A forging method for an elliptical ring

Abstract

The present invention relates to a forging method for an elliptical ring, and belongs to the technical field of steel forging. In order to solve the problems of large forging allowance and waste of raw materials in the existing forging forming method for elliptical ring forgings, the present invention provides a forging method for an elliptical ring, wherein a steel ingot is heated to a forging temperature, the steel ingot is upset by a first forging process, the steel ingot is stretched to the required size by a second forging process, the steel ingot is upset by a third forging process, a hole is punched in the center after being upset, the steel ingot is expanded, stretched and flattened to the required size by a mandrel by a fourth forging process, and the finished elliptical ring is forged by a fifth forging process using an upper V and lower flat anvil. The present invention can reduce the forging allowance of the elliptical ring, thereby saving the use of raw materials, achieving cost reduction, efficiency improvement, energy conservation and emission reduction. The present invention realizes the precise control of the size of the elliptical ring during the integral forging, improves the precision size and angle of the inner ellipse, achieves a one-time qualified rate of 100%, reduces the forging difficulty of the elliptical ring, improves production efficiency, improves the production environment, and facilitates mass production.

Description

Technical Field

[0001] The invention belongs to the technical field of steel forging, and in particular relates to a forging method of an elliptical ring. Background Art

[0002] Free forging is a machining process that uses impact or static pressure to plastically deform a metal blank on an anvil or between the upper and lower anvils of a forging press, resulting in a forged part. Compared to castings, free forging not only eliminates defects such as shrinkage, porosity, and pores, but also refines the grain size and improves the mechanical properties of the part. Free forging relies on manual control of the forging's shape and size, resulting in low precision, large machining allowances, high labor intensity, and low productivity. Therefore, it is primarily used for single-piece and small-batch production.

[0003] The current production technology for elliptical ring forgings involves heating and forging steel ingots, then normalizing, annealing, and forming. The primary forming method involves forging steel ingots. The first fire involves pressing the jaws, removing the bottom, and upsetting the ingot. The second fire involves drawing the ingot into a round shape with a desired size and blanking it. The third fire involves upsetting the ingot and punching the holes. The fourth fire involves expanding the hole, drawing the ring, and flattening it into a finished ring. Air cooling replaces normalizing and annealing, and the ring is then processed. The main drawbacks of this forming method are large forging allowances, long subsequent machining times, and significant material waste. When directly forging an elliptical ring from a pre-deformed ring, the inner ring dimensions calculated using the ellipse circumference formula (L = 2πb + 4(ab)) often result in the resulting elliptical ring's inner hole dimensions not matching the design dimensions, making it impossible to machine to the required size. Summary of the Invention

[0004] In order to solve the problems of large forging allowance, waste of raw materials and uneven sizes in the existing elliptical ring forging forming method, the present invention provides an elliptical ring forging method.

[0005] The technical solution of the present invention:

[0006] A forging method for an elliptical ring comprises heating a steel ingot to a forging temperature, performing a first forging process to upset the steel ingot, performing a second forging process to lengthen the steel ingot to a required size, and then blanking the steel ingot, performing a third forging process to upset the blanked steel ingot and then punching a hole in the center, performing a fourth forging process to expand the hole, lengthen the steel ingot, and flatten the steel ingot to a required size using a mandrel, and performing a fifth forging process to forge the finished elliptical ring using an upper V-shaped and lower flat anvil.

[0007] Furthermore, the forging temperature is 1180-1200° C., and the steel ingot is heated to the forging temperature and then kept warm for 5-7 hours.

[0008] Furthermore, during the first forging, the steel ingot is firstly clamped, chamfered, and the ingot tail removed, and then upset to Φ870-1040mm.

[0009] Furthermore, during the second forging, the steel ingot is stretched to Φ480-550 mm and a height of 1990-2230 mm, and then cut to obtain two steel ingots of equal height with a height-to-diameter ratio of 1.8-2.5.

[0010] Furthermore, during the third forging, the steel ingot obtained by the second forging is upset to a height of 500 mm, and a hole of Φ250-300 mm is punched in the center of the steel ingot.

[0011] Furthermore, during the fourth fire forging, a Φ200 mandrel is used for hole expansion. After the hole is expanded to an inner diameter of Φ350, a Φ350 mandrel is used for drawing. After leveling, the hole is further expanded until a ring with an outer diameter of Φ905-990 mm, an inner diameter of Φ522-540 mm, and a height of 390-560 mm is obtained.

