Forming method for optimizing internal structure of Ti6AL4V forge piece

Abstract

The invention belongs to the field of forging hot working, and relates to a forming method for optimizing the internal structure of a Ti6AL4V forge piece. Comprising the steps that 1, the forging step, the production heating number, the transfer time, the forging time, the remelting cooling time, the hammering frequency, the hammering pause time, the deformation amount between the heating numbers, the charging number and the charging distance are determined according to the weight of a forge piece; 2, charging according to the determined charging number and charging spacing, heating to a forging temperature, preserving heat for a preset time, and forging according to the determined forging step, production heating number, transfer time, forging time, remelting cooling time, hammering frequency, hammering dwell time and deformation between heating numbers; 3, after forging is completed, sand blasting and polishing are carried out to inspect whether the size meets the requirements of forgings or not; and 4, performing heat treatment and physical and chemical detection after the inspection is qualified.

Description

Technical Field

[0001] The invention belongs to the field of forging hot processing and relates to a method for optimizing the internal structure forming of a Ti6AL4V forging. Background Art

[0002] The composition of titanium alloy TC4 material is Ti-6Al-4V, an alloy composed of three elements: titanium (Ti), aluminum (Al), and vanadium (V). It has excellent comprehensive performance and belongs to the (α+β) type titanium alloy with good comprehensive mechanical properties. High specific strength. The strength of TC4 is sb = 1.012GPa, the density is g = 4.51g / cm3, the specific strength is sb / g = 23.5, while the specific strength of alloy steel is less than 18. Titanium alloy has low thermal conductivity. The thermal conductivity of titanium alloy is 1 / 5 of that of iron and 1 / 10 of that of aluminum. The thermal conductivity of TC4 is l = 7.955W / m·K. The alloy has high strength, heat resistance, and corrosion resistance and can be used in parts that work for a long time below 400°C.

[0003] It is used in aircraft structure beams, bulkheads, slide rails, landing gear beams, engine fans, compressor discs, blades and other important load-bearing components. Its long-term working temperature can reach 400°C, and it can also be used to manufacture low-temperature and high-pressure containers, such as liquid hydrogen fuel tanks for rockets and missiles;

[0004] A certain type of civil aircraft uses Ti6Al4V titanium alloy material. Ti6Al4V (TC4, GB / T3620) is a medium-strength (>900MPa) α+β type alloy with excellent comprehensive properties such as high strength and modulus, high damage tolerance, high temperature resistance, and corrosion resistance.

[0005] In a certain type of civil aircraft, the net mass of titanium alloy parts accounts for about 10% of the total net mass of the aircraft, and its specific application parts include the nose, suspension, tail, outer wing, center wing, landing gear system, etc. For example, the nose uses Ti-6Al-4V ELI forgings; the suspension uses Ti-6Al-4V alloy forgings, plates and titanium alloy 55531 forgings; the tail, outer wing, and center wing use Ti-6Al-4V alloy forgings; the landing gear system uses Ti-6Al-4V alloy forgings.

[0006] Conventional free forging method: forging can be done according to the size of the forging, but there is little control requirement for the forging process. Conventional forming forging has little research on the final forging internal structure and performance required by the design. How to ensure that the internal structure and performance of the forging are qualified after forging and heat treatment is the key to this product.

[0007] Conventional forging has no definite quantitative requirements for the technical parameters related to the forging process, and there is no accurate control requirement for the forging technical parameters during the forging process; therefore, any change in any of the above parameters will affect the final internal structure and performance, resulting in the final physical and chemical testing and performance measurement of the forgings not being qualified, resulting in rework and scrapping.

[0008] Therefore, the method of selecting reasonable forging technical parameters to control the forging process is used to solve the problem of Ti6AL4V free forging forming, so that the physical and chemical results of the final forgings meet the required requirements. The selection and application of forging technical parameters in the quantified production process can improve the qualified rate of forgings and make the material organization meet the required requirements. Summary of the invention

[0009] Purpose of the invention: To provide a method for optimizing the internal structure of Ti6AL4V forgings, so as to solve the problem that conventional forging has no definite quantitative requirements for the technical parameters related to the forging process and no accurate control over the forging technical parameters; therefore, any change in any of the above parameters will affect the final internal structure and performance; resulting in the final physical and chemical testing and performance measurement of the forgings not being qualified, causing the problem of rework and scrapping.

