A method for preparing a large thin-wall titanium alloy ring forging with low cost and short process

Abstract

The application discloses a preparation method of a large thin-wall titanium alloy ring forging with low cost and short process, and comprises the following steps: 1, selecting titanium alloy powder with a proper particle size according to the material of the ring forging; 2, making a package sleeve according to the size of the required ring forging blank, filling the powder and sealing and welding; 3, carrying out hot isostatic pressing treatment on the package sleeve; 4, carrying out homogenizing annealing on the blank after the hot isostatic pressing; 5, carrying out machining on the blank after the homogenizing annealing, and removing the surface package sleeve; 6, carrying out ring rolling on the blank after the machining on a ring rolling equipment; and 7, carrying out heat treatment on the ring forging obtained in the step 6. The application combines the powder metallurgy hot isostatic pressing technology and the ring rolling technology, replaces the traditional multi-step forging process, significantly shortens the process flow, improves the production efficiency, can accurately control the size precision and the organizational performance of the large thin-wall ring forging, and is suitable for the production of the titanium alloy ring forging with large size, thin wall and complex structure.

Description

Technical Field

[0001] This invention belongs to the field of titanium alloy forming technology, specifically relating to a low-cost, short-process method for preparing large thin-walled titanium alloy ring forgings. Background Technology

[0002] Titanium alloys possess excellent properties such as high strength, low density, corrosion resistance, and high temperature resistance, and are widely used in the manufacture of engine compressor discs, blades, casings, as well as aircraft structures such as landing gear, wing spars, and bulkheads. The traditional production of titanium alloy ring forgings for engines mainly employs a process route of forging → upsetting → punching → ring rolling. This process route is lengthy and has low material utilization, which further decreases as the size of the ring forging increases. This is the main reason for the high cost of such forgings.

[0003] Currently, various powder preparation methods and processes in 3D printing generate a large amount of coarse powder particles. These spherical powders have poor compressibility and cannot be sintered using traditional powder metallurgy techniques. Furthermore, during vacuum melting, titanium alloy powder can be sucked away by the vacuum pump, leading to production accidents. With the large-scale application of 3D printing technology in industrial production, the recycling and reuse of waste generated from 3D printing has become a widely concerned issue.

[0004] The closest prior art to this application is a method for preparing high-performance GH4079 disc-ring parts and disc-ring parts for aero-engines disclosed in Chinese Patent CN119703085B. This method first prepares GH4079 spherical powder with a diameter of 106μm to 250μm using a specific method; then, the GH4079 spherical powder is placed into a pre-made sleeve and subjected to degassing and sealing treatment; subsequently, the sleeve is subjected to high-temperature heat treatment and hot isostatic pressing (HIP); finally, the sleeve is removed to obtain a powder metallurgy GH4079 billet; the powder metallurgy GH4079 billet is then heat-treated to obtain the GH4079 disc-ring part. This method does not take into account the sintering shrinkage during HIP, resulting in numerous gaps between the titanium alloy powder particles. The yield after sintering is typically greater than 20%, therefore this method is unsuitable for larger parts. Summary of the Invention

[0005] The purpose of this invention is to provide a low-cost, short-process method for preparing large thin-walled titanium alloy ring forgings, in order to solve the problems of difficult forming, low material utilization, and high production cost of large thin-walled titanium alloy ring forgings.

[0006] The technical solution of the present invention: A low-cost, short-process method for preparing large, thin-walled titanium alloy ring forgings includes the following steps: Step 1: Prepare the powder material. Prepare titanium alloy powder according to the material of the ring forging. Step 2: Encasing; fabricate an encasing according to the required dimensions of the ring forging blank, and fill with powder for sealing. Step 3: Hot isostatic pressing, the cladding is subjected to hot isostatic pressing treatment; Step 4: Homogenization annealing, the hot isostatic pressed billet is homogenized and annealed; Step 5: Machining. Machining is performed on the homogenized annealed billet to remove the surface coating. Step Six: Ring rolling, the machined billet is ring rolled on a ring rolling equipment; Step 7: Heat treatment. The ring forging obtained in Step 6 is subjected to heat treatment.

[0007] The selected titanium alloy powder has a particle size of 50~120μm and an oxygen content of 1400~1600ppm.

[0008] Step two includes: loading titanium alloy powder into a casing, sealing it, and leaving a vent pipe; heating the casing to 250~400℃ and simultaneously evacuating the gas to ensure a vacuum degree ≤10 inside the casing. -3 Pa, degassing for 2-5 hours.

[0009] In step three, the sintering temperature is 800~1200℃, the processing pressure is 100~150MPa, and the holding time is 3~4 hours.

[0010] In step four, the temperature is kept at 30-50°C lower than Tβ for 8-24 hours.

[0011] In step two, the sheath is made of titanium alloy of the same material as the ring forging. In step five, the sheath material retained after machining becomes part of the billet.

