A forging method for GH4586 high-temperature alloy bladed disks

Abstract

This invention relates to the field of forging, and particularly to a forging method for GH4586 high-temperature alloy bladed disks. The method includes: cutting GH4586 high-temperature alloy bars to specifications; heating the bars in an electric furnace; upsetting the blank on a hydraulic press to obtain a rough shape; adding high-temperature cotton pads above and below the blank during upsetting; controlling the pressing amount in each pressing step; performing pre-forging and die forging after machining the rough shape; preheating the die; heating the rough shape according to heating requirements; placing it in the die on the hydraulic press; lining the lower die cavity wall corresponding to areas prone to cracking with high-temperature cotton based on Deform simulation results; the high-temperature cotton is used to compensate for the temperature loss during forging deformation as the rough shape or pre-forging expands outward from the outer protective sleeve; and performing pre-heat machining and heat treatment.

Description

Technical Field

[0001] This invention relates to the field of forging, and in particular to a forging method for GH4586 high-temperature alloy bladed disk forgings. Background Technology

[0002] GH4586 is a precipitation-strengthened nickel-based superalloy. It exhibits excellent strength, oxidation resistance, and corrosion resistance within a temperature range from liquid nitrogen to 850°C, and is primarily used in engine bladed disk forgings. Bladed disk forgings are large in size and, due to the presence of mounting edges, are quite tall. GH4586 alloy has high deformation resistance and poor plasticity, making it prone to cracking during die forging, which affects the final forming of the forging. Therefore, a combination of pre-forging and die forging is necessary, requiring careful design of the rough mold dimensions, and the addition of insulation and lubrication measures to ensure proper forging formation. Optimal forging temperature and deformation amount must be set to guarantee the final performance requirements of the forging. Summary of the Invention

[0003] Purpose of the invention: To provide a method for forging GH4586 high-temperature alloy bladed disks. This forging method can minimize the generation of cracks during the forging process and forge engine bladed disks that meet the requirements of forging technical mechanical properties, microstructure, flaw detection and other indicators.

[0004] Technical solution

[0005] A method for forging GH4586 high-temperature alloy bladed disk forgings is provided, including:

[0006] Step 1: Cut the GH4586 high-temperature alloy bars according to specifications and place them in an electric furnace for heating;

[0007] Step 2: Upsetting the billet on a hydraulic press to obtain a rough shape; high-temperature cotton is placed on both sides of the billet during upsetting; control the amount of pressure applied in each pressing step;

[0008] Step 3: After machining the rough shape, perform pre-forging and die forging: preheat the mold, heat the rough shape according to the heating requirements, and place it in the mold of the hydraulic press. According to the Deform simulation results, high temperature cotton is laid on the lower mold cavity wall corresponding to the area prone to cracking. The high temperature cotton is used to compensate for the temperature loss of the rough shape or pre-forging part from the outer protective sleeve during the forging deformation process.

[0009] Step 4: Perform pre-hot roughing and heat treatment on the forged parts after die forging.

[0010] Furthermore, the method also includes:

[0011] During the upsetting process, add cotton padding and preheat the upper and lower flat molds or hammer anvils with dummy material for 20 minutes before upsetting; the preheating temperature of the dummy material is 1000~1100℃, and the temperature is maintained for ≥2h.

[0012] Furthermore, during the upsetting process, the forging equipment should use full anvil pressing as much as possible; the pressing amount of each pressing step should be controlled at 10-15mm, and 10-15mm of high-temperature cotton should be added above and below the billet during upsetting.

[0013] Furthermore, the heating regime in step 1:

[0014] The preheating temperature of the dummy material is 1000~1100℃, and the preheating and holding time is calculated based on a heating coefficient of 1.0min / mm;

[0015] During the forming process, the heating temperature of the bar stock is 1060~1080℃, and the heating and holding time coefficient is calculated as 0.6min / mm. The heating time t = heating coefficient × effective thickness;

[0016] During the pre-forging and die forging processes, the dummy material adopts the dummy material heating regime of step 1;

[0017] Both the rough shape and the pre-forged parts adopt the bar heating process of step 1.

[0018] Furthermore, following step 1, the method further includes:

[0019] After heat preservation, the billet is wrapped with 10-15mm thick high-temperature cotton and high-temperature adhesive after being taken out of the furnace.

[0020] Furthermore, in step 3, both the pre-forging die and the die forging die adopt preheating and bonding type dummy material preheating.

