Ring rolling process method of titanium alloy seamless barrel for four-meter unmanned deep diving

Abstract

The invention discloses a ring rolling process method of a titanium alloy seamless barrel for four-meter unmanned deep diving, and belongs to the technical field of hot rolling forming of large barrel parts. The method comprises the following steps that a titanium alloy cast ingot is smelted, and the chemical components of the titanium alloy cast ingot and the actual temperature of a phase transformation point T beta are detected; the titanium alloy cast ingot is cogged, and then the cogged cast ingot is subjected to reversing upsetting and rounding according to the actual temperature of the phase transformation point T beta to be manufactured into a bar billet; punching is conducted on the bar blank, and a ring blank is manufactured; a core rod is inserted into the ring blank, and the ring blank is drawn to the length of a finished cylinder piece; chambering the ring blank on a mandrel supporter; rolling the ring blank into a 4000 mm cylinder piece; the 4000 mm cylinder part is subjected to heat treatment bulging; performing bulging treatment on the cylinder part; surface and wall thickness machining is conducted on the cylinder part; and carrying out finished product detection on the cylinder piece. The problems that an existing four-meter titanium alloy barrel part cannot be integrally formed, the structure and performance are not uniform, the material utilization rate is low, the production cost is high, the use safety is low, and the service life is short can be solved.

Description

Technical Field

[0001] The invention belongs to the technical field of hot rolling forming of large cylinder parts, and specifically relates to a ring rolling process method of a titanium alloy seamless cylinder for a four-meter-class unmanned deep-sea diving. Background Art

[0002] Titanium and titanium alloys have the characteristics of low density, corrosion resistance, oxidation resistance, high specific strength and light weight. They are widely used in aerospace, rail transportation, petrochemical, weapon equipment and deep-sea equipment. Among them, the deep-sea pressure hull is an important component of unmanned submarines. It can effectively reduce the noise level, improve concealment and threat. The integrity of the pressure hull is an important factor in its comprehensive performance and service life.

[0003] The traditional production method of four-meter-level cylinder parts is: first forge and punch the blank, then machine thinning and shaping, and finally weld multiple cylinder parts to meet the product height requirements. This production method has low material utilization, low production efficiency and high cost. In addition, there are a large number of welds in the cylinder parts after welding, which makes the structure and performance of the parent material and the weld uneven, and the overall performance is poor, which increases the risk of using the cylinder parts and greatly reduces the service life. Summary of the invention

[0004] The present invention is aimed at the above-mentioned problems, makes up for the deficiencies of the prior art, and provides a ring rolling process method for a seamless titanium alloy cylinder for a four-meter-class unmanned deep-sea diving vehicle. The present invention can solve the problems of the current four-meter-class titanium alloy cylinder parts that cannot be formed in one piece, uneven structure and performance, low material utilization, high production cost, low safety of use and short service life.

[0005] To achieve the above purpose, the present invention adopts the following technical solution.

[0006] The present invention provides a ring rolling process method for a titanium alloy seamless cylinder for a four-meter-class unmanned deep-sea diving, characterized in that the method comprises the following steps: Step 1: Melting titanium alloy ingots, detecting the chemical composition of the titanium alloy ingots and the actual temperature of the phase transition point Tβ; Step 2: the titanium alloy ingot of step 1 is opened, and then the opened ingot is subjected to reversing upsetting and rounding according to the actual temperature of the phase transformation point Tβ to form a rod blank; Step 3: Punching the rod blank made in step 2 to make a ring blank; Step 4: insert a mandrel into the ring blank made in step 3, and extend the length of the ring blank to the length of the finished tube; Step 5: Expand the ring blank after being stretched in step 4 on the horse frame; Step 6: rolling the ring blank expanded in step 5 into a 4000 mm tube; Step 7: heat-treating and bulging the 4000 mm tube rolled in step 6; Step 8: Perform bulging treatment on the tube after heat treatment and annealing in step 7; Step 9: Perform surface and wall thickness processing on the cylinder after bulging in step 8; Step 10: Perform finished product inspection on the cylinder machined in step 9.

[0007] Furthermore, the step 2 is: heating the titanium alloy ingot prepared in step 1, opening the blank on a forging press, and then performing 4 to 6 fire reversing upsetting and at least one rounding forging to form a rod blank with a diameter of 1800 mm. The intermediate blank after each fire reversing upsetting is polished, and the surface of the polished intermediate blank is free of cracks and oxide scale. The forging process adopts β phase zone forging and α+β two-phase zone forging in sequence. The heating time is calculated according to the heating rate of 1 mm / min, and the final forging temperature is ≥800°C.

