 to 5 mm / s, and the rotary forward extrusion process is carried out. When the punch and the lower end corner of the mandrel coincide, the punch and the mandrel are pressed down as a whole at the same rate. When the inner position of the punch and the die coincide, the upper platform stops applying pressure. At this time, the upper ejector cylinder ejects the mandrel, and the mandrel pushes the extruded forging from the die into the base, and the rotary forward extrusion process is completed.

[0014] Preferably, in step 2, for TC4 material forgings, the final forging temperature is ≥800°C.

[0015] Beneficial effects: (1) The composite forming method of rotary reverse extrusion + unidirectional flow rotary forward extrusion has a larger forming load and an increased deformation compared to the other bidirectional flow rotary forward extrusion forming method, which is expected to produce ultrafine-grained materials with fine grains; (2) The interaction of shear force and triaxial compressive stress increases deformation while reducing load; (3) The extruded forgings produced by the method provided by the present invention have good strain uniformity between the core and the edge of the forging, refined structure, and synchronously improved strength and plasticity. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is the mold assembly drawing.

[0017] Figure 2 This is a diagram of rotary reverse extrusion forming.

[0018] Figure 3 Diagram of bidirectional flow rotary forward extrusion forming.

[0019] Figure 4 Diagram of unidirectional flow rotary forward extrusion. DETAILED DESCRIPTION

[0020] In order to make the purpose, technical solutions and advantages of the implementation of this application clearer, the technical solutions in the implementation of this application will be described in more detail below in conjunction with the drawings in the implementation of this application. In the drawings, the same or similar numbers throughout represent the same or similar elements or elements with the same or similar functions. The described implementation is a part of the implementation of this application, not all of the implementations. The implementation described below with reference to the drawings is exemplary and is intended to be used to explain this application, and should not be understood as a limitation on this application. Based on the implementation in this application, all other implementations obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application. The implementation of this application is described in detail below in conjunction with the drawings.

[0021] In the description of the present invention, it should be understood that the terms "center", "axial", "vertical", "up", "down", "upper end", "bottom end", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the scope of protection of the present invention.

[0022] A composite rotary extrusion uniform forming process method, the method comprising the following steps: Step 1: Cutting and chamfering process The material is: TC4, and the required blank is cut according to the process regulations and raw material standard Q / S10-0342-2004; then the edge is rounded to R10~R15 using a lathe.

[0023] Step 2: Die forging process 1. Heating: The electric furnace used for billet heating (with an accuracy of ±10°C or better) must comply with the requirements of Class III and above in GJB904. During production, the furnace is heated to a temperature of 40°C below the phase transition point, and the heating and insulation coefficient is calculated as 0.6 min / mm. The natural gas furnace used for mold heating (including the die, punch, and mandrel) must comply with Class IV in GJB904. During production, the temperature is raised with the furnace (temperature is 450°C), and the heating and insulation coefficient is calculated as 0.5 min / mm. 2. Forging: On a die forging hydraulic press (with a rotating device on the lower platform), assemble the punch and the core shaft (the core shaft is T-shaped and has a round convex top at the end), then fix the punch to the upper platform (with an upper ejector hydraulic cylinder) with bolts. The upper ejector cylinder presses the core shaft to the bottom of the punch cavity, keeping the upper ejector cylinder and the core shaft in the same position. Next, fix the base to the lower platform with a U-shaped key block and bolts. Similarly, fix the die to the base with a U-shaped key block. Finally, adjust the upper and lower platforms to align the punch and die vertically with the same axis. The mold assembly diagram is as follows: Figure 1 As shown; Rotary reverse extrusion: put the blank into the die, the upper platform starts to move downward, wait for the mandrel to enter the inner cavity of the die (not in contact with the blank), the lower platform drives the die to start rotating clockwise (speed 0.5 ~ 1.2rad / s), the mandrel presses down at a speed of 1 ~ 5mm / s, and the rotary reverse extrusion process is carried out (such as Figure 2 As shown in the figure), until the end of the mandrel and the upper opening of the extrusion ratio in the die are at the same horizontal line, the mandrel stops moving and the rotary reverse extrusion process is completed; Rotary forward extrusion: The extrusion ratio is 5 to 10. According to the billet flow mode (unidirectional flow and bidirectional flow), deformation, and load, rotary forward extrusion is divided into two types: 1) Bidirectional flow: The die always rotates clockwise at the same speed, and the upper ejector cylinder is retracted to the position where it coincides with the bottom of the upper platform. The punch continues to press down under the action of the upper platform. After contacting the billet, the pressing speed is 1 to 5 mm / s, and the rotary positive extrusion process is carried out (such as Figure 3 As shown in the figure, at this time, due to the reaction force of the blank, the mandrel moves upward at a certain speed. When the positions of the punch and the inner cavity of the die coincide, the upper platform stops pressurizing. At this time, the upper ejection cylinder ejects the mandrel, and the mandrel pushes the extruded forging from the die into the base, and the rotary forward extrusion process is completed; 2) One-way flow: The die always keeps rotating clockwise at the same speed, and the mandrel is fixed in the position of rotating reverse extrusion by pressurizing the upper ejection cylinder. The mandrel position remains unchanged during the entire forging process, and the punch starts to press down. After contacting the billet, the pressing speed is 1 to 5 mm / s, and the rotating forward extrusion process is carried out (such as Figure 4 As shown in the figure), when the corners of the punch and the lower end of the mandrel coincide with each other, the punch and the mandrel are pressed down as a whole at the same rate. When the positions of the punch and the inner cavity of the die coincide with each other, the upper platform stops pressurizing. At this time, the upper ejection cylinder ejects the mandrel, and the mandrel pushes the extruded forging from the die into the base, and the rotary positive extrusion process is completed. 3.1 After quenching, the final forging temperature is ≥800℃; 4. Cooling method: air cooling with pad.

