Preparation method of GH4169 alloy ultra-fine grain annular die forging

Abstract

The invention provides a preparation method of a GH4169 alloy ultra-fine grain annular die forging. The preparation method comprises the following steps: carrying out cake upsetting treatment on a GH4169 bar; carrying out heat preservation and punching treatment on the cake blank, carrying out end face flattening operation after punching, and carrying out air cooling treatment on a forge piece; inner hole machining operation is carried out on the cake blank, and sand blasting treatment and polishing treatment are carried out on the cake blank; carrying out heating, heat preservation and chambering treatment on the cake blank, returning a hot material to a furnace, and carrying out air cooling treatment on a forge piece; carrying out machining treatment on the ring blank; the ring blank is subjected to die forging treatment, heating and heat preservation, the ring blank is subjected to sheathing treatment, a forge piece is returned to the furnace again for heat preservation treatment, and the forge piece is taken out of the furnace for forging and air cooling treatment; the forge piece is subjected to sand blasting treatment and polishing treatment; performing rough machining on the forge piece before heating; and performing heat treatment on the forge piece, performing furnace cooling to a preset temperature, preserving heat, discharging the forge piece and performing air cooling. By means of the preparation method, the ultra-fine grain annular die forging can be successfully produced, the structure is stable, and the performance is excellent.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of GH4169 alloy forging, and particularly relates to a preparation method of a GH4169 alloy ultra-fine grain ring-shaped die forging. BACKGROUND

[0002] GH4169 alloy is a precipitation-strengthened nickel-based high-temperature alloy, which has good fatigue resistance, oxidation resistance, corrosion resistance, and good processing performance, welding performance, etc. GH4169 alloy forgings are very sensitive to forging process parameters, and the average grain size of GH4169 alloy ring-shaped die forgings is required to reach 10 levels or finer, and the room temperature yield strength is greater than or equal to 1240 MPa. It is difficult to forge and shape, and the conventional preparation method of GH4169 alloy ring-shaped die forgings is usually to prepare such ring-shaped die forgings through the expanding ring process. It is difficult to achieve such fine grain size, and the organization control is difficult. SUMMARY

[0003] To solve the problem that it is difficult to achieve such fine grain size and the organization control is difficult in the prior art by the expanding ring process to prepare such ring-shaped die forgings, the application provides a preparation method of a GH4169 alloy ultra-fine grain ring-shaped die forging, which can successfully produce such ring-shaped die forgings, the surface quality of the forging is good, the grain size can reach more than 10 levels, the room temperature yield strength is greater than or equal to 1240 MPa and has a margin.

[0004] The technical scheme is as follows: A preparation method of a GH4169 alloy ultra-fine grain ring-shaped die forging, comprising: Step 1: performing upsetting treatment on GH4169 bar stock, and the final upsetting height is 1.5-1.8 times the final ring blank thickness; Step 2: performing heat preservation and punching treatment on the cake blank prepared in step 1, performing flat end face operation after punching, keeping the cake blank outer circle in a free bulging state, and performing air cooling treatment on the forging; Step 3: performing machining of inner holes on the cake blank of step 2, and performing sandblasting treatment and polishing treatment on the cake blank to completely eliminate surface defects of the cake blank; Step 4: performing heating and heat preservation and hole expanding treatment on the cake blank prepared in step 3, and the hot material is recycled, the ratio of the ring blank height to the ring blank thickness is 1.5-1.8, and air cooling treatment is performed on the forging; Step 5: performing machining treatment on the ring blank prepared in step 4; Step 6: performing die forging treatment and heating and heat preservation on the ring blank prepared in step 5, after the heat preservation is completed, performing package treatment on the ring blank, recycling the forging for heat preservation treatment, taking the forging out of the furnace for forging, and performing air cooling treatment; Step 7: performing sandblasting treatment and polishing treatment on the forging prepared in step 6 to completely eliminate surface defects of the forging; Step 8: Hot rough machining is performed on the forging prepared in step 7; Step 9: The forging prepared in step 8 is heat treated, then cooled in the furnace to a preset temperature, and then kept warm, and then the forging is taken out of the furnace and air cooled.