[0021] Furthermore, a protective lubricant must be sprayed onto the mold cavity before forging.

[0022] Furthermore, the solution heat treatment regime is: 1080℃±10℃×4h~4.5h, water cooling; aging treatment is: 760℃±10℃×16~16.5h, air cooling. Beneficial effects

[0023] This invention cuts GH4586 high-temperature alloy bars into sections according to specifications, heats them according to a heating curve, and after holding them at the heat, wraps the billets with high-temperature cotton and high-temperature binder to prevent heat loss during the transfer process. During the upsetting operation, the amount of pressure applied in each step is strictly controlled, and preheating of the upper and lower flat dies or anvils is required. High-temperature cotton is also required to ensure the temperature field during upsetting. The forging equipment should use full anvil pressure as much as possible to avoid cracking of the forging caused by excessive local pressure from split anvil pressure. Based on Deform simulation results, high-temperature cotton is laid in areas prone to cracking. Before die forging, a protective lubricant is sprayed onto the die cavity. Although padding in crack-prone areas sacrifices some die temperature, the resulting "soft" contact is significantly better than the "hard" contact caused by not padding. After die forging, the forging undergoes pre-heat roughing and heat treatment. The heat treatment regime is solution treatment + aging heat treatment. Selecting a reasonable heat treatment regime yields high-performance finished forgings. This invention mainly focuses on developing reasonable measures for each process in the forging process that is prone to causing cracks in the forging work, thereby reducing the risk of crack formation during the forging process.

[0024] Furthermore, this invention proposes to use high-temperature cotton and high-temperature adhesive to wrap the billet after heat preservation when it is taken out of the furnace, so as to avoid heat loss during the transfer process.

[0025] Furthermore, during the upsetting process, the forging equipment should use full anvil pressing as much as possible to avoid cracking of the forging caused by excessive local pressure from split anvil pressing.

[0026] Furthermore, this invention proposes to strictly control the amount of pressure applied in each step of the upsetting process to reduce the risk of surface cracking of the billet caused by excessive pressure.

[0027] Furthermore, this invention proposes that during the pre-forging and die forging processes, the die needs to be preheated with a fitted "dummy material" to ensure the die temperature.

[0028] Furthermore, this invention proposes for the first time, based on Deform simulation results, to lay high-temperature cotton in areas prone to cracking to create a certain gap between the rough mold and the die. The resulting "soft" contact is significantly better than the "hard" contact caused by not padding with cotton. Compared with traditional lubricants, this gap is less likely to decrease rapidly during the compression between the rough mold and the die.

[0029] Furthermore, this invention clarifies that the forging temperature of GH4586 alloy bladed disk is 1060~1080℃. Forgings forged at this temperature do not exhibit abnormal grain growth and have uniform grain size. Attached Figure Description

[0030] Figure 1 This is a diagram showing the easily cracked areas in the pre-forging of a certain type of turbine bladed disk forging. Detailed Implementation

[0031] This invention designs a reasonable forging drawing based on the rough machining drawing, and, combined with the requirements of GH4586 high-temperature alloy, designs reasonable rough mold dimensions using Deform finite element simulation software to ensure that the equivalent strain of the final die forging is controlled above 0.4. It proposes a forging method for GH4586 high-temperature alloy bladed disk forgings, including:

[0032] Step 1: Cut the GH4586 high-temperature alloy bars according to specifications and place them in an electric furnace for heating.

[0033] Step 2: Upsetting on a hydraulic press. Before upsetting, preheat the upper and lower dies with a dummy material; during upsetting, place high-temperature cotton pads on both sides of the billet; control the amount of pressure applied in each pressing step.

[0034] Step 3: After machining the rough shape, perform pre-forging and die forging. The die needs to be preheated. After heating the rough shape according to the heating requirements, place it in the die on the hydraulic press. According to the Deform simulation results, high-temperature cotton is laid in the areas prone to cracking. Before die forging, a protective lubricant is sprayed onto the die cavity.

[0035] Step 4: Perform pre-hot machining and heat treatment on the forged parts after die forging. The heat treatment process is solution treatment followed by aging heat treatment. The finished forging is obtained after heat treatment.