[0010] Technical solution:

[0011] A method for optimizing the internal structure of a Ti6AL4V forging, comprising:

[0012] Step 1: Determine the forging steps, production fire times, transfer time, forging time, remelting cooling time, hammering frequency, hammering pause time, deformation between fire times, number of furnaces loaded, and furnace spacing based on the weight of the forging;

[0013] Step 2: Load the furnace according to the determined number of furnaces and the distance between furnaces, heat it to the forging temperature and keep it warm for a predetermined time, and forge according to the determined forging steps, production times, transfer time, forging time, return cooling time, hammering frequency, hammering pause time, and deformation between times;

[0014] Step 3: After forging, sandblasting and grinding are performed to check whether the dimensions meet the forging requirements;

[0015] Step 4: After passing the inspection, heat treatment and physical and chemical testing are carried out.

[0016] Preferably, in step 1, the forging steps are determined according to the weight of the forging:

[0017] Forging weight G(Kg) G≤30 30＜G≤50 50＜G≤80 80＜G≤110 G≥110 Number of forging steps (I) 1 2 3 4 5 .

[0018] Preferably, in step 1, the production fire order is determined according to the weight of the forgings, specifically:

[0019] Forging weight G(Kg) G≤30 30＜G≤50 50＜G≤80 80＜G≤110 G≥110 Production fire times (n) 1 fire 2 fire times 3 fire times 4 fire times 5 fire times .

[0020] Preferably, in step 1, the transfer time for each fire is determined according to the weight of the forging, specifically:

[0021] Forging weight G(Kg) G≤30 30＜G≤50 50＜G≤80 80＜G≤110 G≥110 Transfer time (t) seconds ≤10S ≤15S ≤20S ≤25S ≤30S .

[0022] Preferably, in step 1, the forging time is adjusted according to the weight of the forging, specifically:

[0023] Forging weight G(Kg) G≤30 30＜G≤50 50＜G≤80 80＜G≤110 G≥110 Forging time (t) seconds ≤90S ≤100S ≤110S ≤120S ≤130S .

[0024] Preferably, in step 1, the air cooling time before forging and remelting is adjusted according to the weight of the forging, specifically:

[0025]

[0026] Preferably, in step 1, the forging hammer frequency is adjusted according to the weight of the forging, specifically:

[0027]

[0028] Preferably, in step 1, the number of forging furnaces is set according to the weight of the forgings, specifically:

[0029] Forging weight G(Kg) G≤30 30＜G≤50 50＜G≤80 80＜G≤110 G≥110 Furnace quantity (pieces) ≤10 pieces ≤9 pieces ≤8 pieces ≤7 pieces ≤6 pieces .

[0030] Preferably, in step 1, the forging furnace spacing is adjusted according to the weight of the forgings, specifically:

[0031]

[0032] Preferably, in step 1, the hammering pause time is adjusted according to the weight of the forging, specifically:

[0033] Forging weight G(Kg) G≤30 30＜G≤50 50＜G≤80 80＜G≤110 G≥110 Pause time(S) 0.5～1.0 1.1～1.5 1.6～2.0 2.1～2.5 2.6～3.0 .

[0034] Beneficial effects:

[0035] By controlling the above technical parameters and using the above method to produce, the physical and chemical test results of TI6AL4V free forgings are improved. Compared with conventional forging, when the above technical conditions are not adopted, the final results of forgings are improved, the qualified rate of forgings is increased, and the phenomenon of forging rework and scrapping is reduced.

[0036] The present invention lays a foundation for providing the internal structure required for the final forging of the forging to be qualified, and finally meets the requirements of the forging. DETAILED DESCRIPTION

[0037] The applicant has adopted a method of controlling forging technical parameters for forgings of different specifications (divided by forging weight) through long-term practice and on-site production process control to improve the qualified rate of forgings and reduce the probability of rework and scrapping. At the same time, the organization and performance of forgings have been greatly improved.