[0005] In step 1, the GH4169 bar is treated by upsetting at 995-1000°C using a free forging press. The number of upsetting fires is determined according to the height of the blank, and the single-fire deformation is ≤60%. The hot material reheat insulation coefficient is 0.3 mm / s.

[0006] In step 2, the cake blank prepared in step 1 is kept warm at 995-1000°C. After the warm-keeping is completed, the cake blank is punched. The punched core material diameter is ≤Φ220 mm, the punched core material thickness is ≤80 mm, and the punching time is ≤120 s.

[0007] In step 3, the cake blank punched in step 2 is machined to have an inner hole. When machining, the center of the cake blank is determined, and the cake blank is machined. The single-side machining amount of the cake blank inner hole is ≤5 mm. The upper and lower corners of the inner hole need to be chamfered, and the corner chamfering is R15-R20 mm.

[0008] In step 4, the cake blank prepared in step 3 is heated and kept warm at 995-1000°C. The warm-keeping coefficient is 0.6 mm / s. After the warm-keeping is completed, the cake blank is expanded on an expander. The expansion deformation of each fire is 20-30%. After one fire of expansion is completed, the hot material is reheated. The hot material reheat insulation coefficient is 0.3 mm / s.

[0009] In step 5, the roughness of each face of the ring blank reaches Ra3.2. The corners of the ring blank are chamfered, and each corner reaches R15-R20 mm. For forgings with positioning requirements, positioning needs to be machined on the ring blank.

[0010] In step 6, the ring blank prepared in step 5 is die forged using an electric screw press. The blank is heated and kept warm at 995-1000°C. After the warm-keeping is completed, the ring blank is sleeved. The sleeve is made of 10 mm thick aluminum silicate fiber cotton and high temperature adhesive. After the sleeve is completed, the forging is reheated and kept warm. The warm-keeping time is 0.3 times the thickness of the ring blank. After the sleeve reheat warm-keeping is completed, the forging is taken out of the furnace and forged. The forging parameters are as follows: the first hammer: speed 0.3 m / s, striking energy 60-90%; the second hammer: speed 0.3 m / s, striking energy 60-90%.

[0011] In step 8, the single-side machining amount is ≤3 mm. The surface roughness of the forging reaches Ra3.2, and the chamfering of all corners of the forging is R15-R20 mm.

[0012] In step 9, the forging prepared in step 8 is subjected to heat treatment. During heat treatment, a direct aging process is adopted. When the furnace temperature is ≤600℃, the forging is put into the furnace, heated to 600±10℃ and held for a preset time, then heated to 700±10℃ and held for a preset time, then heated to 720±10℃ and held for 480±10 minutes. After the holding time is completed, it is cooled in the furnace at a cooling rate of 50±10℃ / h to 620±10℃ and held for 480±10 minutes. The preset time is equal to the maximum thickness of the forging × 0.6.

[0013] Furthermore, the method also includes: Step 10: Perform rough machining on the heat-treated forgings from Step 9, with a single-sided machining allowance of ≤3mm, a surface roughness of Ra1.6, and chamfering of all edges and corners of the forgings to R2~R5mm; Step 11: For the forgings that have undergone rough machining in Step 10, perform surface etching using GH4169 alloy-specific etchant for full-surface etching treatment, and inspect the surface quality of the forgings. Step 12: For the forgings that have undergone full surface corrosion in Step 11, perform rough machining treatment with a single-sided machining allowance of ≤2mm, the surface roughness of the forgings reaches Ra1.6, and all edges and corners of the forgings are chamfered to R2~R5mm; Step 13: Perform water immersion testing on the forgings that have undergone rough machining in Step 12; Step 14: Perform physical and chemical tests on the forgings that have undergone water immersion testing to detect their grain size and mechanical properties.