[0012] Furthermore, during the fifth fire forging, an upper V-shaped anvil and a lower flat anvil are used to forge the pre-deformed circular ring side surface, forging the elliptical ring to have an outer major axis of 1090-1220 mm, an inner major axis of 740-770 mm, an outer minor axis of 590-730 mm, an inner minor axis of 240-270 mm, and a height of 390-560 mm.

[0013] Furthermore, the return heating temperature of the first fire forging, the second fire forging and the third fire forging is 1180-1200° C., and the holding time is not less than 2.5 hours.

[0014] Furthermore, the reheating temperature of the fourth forging is 1180-1200°C, and the holding time is not less than 40-60 minutes. When the fifth forging is performed on the side of the pre-deformed ring, the material temperature is 750-800°C.

[0015] Furthermore, the elliptical ring obtained by the fifth forging is air-cooled to 600-650° C., placed in a heat treatment furnace and annealed at 680±10° C. for 7-8 hours to complete the heat treatment.

[0016] Beneficial effects of the present invention:

[0017] By improving the forging deformation process, the present invention develops a method for integrally forging elliptical rings. This method reduces the forging allowance of the elliptical rings, thereby conserving raw materials and achieving cost reduction, efficiency improvement, energy conservation, and emission reduction. By controlling the inner and outer diameters of the fourth-fire pre-deformed circular ring, the present invention achieves precise control of the major and minor axis dimensions of the inner and outer ellipses during integral forging, improving the precision dimensions and angles of the inner ellipse, achieving a 100% first-pass yield, and reducing the difficulty of forging the elliptical rings. This improves production efficiency, enhances the production environment, and facilitates mass production. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a photo of the finished oval ring prepared in Example 1;

[0019] Figure 2 This is a photo of the pre-deformed ring obtained by the fourth fire forging in Example 1;

[0020] Figure 3 This is a photo of the elliptical ring obtained by the fifth fire forging in Example 1. DETAILED DESCRIPTION

[0021] The technical solution of the present invention is further described below with reference to the embodiments, but is not limited thereto. Any modification or equivalent replacement of the technical solution of the present invention without departing from the spirit and scope of the technical solution of the present invention shall be included in the scope of protection of the present invention. The process equipment or devices not specifically noted in the following examples are all conventional equipment or devices in the art. Unless otherwise specified, the raw materials used in the examples of the present invention can be obtained commercially; unless otherwise specified, the technical means used in the examples of the present invention are all conventional means well known to those skilled in the art.

[0022] Example 1

[0023] This embodiment provides a method for forging an elliptical ring.

[0024] Forged using a 30MN hydraulic press, the product model is 925A and the ingot weight is 4.29 tons.

[0025] Specifications of the elliptical ring: outer ellipse 1220±8mm×730±8mm, inner ellipse 762~770mm×270±8mm, height 390±8mm.

[0026] The specific forging process of this embodiment is: heating the steel ingot → pressing the jaws → lightly chamfering → removing the bottom of the ingot → upsetting → drawing to the required size and cutting → upsetting to a pancake shape, punching → drawing, expanding the hole, and flattening the height to the required size → using an upper V and lower flat anvil to forge the finished elliptical ring.

[0027] The specific forging method steps of the elliptical ring in this embodiment are as follows:

[0028] Step 1: Place the steel ingot into a gas-fired heating furnace and heat it at a temperature of 1180-1200°C for 5-7 hours to ensure that the temperature of the steel ingot is uniform and thoroughly burned.

[0029] Step 2, first fire forging: the steel ingot is pressed, chamfered, and the ingot tail is removed, and the ingot is upset to Φ980mm and the height is 580mm. The temperature of the steel ingot is not lower than 850℃, and it is heated to 1180-1200℃ and kept warm for 3 hours.

[0030] Step 3, second fire forging: draw the steel ingot to Φ520mm and a height of 2000mm, cut the steel ingot into two ingots of 1000mm height each; return to the furnace and heat to 1180-1200℃ and keep warm for 3h;

[0031] Step 4, third fire forging: upset the 1000mm high steel ingot obtained by the second fire to a height of 500mm and a diameter of 690mm, punch a 250mm hole in the center of the ingot, return to the furnace and heat to 1180-1200℃ and keep warm for 3h;

[0032] Step 5, fourth fire forging: use Φ200 mandrel to expand the hole, expand the hole to an inner diameter of Φ350, use Φ350 mandrel to stretch it, flatten it to 390±8mm, then use Φ200 mandrel and Φ350 mandrel to expand the hole in turn, until a ring with an outer diameter of Φ990±8mm, an inner diameter of Φ542~550mm, and a height of 390±8mm is obtained. Figure 2 As shown, return to the furnace and heat to 1180-1200℃ and keep warm for 60 minutes;

