A method for forging an eccentric valve body for a preheater tree

Abstract

This invention provides a forging method for an eccentric valve body used in oil wellheads, comprising the following steps: billet forming: providing a metal material and forging it into a billet; primary eccentricity: forging a first eccentric body at both ends of the billet, the first eccentric body having a protrusion and a middle part, the axis of the protrusion and the axis of the middle part being non-collinear; secondary eccentricity: setting a pair of first dies, the protrusion being limited and installed on the first dies, forging the middle part so that, under the limitation of the first dies, the axis of the middle part moves away from the axis of the protrusion, forming a second eccentric body; blank forming: shaping the second eccentric body and cooling it to form a valve body blank. By limiting the protrusion with the first dies, and the axis of the middle part moving away from the axis of the protrusion under the forging pressure of the press, a second eccentric body with a larger eccentricity is formed. Furthermore, because the height of the first dies is fixed, the eccentric distance between the axes is constant, thereby ensuring the accuracy of the eccentricity and improving processing efficiency.

Description

Technical Field

[0001] This invention relates to the field of forging technology, specifically to a forging method for an eccentric valve body used in oil wellheads. Background Technology

[0002] An eccentric valve body for a production line is a valve component specifically designed to control fluid media. It typically consists of a valve body, valve, sealing rings, and a transmission mechanism. Forging is an essential step in the manufacturing of eccentric valve bodies, and its purpose is to effectively improve the performance and quality of the valve body through the forging process.

[0003] Currently, the manufacturing processes for eccentric valve bodies used in oil wellheads mainly include casting, forging, and welding. Among these, forging is one of the most important processes in manufacturing eccentric valve bodies. Because forging can improve the internal structure and some mechanical properties of the material, it is widely used in the manufacturing process of eccentric valve bodies.

[0004] The eccentric valve body used in oil wellheads has a complex structure with asymmetrical center along its height. To ensure the forging passes inspection and to control large deformations during manufacturing, existing valve body manufacturing processes mainly rely on free forging, manually upsetting and shaping the center in different directions to achieve the eccentric structure. This process has many drawbacks, such as consuming a significant amount of time for upsetting and shaping the center, greatly reducing forging efficiency, and making it difficult to guarantee the quality of the forging. Summary of the Invention

[0005] The technical problem to be solved by this invention is that the existing forging process has low efficiency when forging eccentric structures.

[0006] This invention provides a method for forging an eccentric valve body for a preheater, comprising the following steps:

[0007] Billet forming: A metal material is provided, and the metal material is forged into a billet;

[0008] First eccentricity: A first eccentric body is formed by forging at both ends of the billet. The first eccentric body has a protrusion and a middle part. The axis of the protrusion and the axis of the middle part are not collinear.

[0009] Secondary eccentricity: A pair of first molds are set up, the protrusion is limited and installed on the first molds, and the middle part is forged so that under the limitation of the first molds, the axis of the middle part moves in the direction away from the axis of the protrusion to form a second eccentric body;

[0010] Blank forming: The second eccentric body is shaped and cooled to form a valve body blank.

[0011] Optionally, the above-mentioned forging method for the eccentric valve body of the wellhead includes the following steps in the first eccentric step:

[0012] Marking and material separation: Symmetrically mark the upper end face of the blank at the same distance from the two end faces, and chamfer and round the protrusions;

[0013] Secondary forging: Second molds are respectively fitted at both ends of the billet, and the billet is upsetting upright. Under the drive of the press, the two second molds approach each other to drive the two ends of the billet to fill the inner cavity of the second mold.

[0014] Optionally, in the above-mentioned forging method for the eccentric valve body of the oil well tree, in the secondary eccentric step, the first mold is set on the anvil of the forging equipment, the press upsets and drives the middle part close to the lower anvil surface until it contacts the lower anvil surface and then stops forging.

[0015] Optionally, the above-described forging method for the eccentric valve body of the wellhead further includes the following steps after the secondary eccentric step:

[0016] Three forging processes: Remove the first mold, install the second mold, and stand the second eccentric body upright and upsetting it again.

