A method for fine-grain high-strength and high-toughness shape deformation heat treatment of a large-section ring

Abstract

This invention discloses a fine-grained, high-strength, and tough deformation heat treatment method for large-section ring components, relating to the field of aluminum alloy ring components. The key technical points are: S1: raw material proportioning; S2: raw material smelting; S3: raw material impurity removal; S4: forging and ring making; S5: ring component preheating and heat preservation; S6: rolling and grain breaking; S7: first low-temperature annealing; S8: room temperature cold rolling; S9: second low-temperature annealing; S10: cyclic rolling, solution treatment, and aging treatment. This invention introduces a multi-pass deformation heat treatment coupling process involving high-temperature rolling, low-temperature intermediate annealing, room temperature cold rolling, and second low-temperature annealing, and sets up a multi-cycle rolling annealing process. This can release the rolling internal stress of large-section ring components layer by layer, continuously break up coarse grains, induce uniform dynamic recrystallization, and avoid uneven grain structure.

Description

Technical Field

[0001] This invention relates to the field of aluminum alloy ring processing, and more specifically, to a fine-grained, high-strength, and tough deformation heat treatment method for large-section rings. Background Technology

[0002] A ring forging is a seamless integral ring forging formed by melting and billet preparation, forging, and ring rolling. Large cross-section ring forgings are often needed as reinforcing rings at the ends of large cylinders, towers, and machine frames. Large cross-section ring forgings have a dense structure and uniform grains. Compared with welded parts, they can effectively disperse localized stress concentration at the end of the equipment, suppress radial deformation and operating vibration, and have better fatigue resistance and crack resistance.

[0003] To ensure the stability of large-section ring forgings during long-term use and avoid brittle fracture, grain refinement treatment is required during the ring forging process. Grain refinement increases the number of grain boundaries, hinders crack propagation, and simultaneously improves the strength, toughness, and fatigue resistance of the ring forgings.

[0004] Existing methods for grain refinement mainly include ultra-fast heating, rapid cyclic heating and quenching, and deformation heat treatment. Among them, when using deformation heat treatment, the material is usually heated to a predetermined temperature to austenitize it, followed by hot rolling to cause strong deformation of the austenite. Then, it is held isothermally for an appropriate time to allow the deformed austenite to undergo initial recrystallization, and quenching is performed before the grains begin to expand, thereby obtaining a significant ultra-fine grain effect.

[0005] However, due to the large size of the large cross-section ring forging, the temperature, strain and strain rate distribution in different parts of the ring often vary significantly, resulting in inconsistent dynamic recrystallization behavior in different regions. This leads to localized areas undergoing full recrystallization to form fine-grained regions, while other regions only undergo partial recrystallization or even residual deformed structures. This structural inhomogeneity directly causes fluctuations in the overall mechanical properties of the ring, reduces the strength and toughness of the material, and affects the stability and reliability of the large cross-section ring under long-term use.

[0006] Therefore, in order to solve the above-mentioned technical problems, this application proposes a fine-grained, high-strength and tough deformation heat treatment method for large cross-section ring parts. Summary of the Invention

[0007] To address the shortcomings of existing technologies, the present invention aims to provide a fine-grained, high-strength, and tough deformation heat treatment method for large-section ring components.

[0008] To achieve the above objectives, the present invention provides the following technical solution: a method for fine-grained, high-strength, and high-toughness deformation heat treatment of large-section ring components, the method comprising the following steps:

[0009] S1. Raw material preparation: This includes the following elements and their percentage in the raw materials, as follows:

[0010] Si: 0.31~0.62, Mg: 0.62~0.92, Cu: 0.03~0.12, Mn: 0.25~0.43, Zn: 0.03~0.15, Ti: 0.02~0.12, Cr: 0.13~0.27, Fe: 0.13~0.27, Al: 97.40~98.75;

[0011] S2, Smelting: Raise the furnace temperature of the smelting furnace to between 740 and 760°C, maintain this temperature range and melt Al, and then add the elements from step S1 to the smelting furnace in the form of an intermediate alloy to obtain an alloy melt.

[0012] S3. Impurity Removal: The alloy melt is refined and impurity removed to remove gas and inclusions. After standing, the melt temperature is adjusted and the melt is poured out of the furnace to obtain an alloy forging billet.

[0013] S4. Forging the billet into a ring blank: Place the forging billet from step S3 into a heating furnace and heat it to 450-550°C. Place the heated billet on a free forging hammer and repeatedly draw and upset it to form a round disc. After reheating the disc to the forging temperature, place it on a press and press the punch to punch out a through hole to obtain a ring blank.

[0014] S5. Preheating: Place the ring blank formed in step S4 into a heating furnace and heat and keep it at a constant temperature to ensure that the temperature inside and outside the ring blank is uniform.

[0015] S6. Rolling: Transfer the ring billet after heat preservation in step S5 to the ring rolling mill for rolling;

[0016] S7. First annealing: The ring billet rolled in step S6 is placed in an electric resistance furnace for intermediate low-temperature annealing, and then cooled to room temperature to relieve rolling internal stress and initially refine the grains.

[0017] S8. Cold rolling: Under room temperature conditions, the ring after annealing in step S7 is subjected to a second cold rolling to precisely control the dimensional accuracy and wall thickness uniformity of the ring.

[0018] S9. Second annealing: The ring billet rolled in step S8 is subjected to intermediate low-temperature annealing again to further eliminate internal stress and improve the toughness of the ring.

[0019] S10. Repeat steps S6 to S9 for 2 to 3 cycles. After completing all the rolling cycles, the ring is subjected to standard solution treatment and aging treatment to finally obtain a fine-grained, high-strength and tough ring.

[0020] Preferably, in step S3, the melt temperature is controlled at 720-740°C, and nitrogen gas with a purity ≥99.99% is introduced into the melt through a refining pipe at a flow rate of 0.8 m³ / h for 15 min. After removing the gas and inclusions from the melt, it is allowed to stand for 10-20 minutes, and the melt temperature is controlled within a suitable range of 680-720°C before being unloaded and poured.

[0021] Preferably, in step S5, the ring billet is heated in a heating furnace to 420-480°C at a heating rate of 5-15°C / min, and held for 30-90min.

[0022] Preferably, in step S6, the rolling temperature is controlled at 390-450°C, the linear speed of the drive roller of the ring rolling mill is 300-600 mm / s, the linear speed of the core roller is 200-400 mm / s, the linear speed ratio is 1.2-1.8, and the radial feed speed is 0.5-2 mm / s.

[0023] Preferably, in step S6, the deformation amount per rolling pass is 5% to 15%, the temperature is monitored in real time during the rolling process, and the rolling is paused and reheated when it is below 390°C.

[0024] Preferably, in step S7, the heating rate of the resistance furnace is controlled at 8-12℃ / min, the annealing temperature is 250-350℃, the holding time is 1.5-2.5h, and after the holding time is completed, the furnace is cooled to below 150℃ and then air-cooled to room temperature.

[0025] Preferably, in step S8, the cold rolling deformation is controlled at 4-6%, and an emulsion is used for lubrication and cooling during the rolling process. The ring size accuracy error is ≤ ±0.05 mm, and the wall thickness uniformity error is ≤ 0.03 mm.

[0026] Preferably, the concentration of the emulsion is controlled at 3% to 5%, and the operating temperature is maintained at 35 to 55°C.

[0027] Preferably, in step S9, the heating rate of the resistance furnace is controlled at 8-12℃ / min, the annealing temperature is 250-350℃, the holding time is 2.0-3.0h, and then it is air-cooled to room temperature.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] 1. This invention introduces a multi-pass deformation heat treatment coupling process of high temperature rolling, low temperature intermediate annealing, room temperature cold rolling, and secondary low temperature annealing, and sets up a multi-cycle rolling and annealing process, which can release the rolling internal stress of large cross-section rings layer by layer, continuously break up coarse grains, induce uniform dynamic recrystallization, and avoid uneven grain structure.