[0038] In order to solve the above problems, the method adopts a method of controlling the forging technical parameters in the forging process according to the weight of the forging piece as the forging method of TI6AL4V free forging piece; its core technology is as follows: forging process control of technical parameters such as forging steps, production fire times, transfer time, forging time, re-furnace cooling time, number of furnaces loaded, hammering frequency, furnace loading spacing, hammering pause time, deformation between fire times, etc., so as to achieve the final and internal organizational requirements of the forging piece;

[0039] The technical parameters of the method of the present invention are divided according to the weight of the forging, and the technical parameters include: (1) forging steps, (2) production fire times, (3) transfer time, (4) forging time, (5) re-furnace cooling time, (6) number of furnace loads, (7) hammering frequency, (8) furnace load spacing, (9) hammering pause time, and (10) deformation between fire times.

[0040] A method for optimizing the internal structure of a Ti6AL4V forging according to the present invention comprises:

[0041] Step 1: Determine the forging process settings according to the weight of the forging:

[0042] Forging weight G(Kg) G≤30 30＜G≤50 50＜G≤80 80＜G≤110 G≥110 Number of forging steps (I) 1 2 3 4 5

[0043] Step 2: Determine the production fire setting according to the weight of the forgings:

[0044] Forging weight G(Kg) G≤30 30＜G≤50 50＜G≤80 80＜G≤110 G≥110 Production fire times (n) 1 fire 2 fire times 3 fire times 4 fire times 5 fire times

[0045] Step 3: Set the transfer time for each fire according to the weight of the forging:

[0046] Forging weight G(Kg) G≤30 30＜G≤50 50＜G≤80 80＜G≤110 G≥110 Transfer time (t) seconds ≤10S ≤15S ≤20S ≤25S ≤30S

[0047] Step 4: Set the forging time according to the weight of the forging:

[0048] Forging weight G(Kg) G≤30 30＜G≤50 50＜G≤80 80＜G≤110 G≥110 Forging time (t) seconds ≤90S ≤100S ≤110S ≤120S ≤130S

[0049] Step 5: Set the air cooling time before forging and re-melting according to the weight of the forging:

[0050]

[0051] Step 6: Set the forging hammer frequency according to the weight of the forging:

[0052]

[0053] Step 7: Set the forging furnace quantity according to the weight of the forging:

[0054] Forging weight G(Kg) G≤30 30＜G≤50 50＜G≤80 80＜G≤110 G≥110 Furnace quantity (pieces) ≤10 pieces ≤9 pieces ≤8 pieces ≤7 pieces ≤6 pieces

[0055] Step 8: Set the forging furnace spacing according to the weight of the forging:

[0056]

[0057] Step 9: Set the hammer pause time according to the weight of the forging:

[0058] Forging weight G(Kg) G≤30 30＜G≤50 50＜G≤80 80＜G≤110 G≥110 Pause time(S) 0.5～1.0 1.1～1.5 1.6～2.0 2.1～2.5 2.6～3.0

[0059] Step 10: Set the deformation between firings according to the weight of the forging:

[0060]

[0061] By adopting the above method, before forging a forging, reasonable forging parameters are selected according to the weight of the forging according to the above steps to complete the above forging process; the above parameters are selected in no particular order; the forging process is controlled according to the selected forging technical parameters; the final required internal structure and mechanical property requirements of the forging can be obtained.

[0062] After completing the required technical parameters selected above, the raw materials are cut according to the conventional method according to the volume of raw materials required for each process step, and each forging is completed step by step after heating. The heating and production firing steps are completed according to the forging forming design process step.

[0063] Specifically, the furnace is loaded and heated to the forging temperature and kept warm for a predetermined time according to the determined number of furnaces and the distance between furnaces, and forging is performed according to the determined forging steps, production fires, transfer time, forging time, return to the furnace cooling time, hammering frequency, hammering pause time, and deformation between fires;

[0064] Step 8: After forging, sandblasting and grinding are performed to check whether the dimensions meet the forging requirements.

[0065] Step 9: Heat treatment.

[0066] Step 10: Physical and chemical testing, final inspection and storage.

