A method for manufacturing medium and small-sized high-strength GH4169 alloy ring forgings based on TCAP

Abstract

The present invention discloses a method for manufacturing medium and small-sized high-strength GH4169 alloy ring forgings based on TCAP, comprising the following steps: inspection - forging modification - inspection - blank preparation - cage upsetting - ring rolling - TCAP extrusion forming - heat treatment - physical and chemical testing. In the manufacturing process of high-strength GH4169 ring forgings, the present invention adds the TCAP corner extrusion process method, so that cage upsetting and ring rolling processes with large deformation amounts can be carried out to form a ring forging blank with a larger inner diameter. Through TCAP extrusion, high-performance forgings of GH4169 with fine grains and uniform grains are finally obtained, meeting the product technical requirements; the forming of a ring blank with a larger inner diameter size also means that larger-diameter mandrels and core rolls can be used, thereby improving the service life of mandrels and core rolls, reducing the manufacturing cost, and improving the batch production efficiency; it is convenient for the engineering application of SPD process technology and meets the engineering requirements of future high-performance aviation and even aerospace ring forgings.

Description

Technical Field

[0001] The present invention relates to a method for manufacturing medium and small-sized high-strength GH4169 alloy ring forgings based on TCAP, belonging to the technical field of forging of aviation parts. Background Art

[0002] For medium and small-sized high-strength GH4169 ring forgings for aeroengines (with an outer diameter less than 400 mm, and the grain size must be grade 6 or finer and uniform), the requirements for the structure and performance of the forgings are extremely high. However, due to the relatively small outer diameter of the ring, the ring rolling forming process method with a large deformation amount cannot be carried out, and only the process method of "low temperature + multiple upsetting and drawing modification + low temperature + mandrel expanding + low temperature + small deformation amount ring rolling" can be adopted. This method has the characteristics of many forming heats, large deformation resistance, and high production difficulty. Nevertheless, it is also difficult to meet the technical indicators of homogeneous crystal and fine crystal high-strength GH4169.

[0003] In addition, the forging forming temperature of high-strength GH4169 is low and the deformation resistance is large, resulting in the easy fracture of small-diameter mandrels and core rolls during the mandrel expanding and ring rolling processes, which seriously restricts the improvement of the mass production efficiency of products.

[0004] Therefore, it is necessary to develop a new manufacturing process method that can not only meet the requirements of fine crystal structure and high performance of high-strength GH4169, but also reduce the manufacturing difficulty, improve the manufacturing efficiency, and reduce the manufacturing cost.

[0005] In recent years, many scientific research institutions have conducted a large number of studies on the SPD (Severe Plastic Deformation) severe plastic deformation technology, and developed a variety of fine crystal preparation and forming technologies based on the SPD theory, such as TCAP (Twist Channel Angular Pressing) angular extrusion technology, ECAP (Equal Channel Angular Pressing) equal channel angular extrusion, ARB (Accumulative Roll Bonding) accumulative roll bonding, HPT (High Pressure Torsion) high-pressure torsion deformation, CEC (Cyclic Extrusion Compression) reciprocating extrusion, etc. Small-sized bar materials, sheet materials, and block specimens have been prepared. Some enterprises have only manufactured a small number of small-sized structural parts, such as screws and small gears, using the above technologies, and have not carried out mass production, nor has anyone successfully produced aerospace ring forgings.

[0006] A Chinese patent with the authorization announcement number CN107287538B and the patent name "A Method for Improving the Comprehensive Performance of Ultra-High Strength Aluminum Alloys by Combining Two-Pass ECAP Processing" discloses a method for improving the comprehensive performance of ultra-high strength aluminum alloys by combining two-pass ECAP processing. For the alloy processed by this method, while its strength is greatly improved, its intergranular corrosion resistance and exfoliation corrosion resistance are both significantly improved, and its corrosion resistance is greatly improved, which can effectively improve the comprehensive performance of ultra-high strength aluminum alloys. However, the research of this patent is limited to ultra-high strength aluminum alloys and cannot be directly applied to the manufacturing of aerospace ring forgings. Summary of the Invention

[0007] The technical problem to be solved by the present invention is to provide a method for manufacturing small and medium-sized high-strength GH4169 alloy ring forgings based on TCAP to solve the problems of high production difficulty and low production efficiency existing in the existing production methods of small and medium-sized high-strength GH4169 ring forgings.