[0030] 2. In this invention, cold rolling can be used to refine and correct the wall thickness, roundness, and external dimensions of the ring, strictly control the dimensional accuracy and wall thickness uniformity, eliminate the shape deviation caused by hot rolling and annealing, meet the high-precision assembly requirements of large cross-section rings, and the cold rolling process is combined with special emulsion lubrication and cooling to make the circumferential and radial deformation of the ring more uniform, balance the strain distribution of each part, and weaken the inherent temperature and strain distribution differences of large cross-section rings.

[0031] 3. In this invention, a low-temperature intermediate annealing process with two different holding times is used to release residual stress from rolling and cold rolling in stages, gradually control the grain boundary state and morphology of precipitated phases, and simultaneously improve the overall strength and toughness of the ring, thus solving the problem of large fluctuations in mechanical properties and insufficient service stability and reliability caused by uneven microstructure in the existing technology. Attached Figure Description

[0032] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this application, illustrate exemplary embodiments of the invention and, together with their description, serve to explain the invention and do not constitute an undue limitation thereof. In the drawings:

[0033] Figure 1 This is a flowchart of the preparation method in this invention. Detailed Implementation

[0034] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0035] This invention provides a method for fine-grained, high-strength, and high-toughness deformation heat treatment of large-section ring components.

[0036] Example 1

[0037] The method includes the following steps:

[0038] S1. Raw material preparation: This includes the following elements and their percentage in the raw materials, as follows:

[0039] Si: 0.32, Mg: 0.63, Cu: 0.04, Mn: 0.26, Zn: 0.04, Ti: 0.11, Cr: 0.14, Fe: 0.14, Al: 98.32;

[0040] S2. Raise the furnace temperature of the melting furnace to 750°C, maintain this temperature range and melt Al, and then add the elements from step S1 to the melting furnace in the form of an intermediate alloy to obtain an alloy melt.

[0041] S3. Control the melt temperature at 730℃, and introduce nitrogen gas with a purity of ≥99.99% into the melt through the refining pipe at a flow rate of 0.8 m³ / h and a duration of 15 min. After removing the gas and inclusions from the melt, let it stand for 13 minutes to remove the gas and inclusions from the melt. Then, control the melt temperature at a suitable range of 685℃ and pour it out of the furnace to obtain the alloy forging billet.

[0042] S4. Place the forging billet in a heating furnace and heat it to 500℃. Place the heated billet on a free forging hammer and repeatedly draw and upset it to shape it into a round cake. After reheating the cake to the forging temperature, place it on a press and press the punch to punch out a through hole to obtain a ring billet.

[0043] S5. The ring billet is heated in a heating furnace at a heating rate of 8℃ / min to 450℃, and held for 70min.

[0044] S6. Transfer the heat-insulated ring billet to the ring rolling mill for rolling. The deformation amount per rolling pass is 8.3%. Monitor the temperature in real time during the rolling process. If the temperature drops below 390℃, pause and reheat.

[0045] S7. Place the rolled ring billet into an electric resistance furnace for intermediate low-temperature annealing. The heating rate of the electric resistance furnace is controlled at 10℃ / min, the annealing temperature is 300℃, and the holding time is 2h. After the holding time is completed, the furnace is cooled to below 150℃ and then air-cooled to room temperature to relieve the rolling internal stress and initially refine the grains.

[0046] S8. Under room temperature conditions, the annealed ring is subjected to a second cold rolling, and the dimensional accuracy and wall thickness uniformity of the ring are precisely controlled. The cold rolling deformation is controlled within 5%. During the rolling process, an emulsion is used for lubrication and cooling. The concentration of the emulsion is controlled within 4%. The operating temperature is maintained at 40℃. The dimensional accuracy error of the ring is ≤ ±0.05mm, and the wall thickness uniformity error is ≤ 0.03mm.

[0047] S9. The ring billet is subjected to intermediate low-temperature annealing again. The heating rate of the resistance furnace is controlled at 10℃ / min, the annealing temperature is 300℃, and the holding time is 2.5h. Then it is air-cooled to room temperature to further eliminate internal stress and improve the toughness of the ring.

[0048] S10. Repeat steps S6 to S9 for 2 cycles. After completing all cycles of rolling, perform standard solution treatment and aging treatment on the ring to finally obtain a fine-grained, high-strength and tough ring.

[0049] Example 2

[0050] S1. Raw material preparation: This includes the following elements and their percentage in the raw materials, as follows:

[0051] Si: 0.35, Mg: 0.62, Cu: 0.03, Mn: 0.25, Zn: 0.03, Ti: 0.12, Cr: 0.15, Fe: 0.13, Al: 98.32;

[0052] S2. Raise the furnace temperature of the melting furnace to 750°C, maintain this temperature and melt Al, and then add the above elements to the melting furnace in the form of intermediate alloy to obtain alloy melt;

[0053] S3. Control the melt temperature at 730℃, and introduce nitrogen gas with a purity of ≥99.99% into the melt through the refining pipe at a flow rate of 0.8 m³ / h and a duration of 15 min. After removing the gas and inclusions from the melt, let it stand for 13 minutes to remove the gas and inclusions from the melt. Then, control the melt temperature at a suitable range of 685℃ and pour it out of the furnace to obtain the alloy forging billet.

[0054] S4. Place the forging billet in a heating furnace and heat it to 500℃. Place the heated billet on a free forging hammer and repeatedly draw and upset it to shape it into a round cake. After reheating the cake to the forging temperature, place it on a press and press the punch to punch out a through hole to obtain a ring billet.

[0055] S5. The ring billet is heated in a heating furnace at a heating rate of 8℃ / min to 450℃, and held for 70min.

[0056] S6. Transfer the heat-insulated ring billet to the ring rolling mill for rolling. The deformation amount per rolling pass is 8.3%. Monitor the temperature in real time during the rolling process. If the temperature drops below 390℃, pause and reheat.

[0057] S7. Place the rolled ring billet into an electric resistance furnace for intermediate low-temperature annealing. The heating rate of the electric resistance furnace is controlled at 10℃ / min, the annealing temperature is 300℃, and the holding time is 2h. After the holding time is completed, the furnace temperature is lowered to below 150℃ and then air-cooled to room temperature.

[0058] S8. Under room temperature conditions, the annealed ring is subjected to a second cold rolling, with the cold rolling deformation controlled at 5%. During the rolling process, an emulsion is used for lubrication and cooling, with the concentration of the emulsion controlled at 4%. The operating temperature is maintained at 40℃. The dimensional accuracy error of the ring is ≤ ±0.05mm, and the wall thickness uniformity error is ≤ 0.03mm.

[0059] S9. The ring billet is subjected to intermediate low-temperature annealing again. The heating rate of the resistance furnace is controlled at 10℃ / min, the annealing temperature is 300℃, the holding time is 2.5h, and then it is air-cooled to room temperature.

[0060] S10. Repeat steps S6 to S9 for 2 cycles. After completing all cycles of rolling, perform standard solution treatment and aging treatment on the ring to finally obtain a fine-grained, high-strength and tough ring.

[0061] Example 3

[0062] S1. Raw material preparation: This includes the following elements and their percentage in the raw materials, as follows:

[0063] Si: 0.31, Mg: 0.65, Cu: 0.05, Mn: 0.27, Zn: 0.05, Ti: 0.10, Cr: 0.13, Fe: 0.15, Al: 98.29;

[0064] S2. Raise the furnace temperature of the melting furnace to between 750°C, maintain this temperature range and melt Al, and then add the elements from step S1 to the melting furnace in the form of an intermediate alloy to obtain an alloy melt.

[0065] S3. Control the melt temperature at 730℃, and introduce nitrogen gas with a purity of ≥99.99% into the melt through the refining pipe at a flow rate of 0.8 m³ / h and a duration of 15 min. After removing the gas and inclusions from the melt, let it stand for 13 minutes to remove the gas and inclusions from the melt. Then, control the melt temperature at a suitable range of 685℃ and pour it out of the furnace to obtain the alloy forging billet.

