Forging method for GH4586 high-temperature alloy blade disc forge piece

Abstract

The invention relates to the field of forging, in particular to a forging method for a GH4586 high-temperature alloy bladed disc forge piece. The method comprises the steps that a GH4586 high-temperature alloy bar is blanked according to the specification, and the bar is placed in an electric furnace to be heated; upsetting a cake on an oil press to obtain a crude mold; high-temperature cotton is padded above and below the blank during cake upsetting; the pressing amount of each pressing step is controlled; after machining a rough mold, carrying out sheath pre-forging and die forging: preheating a die, heating the rough mold according to a heating requirement, putting the rough mold into a die on oil press equipment, paving high-temperature cotton on a lower die cavity wall corresponding to an area which is easy to generate cracks according to a Deform simulation result, and carrying out die forging; the high-temperature cotton is used for compensating the temperature lost due to the fact that the rough shape or the pre-forged piece expands outwards from the outer protective sleeve in the forging deformation process; and carrying out rough machining and heat treatment before heating.

Description

Technical Field

[0001] The invention relates to the field of forging, and in particular to a forging method for a GH4586 high-temperature alloy blade disk forging. Background Art

[0002] GH4586 high temperature alloy is a precipitation-strengthened nickel-based high temperature alloy. It has excellent strength, good oxidation resistance and corrosion resistance in the range of liquid nitrogen temperature to 850℃. It is mainly used for engine blade disc forgings. Blade disc forgings are large in size, and have mounting edges and other factors, so they are high in height. GH4586 alloy has large deformation resistance and poor material plasticity. It is easy to produce cracks during the die forging process, which affects the final forming of the forgings. It is necessary to adopt a combination of pre-forging + final forging, reasonably design the rough size, and increase insulation and lubrication measures to ensure the forging forming, set a reasonable forging temperature and deformation, and ensure the final performance requirements of the forgings. Summary of the invention

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

[0004] Technical solution:

[0005] A method for forging a GH4586 high temperature alloy blade disk forging is provided, comprising:

[0006] Step 1, cutting GH4586 high temperature alloy bars according to specifications, and placing the bars in an electric furnace for heating;

[0007] Step 2: Perform upsetting on the hydraulic press to obtain rough shape; when upsetting, pad the upper and lower parts with high temperature cotton; control the pressing amount in each pressing step;

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

[0009] Step 4: Perform rough machining and heat treatment before heat treatment.

[0010] Furthermore, the method further comprises:

[0011] In the process of upsetting, add cotton padding and use dummy material to preheat the upper and lower flat dies or hammer anvil for 20 minutes before upsetting; the preset temperature of the dummy material is 1000-1100℃, and the insulation is ≥2h.

[0012] Furthermore, during the upsetting process, the forging equipment should use full anvil downward pressure as much as possible; the downward pressure amount of each downward pressure step should be controlled at 10 to 15 mm, and 10 to 15 mm high-temperature cotton should be added to the upper and lower parts of the blank during upsetting.

[0013] Further, the heating system of step 1:

[0014] The preheating temperature of the material is 1000-1100℃, and the heating coefficient of the preheating and holding time is calculated as 1.0min / mm;

[0015] During the upsetting process, the bar material heating temperature is 1060-1080℃, the heating coefficient of the heating and holding time is calculated as 0.6min / mm, and the heating time t = heating coefficient × effective thickness;

[0016] During the pre-forging process and the final forging process, the dummy material adopts the dummy material heating system of step 1;

[0017] Both the blank and the pre-forged parts adopt the bar heating system of step 1.

[0018] Furthermore, after step 1, the method further comprises:

[0019] After heat preservation, the blank is wrapped with 10-15mm thick high-temperature cotton and high-temperature adhesive.

[0020] Furthermore, in step 3, both the pre-forging die and the final forging die are preheated by preheating and fitting dummy material preheating.

[0021] Furthermore, the die cavity needs to be sprayed with a protective lubricant before die forging.