[0014] The beneficial effects of this invention are as follows: This invention successfully produced GH4169 ring forgings using a combination of free forging press, reamer, and electric screw press. The forgings have an average grain size of over 10, uniform microstructure, excellent mechanical properties, and a smooth and flat surface. Surface corrosion and water immersion testing both meet the requirements of aero-engine standards. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of a bar stock; Figure 2 This is a schematic diagram of a ring-shaped billet; Figure 3 This is a schematic diagram of a forging. Figure 4 This is a high-magnification microstructure diagram of the forging. Detailed Implementation

[0016] This invention provides a method for producing ring forgings using a combination of a free forging press, a reamer, and an electric screw press. This method can successfully produce GH4169 ultrafine-grained ring forgings with an average grain size of over 10, uniform microstructure, excellent mechanical properties, a smooth and flat surface, and surface corrosion and water immersion testing that meet the standards for aero-engines.

[0017] The present invention discloses a method for preparing a GH4169 alloy ultrafine-grained annular die forging, the specific steps of which are as follows: Step 1: Upset the GH4169 bar stock at 995℃~1000℃. The number of upset passes depends on the height of the billet. The deformation per pass is ≤60%. The heat preservation coefficient of hot material returning to the furnace is calculated as 0.3mm / s. The final upset height is 1.5 to 1.8 times the final ring billet thickness.

[0018] Step 2: The blank produced in Step 1 is held at 995℃~1000℃. After holding, the blank is punched with a core material diameter ≤ Φ220mm and a core material thickness ≤ 80mm. The punching time is ≤ 120s. After punching, the end face is flattened, and the outer circle of the blank remains in a free bulging state. The forging is then air-cooled.

[0019] Step 3: Perform internal machining on the blank that has been punched in Step 2. When machining, use the outer circle of the blank to align it. Machining the blank, the machining amount on one side of the inner hole should be ≤5mm. The upper and lower edges of the inner hole should be chamfered with a chamfer of R15~R20mm. The blank should also be sandblasted and polished to completely eliminate surface defects.

[0020] Step 4: Heat and hold the prepared blank from Step 3 at 995℃~1000℃, with a holding coefficient of 0.6mm / s. After holding, perform hole expansion on the blank. Hole expansion is performed on a hole expander, with a deformation of 20%~30% per expansion pass. When multiple expansion passes are required, the deformation per pass should be controlled at 20%~30%. After one expansion pass, the hot material is returned to the furnace, with a holding time of 0.3mm / s. At the end of expansion, the ratio of the ring billet height to the ring billet thickness should be 1.5~1.8. The forged part is then air-cooled.

[0021] Step 5: Machining the ring blank prepared in Step 4. The surface roughness of each surface of the ring blank reaches Ra3.2, and the edges of the ring blank are all chamfered to R15~R20mm. For forgings with positioning requirements, positioning is required at the machining point on the ring blank.

[0022] Step 6: Perform die forging on the ring billet prepared in Step 5 using an electric screw press. Heat the billet to 995℃~1000℃ and hold it thereafter. After holding, wrap the ring billet with 10mm thick aluminum silicate fiber cotton and a high-temperature adhesive. After wrapping, return the forging to the furnace for heat treatment for 40~60 minutes (calculated based on 0.3 times the ring billet thickness). After the heat treatment, remove the forging from the furnace for forging. Forging parameters are: first hammer: speed 0.3m / s, impact energy 60%~90%; second hammer: speed 0.3m / s, impact energy 60%~90%. After forging, the forging is air-cooled.

[0023] Step 7: Perform sandblasting and grinding on the forgings prepared in Step 6 to completely eliminate surface defects.

[0024] Step 8: Perform pre-heat roughing on the forgings prepared in Step 7, with a single-sided machining allowance of ≤3mm; the surface roughness of the forgings reaches Ra3.2, and all edges and corners of the forgings are chamfered to R15~R20mm.