[0024] In the forging process of step 2, a combined rotary reverse extrusion and rotary forward extrusion method is used to rationally utilize a combination of rotary shear force and three-dimensional compressive stress. The die drives the blank to rotate, while the outer wall of the mandrel and the inner wall of the die apply rotary shear force. The punch, mandrel, and die jointly apply three-dimensional compressive stress. This increases deformation while ensuring the uniformity of the forging's overall structure, reducing forming loads and facilitating forging. Die forging can rationally utilize resources, improve forging quality, reduce energy consumption, and effectively increase production efficiency.

[0025] Step 3: Heat treatment process 1. Equipment used: The uniformity of the equipment should not exceed ±10℃; the forgings must be placed in the effective heating area of ​​the furnace; 2. Annealing: put into the furnace at ≤700℃, then heat to the heating temperature (standard required temperature); 3. Dissipate air cooling.

[0026] Inspect and monitor the entire heat treatment process (furnace loading, heating temperature, holding time, furnace unloading and cooling method).

[0027] The extruded forgings for aviation use are made of TC4 and are formed using a rotary forward extrusion + bidirectional flow method. The specific forming method is as follows: Example 1: 1. Cutting: sawing machine, according to Q / 4GG-68; cutting size: Φ300×100mm; Marking: forging drawing suffix number, smelting furnace (code) number, ingot section number; inspection.

[0028] 2. Machining blank: Chamfering: Chamfer the edges and corners of both ends of the bar to R10; Marking: forging drawing suffix number, smelting furnace (code) number, ingot section number; inspection.

[0029] 3. Die forging: Equipment 365MN hydraulic press Heating: The electric furnace used for billet heating (accuracy of ±10℃ and above) complies with the requirements of Class III and above in GJB904. During production, the furnace is loaded when it reaches temperature (40℃ below the phase change point) and the holding time is 60 minutes. The natural gas furnace used for mold heating complies with Class IV in GJB904. During production, the temperature is raised with the furnace (temperature is 450℃) and the holding time is 10 hours. Forging: The transfer time of the billet from the opening of the heating furnace door to forging is ≤ 60s; Forging parameters: punch diameter Φ298, mandrel Φ130, die inner diameter Φ305, extrusion ratio 5; when the upper ejector cylinder is ejected 220mm, the mandrel reaches the bottom of the punch cavity; Mandrel pressing speed: 2mm / s, punch pressing speed 4mm / s, die rotation speed 0.5rad / s; Forging size: Φ300×100, rotary reverse extrusion to Φ300×220±3, rotary forward extrusion to Φ133×508±3; unit: mm; final forging temperature ≥800℃; Cooling method: air cooling with padding; Marking: forging drawing tail number, melting furnace (code) number, ingot section number; Inspection; 4. Sand blasting and grinding: according to Q / 4GG-64, remove residual defects on the forging blank surface and inner hole; inspection; 5. Heat treatment: Executed according to the special heat treatment process 6. Cutting of samples; 7. Physical and chemical testing; 8. Delivery for rough processing; 9. NDT; 10. Final inspection; 11. Warehousing.