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

[0023] Beneficial effects:

[0024] The present invention cuts GH4586 high-temperature alloy bars into sections according to specifications, heats them according to a heating curve, and after heat preservation, the blanks are taken out of the furnace and are wrapped with high-temperature cotton and high-temperature adhesive to avoid heat loss during the transfer process; in the upsetting operation, the pressing amount of each step of the upsetting is strictly controlled, and the upper and lower flat dies or hammer anvils are required to be preheated, and high-temperature cotton is required to be padded on the upper and lower sides to ensure the temperature field of the upsetting process, and the forging equipment uses full anvil pressing as much as possible to avoid cracking of the forging caused by excessive local pressure of the divided anvil pressing; according to the Deform simulation result, high-temperature cotton is padded in the crack-prone area, and a protective lubricant needs to be sprayed on the mold cavity before die forging. Although the padding of cotton in the crack-prone area will sacrifice a certain mold temperature, the "soft" contact brought by it is obviously better than the "hard" contact caused by no padding of cotton; after the die forging is completed, the forging is subjected to pre-heat rough processing and heat treatment, and the heat treatment system is solid solution + aging heat treatment, and a reasonable heat treatment system is selected to obtain a finished forging with excellent performance. The present invention mainly formulates reasonable measures for each process in the forging process that is likely to cause cracks in the forging, thereby reducing the risk of cracks in the forging process.

[0025] Furthermore, the present invention proposes to wrap the blank with high temperature cotton and high temperature adhesive after heat preservation, so as to avoid heat loss during the transfer process.

[0026] Furthermore, in the upsetting process, the forging equipment should use full anvil pressure as much as possible to avoid cracking of the forging caused by excessive local pressure due to partial anvil pressure.

[0027] Furthermore, the present invention proposes to strictly control the pressing amount in each step during the upsetting process, thereby reducing the risk of cracking on the surface of the rod blank caused by excessive pressing amount.

[0028] Furthermore, the present invention proposes that during the pre-forging and final forging processes, the mold needs to be preheated with a fitted "dummy material" to ensure the mold temperature.

[0029] Furthermore, the present invention proposes for the first time to pave high-temperature cotton in the crack-prone area according to the Deform simulation results to create a certain gap between the blank and the mold. The "soft" contact brought about by this is significantly better than the "hard" contact caused by no cotton padding. Compared with traditional lubricants, this gap is not easy to reduce rapidly during the extrusion of the blank and the mold.

[0030] Furthermore, the present invention specifies that the forging temperature of the GH4586 alloy blade disk is 1060-1080° C., and the grain size of the forging forged at this temperature does not grow abnormally and the grain size is uniform. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is a diagram showing the prone-to-crack areas in the pre-forging of a certain type of machine blade forging. DETAILED DESCRIPTION

[0032] The present invention designs a reasonable forging drawing according to the rough machining drawing, combines the requirements of GH4586 high-temperature alloy, and designs a reasonable rough size through Deform finite element simulation software to ensure that the final die forging equivalent strain is controlled above 0.4. A method for forging GH4586 high-temperature alloy blade disk forgings is proposed, including:

[0033] Step 1: Cut GH4586 high-temperature alloy bars according to specifications and place the bars in an electric furnace for heating.

[0034] Step 2: Perform upsetting on the hydraulic press. Use dummy material to preheat the upper and lower flat dies before upsetting; add high-temperature cotton pads on the upper and lower parts of the blank during upsetting; control the pressing amount in each pressing step;

[0035] Step 3: After machining the rough mold, pre-forging and die forging are performed. The mold needs to be preheated. After heating the rough mold according to the heating requirements, place it in the mold on the hydraulic press equipment. According to the Deform simulation results, high-temperature cotton is laid in the area prone to cracks. Before die forging, protective lubricant needs to be sprayed on the mold cavity;

[0036] Step 4: Perform rough machining and heat treatment before heat treatment. The heat treatment system is solid solution + aging heat treatment. After heat treatment, the finished forging is obtained.

[0037] The improvement of the present invention is:

[0038] Preferably, in step 1, the preheating temperature is 1000-1100°C, the preheating holding time heating coefficient is calculated as 1.0 min / mm, the heating temperature is 1060-1080°C, the heating holding time heating coefficient is calculated as 0.6 min / mm, the heating time t = heating coefficient × effective thickness, and this heating method is used for heating in the upsetting process and the pre-forging and final forging processes.