[0025] Step 9: Perform heat treatment on the forgings prepared in Step 8. Heat treatment regime: direct aging. The forgings are placed in the furnace at ≤600℃, heated to 600±10℃ and held for (maximum thickness of forging) minutes, then heated to 700±10℃ and held for (maximum thickness of forging) minutes, then heated to 720±10℃ and held for 480±10 minutes. After holding, the forgings are cooled in the furnace at a cooling rate of 50±10℃ / h to 620±10℃ and held for 480±10 minutes. Then the forgings are removed from the furnace and air-cooled.

[0026] Step 10: Perform rough machining on the heat-treated forgings from Step 9, with a single-sided machining allowance of ≤3mm, a surface roughness of Ra1.6, and chamfering of all edges and corners of the forgings to R2~R5mm.

[0027] Step 11: For the forgings that have undergone rough machining in Step 10, perform surface etching using GH4169 alloy-specific etchant for full surface etching treatment, and check the surface quality of the forgings.

[0028] Step 12: Perform rough machining on the forgings that have undergone full surface corrosion in Step 11. The single-sided machining allowance is ≤2mm, the surface roughness of the forgings reaches Ra1.6, and all edges and corners of the forgings are chamfered to R2~R5mm.

[0029] Step 13: Perform water immersion testing on the forgings that have undergone rough machining in Step 12.

[0030] Step 14: Perform physical and chemical tests on the forgings that have undergone water immersion testing to detect their grain size and mechanical properties.

[0031] In one embodiment, the GH4169 alloy annular die forging for aero-engines uses a forging bar with dimensions of φ250×328mm, as shown in the schematic diagram of the bar stock. Figure 1 As shown.

[0032] Step 1: Upsetting the bar stock is done in two stages. In the first stage, the GH4169 bar stock is held at 1000℃ for 150 minutes. After holding, it is removed from the furnace and forged using a 16MN free forging press. The forging size in the first stage is Φ250×328, upset to Φ422×115. After upsetting, the forging is returned to the furnace for further heating and holding, in preparation for the second stage of upsetting and punching. The second stage is held for 40 minutes. After holding, the forging is removed from the furnace and forged again, upset to Φ422×115, and punched to Φ439×Φ180×115. A schematic diagram of the ring billet is shown below. Figure 2 As shown. After forging, the forging undergoes air cooling treatment.

[0033] Step 2: Machine the inner hole of the ring blank that has been punched in Step 1. When machining, use the outer circle of the blank as the guide. The machining amount on one side of the inner hole should be ≤5mm. The upper and lower edges of the inner hole should be chamfered with a chamfer radius of R15mm. The blank should also be sandblasted and polished to completely eliminate surface defects of the ring blank.

[0034] Step 3: The ring billet prepared in Step 2 is subjected to a hole-expanding process, performed in two heat treatments. In the first heat treatment, the ring billet is heated to 1000℃ and held for 70 minutes. After holding, it is removed from the furnace and expanded from Ø439×Ø190×115 to a flat end face of Ø509×Ø320×113. After the first heat treatment, the ring billet is returned to the furnace and held at 1000℃ for a second heat treatment of 50 minutes. After holding, the forging is removed from the furnace and expanded from Ø509×Ø320×113 to a flat end face of Ø650×Ø516×113. The forging is then air-cooled.

[0035] Step 4: Roughly machine the ring blank prepared in Step 3. The surface roughness of each ring blank should reach Ra3.2. All edges and corners should be chamfered to R15~R20mm. For forgings with positioning requirements, positioning surfaces need to be machined.