[0066] S4. Place the forging billet in a heating furnace and heat it to 500℃. Place the heated billet on a free forging hammer and repeatedly draw and upset it to shape it into a round cake. After reheating the cake to the forging temperature, place it on a press and press the punch to punch out a through hole to obtain a ring billet.

[0067] S5. The ring billet is heated in a heating furnace at a heating rate of 8℃ / min to 450℃, and held for 70min.

[0068] S6. Transfer the heat-insulated ring billet to the ring rolling mill for rolling. The deformation amount per rolling pass is 8.3%. Monitor the temperature in real time during the rolling process. If the temperature drops below 390℃, pause and reheat.

[0069] S7. Place the rolled ring billet into an electric resistance furnace for intermediate low-temperature annealing. The heating rate of the electric resistance furnace is controlled at 10℃ / min, the annealing temperature is 300℃, and the holding time is 2h. After the holding time is completed, the furnace is cooled to below 150℃ and then air-cooled to room temperature to relieve the rolling internal stress and initially refine the grains.

[0070] S8. Under room temperature conditions, the annealed ring is subjected to a second cold rolling, and the dimensional accuracy and wall thickness uniformity of the ring are precisely controlled. The cold rolling deformation is controlled within 5%. During the rolling process, an emulsion is used for lubrication and cooling. The concentration of the emulsion is controlled within 4%. The operating temperature is maintained at 40℃. The dimensional accuracy error of the ring is ≤ ±0.05mm, and the wall thickness uniformity error is ≤ 0.03mm.

[0071] S9. The ring billet is subjected to intermediate low-temperature annealing again. The heating rate of the resistance furnace is controlled at 10℃ / min, the annealing temperature is 300℃, and the holding time is 2.5h. Then it is air-cooled to room temperature to further eliminate internal stress and improve the toughness of the ring.

[0072] S10. Repeat steps S6 to S9 for 2 cycles. After completing all cycles of rolling, perform standard solution treatment and aging treatment on the ring to finally obtain a fine-grained, high-strength and tough ring.

[0073] Example 4

[0074] S1. Raw material preparation: This includes the following elements and their percentage in the raw materials, as follows:

[0075] Si: 0.60, Mg: 0.88, Cu: 0.10, Mn: 0.40, Zn: 0.12, Ti: 0.03, Cr: 0.26, Fe: 0.25, Al: 97.36;

[0076] S2. Raise the furnace temperature of the melting furnace to 750°C, maintain this temperature and melt Al, and then add the above elements to the melting furnace in the form of intermediate alloy to obtain alloy melt;

[0077] S3. Control the melt temperature at 730℃, and introduce nitrogen gas with a purity of ≥99.99% into the melt through the refining pipe at a flow rate of 0.8 m³ / h and a duration of 15 min. After removing the gas and inclusions from the melt, let it stand for 13 minutes to remove the gas and inclusions from the melt. Then, control the melt temperature at a suitable range of 685℃ and pour it out of the furnace to obtain the alloy forging billet.

[0078] S4. Place the forging billet in a heating furnace and heat it to 500℃. Place the heated billet on a free forging hammer and repeatedly draw and upset it to shape it into a round cake. After reheating the cake to the forging temperature, place it on a press and press the punch to punch out a through hole to obtain a ring billet.

[0079] S5. The ring billet is heated in a heating furnace at a heating rate of 8℃ / min to 450℃, and held for 70min.

[0080] S6. Transfer the heat-insulated ring billet to the ring rolling mill for rolling. The deformation amount per rolling pass is 8.3%. Monitor the temperature in real time during the rolling process. If the temperature drops below 390℃, pause and reheat.

[0081] S7. Place the rolled ring billet into an electric resistance furnace for intermediate low-temperature annealing. The heating rate of the electric resistance furnace is controlled at 10℃ / min, the annealing temperature is 300℃, and the holding time is 2h. After the holding time is completed, the furnace temperature is lowered to below 150℃ and then air-cooled to room temperature.

[0082] S8. Under room temperature conditions, the annealed ring is subjected to a second cold rolling, with the cold rolling deformation controlled at 5%. During the rolling process, an emulsion is used for lubrication and cooling, with the concentration of the emulsion controlled at 4%. The operating temperature is maintained at 40℃. The dimensional accuracy error of the ring is ≤ ±0.05mm, and the wall thickness uniformity error is ≤ 0.03mm.

[0083] S9. The ring billet is subjected to intermediate low-temperature annealing again. The heating rate of the resistance furnace is controlled at 10℃ / min, the annealing temperature is 300℃, the holding time is 2.5h, and then it is air-cooled to room temperature.

[0084] S10. Repeat steps S6 to S9 for 2 cycles. After completing all cycles of rolling, perform standard solution treatment and aging treatment on the ring to finally obtain a fine-grained, high-strength and tough ring.

[0085] Example 5

[0086] S1. Raw material preparation: This includes the following elements and their percentage in the raw materials, as follows:

[0087] Si: 0.55, Mg: 0.85, Cu: 0.11, Mn: 0.35, Zn: 0.10, Ti: 0.04, Cr: 0.24, Fe: 0.24, Al: 97.52;

[0088] S2. Raise the furnace temperature of the melting furnace to 750°C, maintain this temperature and melt Al, and then add the above elements to the melting furnace in the form of intermediate alloy to obtain alloy melt;

[0089] S3. Control the melt temperature at 730℃, and introduce nitrogen gas with a purity of ≥99.99% into the melt through the refining pipe at a flow rate of 0.8 m³ / h and a duration of 15 min. After removing the gas and inclusions from the melt, let it stand for 13 minutes to remove the gas and inclusions from the melt. Then, control the melt temperature at a suitable range of 685℃ and pour it out of the furnace to obtain the alloy forging billet.

[0090] S4. Place the forging billet in a heating furnace and heat it to 500℃. Place the heated billet on a free forging hammer and repeatedly draw and upset it to shape it into a round cake. After reheating the cake to the forging temperature, place it on a press and press the punch to punch out a through hole to obtain a ring billet.

[0091] S5. The ring billet is heated in a heating furnace at a heating rate of 8℃ / min to 450℃, and held for 70min.

[0092] S6. Transfer the heat-insulated ring billet to the ring rolling mill for rolling. The deformation amount per rolling pass is 8.3%. Monitor the temperature in real time during the rolling process. If the temperature drops below 390℃, pause and reheat.

[0093] S7. Place the rolled ring billet into an electric resistance furnace for intermediate low-temperature annealing. The heating rate of the electric resistance furnace is controlled at 10℃ / min, the annealing temperature is 300℃, and the holding time is 2h. After the holding time is completed, the furnace temperature is lowered to below 150℃ and then air-cooled to room temperature.

[0094] S8. Under room temperature conditions, the annealed ring is subjected to a second cold rolling, with the cold rolling deformation controlled at 5%. During the rolling process, an emulsion is used for lubrication and cooling, with the concentration of the emulsion controlled at 4%. The operating temperature is maintained at 40℃. The dimensional accuracy error of the ring is ≤ ±0.05mm, and the wall thickness uniformity error is ≤ 0.03mm.

[0095] S9. The ring billet is subjected to intermediate low-temperature annealing again. The heating rate of the resistance furnace is controlled at 10℃ / min, the annealing temperature is 300℃, the holding time is 2.5h, and then it is air-cooled to room temperature.

[0096] S10. Repeat steps S6 to S9 for 2 cycles. After completing all cycles of rolling, perform standard solution treatment and aging treatment on the ring to finally obtain a fine-grained, high-strength and tough ring.