[0008] The technical solution adopted by the present invention is as follows: A method for manufacturing small and medium-sized high-strength GH4169 alloy ring forgings based on TCAP, comprising the following steps:

[0009] (1) Process design, calculate the size of the required bar stock according to the need for the final forging to be formed;

[0010] (2) Blanking, use a sawing machine to saw and blank the bar stock;

[0011] (3) Inspection, check the grain size of the billet end face at the center, at the 1 / 2 radius, and at the edge;

[0012] (4) Reducing forging, use a quick forging machine to perform multiple upsetting and drawing operations on the billet;

[0013] (5) Inspection, check the grain size of the forging end face at the center, at the 1 / 2 radius, and at the edge;

[0014] (6) Billet making, use a quick forging machine to upset, roll round, punch holes, and flatten the end face of the forging;

[0015] (7) Mandrel expanding, use a quick forging machine to perform mandrel expanding and flatten the end face of the forging;

[0016] (8) Ring rolling, use a ring rolling machine to roll the forging;

[0017] (9) TCAP extrusion forming, use a forging hydraulic press to extrude and form the forging;

[0018] (10) Heat treatment, perform solution treatment and aging treatment on the forging;

[0019] (12) Physical and chemical testing, perform microstructure and property testing on the forging.

[0020] Preferably, in the steps (4), (6), (7), (8) and (9), an electric furnace is used for heating, the heating temperature is 1020°C - 1050°C, the holding time is calculated at 0.7 - 1.0 mm / min, and the temperature uniformity of the electric furnace must reach ±15°C.

[0021] Preferably, in the step (4), multiple upsetting and drawing operations are required. After upsetting, re-rounding must be carried out, and the upsetting or drawing deformation amount per single time is controlled within 20 - 40%.

[0022] Preferably, in the step (5), the grain sizes at the center of the end face, at the 1 / 2 radius, and at the edge of the forging must be inspected to ensure that the grain sizes of the forging are uniform before forming.

[0023] Preferably, in the step (6), a quick forging machine is used to upset, round, punch, and flatten the end face of the forging to ensure that there are no defects such as drawing, distortion, and horseshoe shape in the forging.

[0024] Preferably, in the step (7), a quick forging machine is used to expand the hole with a horse frame and flatten the end face of the blank to ensure that the deformation amount of the horse frame hole expansion reaches more than 25%, the inner diameter of the forging is greater than Φ180 mm, and the wall thickness of the forging is uniform.

[0025] Preferably, when a ring rolling machine is used to roll the forging in the step (8), it is ensured that the rolling deformation amount reaches more than 25%, the ovality of the ring forging is ≤4 mm, and there are no fish-tail defects on the end face of the ring forging.

[0026] Preferably, in the step (7), a forging hydraulic press must be used and formed in a special extrusion die. The extrusion speed is controlled within 10 - 20 mm / s. The die must be preheated to 200 - 300°C and sprayed with a water-based graphite lubricant, and a glass lubricant is applied to the forging before heating.

[0027] Advantages of the present invention:

[0028] 1. Compared with the prior art, in the manufacturing process of high-strength GH4169 ring forgings, the present invention adds the TCAP corner extrusion process method, so that large-deformation horse frame hole expansion and ring rolling processes can be carried out to form a ring forging blank with a larger inner diameter. Through TCAP extrusion, a fine-grained and uniform-grained GH4169 high-performance forging is finally obtained, meeting the product technical requirements; the forming of a ring blank with a larger inner diameter size also means that larger-diameter horse rods and core rolls can be used, thereby improving the service life of the horse rods and core rolls, reducing the manufacturing cost, and improving the batch production efficiency.