[0036] Step 5: Perform die forging on the ring billet prepared in Step 4 using a 365MN electric screw press. Heat the billet to 995℃ and hold for 45 minutes. After holding, remove the forging from the furnace and encase it with 10mm thick aluminum silicate fiber cotton and a high-temperature adhesive. After encasement, return the forging to the furnace for holding for 40 minutes. After the encasement and reheating, remove the forging from the furnace for forging. Forging is performed in three hammer blows: the first blow has a speed of 0.3m / s and an impact energy of 60%; the second blow also has a speed of 0.3m / s and an impact energy of 60%. A schematic diagram of the forging is shown below. Figure 3 As shown. The forging is air-cooled after forging.

[0037] Step 6: Perform sandblasting and grinding on the forgings prepared in Step 5 to completely eliminate surface defects.

[0038] Step 7: Perform pre-heat roughing on the forgings prepared in Step 6, with a single-sided machining allowance of ≤3mm; the surface roughness of the forgings reaches Ra3.2, and all edges and corners of the forgings are chamfered to R15mm.

[0039] Step 8: Perform heat treatment on the forgings prepared in Step 7. Heat treatment regime: direct aging. The forgings are placed in the furnace at ≤600℃, heated to 600±10℃ and held for 60 minutes, then heated to 700±10℃ and held for 60 minutes, then heated to 720±10℃ and held for 480 minutes. After the holding period, the forgings are cooled in the furnace at a cooling rate of 50±10℃ / h to 620±10℃ and held for 480 minutes. After that, the forgings are removed from the furnace and air-cooled.

[0040] Step 9: Perform rough machining on the heat-treated forgings from Step 8, with a single-sided machining allowance of ≤3mm, a surface roughness of Ra1.6, and a chamfer of R2mm on all edges and corners of the forgings.

[0041] Step 10: For the forgings that have undergone rough machining in Step 9, perform surface etching using GH4169 alloy-specific etchant for full surface etching treatment, and check the surface quality of the forgings.

[0042] Step 11: For the forgings that have undergone full surface corrosion in Step 10, perform rough machining treatment with a single-sided machining allowance of ≤2mm, the surface roughness of the forgings reaches Ra1.6, and all edges and corners of the forgings are chamfered to R2mm.

[0043] Step 12: Perform water immersion testing on the forgings that have undergone rough machining in Step 11.

[0044] Step 13: Perform physical and chemical tests on the forgings that underwent water immersion testing in Step 12, examining their grain size and mechanical properties. See the high-magnification microstructure image of the forgings. Figure 4 .

[0045] The above description merely illustrates embodiments of the present invention and is quite specific and detailed; however, it should not be construed as limiting the scope of the patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the scope of protection of the present invention. Furthermore, any parts of the present invention not described in detail are conventional techniques.

Claims

1. A method for preparing an ultrafine-grained annular die forging of GH4169 alloy, characterized in that, include: Step 1: Upset the GH4169 bar stock, with the final upset height being 1.5 to 1.8 times the final ring billet thickness; Step 2: The blank prepared in Step 1 is heat-insulated and punched. After punching, the end face is flattened and the outer circle of the blank is kept in a free bulging state. The forging is then air-cooled. Step 3: Perform internal machining on the blank from Step 2, and then perform sandblasting and polishing to completely eliminate surface defects. Step 4: The blank prepared in Step 3 is heated, kept warm and expanded, the hot material is returned to the furnace, the ratio of the ring blank height to the ring blank thickness is 1.5 to 1.8, and the forging is air-cooled. Step 5: Machining the ring blank prepared in Step 4; Step 6: The ring billet prepared in Step 5 is subjected to die forging, heating and heat preservation. After the heat preservation is completed, the ring billet is wrapped. The forging is returned to the furnace for heat preservation. The forging is then taken out of the furnace for forging and air-cooled. Step 7: Perform sandblasting and grinding on the forgings prepared in Step 6 to completely eliminate surface defects. Step 8: Perform pre-heat roughing on the forging prepared in Step 7; Step 9: Heat treat the forging prepared in step 8, then cool it in the furnace to the preset temperature and hold it at that temperature before removing the forging from the furnace and air cooling it.