[0039] Preferably, in step 1, after heat preservation, the blank is wrapped with high-temperature cotton and high-temperature adhesive with a thickness of 10 to 15 mm to avoid heat loss during the transfer process.

[0040] Preferably, in step 2, the forging process is increased by preheating the upper and lower flat dies or the hammer anvil with dummy materials for 20 minutes before upsetting with cotton padding (heating the dummy materials to 1000-1100°C and keeping warm for ≥2h) to ensure the tooling temperature during the upsetting process and avoid the tooling temperature being too low to affect the surface temperature of the bar blank and cause cracks.

[0041] Preferably, in step 2, the pressing amount of each pressing step is controlled at 10 to 15 mm, and 10 to 15 mm high-temperature cotton must be padded above and below the blank during upsetting, and the pressing amount of each step is strictly controlled to avoid surface cracks caused by excessive pressing amount.

[0042] Preferably, in step 2, the forging equipment uses full anvil pressing as much as possible to avoid cracking of the forging caused by excessive local pressure due to partial anvil pressing.

[0043] Preferably, in step 3, the mold needs to be preheated to 500°C ± 50°C for ≥ 20h, and the cavity is preheated with a dummy material heated to 1000-1100°C for 10-20min before pre-forging and die forging. Preheating and laminating dummy material preheating are used to ensure the mold temperature, thereby reducing the risk of excessive die forging tonnage and tearing of forgings caused by the forging contacting the die temperature which is too low.

[0044] Preferably, in step 3, before die forging, a protective lubricant is sprayed on the mold cavity, and high-temperature cotton is laid on the crack-prone area according to the Deform simulation results to enhance the lubrication effect between the rough mold and the mold and improve the tearing caused by the rough mold filling.

[0045] Preferably, in step 3, the forging temperature is set to 1060-1080° C., and when forging at this temperature, the grains do not grow abnormally.

[0046] Preferably, in step 4, the solution heat treatment system is: 1080°C±10°C×4h~4.5h, water cooling; aging treatment: 760°C±10°C×16~16.5h, air cooling.

[0047] Example

[0048] The seventh stage blade disc forging of a certain type of machine GH4586 alloy compressor, the raw material diameter is Φ400. The forging scheme of one fire upsetting + two fire pre-forging + one fire die forging is adopted.

[0049] Step 1: Design a reasonable forging drawing based on the rough machining drawing. Combined with the crack-prone characteristics of GH4586 alloy material, the forging drawing design should be fully considered, and the crack-prone area should be designed with a larger margin. Through the Deform finite element simulation software, a reasonable rough size is designed to ensure that the final die forging equivalent strain is controlled above 0.4.

[0050] Step 2: Cut GH4586 alloy bars into sections according to specifications, preheating temperature 1000℃, preheating holding time heating coefficient calculated as 1.0min / mm, heating temperature 1060~1080℃, heating holding time heating coefficient calculated as 0.6min / mm, heating time t=heating coefficient×effective thickness. For example, based on the bar Φ400mm, the preheating holding time is calculated as 400min, and the holding time when the temperature rises to 1060℃ is 240min.

[0051] Step 3: Use a 600MN hydraulic press for upsetting, heat the dummy material to 1000-1100℃, keep it warm for ≥2h, preheat the upper and lower flat dies with the dummy material for 10-20min before upsetting, and pad the upper and lower parts of the blank with insulation cotton when upsetting. During the pressing process, control the pressing amount of each pressing step to 10-15mm, and the forging temperature is 1070℃. Upsetting from Φ400×896 to Φ515×540. Pay attention to whether the upsetting process is too long, resulting in low surface temperature of the blank. If cracks appear, stop upsetting immediately.

[0052] Step 4: Perform pre-forging rough mold processing according to design requirements, and recalculate the preheating and heating time according to the size according to step 2. The recalculated time is 515min and 310min respectively. Pre-forging is performed on 600MN. The mold needs to be preheated to 500℃±50℃ for ≥20h, and the cavity is preheated with a dummy heated to 1000-1100℃ for 10-20min before pre-forging and die forging. Preheating and laminating dummy preheating are used to ensure the mold temperature. Spray lubricant, and the coating should be uniform to cover the entire surface of the blank. According to the Deform simulation results, high-temperature cotton is padded in the crack-prone area. The forging temperature is 1070℃. The billet height of the 600MN hydraulic press is set to 415mm, and the underpressure is ≤3mm at 5mm / s.