[0012] First, a primary ring blank is prepared and hot isostatically pressed into an inner cladding. Using this ring blank as the core, an outer cladding is designed and filled with powder, followed by a second hot isostatic pressing.

[0013] The beneficial effects of this invention are: 1. Combining powder metallurgy hot isostatic pressing technology with ring rolling technology replaces the traditional multi-step forging process, significantly shortening the process flow and improving production efficiency.

[0014] 2. By preparing ring parts through near-net-shape hot isostatic pressing, the material utilization rate is improved and the raw material cost is significantly reduced. The hot isostatic pressing billet has a uniform microstructure and small compositional segregation, which lays the foundation for subsequent ring rolling and obtaining high-performance products.

[0015] 3. By optimizing the ring rolling process parameters, the dimensional accuracy and microstructure of large thin-walled ring forgings can be precisely controlled. The method of this invention is particularly suitable for the production of large, thin-walled, and complex titanium alloy ring forgings, and has broad application prospects. Attached Figure Description

[0016] Figure 1This is a schematic diagram of a double-layer sintered cladding. Detailed Implementation

[0017] Example 1: This invention discloses a low-cost, short-process method for preparing large, thin-walled TA15 titanium alloy ring forgings. The ring forging dimensions are Φ1200×Φ1000×500 mm. The method mainly includes the following steps: Step 1: Powder Selection: Select TA15 titanium alloy powder (Tβ=995℃) with a particle size of 50-120μm and an oxygen content of approximately 1500ppm. See the table below for specific parameters.

[0018] Step Two: Encasing: Select TA15 titanium alloy powder (Tβ=995℃) with a particle size of 50-120μm and an oxygen content of approximately 1500ppm. Design the steel casing dimensions as follows: Φ800 (outer diameter) × Φ190 (inner diameter) × 600mm. Fill the casing with the titanium alloy powder, vibrate to compact, seal, and leave vent pipes at the top and bottom of the casing. Place the casing in a muffle furnace, close one side of the vent pipe, and heat while simultaneously evacuating the casing to remove gas. The heating temperature is 300℃, and the vacuum degree inside the casing is ≤10. -3 Pa, degassing for 3.5 hours.

[0019] Step 3: Hot isostatic pressing: Control the oxygen content based on the vacuum level of hot isostatic pressing.

[0020] Hot isostatic pressing parameters: sintering temperature 800℃, processing pressure 100MPa, holding time 3 hours.

[0021] The dimensions after hot isostatic pressing are: Φ720×Φ210×510.

[0022] Step 4: Annealing: Anneal the billet obtained in Step 3 at a temperature of 930℃ for 12 hours.

[0023] Step 5: Machin the blank obtained in Step 4 to remove the outer casing and excess material. The surface roughness Ra ≤ 1.6. The dimensions after machining are: Φ705×Φ230×500mm.

[0024] Step Six: Rolling: The machined billet is rolled in multiple passes on a ring rolling mill.

[0025] Core roll feed rate: 0.7 mm / s, rolling time ≤ 90 s.

[0026] First heating: Heating regime: 960℃ / 2h Ring rolling dimensions: Φ705×Φ230→Φ775×Φ400.

[0027] Second heating cycle: Heating regime: 965℃ / 1.5h Ring rolling dimensions: Φ775×Φ400→Φ965×Φ700.

[0028] Third heating cycle: Heating regime: 960℃ / 1.5h Ring rolling dimensions: Φ965×Φ700→Φ1200×Φ1000.

[0029] Step 7: Heat treat the billet rolled in Step 6. Heat treatment regime: 850℃ / 2h, air cooling, and remove excess material from the end face to achieve a final thickness of 500.

[0030] Example 2: This embodiment of the invention discloses a low-cost, short-process method for preparing large, thin-walled TC11 titanium alloy ring forgings. The ring forging dimensions are Φ1350×Φ1200×460 mm. The main steps include: Step 1: Powder selection: In this embodiment, TC11 titanium alloy powder is used. The specific parameters are shown in the table below.

[0031] Step Two: Encasing: Encasing dimensions: Φ750×Φ180×500mm. Fill the encasing with titanium alloy powder, seal it, and leave vent pipes at the top and bottom of the encasing. Place the encasing in a muffle furnace, close one side of the vent pipe, and heat while simultaneously evacuating the encasing to remove gas. The heating temperature is 300℃, and the vacuum degree inside the encasing is ≤10. -3 Pa, degassing for 3.5 hours.

[0032] Step 3: Hot isostatic pressing: Control the oxygen content based on the vacuum level of hot isostatic pressing.

[0033] Hot isostatic pressing parameters: sintering temperature 1000℃, processing pressure 120MPa, holding time 3 hours.

[0034] The dimensions after hot isostatic pressing are: Φ675×Φ190×460 mm.