2. The method according to claim 1, characterized in that, In step 1, the GH4169 bar stock is upheaded at 995℃~1000℃ using a free forging press. The number of upheading passes depends on the height of the billet, with a single uphead deformation of ≤60%, and the hot material reheat insulation coefficient is 0.3mm / s.

3. The method according to claim 1, characterized in that, In step 2, the cake blank prepared in step 1 is kept at 995℃~1000℃. After the heat preservation is completed, the cake blank is punched. The diameter of the punched core material is ≤Φ220mm and the thickness of the punched core material is ≤80mm. The punching time is ≤120s.

4. The method according to claim 1, characterized in that, In step 3, the blank that has been punched in step 2 is machined to make an inner hole. During machining, the center of the outer circle of the blank is determined. The inner hole of the blank is machined with a single-sided machining amount of ≤5mm. The upper and lower edges of the inner hole need to be chamfered with a chamfer of R15~R20mm.

5. The method according to claim 1, characterized in that, In step 4, the blank prepared in step 3 is heated and kept at 995℃~1000℃ with a heat preservation coefficient of 0.6mm / s. After the heat preservation is completed, the blank is expanded on a hole expander. The deformation amount of each hole expansion is 20%~30%. After one hole expansion is completed, the hot material is returned to the furnace with a heat preservation coefficient of 0.3mm / s.

6. The method according to claim 1, characterized in that, In step 5, the surface roughness of each surface of the ring billet reaches Ra3.2, and the edges of the ring billet are all chamfered, with each edge reaching R15~R20mm. For forgings with positioning requirements, positioning is required at the machining point on the ring billet.

7. The method according to claim 1, characterized in that, In step 6, the ring blank prepared in step 5 is forged using an electric screw press. The blank is heated and held at 995℃~1000℃. After the holding is completed, the ring blank is encased in a 10mm thick aluminum silicate fiber cotton and high-temperature adhesive. After encasing, the forging is returned to the furnace for heat treatment. The heat treatment time is 0.3 times the thickness of the ring blank. After the forging is reheated and kept warm, it is taken out of the furnace for forging. The forging parameters are: first hammer: speed 0.3m / s, impact energy 60%~90%; second hammer: speed 0.3m / s, impact energy 60%~90%.

8. The method according to claim 1, characterized in that, In step 8, the single-sided machining allowance is ≤3mm; the surface roughness of the forging reaches Ra3.2; and all edges and corners of the forging are chamfered to R15~R20mm.

9. The method according to claim 1, characterized in that, In step 9, the forging prepared in step 8 is subjected to heat treatment. During heat treatment, a direct aging process is adopted. When the furnace temperature is ≤600℃, the forging is put into the furnace, heated to 600±10℃ and held for a preset time, then heated to 700±10℃ and held for a preset time, then heated to 720±10℃ and held for 480±10 minutes. After the holding time is completed, the forging is cooled to 620±10℃ with the furnace at a cooling rate of 50±10℃ / h and held for 480±10 minutes. The preset duration is equal to the product of the maximum thickness of the forging and 0.

6.

10. The method according to claim 1, characterized in that, The method further includes: Step 10: Perform rough machining on the heat-treated forgings from Step 9, with a single-sided machining allowance of ≤3mm, a surface roughness of Ra1.6, and chamfering of all edges and corners of the forgings to R2~R5mm; Step 11: For the forgings that have undergone rough machining in Step 10, perform surface etching using GH4169 alloy-specific etchant for full-surface etching treatment, and inspect the surface quality of the forgings. Step 12: For the forgings that have undergone full surface corrosion in Step 11, perform rough machining treatment with a single-sided machining allowance of ≤2mm, the surface roughness of the forgings reaches Ra1.6, and all edges and corners of the forgings are chamfered to R2~R5mm; Step 13: Perform water immersion testing on the forgings that have undergone rough machining in Step 12; Step 14: Perform physical and chemical tests on the forgings that have undergone water immersion testing to detect their grain size and mechanical properties.

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