[0036] The improvement of this invention is as follows:

[0037] Preferably, in step 1, the preheating temperature is 1000~1100℃, the preheating holding time heating coefficient is calculated as 1.0min / mm, the heating temperature is 1060~1080℃, the heating holding time heating coefficient is calculated as 0.6min / mm, and the heating time t = heating coefficient × effective thickness. This heating method is used for the upsetting process, as well as the pre-forging and die forging processes.

[0038] Preferably, in step 1, after heat preservation, the billet is wrapped with 10-15mm thick high-temperature cotton and high-temperature adhesive to prevent heat loss during the transfer process.

[0039] Preferably, in step 2, before upsetting, the upper and lower flat dies or anvils are preheated with dummy material for 20 minutes (the dummy material is heated to 1000-1100℃ and kept at that temperature for ≥2 hours) to ensure the tooling temperature during the upsetting process and to avoid the tooling temperature being too low, which would affect the surface temperature of the billet and cause cracks.

[0040] Preferably, in step 2, the pressing amount of each pressing step is controlled at 10-15mm, and 10-15mm of high-temperature cotton must be added to the top and bottom of the blank during the upsetting process. The pressing amount of each step is strictly controlled to avoid surface cracks caused by excessive pressing.

[0041] Preferably, in step 2, the forging equipment should use full anvil pressing as much as possible to avoid cracking of the forging caused by excessive local pressure during partial anvil pressing.

[0042] Preferably, in step 3, the mold needs to be preheated to 500℃±50℃ for ≥20h, and the cavity is preheated for 10-20min with dummy material heated to 1000~1100℃ before pre-forging and die forging. The use of preheating and dummy material preheating ensures the mold temperature and reduces the risk of excessive die forging tonnage and forging tearing caused by the low temperature of the forging contacting the mold.

[0043] Preferably, in step 3, a protective lubricant is sprayed onto the mold cavity before die forging, and high-temperature cotton is laid in areas prone to cracking based on the Deform simulation results to enhance the lubrication between the rough mold and the die and improve the tearing caused by the rough mold filling.

[0044] Preferably, in step 3, the forging temperature is set to 1060–1080°C. At this temperature, the grains do not grow abnormally.

[0045] Preferably, in step 4, the solution heat treatment regime is: 1080℃±10℃×4h~4.5h, water cooling; the aging treatment is: 760℃±10℃×16~16.5h, air cooling. Example

[0046] The forging of the seventh-stage bladed disk for a certain type of GH4586 alloy compressor has a raw material diameter of Φ400. The forging scheme adopts one-fire upsetting + two-fire pre-forging + one-fire die forging.

[0047] Step 1: Design a reasonable forging drawing based on the rough machining drawing. Considering the crack-prone characteristics of GH4586 alloy material, the forging drawing design should take this into full consideration. The crack-prone areas should have increased allowances. Using Deform finite element simulation software, design reasonable rough mold dimensions to ensure that the final equivalent strain of the die forging is controlled above 0.4.

[0048] Step 2: Cut the GH4586 alloy bar into sections according to specifications. Preheat to 1000℃, with a preheating holding time calculated using a heating coefficient of 1.0 min / mm. The heating temperature is 1060–1080℃, with a heating holding time calculated using a heating coefficient of 0.6 min / mm. Heating time t = heating coefficient × effective thickness. For example, based on a bar diameter of 400mm, the preheating holding time is calculated to be 400 min, and the holding time to reach 1060℃ is 240 min.

[0049] Step 3: Use a 600MN hydraulic press for upsetting. Heat the dummy material to 1000-1100℃ and hold for ≥2 hours. Before upsetting, preheat the upper and lower flat dies with the dummy material for 10-20 minutes. When upsetting the billet, insulation cotton must be added to the top and bottom of the billet. During the pressing process, control the pressing amount of each pressing step to be 10-15mm. The forging temperature is 1070℃. Upset from Φ400×896 to Φ515×540. Pay attention to whether the upsetting process takes too long and causes the surface temperature of the billet to be low. If cracks appear, stop upsetting immediately.

[0050] Step 4: Perform pre-forging blank machining according to design requirements. Recalculate the preheating and holding times based on the dimensions in Step 2. The recalculated times are 515 min and 310 min, respectively. Perform pre-forging on a 600MN press. The die needs to be preheated to 500℃±50℃ for ≥20 hours. Before pre-forging and die forging, preheat the cavity with dummy material heated to 1000~1100℃ for 10~20 minutes. Use preheating and dummy material preheating to ensure the die temperature. Spray lubricant, ensuring a uniform coating that covers the entire blank surface. Based on Deform simulation results, apply high-temperature cotton to areas prone to cracking. The forging temperature is 1070℃. Set the blank height to 415mm on the 600MN hydraulic press and press at 5mm / s with a pressure ≤3mm under-pressure.