[0035] Step 4: Annealing: Anneal the billet obtained in Step 3 at a temperature of 930℃ for 12 hours.

[0036] Step 5: Machin the blank obtained in Step 4 to remove the cladding. The surface roughness Ra ≤ 1.6. The dimensions after machining are: Φ665×Φ200×440mm.

[0037] Step Six: Rolling: The machined billet is rolled in multiple passes on a ring rolling mill.

[0038] Core roll feed rate: 0.8 mm / s, rolling time ≤ 90 s.

[0039] First heating cycle: Heating regime: 975℃ / 2.5h Ring rolling dimensions: Φ655×Φ210→Φ710×Φ350.

[0040] Second heating: Heating regime: 980℃ / 2h Ring rolling dimensions: Φ710×Φ350→Φ830×Φ550.

[0041] Third heating cycle: Heating regime: 965℃ / 1.5h Ring rolling dimensions: Φ830×Φ550→Φ1050×Φ850.

[0042] Fourth heating element: Heating regime: 965℃ / 1h Ring rolling dimensions: Φ1050×Φ850→Φ1350×Φ1200.

[0043] Step 7: Heat treat the billet rolled in Step 6. Heat treatment regime: 970℃ / 3h, air cooling + 530℃ / 6h, air cooling.

[0044] Example 3: Preparation of ultra-large ring forgings by nested encapsulation molding This embodiment prepares a large TA15 titanium alloy ring forging with a diameter of Φ1500×Φ1300×600 mm.

[0045] Powder selection: Select TA15 titanium alloy powder with a particle size of 50-120μm and an oxygen content of about 1500ppm (Tβ=995℃).

[0046] Nested sheath preparation: Two layers of sheath are made using TA15 titanium alloy plates.

[0047] First hot isostatic pressing: Design the inner cladding (Φ800×Φ500×500), and obtain the primary ring billet (approximately Φ723×Φ443×420) according to conventional process (820℃, 110MPa, 3.5h).

[0048] Second hot isostatic pressing: such as Figure 1 Using the primary ring blank as the core, an outer sheath (outer diameter Φ1250, inner diameter 600, height 600mm) is designed, and powder is filled in the gaps and degassed.

[0049] Hot isostatic pressing: The nested cladding is subjected to a second hot isostatic pressing (810℃, 105MPa, 4h) to obtain an integral billet. After removing excess material, the billet is approximately Φ1142mm×Φ633mm×542mm.

[0050] Subsequent processes: After multiple ring rolling and heat treatment, the final product is obtained.

Claims

1. A low-cost, short-process method for preparing large thin-walled titanium alloy ring forgings, characterized in that... Includes the following steps: Step 1: Prepare the powder material. Prepare titanium alloy powder according to the material of the ring forging. Step 2: Encasing; fabricate an encasing according to the required dimensions of the ring forging blank, and fill with powder for sealing. Step 3: Hot isostatic pressing, the cladding is subjected to hot isostatic pressing treatment; Step 4: Homogenization annealing, the hot isostatic pressed billet is homogenized and annealed; Step 5: Machining. The homogenized annealed billet is machined to remove the surface coating. Step Six: Ring rolling, the machined billet is ring rolled on a ring rolling equipment; Step 7: Heat treatment. The ring forging obtained in Step 6 is subjected to heat treatment.

2. The method for preparing large thin-walled titanium alloy ring forgings with low cost and short process according to claim 1, characterized in that... Step 1: The titanium alloy powder has a particle size of 50~120μm and an oxygen content of 1400~1600ppm.

3. The method for preparing large thin-walled titanium alloy ring forgings with low cost and short process according to claim 1, characterized in that... Step two includes: loading titanium alloy powder into a casing, sealing it, and leaving a vent pipe; heating the casing to 250~400℃ and simultaneously evacuating the gas to ensure a vacuum degree ≤10 inside the casing. -3 Pa, degassing for 2-5 hours.

4. The method for preparing large thin-walled titanium alloy ring forgings with low cost and short process according to claim 1, characterized in that: In step three, the sintering temperature is 800~1200℃, the processing pressure is 100~150MPa, and the holding time is 3~4 hours.

5. The method for preparing large thin-walled titanium alloy ring forgings with low cost and short process according to claim 1, characterized in that: In step four, the temperature is maintained at 30-50°C lower than the phase transition temperature Tβ for 8-24 hours.

6. The method for preparing large thin-walled titanium alloy ring forgings with low cost and short process according to claim 1, characterized in that: In steps two and three, a primary ring blank is first prepared and hot isostatically pressed into an inner cladding. Using this ring blank as the core, an outer cladding is designed and filled with powder, and then a second hot isostatic pressing is performed.

7. The method for preparing large thin-walled titanium alloy ring forgings with low cost and short process according to claim 1, characterized in that: In step two, the sheath is made of titanium alloy of the same material as the ring forging; in step five, the sheath material retained after machining becomes part of the billet.

Images