[0029] 2. Compared with the prior art, by adopting the TCAP extrusion technology, the present invention obtains GH4169 ring forgings with high strength grade six, and the tissue properties all meet the relevant technical requirements; through on-site production tests, after the ring forgings are subjected to TCAP extrusion once, the grain size of the forgings can be increased by more than 2 levels. Due to the characteristics of small dependence on equipment, high forming efficiency, simple extrusion die, large inner diameter of the ring blank, and sufficient deformation of the ring blank in TCAP extrusion, the manufacturing difficulty of high-strength GH4169 ring forgings is greatly reduced; at the same time, due to the use of large-deformation ring rolling and large-deformation TCAP extrusion, the circumferential deformation of the ring is uniform, and the degree of grain refinement is uniform, which is convenient for obtaining a homogeneous crystal structure and solves the problem of uneven deformation caused by the original "low temperature + multiple small deformations".

[0030] 3. Compared with the prior art, the TCAP technology proposed by the present invention is convenient to implement in the manufacture of ring forgings, convenient for the engineering application of the SPD process technology, and meets the engineering requirements of future high-performance aviation and even aerospace ring forgings. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is the forming process diagram of the present invention;

[0032] Figure 2 It is the schematic diagram of the extrusion forming of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0033] The present invention will be further introduced below in conjunction with the drawings and specific embodiments.

[0034] Embodiment 1:

[0035] A method for manufacturing small and medium-sized high-strength GH4169 alloy ring forgings based on TCAP, as Figure 1 shown, includes the following steps:

[0036] (1) Process design

[0037] According to the requirements of the final forging forming, calculate the size of the rectangular ring blank before TCAP extrusion. The size of the rectangular ring blank calculated in this example is: outer diameter Φ512mm × inner diameter Φ434mm × height H91mm, and according to the forming characteristics of the ring forging, calculate the size of the required bar stock as: diameter Φ200mm × height H91mm;

[0038] (2) Blanking

[0039] Use a sawing machine to saw and blank the cylindrical bar stock, and the blanking size is diameter Φ200mm × height 91mm ± 5mm; after sawing, chamfer the two end faces of the bar stock, and the chamfer is carried out according to R equal to 15mm;

[0040] (3) High-magnification tissue detection of the surface of the sawn bar stock

[0041] Perform high-magnification microstructure inspection on the end face of the sawn bar stock. The inspection positions are: the center of the end face, the 1 / 2 radius position, and the edge. Ensure that the grain size of the raw materials put into production is finer than grade 5 or finer and the microstructure of each part is uniform. Otherwise, the blank must be remanufactured by forging until the requirements are met.

[0042] (4)Remanufacturing by forging

[0043] Heat the blank using an electric furnace. The heating temperature of the blank is 1050 °C, the shortest holding time is 135 min, and the longest holding time is 200 min. The temperature uniformity of the electric furnace must reach ±10 °C. Subsequently, use a quick forging machine to perform double upsetting and drawing on the blank. After upsetting, re-rounding must be carried out. The deformation amount for each upsetting or drawing is controlled within 30% ± 5%. During the upsetting and drawing process, asbestos must be placed between the blank and the anvil surface during the forging process to prevent the surface temperature of the blank from dropping too quickly.

[0044] (5)High-magnification microstructure inspection of the blank surface

[0045] Check the grain size at the center of the end face, the 1 / 2 radius position, and the edge of the blank after forging. Ensure that the grain size of the blank after forging is finer than grade 5 or finer and the microstructure of each part is uniform. Otherwise, the forgings must continue to be remanufactured by forging.

[0046] (6)Blank preparation

[0047] Heat the forgings using an electric furnace. The heating temperature is 1020 °C, the shortest holding time is 90 min, and the longest holding time is 170 min. The temperature uniformity of the electric furnace must reach ±10 °C. Subsequently, use a quick forging machine to upset (the upset height H = 96 mm ± 5 mm), round, punch (the punch diameter is Φ110 mm), and flatten the end face (flatten the end face according to H = 96 mm ± 5 mm) the forgings to ensure that there are no defects such as material drawing, distortion, and horseshoe shape in the blank.