[0051] Step 5: Die forging. Recalculate the preheating and holding times according to the dimensions in Step 2. The recalculated times are 210 min and 130 min, respectively. Perform pre-forging on a 600MN die. The die needs to be preheated to 500℃±50℃ for ≥20 hours. Before pre-forging and die forging, preheat the cavity with dummy material heated to 1000~1100℃ for 10~20 minutes. Use preheating and dummy material preheating to ensure the die temperature. Spray lubricant, and the coating should be uniform, covering the entire surface of the blank. According to the Deform simulation results, high-temperature cotton should be used to pad the crack-prone areas. The forging temperature is 1070℃. Set the blank height to 155mm on the 600MN hydraulic press and press at 5mm / s with a pressure under-pressure ≤3mm.

[0052] Step 6: Perform pre-hot machining and heat treatment on the forged parts after die forging. The heat treatment regime is solution treatment + aging heat treatment. Solution heat treatment regime: 1080℃±10℃×4h~4.5h, water cooling; Aging treatment: 760℃±10℃×16~16.5h, air cooling. The finished forging parts are obtained after heat treatment.

[0053] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily conceive of various equivalent modifications or substitutions within the technical scope disclosed in the present invention, and these modifications or substitutions should be covered within the protection scope of the present invention.

Claims

1. A method for forging GH4586 high-temperature alloy bladed disk forgings, characterized in that, include: Step 1: Cut the GH4586 high-temperature alloy bars according to specifications and place them in an electric furnace for heating; Step 2: Upsetting the billet on a hydraulic press to obtain a rough shape; high-temperature cotton is placed on both sides of the billet during upsetting; control the amount of pressure applied in each pressing step; Step 3: After machining the rough shape, perform pre-forging and die forging: preheat the mold, heat the rough shape according to the heating requirements, and place it in the mold of the hydraulic press. According to the Deform simulation results, high temperature cotton is laid on the lower mold cavity wall corresponding to the area prone to cracking. The high temperature cotton is used to compensate for the temperature loss of the rough shape or pre-forging part from the outer protective sleeve during the forging deformation process. Step 4: Perform pre-hot roughing and heat treatment on the forged parts after die forging.

2. The method according to claim 1, characterized in that, The method further includes: During the upsetting process, padding with cotton is added. Before upsetting, preheat the upper and lower flat molds or hammer anvils with dummy material for 20 minutes. The preheating temperature of the dummy material is 1000-1100℃, and the temperature is maintained for ≥2 hours.

3. The method according to claim 2, characterized in that, During the upsetting process, the forging equipment adopts full anvil pressing; the pressing amount of each pressing step is controlled at 10-15mm, and 10-15mm of high-temperature cotton is added above and below the billet during upsetting.

4. The method according to claim 2, characterized in that, The heating process in step 1 is as follows: The preheating temperature of the dummy material is 1000~1100℃, and the preheating and holding time is calculated based on a heating coefficient of 1.0min / mm. During the forming process, the heating temperature of the bar stock is 1060~1080℃, and the heating and holding time coefficient is calculated as 0.6min / mm. The heating time t = heating coefficient × effective thickness; During the pre-forging and die forging processes, the dummy material adopts the dummy material heating regime of step 1; Both the rough shape and the pre-forged parts adopt the bar heating process of step 1.

5. The method according to claim 1, characterized in that, Following step 1, the method further includes: After heat preservation, the billet is wrapped with 10-15mm thick high-temperature cotton and high-temperature adhesive after being taken out of the furnace.

6. The method according to claim 2, characterized in that, In step 3, both the pre-forging die and the die forging die adopt preheating and bonding type dummy material preheating.

7. The method according to claim 1, characterized in that, In step 3, a protective lubricant must be sprayed onto the mold cavity before forging.

8. The method according to claim 1, characterized in that, The heat treatment in step 4 is a solution treatment followed by aging heat treatment, and its process is as follows: Solution heat treatment: 1080℃±10℃×4h~4.5h, water cooling; Aging treatment: 760℃±10℃×16~16.5h, air cooling.

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