[0097] Example 6

[0098] S1. Raw material preparation: This includes the following elements and their percentage in the raw materials, as follows:

[0099] Si: 0.50, Mg: 0.80, Cu: 0.08, Mn: 0.30, Zn: 0.08, Ti: 0.05, Cr: 0.20, Fe: 0.20, Al: 97.79;

[0100] S2. Raise the furnace temperature of the melting furnace to 750°C, maintain this temperature and melt Al, and then add the above elements to the melting furnace in the form of intermediate alloy to obtain alloy melt;

[0101] S3. Control the melt temperature at 730℃, and introduce nitrogen gas with a purity of ≥99.99% into the melt through the refining pipe at a flow rate of 0.8 m³ / h and a duration of 15 min. After removing the gas and inclusions from the melt, let it stand for 13 minutes to remove the gas and inclusions from the melt. Then, control the melt temperature at a suitable range of 685℃ and pour it out of the furnace to obtain the alloy forging billet.

[0102] S4. Place the forging billet in a heating furnace and heat it to 500℃. Place the heated billet on a free forging hammer and repeatedly draw and upset it to shape it into a round cake. After reheating the cake to the forging temperature, place it on a press and press the punch to punch out a through hole to obtain a ring billet.

[0103] S5. The ring billet is heated in a heating furnace at a heating rate of 8℃ / min to 450℃, and held for 70min.

[0104] S6. Transfer the heat-insulated ring billet to the ring rolling mill for rolling. The deformation amount per rolling pass is 8.3%. Monitor the temperature in real time during the rolling process. If the temperature drops below 390℃, pause and reheat.

[0105] S7. Place the rolled ring billet into an electric resistance furnace for intermediate low-temperature annealing. The heating rate of the electric resistance furnace is controlled at 10℃ / min, the annealing temperature is 300℃, and the holding time is 2h. After the holding time is completed, the furnace temperature is lowered to below 150℃ and then air-cooled to room temperature.

[0106] S8. Under room temperature conditions, the annealed ring is subjected to a second cold rolling, with the cold rolling deformation controlled at 5%. During the rolling process, an emulsion is used for lubrication and cooling, with the concentration of the emulsion controlled at 4%. The operating temperature is maintained at 40℃. The dimensional accuracy error of the ring is ≤ ±0.05mm, and the wall thickness uniformity error is ≤ 0.03mm.

[0107] S9. The ring billet is subjected to intermediate low-temperature annealing again. The heating rate of the resistance furnace is controlled at 10℃ / min, the annealing temperature is 300℃, the holding time is 2.5h, and then it is air-cooled to room temperature.

[0108] S10. Repeat steps S6 to S9 for 2 cycles. After completing all cycles of rolling, perform standard solution treatment and aging treatment on the ring to finally obtain a fine-grained, high-strength and tough ring.

[0109] Example 7

[0110] S1. Raw material preparation: This includes the following elements and their percentage in the raw materials, as follows:

[0111] Si: 0.45, Mg: 0.75, Cu: 0.09, Mn: 0.28, Zn: 0.07, Ti: 0.06, Cr: 0.18, Fe: 0.18, Al: 97.94;

[0112] S2. Raise the furnace temperature of the melting furnace to 750°C, maintain this temperature and melt Al, and then add the above elements to the melting furnace in the form of intermediate alloy to obtain alloy melt;

[0113] S3. Control the melt temperature at 730℃, and introduce nitrogen gas with a purity of ≥99.99% into the melt through the refining pipe at a flow rate of 0.8 m³ / h and a duration of 15 min. After removing the gas and inclusions from the melt, let it stand for 13 minutes to remove the gas and inclusions from the melt. Then, control the melt temperature at a suitable range of 685℃ and pour it out of the furnace to obtain the alloy forging billet.

[0114] S4. Place the forging billet in a heating furnace and heat it to 500℃. Place the heated billet on a free forging hammer and repeatedly draw and upset it to shape it into a round cake. After reheating the cake to the forging temperature, place it on a press and press the punch to punch out a through hole to obtain a ring billet.

[0115] S5. The ring billet is heated in a heating furnace at a heating rate of 8℃ / min to 450℃, and held for 70min.

[0116] S6. Transfer the heat-insulated ring billet to the ring rolling mill for rolling. The deformation amount per rolling pass is 8.3%. Monitor the temperature in real time during the rolling process. If the temperature drops below 390℃, pause and reheat.

[0117] S7. Place the rolled ring billet into an electric resistance furnace for intermediate low-temperature annealing. The heating rate of the electric resistance furnace is controlled at 10℃ / min, the annealing temperature is 300℃, and the holding time is 2h. After the holding time is completed, the furnace temperature is lowered to below 150℃ and then air-cooled to room temperature.

[0118] S8. Under room temperature conditions, the annealed ring is subjected to a second cold rolling, with the cold rolling deformation controlled at 5%. During the rolling process, an emulsion is used for lubrication and cooling, with the concentration of the emulsion controlled at 4%. The operating temperature is maintained at 40℃. The dimensional accuracy error of the ring is ≤ ±0.05mm, and the wall thickness uniformity error is ≤ 0.03mm.

[0119] S9. The ring billet is subjected to intermediate low-temperature annealing again. The heating rate of the resistance furnace is controlled at 10℃ / min, the annealing temperature is 300℃, the holding time is 2.5h, and then it is air-cooled to room temperature.

[0120] S10. Repeat steps S6 to S9 for 2 cycles. After completing all cycles of rolling, perform standard solution treatment and aging treatment on the ring to finally obtain a fine-grained, high-strength and tough ring.

[0121] Example 8

[0122] S1. Raw material preparation: This includes the following elements and their percentage in the raw materials, as follows:

[0123] Si: 0.52, Mg: 0.82, Cu: 0.12, Mn: 0.43, Zn: 0.13, Ti: 0.03, Cr: 0.27, Fe: 0.25, Al: 97.50;

[0124] S2. Raise the furnace temperature of the melting furnace to 750°C, maintain this temperature and melt Al, and then add the above elements to the melting furnace in the form of intermediate alloy to obtain alloy melt;

[0125] S3. Control the melt temperature at 730℃, and introduce nitrogen gas with a purity of ≥99.99% into the melt through the refining pipe at a flow rate of 0.8 m³ / h and a duration of 15 min. After removing the gas and inclusions from the melt, let it stand for 13 minutes to remove the gas and inclusions from the melt. Then, control the melt temperature at a suitable range of 685℃ and pour it out of the furnace to obtain the alloy forging billet.

[0126] S4. Place the forging billet in a heating furnace and heat it to 500℃. Place the heated billet on a free forging hammer and repeatedly draw and upset it to shape it into a round cake. After reheating the cake to the forging temperature, place it on a press and press the punch to punch out a through hole to obtain a ring billet.

[0127] S5. The ring billet is heated in a heating furnace at a heating rate of 8℃ / min to 450℃, and held for 70min.

[0128] S6. Transfer the heat-insulated ring billet to the ring rolling mill for rolling. The deformation amount per rolling pass is 8.3%. Monitor the temperature in real time during the rolling process. If the temperature drops below 390℃, pause and reheat.

[0129] S7. Place the rolled ring billet into an electric resistance furnace for intermediate low-temperature annealing. The heating rate of the electric resistance furnace is controlled at 10℃ / min, the annealing temperature is 300℃, and the holding time is 2h. After the holding time is completed, the furnace temperature is lowered to below 150℃ and then air-cooled to room temperature.

[0130] S8. Under room temperature conditions, the annealed ring is subjected to a second cold rolling, with the cold rolling deformation controlled at 5%. During the rolling process, an emulsion is used for lubrication and cooling, with the concentration of the emulsion controlled at 4%. The operating temperature is maintained at 40℃. The dimensional accuracy error of the ring is ≤ ±0.05mm, and the wall thickness uniformity error is ≤ 0.03mm.

[0131] S9. The ring billet is subjected to intermediate low-temperature annealing again. The heating rate of the resistance furnace is controlled at 10℃ / min, the annealing temperature is 300℃, the holding time is 2.5h, and then it is air-cooled to room temperature.