[0053] Step 5: Die forging, recalculate the preheating and heating time according to the size according to step 2, and the recalculated time is 210min and 130min respectively. Pre-forging is performed on 600MN, the die needs to be preheated to 500℃±50℃, the time is ≥20h, and the cavity is preheated with a dummy heated to 1000-1100℃ for 10-20min before pre-forging and die forging. Preheating and laminating dummy preheating are used to ensure the die temperature, spray lubricant, the coating should be uniform, covering the entire blank surface, and high-temperature cotton pads are performed on the crack-prone areas according to the Deform simulation results. The forging temperature is 1070℃, and the billet height of the 600MN hydraulic press is set to 155mm, and the underpressure is ≤3mm at 5mm / s.

[0054] Step 6: Perform rough machining and heat treatment before heat treatment. The heat treatment system is solid solution + aging heat treatment. Solid solution heat treatment system: 1080℃±10℃×4h~4.5h, water cooling; aging treatment: 760℃±10℃×16~16.5h, air cooling. After heat treatment, the finished forging is obtained.

[0055] 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 technician familiar with the field can easily think of various equivalent modifications or substitutions within the technical scope disclosed by the present invention, and these modifications or substitutions should all be covered within the protection scope of the present invention.

Claims

1. A method for forging GH4586 high temperature alloy blade disk forgings, characterized in that: include: Step 1, cutting GH4586 high temperature alloy bars according to specifications, and placing the bars in an electric furnace for heating; Step 2: Perform upsetting on the hydraulic press to obtain rough shape; when upsetting, pad the upper and lower parts with high temperature cotton; control the pressing amount in each pressing step; Step 3: After machining the rough mold, perform sleeve pre-forging and die forging: preheat the die, heat the rough mold according to the heating requirements, and place it in the die on the hydraulic press. According to the Deform simulation results, high-temperature cotton is laid on the lower mold cavity wall corresponding to the crack-prone area. The high-temperature cotton is used to compensate for the temperature lost by the rough mold or pre-forging part expanding outward from the outer protective sleeve during the forging deformation process; Step 4: Perform rough machining and heat treatment before heat treatment.

2. The method according to claim 1, characterized in that The method further comprises: In the process of upsetting, add cotton padding and use dummy material to preheat the upper and lower flat dies or hammer anvil for 20 minutes before upsetting; the preset temperature of the dummy material is 1000-1100℃, and the insulation is ≥2h.

3. The method according to claim 2, characterized in that During the upsetting process, the forging equipment should use full anvil downward pressure as much as possible; the downward pressure amount of each downward pressure step should be controlled at 10 to 15 mm, and 10 to 15 mm high-temperature cotton should be added to the upper and lower parts of the blank during upsetting.

4. The method according to claim 1, characterized in that Heating regime for step 1: The preheating temperature of the material is 1000-1100℃, and the heating coefficient of the preheating and holding time is calculated as 1.0min / mm; During the upsetting process, the bar material heating temperature is 1060-1080℃, the heating coefficient of the heating and holding time is calculated as 0.6min / mm, and the heating time t = heating coefficient × effective thickness; During the pre-forging process and the final forging process, the dummy material adopts the dummy material heating system of step 1; Both the blank and the pre-forged parts adopt the bar heating system of step 1.

5. The method according to claim 4, characterized in that After step 1, the method further comprises: After heat preservation, the blank is wrapped with 10-15mm thick high-temperature cotton and high-temperature adhesive.

6. The method according to claim 5, characterized in that In step 3, both the pre-forging die and the final forging die are preheated by preheating and fitting dummy material.

7. The method according to claim 1, characterized in that Before die forging, the die cavity needs to be sprayed with protective lubricant.

8. The method according to claim 1, characterized in that Solution heat treatment system: 1080℃±10℃×4h~4.5h, water cooling; aging treatment: 760℃±10℃×16~16.5h, air cooling.

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