[0033] Step 6, fifth fire forging: Use upper V and lower flat anvil to forge the side of the pre-deformed ring. The material temperature during forging is 750-800℃, not too high. If the temperature is too high, there will be no elastic deformation and complete creep, while if the temperature is too low, it will be easy to crack. Therefore, in the two-phase region, the material temperature is preferably 750-800℃. Forge the elliptical ring to an outer major axis of 1220±8mm, an inner major axis of 762~770mm, an outer minor axis of 730±8mm, an inner minor axis of 270±8mm, and a height of 730±8mm. Figure 3 As shown;

[0034] Step 7: The forged elliptical ring is air-cooled to 600-650°C and then placed in a heat treatment furnace for annealing at 680±10°C for 7-8 hours. This dehydrogenation and stress relief annealing reduces forging stress and hardness of the forging, which is beneficial for subsequent processing.

[0035] The fourth fire forging in this embodiment is to perform pre-deformation before forging into an elliptical ring. The control of the inner and outer diameter dimensions of the pre-deformed ring is the key point of the present invention. The inner diameter circumference cannot be larger than the inner elliptical size circumference, and the outer diameter circumference needs to be larger than the outer elliptical size circumference. When the pre-deformation meets the required blanking size, the fifth fire forging controls the material temperature and uses an upper flat anvil and a lower platform to forge it into an elliptical ring. During forging, when the dimensions of the major axis and the minor axis of the outer ellipse meet the requirements, the dimensions of the inner ellipse also meet the size requirements. Compared with the original process of forging into a ring first and then machining, the elliptical ring forging method of this embodiment saves at least 0.75 tons of raw materials per piece, while improving the quality of the core, reducing the weight of the forging blank process, and reducing manufacturing costs.

[0036] Example 2

[0037] This embodiment provides a method for forging an elliptical ring.

[0038] Forged using a 30MN hydraulic press, the product model is 925A and the ingot weight is 4.69 tons.

[0039] Specifications of the elliptical ring: outer ellipse 1135±8mm×635±8mm, inner ellipse 752~760mm×260±8mm, height 560±8mm.

[0040] The specific forging process of this embodiment is: heating the steel ingot → pressing the jaws → lightly chamfering → removing the bottom of the ingot → upsetting → drawing to the required size and cutting → upsetting to a pancake shape, punching → drawing, expanding the hole, and flattening the height to the required size → using an upper V and lower flat anvil to forge the finished elliptical ring.

[0041] The specific forging method steps of the elliptical ring in this embodiment are as follows:

[0042] Step 1: Place the steel ingot into a gas-fired heating furnace and heat it at a temperature of 1180-1200°C for 5-7 hours to ensure that the temperature of the steel ingot is uniform and thoroughly burned.

[0043] Step 2, first fire forging: the steel ingot is pressed, chamfered, and the ingot tail is removed, and upsetting is performed to Φ980mm and a height of 635mm. The temperature of the steel ingot is not less than 850℃, and the ingot is heated to 1180-1200℃ and kept warm for 3 hours.

[0044] Step 3, second fire forging: draw the steel ingot to Φ520mm and a height of 2230mm, cut the steel ingot into two ingots with a height of 1115mm each; return to the furnace and heat to 1180-1200℃ and keep warm for 3h;

[0045] Step 4, third fire forging: upset the steel ingot with a height of 1115mm obtained by the second fire to a height of 500mm and Φ710mm, punch a Φ300 hole in the center of the steel ingot, return to the furnace and heat to 1180-1200℃ and keep warm for 3h;

[0046] Step 5, fourth fire forging: Use a Φ200 mandrel to expand the hole. After expanding the hole to an inner diameter of Φ350, use a Φ350 mandrel to stretch it to a flat height of 560±8mm. Then use a Φ200 mandrel and a Φ350 mandrel to continue expanding the hole in sequence until a ring with an outer diameter of Φ905±8mm, an inner diameter of Φ532-540mm, and a height of 560±8mm is obtained. Then return to the furnace and heat to 1180-1200℃ and keep it warm for 60 minutes;

[0047] Step 6, fifth fire forging: Use an upper V-shaped and lower flat anvil to forge the side of the pre-deformed ring. The material temperature during forging is 750-800℃ and should not be too high. Forge until the outer major axis of the elliptical ring is 1135±8mm, the inner major axis is 752-760mm, the outer minor axis is 635±8mm, the inner minor axis is 260±8mm, and the height is 560±8mm.