[0132] S10. Repeat steps S6 to S9 for 2 cycles. After completing all cycles of rolling, perform standard solution treatment and aging treatment on the ring to finally obtain a fine-grained, high-strength and tough ring.

[0133] The rings prepared according to Examples 1-8 were subjected to performance testing using the following experimental methods. Rings with the same outer and inner diameters were used as test subjects to test the product grain size, grain size difference along the full thickness, circumferential hardness deviation, and elongation (%). The specific tests included the following:

[0134] Product grain size testing: Metallographic microscopy is used. After sampling the ring, the grain boundaries are displayed by grinding, polishing and etching. The average grain size and grade are evaluated by comparing it with the standard rating chart under a microscope.

[0135] Grain size difference along the full thickness: The multi-layer metallographic gradient sampling method is used to cut metallographic samples in layers along the wall thickness of the ring, and the grain size of each layer is measured. The difference between the maximum and minimum grades is calculated, which is the grain size difference along the full thickness.

[0136] Circumferential hardness deviation: Brinell hardness multi-point cyclic testing is adopted. 6-12 measuring points are evenly selected in the circumference of the ring. The surface and cross-sectional hardness are measured with a hardness tester. The maximum value, minimum value and standard deviation are calculated to evaluate the circumferential uniformity.

[0137] Elongation: A static tensile test at room temperature was conducted. A standard dumbbell specimen was cut radially from the ring and stretched to fracture on a universal testing machine. The gauge length elongation after fracture was measured, and the elongation after fracture was calculated.

[0138] The data obtained from the above experiments are shown in Table (1):

[0139] Example Product grain size testing (grade) Grain size difference (grades) throughout the thickness Circumferential hardness deviation (HB) Elongation (%) Example 1 8.92 0.87 9.3 22.75 Example 2 9.13 0.9 8.5 22.24 Example 3 8.7 1.12 9.7 21.5 Example 4 7.56 1.24 11 18.45 Example 5 7.8 1.13 11 18.5 Example 6 8.2 1.3 10 19.35 Example 7 8.42 1.25 9.2 19.75 Example 8 8.73 0.9 12 18.3

[0140] Table (1)

[0141] Comparing Examples 1-8, when the percentage of each element is Si: 0.32, Mg: 0.63, Cu: 0.04, Mn: 0.26, Zn: 0.04, Ti: 0.11, Cr: 0.14, Fe: 0.14, and Al: 98.32, Example 1 has a grain size of 8.9, the smallest grain size difference in the full thickness direction, the lowest circumferential hardness deviation, and the highest elongation. Therefore, the overall result is the best, achieving a high strength and toughness effect for large cross-section ring parts.

[0142] Example 9

[0143] S1. Raw material preparation: This includes the following elements and their percentage in the raw materials, as follows:

[0144] Si: 0.32, Mg: 0.63, Cu: 0.04, Mn: 0.26, Zn: 0.04, Ti: 0.11, Cr: 0.14, Fe: 0.14, Al: 98.32;

[0145] S2. Raise the furnace temperature of the melting furnace to 740°C, maintain this temperature range and melt Al, and then add the elements from step S1 to the melting furnace in the form of an intermediate alloy to obtain an alloy melt.

[0146] S3. Control the melt temperature at 740℃, and introduce nitrogen gas with a purity of ≥99.99% into the melt through the refining pipe at a flow rate of 0.8 m³ / h for 15 min. After removing the gas and inclusions from the melt, let it stand for 20 minutes to remove the gas and inclusions from the melt. Then, control the melt temperature at a suitable range of 680℃ and pour it out of the furnace to obtain the alloy forging billet.

[0147] S4. Place the forging billet in a heating furnace and heat it to 500℃. Place the heated billet on a free forging hammer and repeatedly draw and upset it to shape it into a round cake. After reheating the cake to the forging temperature, place it on a press and press the punch to punch out a through hole to obtain a ring billet.

[0148] S5. The ring billet is heated in a heating furnace at a heating rate of 8℃ / min to 420℃, and held for 90min.

[0149] S6. Transfer the heat-insulated ring billet to the ring rolling mill for rolling. The deformation per rolling pass is 9.2%. Monitor the temperature in real time during rolling. If the temperature drops below 390℃, pause and reheat. Control the rolling temperature at 400℃. The linear speed of the drive roller of the ring rolling mill is 350mm / s, the linear speed of the core roller is 250mm / s, the linear speed ratio is 1.2, and the radial feed speed is 0.75mm / s.

[0150] S7. Place the rolled ring billet into an electric resistance furnace for intermediate low-temperature annealing. The heating rate of the electric resistance furnace is controlled at 10℃ / min, the annealing temperature is 300℃, and the holding time is 2h. After the holding time is completed, the furnace is cooled to below 150℃ and then air-cooled to room temperature to relieve the rolling internal stress and initially refine the grains.

[0151] S8. Under room temperature conditions, the annealed ring is subjected to a second cold rolling, and the dimensional accuracy and wall thickness uniformity of the ring are precisely controlled. The cold rolling deformation is controlled at 5.7%. During the rolling process, an emulsion is used for lubrication and cooling. The concentration of the emulsion is controlled at 4%. The operating temperature is maintained at 40℃. The dimensional accuracy error of the ring is ≤ ±0.05mm, and the wall thickness uniformity error is ≤0.03mm.

[0152] S9. The ring billet is subjected to intermediate low-temperature annealing again. The heating rate of the resistance furnace is controlled at 10℃ / min, the annealing temperature is 300℃, and the holding time is 2.5h. Then it is air-cooled to room temperature to further eliminate internal stress and improve the toughness of the ring.

[0153] S10. Repeat steps S6 to S9 for 2 cycles. After completing all cycles of rolling, perform standard solution treatment and aging treatment on the ring to finally obtain a fine-grained, high-strength and tough ring.

[0154] Example 10

[0155] S1. Raw material preparation: This includes the following elements and their percentage in the raw materials, as follows:

[0156] Si: 0.32, Mg: 0.63, Cu: 0.04, Mn: 0.26, Zn: 0.04, Ti: 0.11, Cr: 0.14, Fe: 0.14, Al: 98.32;

[0157] S2. Raise the furnace temperature of the melting furnace to 740°C, maintain this temperature range and melt Al, and then add the elements from step S1 to the melting furnace in the form of an intermediate alloy to obtain an alloy melt.

[0158] S3. Control the melt temperature at 740℃, and introduce nitrogen gas with a purity of ≥99.99% into the melt through the refining pipe at a flow rate of 0.8 m³ / h for 15 min. After removing the gas and inclusions from the melt, let it stand for 20 minutes to remove the gas and inclusions from the melt. Then, control the melt temperature at a suitable range of 680℃ and pour it out of the furnace to obtain the alloy forging billet.

[0159] S4. Place the forging billet in a heating furnace and heat it to 500℃. Place the heated billet on a free forging hammer and repeatedly draw and upset it to shape it into a round cake. After reheating the cake to the forging temperature, place it on a press and press the punch to punch out a through hole to obtain a ring billet.

[0160] S5. The ring billet is heated in a heating furnace at a heating rate of 8℃ / min to 420℃, and held for 90min.

[0161] S6. Transfer the heat-insulated ring billet to the ring rolling mill for rolling. The deformation per rolling pass is 11.1%. Monitor the temperature in real time during rolling. If the temperature drops below 390℃, pause and reheat. Control the rolling temperature at 400℃. The linear speed of the drive roller of the ring rolling mill is 372mm / s, the linear speed of the core roller is 275mm / s, the linear speed ratio is 1.4, and the radial feed speed is 0.92mm / s.

[0162] S7. Place the rolled ring billet into an electric resistance furnace for intermediate low-temperature annealing. The heating rate of the electric resistance furnace is controlled at 10℃ / min, the annealing temperature is 300℃, and the holding time is 2h. After the holding time is completed, the furnace is cooled to below 150℃ and then air-cooled to room temperature to relieve the rolling internal stress and initially refine the grains.