[0008] Furthermore, the step 3 is: heating the rod blank prepared in step 2 for 1800min~2000min in an environment 20°C~50°C lower than the phase transformation point Tβ temperature, and then using a forging machine and a punching die to prepare the rod blank into a ring blank with an outer diameter of 1800mm and an inner diameter of 400mm.

[0009] Furthermore, the step 4 is: heating the ring blank after punching in step 3 for 700min~730min in an environment 20℃~50℃ lower than the phase transformation point Tβ temperature, then inserting the mandrel, and forging the ring blank using a forging machine to extend its length to the length of the finished tube.

[0010] Furthermore, the step 5 is: heating the ring blank stretched in step 4 in an environment 20°C to 50°C below the phase transformation point Tβ, calculating the heating time of the blank according to a heating speed of 1 mm / min, and then expanding the hole on a horse rack to the required specification of the ring blank.

[0011] Furthermore, the step 6 is: the ring blank after the hole expansion in step 5 is placed in an environment where the temperature is 20°C~50°C lower than the phase transformation point Tβ, and the heating time of the blank is calculated according to the heating speed of 1mm / min, and then placed on the rolling mill for diameter expansion rolling, the rolling speed is not more than 1.4m / s, the final rolling temperature is ≥750°C, and when the outer diameter of the ring blank is rolled to 2500mm and 3500mm, it is returned to the heating furnace for supplementary heating, and the supplementary heating temperature is 20°C~50°C below the phase transformation point Tβ temperature, and the heating time of the blank is calculated according to the heating speed of 1mm / min.

[0012] Furthermore, the step 7 is: heat treating the cylinder with an outer diameter of 4000 mm prepared in step 6 at a temperature of 750°C to 800°C, keeping the cylinder for 120min to 180min, and then air cooling the cylinder.

[0013] Furthermore, the step 8 is: using a bulging machine to bulge the tube after being fired in step 7.

[0014] Furthermore, the step 9 is: using a CNC lathe to process the surface and thickness of the expanded cylinder so that the size and surface quality of the cylinder meet the requirements.

[0015] Furthermore, the step 10 is: using a thickness gauge and an inner diameter ruler to perform finished product inspection on the machined finished tube.

[0016] Beneficial effects of the present invention.

[0017] Compared with the existing process methods, the present invention realizes the one-piece forming of four-meter-level cylinder parts, ensures the uniformity of the cylinder part structure and performance, improves the comprehensive performance of the cylinder parts, avoids the welding process, fundamentally eliminates the appearance of cylinder part welds and the disadvantages caused by them, improves the safety and service life of use, improves the utilization rate of materials and production efficiency, reduces the production cost, and meets the requirements of deep-sea pressure-resistant shells in terms of performance and production cost. In the ring rolling process of the cylinder parts, according to the product specifications and the real-time rolling temperature, the re-melting and heating process is added to make the blank return to the target temperature, ensure that the surface and core temperatures of the blank are consistent, and then ensure the uniformity of the structure, performance, size and surface quality of the finished cylinder parts. The bulging process can effectively solve the above-mentioned problems existing in the cylinder parts after rolling, greatly reduce the processing amount of the machining process, and improve the material utilization rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to make the technical problems, technical solutions and beneficial effects solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and specific implementation methods. It should be understood that the specific implementation methods described herein are only used to explain the present invention and are not used to limit the present invention.

[0019] Figure 1 It is a process flow chart of the present invention.

[0020] Figure 2 It is the forging process curve diagram of the present invention.

[0021] Figure 3 It is the ring rolling process curve diagram of the present invention. DETAILED DESCRIPTION

[0022] As shown in the accompanying drawings, this embodiment provides a ring rolling process method for a four-meter-class unmanned deep-sea titanium alloy seamless cylinder. Taking a TC4 titanium alloy seamless cylinder with an outer diameter of 4000 mm, a wall thickness of 48 mm and a height of 2300 mm as an example, the processing method includes the following steps: Step 1: Prepare TC4 titanium alloy ingot by three smeltings in a vacuum consumable furnace, and detect the chemical composition of the titanium alloy ingot and the actual temperature of the phase transition point Tβ.

[0023] Step 2: The titanium alloy ingot in step 1 is opened, and then the opened ingot is subjected to reversing upsetting and rounding according to the actual temperature of the phase transformation point Tβ to form a rod blank.

[0024] Specifically, the titanium alloy ingot prepared in step 1 is heated at a temperature of 960-1180°C, blanked on a forging press, and then subjected to 4 rounds of reversing upsetting and 1 round forging to form a bar blank with a diameter of 1800 mm. The intermediate blank after each round of reversing upsetting is polished, and the surface of the polished intermediate blank is free of cracks and oxide scale. The forging process adopts β phase forging and α+β two-phase forging in sequence. The heating time is calculated according to a heating speed of 1 mm / min, and the final forging temperature is ≥800°C.