[0030] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in this application should be included in the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection of the claims.

Claims

1. A composite rotary extrusion uniform forming process method, characterized in that: include: Step 1: Cutting and chamfering to obtain the blank; Step 2: Using a die forging hydraulic press to perform rotary reverse extrusion and rotary forward extrusion on the blank in sequence to obtain a die forging; Step 3: Heat treatment of die forgings.

2. The method according to claim 1, characterized in that In step 2, before die forging, the following steps are also included: Heat the blank and mold: the blank is heated in an electric furnace to 40°C below the phase change point, and the heating and thermal insulation coefficient is calculated as 0.6min / mm; the mold is heated to 450°C with the furnace, and the heating and thermal insulation coefficient is calculated as 0.5min / mm; the mold includes a die, a punch and a mandrel.

3. The method according to claim 2, characterized in that In step 2, the forging process is specifically as follows: The punch and mandrel are assembled together. The mandrel is T-shaped with a rounded convex end. The punch is then bolted to the upper platform, which is equipped with an upper hydraulic ejector cylinder. The upper ejector cylinder presses the mandrel to the bottom of the punch cavity, maintaining the position of the upper ejector cylinder and mandrel. Next, the base is fixed to the lower platform using a U-shaped key block and bolts. The lower platform is equipped with a rotating device, and the die is fixed to the base using a U-shaped key block. Finally, by adjusting the upper and lower platforms, the punch and die are aligned vertically along the same axis. Place the blank into the die, move the upper platform downward, wait for the mandrel to enter the inner cavity of the die, and then the lower platform drives the die to rotate clockwise for reverse extrusion. When the mandrel end and the upper opening of the extrusion ratio in the die are at the same horizontal line, the mandrel stops moving and the reverse extrusion process is completed. The rotary forward extrusion method is determined according to the flow pattern of the billet and rotary forward extrusion is performed.

4. The method according to claim 3, characterized in that During the rotational reverse extrusion process, the rotation speed of the lower platform is 0.5 to 1.2 rad / s.

5. The method according to claim 3, characterized in that During the rotary reverse extrusion process, the mandrel pressing speed is 1 to 5 mm / s.

6. The method according to claim 3, characterized in that When the billet flow mode is bidirectional flow, the rotary forward extrusion mode is: The die is kept rotating clockwise at the same rate, and the upper ejector cylinder is retracted to the position where it coincides with the bottom of the upper platform. The punch continues to press down under the action of the upper platform. After contacting the billet, the pressing speed is 1 to 5 mm / s, and the rotary forward extrusion process is carried out. At this time, due to the reaction force of the billet, the core shaft moves upward at a certain rate. When the position of the punch and the inner cavity of the die coincide, the upper platform stops pressurizing. At this time, the upper ejector cylinder ejects the core shaft, and the core shaft pushes the extruded forging from the die into the base, and the rotary forward extrusion process is completed.

7. The method according to claim 3, characterized in that When the billet flow mode is unidirectional flow, the rotary forward extrusion mode is: The die is kept rotating clockwise at the same rate at all times, and the upper ejector cylinder is used to apply pressure to fix the mandrel in the position of rotary reverse extrusion. During the entire forging process, the mandrel position remains unchanged, and the punch begins to press down. After contacting the billet, the pressing speed is 1 to 5 mm / s, and the rotary forward extrusion process is carried out. When the punch and the lower end corner of the mandrel coincide, the punch and the mandrel are pressed down as a whole at the same rate. When the inner position of the punch and the die coincide, the upper platform stops applying pressure. At this time, the upper ejector cylinder ejects the mandrel, and the mandrel pushes the extruded forging from the die into the base, and the rotary forward extrusion process is completed.

8. The method according to claim 3, characterized in that In step 2, for TC4 material forgings, the final forging temperature is ≥800°C.

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