[0048] Step 7: The forged elliptical ring is air-cooled to 600-650°C and then placed in a heat treatment furnace for annealing at 680±10°C for 7-8 hours. This dehydrogenation and stress relief annealing reduces forging stress and hardness of the forging, which is beneficial for subsequent processing.

[0049] Example 3

[0050] This embodiment provides a method for forging an elliptical ring.

[0051] Forged using a 30MN hydraulic press, the product model is 925A and the ingot weight is 3.69 tons.

[0052] Specifications of the elliptical ring: outer ellipse 1090±8mm×590±8mm, inner ellipse 732~740mm×240±8mm, height 480±8mm.

[0053] The specific forging process of this embodiment is: heating the steel ingot → pressing the jaws → lightly chamfering → removing the bottom of the ingot → upsetting → drawing to the required size and cutting → upsetting to a pancake shape, punching → drawing, expanding the hole, and flattening the height to the required size → using an upper V and lower flat anvil to forge the finished elliptical ring.

[0054] The specific forging method steps of the elliptical ring in this embodiment are as follows:

[0055] Step 1: Place the steel ingot into a gas-fired heating furnace and heat it at a temperature of 1180-1200°C for 5-7 hours to ensure that the temperature of the steel ingot is uniform and thoroughly burned.

[0056] Step 2, first fire forging: the steel ingot is pressed, chamfered, and the ingot tail is removed, and the ingot is upset to Φ870mm and the height is 790mm. The temperature of the steel ingot is not lower than 850℃, and it is heated to 1180-1200℃ and kept warm for 3 hours.

[0057] Step 3, second fire forging: draw the steel ingot to Φ480mm and a height of 1990mm, cut the steel ingot into two ingots with a height of 995mm each; return the ingot to the furnace and heat it to 1180-1200℃ and keep it warm for 3h;

[0058] Step 4, third fire forging: upset the 995mm high steel ingot obtained by the second fire to a height of 500mm and Φ650mm, punch a Φ300 hole in the center of the ingot, return to the furnace and heat to 1180-1200℃ and keep warm for 3h;

[0059] Step 5, fourth fire forging: Use a Φ200 mandrel to expand the hole. After expanding the hole to an inner diameter of Φ350, use a Φ350 mandrel to stretch it to a flat height of 480±8mm. Then use a Φ200 mandrel and a Φ350 mandrel to continue expanding the hole in sequence until a ring with an outer diameter of Φ860±8mm, an inner diameter of Φ514-522mm, and a height of 480±8mm is obtained. Then return to the furnace and heat to 1180-1200℃ and keep warm for 60 minutes;

[0060] Step 6, fifth fire forging: Use an upper V-shaped and lower flat anvil to forge the side of the pre-deformed ring. The material temperature during forging is 750-800℃ and should not be too high. Forge until the outer major axis of the elliptical ring is 1090±8mm, the inner major axis is 732-740mm, the outer minor axis is 590±8mm, the inner minor axis is 240±8mm, and the height is 480±8mm.

[0061] Step 7: The forged elliptical ring is air-cooled to 600-650°C and then placed in a heat treatment furnace for annealing at 680±10°C for 7-8 hours. This dehydrogenation and stress relief annealing reduces forging stress and hardness of the forging, which is beneficial for subsequent processing.

[0062] Example 4

[0063] This embodiment provides a method for forging an elliptical ring.

[0064] Forged using a 30MN hydraulic press, the product model is 925A and the ingot weight is 4.99 tons.

[0065] Specifications of the elliptical ring: outer ellipse 1185±8mm×685±8mm, inner ellipse 732~740mm×240±8mm, height 495±8mm.

[0066] The specific forging process of this embodiment is: heating the steel ingot → pressing the jaws → lightly chamfering → removing the bottom of the ingot → upsetting → drawing to the required size and cutting → upsetting to a pancake shape, punching → drawing, expanding the hole, and flattening the height to the required size → using an upper V and lower flat anvil to forge the finished elliptical ring.

[0067] The specific forging method steps of the elliptical ring in this embodiment are as follows:

[0068] Step 1: Place the steel ingot into a gas-fired heating furnace and heat it at a temperature of 1180-1200°C for 5-7 hours to ensure that the temperature of the steel ingot is uniform and thoroughly burned.

[0069] Step 2, first fire forging: the steel ingot is pressed, chamfered, and the ingot tail is removed, and the ingot is upset to Φ1000mm and the height is 650mm. The temperature of the steel ingot is not lower than 850℃, and it is heated to 1180~1200℃ and kept warm for 3h.