[0025] Step 3: Punch the rod blank made in step 2 to make a ring blank.

[0026] Specifically, the oxide scale and microcracks on the rod blank prepared in step 2 are polished until the surface is bright, heated for 2000 minutes at a temperature 20°C to 50°C lower than the phase transition point Tβ (which can be 960°C), and then the rod blank is prepared into a ring blank with an outer diameter of 1800 mm, an inner diameter of 400 mm, a wall thickness of 700 mm and a height of 1000 mm using a forging machine and a punching die.

[0027] Step 4: Insert a mandrel into the ring blank made in step 3, and extend the length of the ring blank to the length of the finished tube.

[0028] Specifically, the oxide scale and cracks on the surface of the ring blank after punching in step 3 are polished clean, heated for 730 minutes at a temperature 20°C to 50°C lower than the phase transformation point Tβ (which can be 960°C), and then the mandrel is inserted. The ring blank is forged using a forging press, and its length is extended to 2300mm, with a wall thickness of about 400mm.

[0029] Step 5: Expand the ring blank stretched in step 4 on a horse stand.

[0030] Specifically, the oxide scale and cracks on the surface of the ring blank after the elongation in step 4 are polished clean, and the ring blank is heated at an environment 20℃~50℃ lower than the phase transformation point Tβ temperature (which can be 960℃). The heating time is calculated according to the heating speed of 1mm / min, which can be 450min. Then, the ring blank is expanded on the horse frame to an outer diameter of 1800mm, an inner diameter of 1400mm, and a wall thickness of 200mm.

[0031] Step 6: Roll the ring blank expanded in step 5 into a 4000mm tube.

[0032] Specifically, the ring billet after hole expansion in step 5 is heated in an environment 20℃~50℃ lower than the phase transformation point Tβ temperature (which can be 960℃), and the heating time is calculated according to the heating speed of 1mm / min, which can be 200min~230min. Then it is placed on the rolling mill for diameter expansion rolling. The rolling speed is not more than 1.4m / s, and the final rolling temperature is ≥750℃. When the outer diameter of the ring billet is rolled to 2500mm and 3500mm, the surface temperature of the billet is below 850℃, and it is returned to the heating furnace for supplementary heating. The supplementary heating temperature is 20℃~50℃ below the phase transformation point Tβ temperature (which can be 960℃). The heating time is calculated according to the heating speed of 1mm / min, which can be 90min. The actual final rolling temperature is about 850℃.

[0033] By returning the blank to the furnace for heating in time, the heating temperature and heating time range can be effectively controlled to avoid the situation where a large number of cracks appear on the surface of the blank due to temperature drop, thereby reducing the surface quality of the final product.

[0034] Step 7: The 4000 mm tube rolled in step 6 is subjected to heat treatment and bulging.

[0035] Specifically, the tube with an outer diameter of 4000 mm prepared in step 6 is placed in a heat treatment furnace for heat treatment at a temperature of 750° C. and kept at the temperature for 120 minutes before being air-cooled.

[0036] Step 8: Perform bulging treatment on the tube after heat treatment and annealing in step 7.

[0037] Specifically, the tube piece taken out of the furnace in step 7 is immediately placed on the bulging machine, and the ring piece is bulged by utilizing the residual heat of the heat treatment.

[0038] The ring-rolled tube is bulged by a bulging machine to further control the shape, surface quality and wall thickness of the tube, greatly reduce the amount of machining process and improve material utilization.

[0039] Step 9: Perform surface and wall thickness processing on the tube after bulging in step 8.

[0040] Specifically, a CNC lathe is used to process the surface and thickness of the expanded cylinder so that the size and surface quality of the cylinder meet the requirements.

[0041] Step 10: Perform finished product inspection on the cylinder machined in step 9.

[0042] Specifically, a thickness gauge and an inner diameter gauge are used to conduct finished product inspection on the machined finished cylinder.

[0043] It can be understood that the above specific description of the present invention is only used to illustrate the present invention and is not limited to the technical solutions described in the embodiments of the present invention. Those skilled in the art should understand that the present invention can still be modified or replaced by equivalents to achieve the same technical effects; as long as the use requirements are met, they are within the protection scope of the present invention.