[0048] (7)Expanding the hole using a horse frame

[0049] Heat the forgings using an electric furnace. The heating temperature is 1000 °C, the shortest holding time is 70 min, and the longest holding time is 125 min. The temperature uniformity of the electric furnace must reach ±10 °C. Subsequently, use a quick forging machine to expand the hole using a horse frame and flatten the end face on the blank. The dimensions for expanding the hole using a horse frame are: outer diameter Φ374 mm ± 5 mm × inner diameter Φ260 mm ± 5 mm × height 100 mm ± 5 mm; the dimensions for flattening the end face are: control the height of the forging according to H = 93 mm ± 5 mm to ensure that the wall thickness of the forging is uniform.

[0050] (8)Ring rolling

[0051] The forging is heated using an electric furnace at a heating temperature of 1000°C, with a minimum holding time of 50 min and a maximum holding time of 90 min. The temperature uniformity of the electric furnace must reach ±10°C; subsequently, the forging is rolled using a ring rolling machine. The dimensions of the rectangular ring blank are: outer diameter Φ512 mm ± 5 mm × inner diameter Φ434 mm ± 5 mm × height 91 mm ± 5 mm, ensuring that the ovality of the ring forging is ≤ 4 mm and there are no fish-tail defects on the end face of the ring forging;

[0052] (9)TCAP Extrusion Forming

[0053] The ring forging is heated using an electric furnace at a heating temperature of 1000°C, with a minimum holding time of 50 min and a maximum holding time of 90 min. The temperature uniformity of the electric furnace must reach ±10°C; before heating, the entire surface of the ring forging must be coated with glass lubricant; after heating, as Figure 2 shown, the ring forging is placed into the special extrusion die 2. The structure of the special extrusion die 2 is existing, cooperating with the upper anvil 1 and the lower anvil 3, and a forging hydraulic press is used to perform TCAP extrusion forming on the ring forging. The extrusion speed is controlled within 10 - 20 mm / s; before extrusion, the extrusion die must be preheated to 200 - 300°C, and the working part of the extrusion die must be sprayed with water-based graphite lubricant for lubrication;

[0054] (10)Heat Treatment

[0055] The forging is subjected to solution treatment and aging treatment. Solution heat treatment regime: 950°C ± 10°C, holding for 1 h, air cooling or faster cooling; aging heat treatment regime: 720°C ± 10°C, holding for 8 h, furnace cooling at a rate of (50 ± 10)°C / h to 620 ± 10°C, holding for 8 h, and air cooling;

[0056] (11)Physical and Chemical Tests

[0057] The forging is dissected and tested for items such as high magnification (grain size, microstructure), low magnification, room temperature tensile, high temperature tensile, high temperature creep rupture, fatigue, and creep. The results of each test meet the requirements:

[0058] High magnification: Grain size 7, Ni3Nb: 2;

[0059] Low magnification: There are no metallurgical defects such as visible shrinkage cavities, porosity, bubbles, voids, cracks, inclusions, and eccentricity by visual inspection; there are no white spots, light corrosion areas, dark corrosion areas, or black spots;

[0060] Room temperature tensile: Tensile strength 1380 Mpa;

[0061] High temperature tensile (650°C): Tensile strength 1197 Mpa;

[0062] High temperature creep rupture (650°C): Greater than 25 h;

[0063] Fatigue: greater than 1×10^7 times;

[0064] Creep: The residual strains at 25h and 50h meet the requirements.

[0065] Example 2:

[0066] (1) Process design

[0067] According to the requirements of the final forging forming, calculate the dimensions of the rectangular ring blank before TCAP extrusion forming. The dimensions of the rectangular ring blank calculated in this example are: outer diameter Φ742mm × inner diameter Φ662mm × height 103mm. And according to the forming characteristics of the ring forging, calculate the dimensions of the required bar stock: diameter Φ200mm × height 315mm.