[0070] Step 3, second fire forging: draw the steel ingot to Φ550mm and a height of 2140mm, cut the steel ingot into two ingots with a height of 1070mm each; return to the furnace and heat to 1180-1200℃ and keep warm for 3h;

[0071] Step 4, third fire forging: upset the steel ingot with a height of 1070mm obtained by the second fire to a height of 500mm and Φ750mm, punch a Φ300 hole in the center of the steel ingot, return to the furnace and heat to 1180-1200℃ and keep warm for 3h;

[0072] Step 5, fourth fire forging: Use a Φ200 mandrel to expand the hole. After expanding the hole to an inner diameter of Φ350, use a Φ350 mandrel to stretch it to a flat height of 495±8mm. Then use a Φ200 mandrel and a Φ350 mandrel to continue expanding the hole in sequence until a ring with an outer diameter of Φ955±8mm, an inner diameter of Φ514-522mm, and a height of 495±8mm is obtained. Then return to the furnace and heat to 1180-1200℃ and keep it warm for 60 minutes;

[0073] Step 6, fifth fire forging: Use an upper V-shaped and lower flat anvil to forge the side of the pre-deformed ring. The material temperature during forging is 750-800℃ and should not be too high. Forge until the outer major axis of the elliptical ring is 1185±8mm, the inner major axis is 732-740mm, the outer minor axis is 685±8mm, the inner minor axis is 240±8mm, and the height is 495±8mm.

[0074] Step 7: The forged elliptical ring is air-cooled to 600-650°C and then placed in a heat treatment furnace for annealing at 680±10°C for 7-8 hours. This dehydrogenation and stress relief annealing reduces forging stress and hardness of the forging, which is beneficial for subsequent processing.

Claims

1. A method for forging an elliptical ring, characterized in that: The steel ingot is heated to forging temperature. The first forging fire upsets the steel ingot. The second forging fire stretches it to the required size and then cuts it. The third forging fire upsets the steel ingot and then punches a hole in the center. The fourth forging fire uses a mandrel to expand the hole, stretch it, and flatten it to the required size. The fifth forging fire uses an upper V-shaped and lower flat anvil to forge it into a finished elliptical ring. During the fourth fire forging, a Φ200 core rod is used for hole expansion. After the hole is expanded to an inner diameter of Φ350, a Φ350 core rod is used for drawing. After leveling, the hole is further expanded until a circular ring with an outer diameter of Φ905-990mm, an inner diameter of Φ522-540mm, and a height of 390-560mm is obtained. During the fifth fire forging, an upper V and a lower flat anvil are used to forge the side of the pre-deformed circular ring until the outer major axis of the elliptical ring is 1090-1220mm, the inner major axis is 740-770mm, the outer minor axis is 590-730mm, the inner minor axis is 240-270mm, and the height is 390-560mm.

2. The forging method of an elliptical ring according to claim 1, characterized in that: The forging temperature is 1180-1200° C., and the steel ingot is heated to the forging temperature and then kept warm for 5-7 hours.

3. A method for forging an elliptical ring according to claim 1 or 2, characterized in that: During the first forging, the steel ingot is firstly clamped, chamfered, and the ingot tail is removed, and then upset to Φ870-1040mm.

4. The forging method of an elliptical ring according to claim 3, characterized in that: During the second forging, the steel ingot is stretched to Φ480-550 mm and a height of 1990-2230 mm, and then cut to obtain two steel ingots of equal height.

5. The forging method of an elliptical ring according to claim 4, characterized in that: During the third forging, the steel ingot obtained by the second forging is upset to a height of 500 mm, and a hole of Φ250-300 mm is punched in the center of the steel ingot.

6. The forging method of an elliptical ring according to claim 5, characterized in that: The return heating temperature of the first fire forging, the second fire forging and the third fire forging is 1180-1200° C., and the holding time is not less than 2.5 hours.

7. The forging method of an elliptical ring according to claim 6, characterized in that: The reheating temperature of the fourth fire forging is 1180-1200°C, and the holding time is not less than 40-60 minutes. When the fifth fire forges the side of the pre-deformed ring, the material temperature is 750-800°C.

8. The forging method of an elliptical ring according to claim 7, characterized in that: The elliptical ring obtained by the fifth forging is air-cooled to 600-650° C., placed in a heat treatment furnace and annealed at 680±10° C. for 7-8 hours to complete the heat treatment.

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