Claims

1. A ring rolling process for a seamless titanium alloy cylinder for a four-meter-class unmanned deep-sea submersible, comprising a main beam, characterized in that: The method comprises the following steps: Step 1: Melting titanium alloy ingots, detecting the chemical composition of the titanium alloy ingots and the actual temperature of the phase transition point Tβ; Step 2: the titanium alloy ingot of step 1 is opened, and then the opened ingot is subjected to reversing upsetting and rounding according to the actual temperature of the phase transformation point Tβ to form a rod blank; Step 3: Punching the rod blank made in step 2 to make a ring blank; Step 4: insert a mandrel into the ring blank made in step 3, and extend the length of the ring blank to the length of the finished tube; Step 5: Expand the ring blank after being stretched in step 4 on the horse frame; Step 6: rolling the ring blank expanded in step 5 into a 4000 mm tube; Step 7: heat-treating and bulging the 4000 mm tube rolled in step 6; Step 8: Perform bulging treatment on the tube after heat treatment and annealing in step 7; Step 9: Perform surface and wall thickness processing on the cylinder after bulging in step 8; Step 10: Perform finished product inspection on the cylinder machined in step 9.

2. The ring rolling process of a four-meter-class unmanned deep-diving titanium alloy seamless cylinder according to claim 1 is characterized in that: The step 2 is: heating the titanium alloy ingot prepared in step 1, blanking it on a forging press, and then performing 4 to 6 fire reversing upsetting and at least one rounding to form a bar blank with a diameter of 1800 mm. The intermediate blank after each fire reversing upsetting is polished, and the surface of the polished intermediate blank is free of cracks and oxide scale. The forging process adopts β phase zone forging and α+β two-phase zone forging in sequence. The heating time is calculated according to the heating speed of 1 mm / min, and the final forging temperature is ≥800°C.

3. The ring rolling process of a four-meter-class unmanned deep-diving titanium alloy seamless cylinder according to claim 1 is characterized in that: The step 3 is: heating the rod blank prepared in step 2 for 1800min~2000min in an environment 20℃~50℃ lower than the phase transformation point Tβ temperature, and then using a forging machine and a punching die to prepare the rod blank into a ring blank with an outer diameter of 1800mm and an inner diameter of 400mm.

4. The ring rolling process of a four-meter-class unmanned deep-diving titanium alloy seamless cylinder according to claim 1 is characterized in that: The step 4 is: heating the ring blank after punching in step 3 for 700min~730min in an environment 20℃~50℃ lower than the phase transformation point Tβ, then inserting the mandrel, forging the ring blank using a forging machine, and extending its length to the length of the finished tube.

5. The ring rolling process of a four-meter-class unmanned deep-diving titanium alloy seamless cylinder according to claim 1 is characterized in that: The step 5 is: heating the ring blank stretched in step 4 at a temperature 20°C to 50°C lower than the phase transition point Tβ, the heating time is calculated according to a heating speed of 1 mm / min, and then expanding the hole on a horse frame to the required specification of the ring blank.

6. The ring rolling process of a four-meter-class unmanned deep-diving titanium alloy seamless cylinder according to claim 1 is characterized in that: The step 6 is: the ring blank after the hole expansion in step 5 is placed in an environment where the temperature is 20°C~50°C lower than the phase transformation point Tβ, and the heating time of the blank is calculated according to the heating speed of 1mm / min, and then placed on the rolling mill for diameter expansion rolling, the rolling speed is not more than 1.4m / s, the final rolling temperature is ≥750°C, and when the outer diameter of the ring blank is rolled to 2500mm and 3500mm, it is returned to the heating furnace for supplementary heating, the supplementary heating temperature is 20°C~50°C below the phase transformation point Tβ temperature, and the heating time of the blank is calculated according to the heating speed of 1mm / min.

7. The ring rolling process of a four-meter-class unmanned deep-diving titanium alloy seamless cylinder according to claim 1 is characterized in that: The step 7 is: heat treating the cylinder with an outer diameter of 4000 mm prepared in step 6 at a temperature of 750° C. to 800° C., keeping the cylinder for 120 min to 180 min, and then taking the cylinder out of the furnace for air cooling.

8. The ring rolling process of a four-meter-class unmanned deep-diving titanium alloy seamless cylinder according to claim 1 is characterized in that: The step 8 is: using a bulging machine to bulge the tube that is taken out of the furnace in step 7.

9. The ring rolling process of a four-meter-class unmanned deep-diving titanium alloy seamless cylinder according to claim 1 is characterized in that: The step 9 is: using a CNC lathe to process the surface and thickness of the expanded cylinder so that the size and surface quality of the cylinder meet the requirements.

10. The ring rolling process of a four-meter-class unmanned deep-diving titanium alloy seamless cylinder according to claim 1 is characterized in that: The step 10 is: using a thickness gauge and an inner diameter ruler to perform finished product inspection on the machined finished tube.

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