[0163] S8. Under room temperature conditions, the annealed ring is subjected to a second cold rolling, and the dimensional accuracy and wall thickness uniformity of the ring are precisely controlled. The cold rolling deformation is controlled within 5%. During the rolling process, an emulsion is used for lubrication and cooling. The concentration of the emulsion is controlled within 4%. The operating temperature is maintained at 40℃. The dimensional accuracy error of the ring is ≤ ±0.05mm, and the wall thickness uniformity error is ≤ 0.03mm.

[0164] S9. The ring billet is subjected to intermediate low-temperature annealing again. The heating rate of the resistance furnace is controlled at 10℃ / min, the annealing temperature is 300℃, and the holding time is 2.5h. Then it is air-cooled to room temperature to further eliminate internal stress and improve the toughness of the ring.

[0165] S10. Repeat steps S6 to S9 for 3 cycles. After completing all cycles of rolling, perform standard solution treatment and aging treatment on the ring to finally obtain a fine-grained, high-strength and tough ring.

[0166] Example 11

[0167] S1. Raw material preparation: This includes the following elements and their percentage in the raw materials, as follows:

[0168] Si: 0.32, Mg: 0.63, Cu: 0.04, Mn: 0.26, Zn: 0.04, Ti: 0.11, Cr: 0.14, Fe: 0.14, Al: 98.32;

[0169] S2. Raise the furnace temperature of the melting furnace to 740°C, maintain this temperature range and melt Al, and then add the elements from step S1 to the melting furnace in the form of an intermediate alloy to obtain an alloy melt.

[0170] S3. Control the melt temperature at 740℃, and introduce nitrogen gas with a purity of ≥99.99% into the melt through the refining pipe at a flow rate of 0.8 m³ / h for 15 min. After removing the gas and inclusions from the melt, let it stand for 20 minutes to remove the gas and inclusions from the melt. Then, control the melt temperature at a suitable range of 680℃ and pour it out of the furnace to obtain the alloy forging billet.

[0171] S4. Place the forging billet in a heating furnace and heat it to 500℃. Place the heated billet on a free forging hammer and repeatedly draw and upset it to shape it into a round cake. After reheating the cake to the forging temperature, place it on a press and press the punch to punch out a through hole to obtain a ring billet.

[0172] S5. The ring billet is heated in a heating furnace at a heating rate of 8℃ / min to 420℃, and held for 90min.

[0173] S6. Transfer the heat-insulated ring billet to the ring rolling mill for rolling. The deformation per rolling pass is 12.3%. Monitor the temperature in real time during rolling. If the temperature drops below 390℃, pause and reheat. Control the rolling temperature at 400℃. The linear speed of the drive roller of the ring rolling mill is 427mm / s, the linear speed of the core roller is 345mm / s, the linear speed ratio is 1.5, and the radial feed speed is 0.88mm / s.

[0174] S7. Place the rolled ring billet into an electric resistance furnace for intermediate low-temperature annealing. The heating rate of the electric resistance furnace is controlled at 10℃ / min, the annealing temperature is 300℃, and the holding time is 2h. After the holding time is completed, the furnace is cooled to below 150℃ and then air-cooled to room temperature to relieve the rolling internal stress and initially refine the grains.

[0175] S8. Under room temperature conditions, the annealed ring is subjected to a second cold rolling, and the dimensional accuracy and wall thickness uniformity of the ring are precisely controlled. The cold rolling deformation is controlled at 4.5%. During the rolling process, an emulsion is used for lubrication and cooling. The concentration of the emulsion is controlled at 4%. The operating temperature is maintained at 40℃. The dimensional accuracy error of the ring is ≤ ±0.05mm, and the wall thickness uniformity error is ≤0.03mm.

[0176] S9. The ring billet is subjected to intermediate low-temperature annealing again. The heating rate of the resistance furnace is controlled at 10℃ / min, the annealing temperature is 300℃, and the holding time is 2.5h. Then it is air-cooled to room temperature to further eliminate internal stress and improve the toughness of the ring.

[0177] S10. Repeat steps S6 to S9 for 2 cycles. After completing all cycles of rolling, perform standard solution treatment and aging treatment on the ring to finally obtain a fine-grained, high-strength and tough ring.

[0178] Example 12

[0179] S1. Raw material preparation: This includes the following elements and their percentage in the raw materials, as follows:

[0180] Si: 0.32, Mg: 0.63, Cu: 0.04, Mn: 0.26, Zn: 0.04, Ti: 0.11, Cr: 0.14, Fe: 0.14, Al: 98.32;

[0181] S2. Raise the furnace temperature of the melting furnace to 740°C, maintain this temperature range and melt Al, and then add the elements from step S1 to the melting furnace in the form of an intermediate alloy to obtain an alloy melt.

[0182] S3. Control the melt temperature at 740℃, and introduce nitrogen gas with a purity of ≥99.99% into the melt through the refining pipe at a flow rate of 0.8 m³ / h for 15 min. After removing the gas and inclusions from the melt, let it stand for 20 minutes to remove the gas and inclusions from the melt. Then, control the melt temperature at a suitable range of 680℃ and pour it out of the furnace to obtain the alloy forging billet.

[0183] S4. Place the forging billet in a heating furnace and heat it to 500℃. Place the heated billet on a free forging hammer and repeatedly draw and upset it to shape it into a round cake. After reheating the cake to the forging temperature, place it on a press and press the punch to punch out a through hole to obtain a ring billet.

[0184] S5. The ring billet is heated in a heating furnace at a heating rate of 8℃ / min to 420℃, and held for 90min.

[0185] S6. Transfer the heat-insulated ring billet to the ring rolling mill for rolling. The deformation per rolling pass is 7.6%. Monitor the temperature in real time during rolling. If the temperature drops below 390℃, pause and reheat. Control the rolling temperature at 400℃. The linear speed of the drive roller of the ring rolling mill is 535mm / s, the linear speed of the core roller is 373mm / s, the linear speed ratio is 1.73, and the radial feed speed is 1.78mm / s.

[0186] S7. Place the rolled ring billet into an electric resistance furnace for intermediate low-temperature annealing. The heating rate of the electric resistance furnace is controlled at 10℃ / min, the annealing temperature is 300℃, and the holding time is 2h. After the holding time is completed, the furnace is cooled to below 150℃ and then air-cooled to room temperature to relieve the rolling internal stress and initially refine the grains.

[0187] S8. Under room temperature conditions, the annealed ring is subjected to a second cold rolling, and the dimensional accuracy and wall thickness uniformity of the ring are precisely controlled. The cold rolling deformation is controlled at 5.7%. During the rolling process, an emulsion is used for lubrication and cooling. The concentration of the emulsion is controlled at 4%. The operating temperature is maintained at 40℃. The dimensional accuracy error of the ring is ≤ ±0.05mm, and the wall thickness uniformity error is ≤0.03mm.

[0188] S9. The ring billet is subjected to intermediate low-temperature annealing again. The heating rate of the resistance furnace is controlled at 10℃ / min, the annealing temperature is 300℃, and the holding time is 2.5h. Then it is air-cooled to room temperature to further eliminate internal stress and improve the toughness of the ring.

[0189] S10. Repeat steps S6 to S9 for 3 cycles. After completing all cycles of rolling, perform standard solution treatment and aging treatment on the ring to finally obtain a fine-grained, high-strength and tough ring.

[0190] The rings prepared in Examples 9-12 were subjected to performance testing using the same experimental methods as in Examples 1-8. The data obtained from the experiments are shown in Table (2).