[0068] (2) Blanking

[0069] Use a sawing machine to saw the cylindrical bar stock. The blanking size is diameter Φ200mm × height 315mm ± 5mm; after sawing, chamfer the two end faces of the bar stock, and the chamfer is carried out according to R equal to 15mm;

[0070] (3) High-magnification microstructure inspection of the sawed bar stock surface

[0071] Conduct high-magnification microstructure inspection on the end face of the sawed bar stock. The inspection positions are: the center of the end face, the 1 / 2 radius position, and the edge, to ensure that the grain size of the raw materials put into production is finer than grade 5 or finer and the microstructure of each part is uniform. Otherwise, the blank must be reforged until it meets the requirements;

[0072] (4) Reforging

[0073] Use an electric furnace to heat the blank. The heating temperature of the blank is 1050°C, the shortest holding time is 135min, the longest holding time is 220min, and the temperature uniformity of the electric furnace must reach ±10°C; subsequently, use a quick forging machine to perform secondary upsetting and drawing on the blank. After upsetting, re-rounding must be carried out, and the upsetting or drawing deformation amount each time is controlled within 33% ± 5%; during the upsetting and drawing process, asbestos must be placed between the blank and the anvil surface during the reforging process to prevent the surface temperature of the blank from dropping too fast;

[0074] (5) High-magnification microstructure inspection of the blank surface

[0075] Check the grain size of the center of the end face, the 1 / 2 radius position, and the edge of the blank after reforging to ensure that the grain size of the blank after reforging is finer than grade 5 or finer and the microstructure of each part is uniform. Otherwise, the forging must continue to be reforged;

[0076] (6) Blank making

[0077] The forging is heated using an electric furnace at a heating temperature of 1020°C, with a minimum holding time of 95 minutes and a maximum holding time of 180 minutes. The temperature uniformity of the electric furnace must reach ±10°C. Subsequently, a quick forging machine is used to upset (the upset height H = 108 mm ± 5 mm), roll, punch (the punch diameter is Φ120 mm), and flatten the end face (flatten the end face according to H = 105 mm ± 5 mm) of the forging to ensure that there are no defects such as material drawing, distortion, and horseshoe shape in the blank.

[0078] (7)Expansion by horse frame

[0079] The forging is heated using an electric furnace at a heating temperature of 1000°C, with a minimum holding time of 90 minutes and a maximum holding time of 120 minutes. The temperature uniformity of the electric furnace must reach ±10°C. Subsequently, a quick forging machine is used to expand the blank by horse frame and flatten the end face. The dimensions of the expansion by horse frame are: outer diameter Φ440 mm ± 5 mm × inner diameter Φ300 mm ± 5 mm × height 115 mm ± 5 mm, and the dimensions of the flattened end face are: the height of the forging is controlled according to H = 106 mm ± 5 mm to ensure uniform wall thickness of the forging.

[0080] (8)Ring rolling

[0081] The forging is heated using an electric furnace at a heating temperature of 1000°C, with a minimum holding time of 50 minutes and a maximum holding time of 90 minutes. The temperature uniformity of the electric furnace must reach ±10°C. Subsequently, a ring rolling machine is used to roll the forging. The dimensions of the rectangular ring blank are: outer diameter Φ742 mm ± 5 mm × inner diameter Φ662 mm ± 5 mm × height 103 mm ± 5 mm, ensuring that the ovality of the ring forging is ≤4 mm and there are no fish-tail defects on the end face of the ring forging.

[0082] (9)TCAP extrusion forming

[0083] The ring forging is heated using an electric furnace at a heating temperature of 1000°C, with a minimum holding time of 50 minutes and a maximum holding time of 90 minutes. The temperature uniformity of the electric furnace must reach ±10°C; before heating, the entire surface of the ring forging must be coated with glass lubricant; after heating, as Figure 2 shown, the ring forging is placed into the special extrusion die 2. The structure of the special extrusion die 2 is existing, cooperating with the upper anvil 1 and the lower anvil 3, and a forging hydraulic press is used to perform TCAP extrusion forming on the ring forging, with the extrusion speed controlled within 10 - 20 mm / s; before extrusion, the extrusion die must be preheated to 200 - 300°C, and the working part of the extrusion die must be sprayed with water-based graphite lubricant for lubrication.