[0067] Example:

[0068] Material: Ti6AL4V: Cutting specifications: Φ250mm×375mm;

[0069] Weight: 82.8Kg; Category: Ⅱ

[0070] Name: No. 5 driving connecting rod; Serial number: 001-028;

[0071] Forging size:

[0072] The method of the present invention comprises:

[0073] Step 1: Divide the weight of the forging into 82.8 kg according to the required forging size; the forging step (I) of the forging needs to be completed according to step 1, step 2, step 3, and step 4;

[0074] Step 2: Divide the forgings into different fires according to the required forging weight; the forgings are completed by 4 fires;

[0075] Step 3: Divide the transfer time of each forging according to the required forging weight; the forging transfer time of the forging is controlled to be ≤25S;

[0076] Step 4: Divide the forging time according to the required forging weight; the forging time is controlled to be ≤120S;

[0077] Step 5: Divide the air cooling time of the forgings before forging and returning to the furnace according to the required forging weight; the forging time of the forgings is controlled to be ≤25min;

[0078] Step 6: Divide the forging hammer frequency according to the required forging weight; the forging hammer frequency is 2.0 to 2.5 (times / second)

[0079] control;

[0080] Step 7: Divide the number of forgings to be charged into the furnace according to the required weight of the forgings; the number of forgings to be charged into the furnace is controlled to be ≤7 pieces.

[0081] Step 8: Divide the forging furnace spacing according to the required forging weight; the forging furnace spacing is controlled to be ≥110mm;

[0082] Step 9: Divide the forging hammer pause time according to the required forging weight; the forging hammer pause time is controlled at 2.1 to 2.5;

[0083] Step 10: Divide the deformation amount of the forging between the forgings according to the required forging weight; the deformation amount of the forging between the forgings is controlled at 31% to 35%;

[0084] Step 11: Complete the four-step four-fire forging according to the control of the forging technical parameters selected above

[0085] First heating: 35℃X200min at phase change point: Forging step 1: Φ250×375; Axial drawing and forging to: 235±5×195±5×~420;

[0086] Second heating: 35℃X160min below the phase change point; Forging step 2: 235×195×420; Axial drawing and forging to: 215±5×185±5×~505;

[0087] The third heating: 35℃X155min below the phase change point; Forging step three: 215×185×505; Axial drawing and forging to: 200±×165±×~550

[0088] The fourth heating: 35℃X145min below the phase change point; Forging step 4: 200×165×550; Axial drawing and forging to:

[0089] The required technical parameters of the forging process can be controlled according to the above steps 1 to 10; the rest are completed step by step according to the requirements of each step by cutting and heating according to the conventional method, and the heating and production firing are completed according to the forging forming design process step.

[0090] Step 12: After forging, sandblast and grind to check that the dimensions meet the forging requirements.

[0091] Step 13: Heat treatment; physical and chemical testing, final inspection and storage.

Claims

1. A method for optimizing the internal structure of Ti6AL4V forgings, characterized in that: include: Step 1: Determine the forging steps, production fire times, transfer time, forging time, remelting cooling time, hammering frequency, hammering pause time, deformation between fire times, number of furnaces loaded, and furnace spacing based on the weight of the forging; Step 2: Load the furnace according to the determined number of furnaces and the distance between furnaces, heat it to the forging temperature and keep it warm for a predetermined time, and forge according to the determined forging steps, production times, transfer time, forging time, return cooling time, hammering frequency, hammering pause time, and deformation between times; Step 3: After forging, sandblasting and grinding are performed to check whether the dimensions meet the forging requirements; Step 4: After passing the inspection, heat treatment and physical and chemical testing are carried out.

2. The method according to claim 1, characterized in that In step 1, the forging steps are determined according to the weight of the forging: 。 3. The method according to claim 2, characterized in that In step 1, the production fire times are determined according to the weight of the forgings, specifically: 。 4. The method according to claim 1, characterized in that: In step 1, the transfer time for each fire is determined according to the weight of the forging, specifically: 。 5. The method according to claim 1, characterized in that In step 1, the forging time is calculated according to the weight of the forging, specifically: 。 6. The method according to claim 1, characterized in that In step 1, the air cooling time before forging and remelting is determined according to the weight of the forging, specifically:

7. The method according to claim 1, characterized in that In step 1, the forging hammer frequency is adjusted according to the weight of the forging, specifically:

8. The method according to claim 1, characterized in that: In step 1, the forging furnace quantity is set according to the weight of the forgings, specifically:

9. The method according to claim 1, characterized in that: In step 1, the forging furnace spacing is adjusted according to the weight of the forgings, specifically:

10. The method according to claim 1, characterized in that In step 1, the hammering pause time is adjusted according to the weight of the forging, specifically: 。

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