[0191] Example Product grain size testing (grade) Grain size difference (grades) throughout the thickness Circumferential hardness deviation (HB) Elongation (%) Example 9 9.2 0.93 8.6 22.57 Example 10 9.41 0.75 9.5 19.2 Example 11 8.93 1.13 10 19.13 Example 12 8.7 1.2 11 18.95

[0192] Table (2)

[0193] Comparing Examples 9-12, when the single-pass deformation is 9.2%, the drive roll linear speed is 350 mm / s, the core roll linear speed is 250 mm / s, the linear speed ratio is 1.2, the radial feed speed is 0.75 mm / s, and the cold rolling deformation is controlled at 5.7%, Example 9 has finer grains, smaller grain size difference along the entire thickness, lower circumferential hardness deviation, and the highest elongation. Therefore, it has the best overall result and achieves high strength and toughness for large cross-section ring parts.

[0194] In summary, the elemental percentages of this invention are as follows: Si: 0.32, Mg: 0.63, Cu: 0.04, Mn: 0.26, Zn: 0.04, Ti: 0.11, Cr: 0.14, Fe: 0.14, Al: 98.32. During the processing, the single-pass deformation is 9.2%, the drive roller linear speed is 350 mm / s, the core roller linear speed is 250 mm / s, the linear speed ratio is 1.2, the radial feed speed is 0.75 mm / s, and the cold rolling deformation is controlled at 5.7%. This results in the optimal fine-grained properties and toughness of the ring material.

[0195] Comparative Example 1

[0196] S1. Raw material preparation: Prepare alloy raw materials according to the following mass percentages: Si: 0.32, Mg: 0.63, Cu: 0.04, Mn: 0.26, Zn: 0.04, Ti: 0.11, Cr: 0.14, Fe: 0.14, Al: 98.32%;

[0197] S2. Heat the melting furnace to 750°C and maintain this temperature to melt Al. Then add the elements in S1 to the melting furnace in the form of an intermediate alloy to obtain an alloy melt.

[0198] S3. The melt temperature is controlled at 730℃. Nitrogen gas with a purity of ≥99.99% is introduced at a flow rate of 0.8m³ / h for 15min. After removing the gas and inclusions, the melt is allowed to stand for 13min. Then, the temperature is lowered to 685℃ and the melt is poured to obtain the alloy forging billet.

[0199] S4. Heat the forging billet to 500℃, repeatedly draw, upset and shape it into a round cake shape on a free forging hammer, reheat it to the forging temperature and punch through holes on a press to obtain a ring billet;

[0200] S5. Heat the ring billet to 450℃ at a heating rate of 8℃ / min and hold for 70min.

[0201] S6. After the alloy material is cooled to room temperature by water, it is rolled and deformed, with a rolling deformation amount of 20%.

[0202] S7. The pre-deformed aluminum alloy material is subjected to long-term low-temperature annealing at 275℃ for 72 hours to change the existence form and distribution state of alloying elements in the aluminum alloy material.

[0203] S8. After cooling the intermediate annealed aluminum alloy material to room temperature, it is rolled and deformed, with a total rolling deformation of 92%.

[0204] S9. The rolled aluminum alloy is recrystallized and annealed at 280°C for 10 hours to achieve a fine-grained structure in the formed alloy material.

[0205] In this comparative example, the performance of the prepared ring was tested using the same experimental method as in Examples 1-8. The results are as follows: product grain size: grade 9.3; grain size difference in the full thickness direction: grade 0.87; circumferential hardness deviation: 9.2 HB; elongation: 20.73%. These results indicate that after processing the ring forging by room temperature cold rolling, the grain size and grain size difference in the full thickness direction of the ring forging are better than those in Example 9. However, the performance of the ring forging in terms of circumferential hardness deviation and elongation is lower than that in Example 9. Therefore, compared with Example 9, Example 9 is a better manufacturing scheme.

[0206] Comparative Example 2

[0207] S1. Raw material preparation: Prepare alloy raw materials according to the following mass percentages: Si: 0.32, Mg: 0.63, Cu: 0.04, Mn: 0.26, Zn: 0.04, Ti: 0.11, Cr: 0.14, Fe: 0.14, Al: 98.32%;

[0208] S2. Heat the melting furnace to 750°C and maintain this temperature to melt Al. Then add the elements in S1 to the melting furnace in the form of an intermediate alloy to obtain an alloy melt.

[0209] S3. The melt temperature is controlled at 730℃. Nitrogen gas with a purity of ≥99.99% is introduced at a flow rate of 0.8m³ / h for 15min. After removing the gas and inclusions, the melt is allowed to stand for 13min. Then, the temperature is lowered to 685℃ and the melt is poured to obtain the alloy forging billet.

[0210] S4. Heat the forging billet to 500℃, repeatedly draw, upset and shape it into a round cake shape on a free forging hammer, reheat it to the forging temperature and punch through holes on a press to obtain a ring billet;

[0211] S5. Under the condition of controlling the heating rate at 5℃ / min, heat the specimen to 530℃, hold it at that temperature for 5h, and then perform rapid water cooling.

[0212] S6. Under the condition of controlling the heating rate at about 5℃ / min, heat the specimen to 160℃, hold it at that temperature for 5h, and then air cool it.

[0213] S7. Heat at a rate of 5℃ / min until it reaches 520℃, then release the sample and hold it at that temperature for 120 minutes, followed by rapid water cooling.

[0214] In this comparative example, the performance of the prepared ring was tested using the same experimental method as in Examples 1-8. The results are as follows: product grain size: 8.9 grade; grain size difference in the full thickness direction: 1.17 grade; circumferential hardness deviation: 8.5 HB; elongation: 22.47%. The results show that after processing the ring forging by cold deformation, the data performance in terms of circumferential hardness deviation and elongation is similar to that in Example 9. However, the grain size and grain size difference in the full thickness direction of the ring forging are lower than those in Example 9. Therefore, compared with Example 9, Example 9 is a better manufacturing scheme.

[0215] Comparative Example 3

[0216] S1. Raw material preparation: Prepare alloy raw materials according to the following mass percentages: Si: 0.32, Mg: 0.63, Cu: 0.04, Mn: 0.26, Zn: 0.04, Ti: 0.11, Cr: 0.14, Fe: 0.14, Al: 98.32%;

[0217] S2. Heat the melting furnace to 750°C and maintain this temperature to melt Al. Then add the elements in S1 to the melting furnace in the form of an intermediate alloy to obtain an alloy melt.

[0218] S3. The melt temperature is controlled at 730℃. Nitrogen gas with a purity of ≥99.99% is introduced at a flow rate of 0.8m³ / h for 15min. After removing the gas and inclusions, the melt is allowed to stand for 13min. Then, the temperature is lowered to 685℃ and the melt is poured to obtain the alloy forging billet.

[0219] S4. Heat the forging billet to 500℃, repeatedly draw, upset and shape it into a round cake shape on a free forging hammer, reheat it to the forging temperature and punch through holes on a press to obtain a ring billet;

[0220] S5. Load the ring forging into the quenching material frame, preheat it, and hold it at the set temperature range for 2 hours.

[0221] S6. After the holding time is reached, quickly open the furnace door and quickly quench the ring forging. The quenching transfer time is ≤25s. After immersion in water, move the quenching material frame up and down to completely immerse the ring forging in water for 25 minutes.

[0222] S7. After quenching, the ring forging is placed on the ring rolling mill. The ring rolling mill is started, and the main roll rotates counterclockwise at a fixed speed. The rolling line speed is 1215 mm / s. The main roll drives the ring forging to rotate clockwise.

[0223] S8. The core roll moves clockwise toward the main roll. The annular forging drives the upper tapered roll to rotate clockwise. The annular forging drives the lower tapered roll, left clamping roll, and right clamping roll to rotate counterclockwise. The core roll feeds toward the main roll at a speed of 0.8 mm / s in the radial direction. Under the action of the main roll and the core roll, the wall thickness of the annular forging gradually decreases, and the deformation is controlled at 2.7%.

[0224] S9. The cold-rolled and deformed ring forgings are subjected to aging treatment.