[0084] (10)Heat treatment

[0085] The forgings are subjected to solution treatment and aging treatment. The solution heat treatment system: 950°C ± 10°C, holding for 1 h, air cooling or faster cooling; the aging heat treatment system: 720°C ± 10°C, holding for 8 h, furnace cooling at a rate of (50 ± 10) °C / h to 620 ± 10°C, holding for 8 h, air cooling;

[0086] (11)Physical and chemical tests

[0087] The forgings are dissected, and high magnification (grain size, microstructure), low magnification, room temperature tensile, high temperature tensile, high temperature creep rupture, fatigue, creep and other items are tested. The test results of each item meet the requirements:

[0088] High magnification: grain size 6.5 level, Ni3Nb: 3 level;

[0089] Low magnification: there are no metallurgical defects such as visible shrinkage cavity marks, porosity, bubbles, cavities, cracks, inclusions and eccentricity by visual inspection; no white spots, light corrosion areas, dark corrosion areas or black spots;

[0090] Room temperature tensile: tensile strength 1395 Mpa;

[0091] High temperature tensile (650°C): tensile strength 1205 Mpa;

[0092] High temperature creep rupture (650°C): greater than 25 h;

[0093] Fatigue: greater than 1×107 times;

[0094] Creep: the residual strains at 25 h and 50 h meet the requirements.

[0095] As described above, it is only the specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention can easily think of changes or substitutions, which should all be covered by the protection scope of the present invention. Therefore, the protection scope of the present invention should be subject to the protection scope of the claims.

Claims

1. A method for manufacturing medium and small-sized high-strength GH4169 alloy ring forgings based on TCAP, characterized in that: It includes the following steps: (1) Process design: Calculate the size of the required bar stock according to the need for the final forging to take shape. (2) Blanking: Use a sawing machine to saw and blank the bar stock. (3) Inspection: Check the grain size at the center of the billet end face, at the 1 / 2 radius, and at the edge. (4) Reducing forging: Use a quick forging machine to perform multiple upsetting and drawing operations on the billet. After upsetting, re-rounding must be carried out. The upsetting or drawing deformation per single time is controlled within 20 - 40%. (5) Inspection: Check the grain size at the center of the forging end face, at the 1 / 2 radius, and at the edge to ensure that the grain size of the forging is uniform before forming. (6) Billet making: Use a quick forging machine to upset, round, punch, and flatten the end face of the forging to ensure that there are no defects such as drawing, distortion, and U-shaped defects in the forging. (7) Mandrel expanding: Use a quick forging machine to perform mandrel expanding and flatten the end face of the forging to ensure that the mandrel expanding deformation reaches more than 25%, the inner diameter of the forging is greater than Φ180mm, and the wall thickness of the forging is uniform. (8) Ring rolling: Use a ring rolling mill to roll the forging to ensure that the rolling deformation reaches more than 25%, the ovality of the ring forging is ≤4mm, and there are no fish-tail defects on the end face of the ring forging. (9) TCAP extrusion forming: Use a forging hydraulic press to perform extrusion forming on the forging. The extrusion speed is controlled at 10 - 20mm / s. The die must be preheated to 200 - 300°C and coated with a water-based graphite lubricant. The forging is coated with a glass lubricant before heating. (10) Heat treatment: Perform solution treatment and aging treatment on the forging. (12) Physical and chemical testing: Perform microstructure and property testing on the forging. In steps (4), (6), (7), (8) and (9) above, an electric furnace is used for heating. The heating temperature is 1020°C - 1050°C. The holding time is calculated at 0.7 - 1.0mm / min. The temperature uniformity of the electric furnace must reach ±15°C.

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