[0225] In this comparative example, the performance of the prepared ring was tested using the same experimental method as in Examples 1-8. The results are as follows: product grain size: 8.7 grade; grain size difference in the full thickness direction: 0.89 grade; circumferential hardness deviation: 9.1 HB; elongation: 21.33%. These results indicate that after processing the ring forging by cold rolling deformation, the grain size difference in the full thickness direction of the ring forging is better than that in Example 9. However, the performance of the product grain size, circumferential hardness deviation, and elongation is lower than that in Example 9. Therefore, compared to Example 9, Example 9 is a better manufacturing scheme.

[0226] Comparative Example 4

[0227] S1. Raw material preparation: Prepare alloy raw materials according to the following mass percentages: Si: 0.32, Mg: 0.63, Cu: 0.04, Mn: 0.26, Zn: 0.04, Ti: 0.11, Cr: 0.14, Fe: 0.14, Al: 98.32%;

[0228] S2. Heat the melting furnace to 750°C and maintain this temperature to melt Al. Then add the elements in S1 to the melting furnace in the form of an intermediate alloy to obtain an alloy melt.

[0229] S3. The melt temperature is controlled at 730℃. Nitrogen gas with a purity of ≥99.99% is introduced at a flow rate of 0.8m³ / h for 15min. After removing the gas and inclusions, the melt is allowed to stand for 13min. Then, the temperature is lowered to 685℃ and the melt is poured to obtain the alloy forging billet.

[0230] S4. Heat the forging billet to 500℃, repeatedly draw, upset and shape it into a round cake shape on a free forging hammer, reheat it to the forging temperature and punch through holes on a press to obtain a ring billet;

[0231] S5. The ring billet is sent into the heating furnace and heated to 530°C. It is held for 6 hours. After the holding period, it is quickly taken out of the furnace and immediately water-cooled within 30 seconds to cool to room temperature.

[0232] S6. After quenching and cooling to room temperature and passing inspection, place the ring in an aging furnace, heat it to 165℃, and hold it at that temperature for 600 minutes to ensure that the strengthening phase is fully released. After holding, allow it to air cool to room temperature to complete the aging process.

[0233] In this comparative example, the same experimental method as in Examples 1-8 was used to test the performance of the prepared ring forging. The results are as follows: product grain size: 9.3 grade; grain size difference in the full thickness direction: 0.91 grade; circumferential hardness deviation: 8.8 HB; elongation: 21.06%. These results indicate that after processing the ring forging with solution treatment and aging treatment, the product grain size, grain size difference in the full thickness direction, and axial hardness deviation of the ring forging are relatively small. However, the elongation performance is lower than that in Example 9. Therefore, compared to Example 9, Example 9 is a better manufacturing scheme.

[0234] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention in any way. Those skilled in the art can readily implement the invention based on the accompanying drawings and the description above. However, any modifications, alterations, or variations made by those skilled in the art without departing from the scope of the present invention, using the disclosed technical content, are equivalent embodiments of the present invention. Furthermore, any modifications, alterations, or variations made to the above embodiments based on the essential technology of the present invention are still within the protection scope of the present invention.

Claims

1. A method for fine-grained, high-strength, and tough deformation heat treatment of large-section ring components, characterized in that, The method includes the following steps: S1. Raw material preparation: This includes the following elements and their percentage in the raw materials, as follows: Si: 0.31~0.62, Mg: 0.62~0.92, Cu: 0.03~0.12, Mn: 0.25~0.43, Zn: 0.03~0.15, Ti: 0.02~0.12, Cr: 0.13~0.27, Fe: 0.13~0.27, Al: 97.40~98.75; S2, Smelting: Raise the furnace temperature of the smelting furnace to between 740 and 760°C, maintain this temperature range and melt Al, and then add the elements from step S1 to the smelting furnace in the form of an intermediate alloy to obtain an alloy melt. S3. Impurity Removal: The alloy melt is refined and impurity removed to remove gas and inclusions. After standing, the melt temperature is adjusted and the melt is poured out of the furnace to obtain an alloy forging billet. S4. Forging the billet into a ring blank: Place the forging billet from step S3 into a heating furnace and heat it to 450-550°C. Place the heated billet on a free forging hammer and repeatedly draw and upset it to form a round disc. After reheating the disc to the forging temperature, place it on a press and press the punch to punch out a through hole to obtain a ring blank. S5. Preheating: Place the ring blank formed in step S4 into a heating furnace and heat and keep it at a constant temperature to ensure that the temperature inside and outside the ring blank is uniform. S6. Rolling: Transfer the ring billet after heat preservation in step S5 to the ring rolling mill for rolling; S7. First annealing: The ring billet rolled in step S6 is placed in an electric resistance furnace for intermediate low-temperature annealing, and then cooled to room temperature to relieve rolling internal stress and initially refine the grains. S8. Cold rolling: Under room temperature conditions, the ring after annealing in step S7 is subjected to a second cold rolling to precisely control the dimensional accuracy and wall thickness uniformity of the ring. S9. Second annealing: The ring billet rolled in step S8 is subjected to intermediate low-temperature annealing again to further eliminate internal stress and improve the toughness of the ring. S10. Repeat steps S6 to S9 for 2 to 3 cycles. After completing all the rolling cycles, the ring is subjected to standard solution treatment and aging treatment to finally obtain a fine-grained, high-strength and tough ring.

2. The method for fine-grained, high-strength, and tough deformation heat treatment of a large cross-section ring as described in claim 1, characterized in that: In step S3, the melt temperature is controlled at 720-740℃. Nitrogen gas with a purity of ≥99.99% is introduced into the melt through a refining pipe at a flow rate of 0.8 m³ / h for 15 min. After removing the gas and inclusions from the melt, it is allowed to stand for 10-20 minutes. The melt temperature is then controlled within a suitable range of 680-720℃ before being unloaded and poured.

3. The method for fine-grained, high-strength, and tough deformation heat treatment of a large cross-section ring as described in claim 1, characterized in that: In step S5, the ring billet is heated in a heating furnace to 420-480°C at a heating rate of 5-15°C / min, and held for 30-90 min.

4. The method for fine-grained, high-strength, and tough deformation heat treatment of a large cross-section ring as described in claim 1, characterized in that: In step S6, the rolling temperature is controlled at 390-450℃, the linear speed of the drive roller of the ring rolling mill is 300-600mm / s, the linear speed of the core roller is 200-400mm / s, the linear speed ratio is 1.2-1.8, and the radial feed speed is 0.5-2mm / s.

5. The method for fine-grained, high-strength, and tough deformation heat treatment of a large cross-section ring as described in claim 1, characterized in that: In step S6, the deformation amount per rolling pass is 5% to 15%. The temperature is monitored in real time during the rolling process, and the rolling is paused and reheated when it is below 390°C.

6. The method for fine-grained, high-strength, and tough deformation heat treatment of a large cross-section ring as described in claim 1, characterized in that: In step S7, the heating rate of the resistance furnace is controlled at 8-12℃ / min, the annealing temperature is 250-350℃, the holding time is 1.5-2.5h, and after the holding time is completed, the furnace is cooled to below 150℃ and then air-cooled to room temperature.

7. The method for fine-grained, high-strength, and tough deformation heat treatment of a large cross-section ring as described in claim 1, characterized in that: In step S8, the cold rolling deformation is controlled at 4-6%, and emulsion is used for lubrication and cooling during the rolling process. The dimensional accuracy error of the ring is ≤ ±0.05mm, and the wall thickness uniformity error is ≤0.03mm.

8. The method for fine-grained, high-strength, and tough deformation heat treatment of a large cross-section ring according to claim 7, characterized in that: The concentration of the emulsion is controlled at 3% to 5%, and the operating temperature is maintained at 35 to 55°C.

9. The method for fine-grained, high-strength, and tough deformation heat treatment of a large cross-section ring as described in claim 1, characterized in that: In step S9, the heating rate of the resistance furnace is controlled at 8-12℃ / min, the annealing temperature is 250-350℃, the holding time is 2.0-3.0h, and then it is air-cooled to room temperature.

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