[0017] Optionally, the above-mentioned forging method for the eccentric valve body of the oil wellhead further includes a primary forging step in the billet forming step, which includes the following steps:

[0018] One-time upsetting: The billet is stood upright and upset to a height of 520mm;

[0019] First drawing: The billet after the first upsetting is first drawn into a square with a side length of 560mm, and then drawn into a columnar billet with a cross-section of a regular octagon with a height of 580mm and a length of 910mm.

[0020] Secondary upsetting: The billet after the first drawing is upset to a height of 520mm.

[0021] Optionally, the above-described forging method for the eccentric valve body of the wellhead further includes the following steps in the billet forming step:

[0022] First shaping: The blank is drawn out and squared into a cube of 470*500*1074mm, and both ends are flattened.

[0023] Optionally, in the above-mentioned forging method for the eccentric valve body of the oil well tree, before the first forging, first shaping, second forging and second eccentric steps, the billet is heated to a temperature of 1200℃-1240℃ and held for 1.5±0.5h.

[0024] Optionally, in the above-mentioned forging method for the eccentric valve body of the oil well tree, in the marking and material distribution step, a narrow anvil is used to mark the upper end face of the billet, the distance between the marked point and the end face of the billet on the same side is 150mm, and the marking depth is 35mm; the protrusion is shaped to the end face radius R≤20mm.

[0025] Optionally, in the above-mentioned forging method for the eccentric valve body of the oil well tree, the upsetting height of the billet in the secondary forging step is 880 mm.

[0026] Optionally, the above-described forging method for the eccentric valve body of the wellhead further includes the following step after the secondary forging step:

[0027] Secondary shaping: The billet after secondary forging is demolded and shaped to a width of 510mm and a height of 630mm in the middle part.

[0028] Optionally, in the above-mentioned forging method for the eccentric valve body of the oil well tree, the first mold and the second mold are preheated before use. The preheating temperature is 250℃-350℃ and the preheating time lasts for 1.5-2.5 hours.

[0029] Optionally, in the above-mentioned forging method for the eccentric valve body of the oil well tree, in the secondary eccentric step, the first mold is raised and placed on the anvil, with a raising height of 15mm-20mm.

[0030] Optionally, in the above-mentioned forging method for the eccentric valve body of the oil well tree, in the secondary eccentric step, after the middle part of the billet contacts the lower anvil, the middle part of the billet is shaped to a width of 508mm and a height of 620mm.

[0031] Optionally, in the above-mentioned forging method for the eccentric valve body of the oil well tree, in the three forging steps, a second mold is set and the billet is upset, and the upset height of the billet is 965mm.

[0032] Optionally, in the above-mentioned forging method for the eccentric valve body of the oil well tree, in the blank forming step, after the blank is forged three times, it is air-cooled to a surface temperature of 700°C-750°C and then placed in a furnace with a furnace temperature of ≤500°C for furnace cooling. After the furnace cooling reaches below 200°C, the blank is taken out and air-cooled again.

[0033] Optionally, in the above-mentioned forging method for the eccentric valve body of the oil well tree, the initial forging temperature is 1200℃-1240℃, and the final forging temperature is ≥850℃.

[0034] Optionally, in the above-mentioned forging method for the eccentric valve body of the oil well tree, the single-process forging ratio is greater than or equal to 1.8, and the total forging ratio of the processes is ≥4.

[0035] The technical solution provided by this invention has the following advantages:

[0036] 1. The forging method for the eccentric valve body of the oil wellhead provided by the present invention includes the following steps:

[0037] Billet forming: A metal material is provided, and the metal material is forged into a billet;

[0038] First eccentricity: A first eccentric body is formed by forging at both ends of the billet. The first eccentric body has a protrusion and a middle part. The axis of the protrusion and the axis of the middle part are not collinear.

[0039] Secondary eccentricity: A pair of first molds are set up, the protrusion is limited and installed on the first molds, and the middle part is forged so that under the limitation of the first molds, the axis of the middle part moves in the direction away from the axis of the protrusion to form a second eccentric body;

[0040] Blank forming: The second eccentric body is shaped and cooled to form a valve body blank.

[0041] This method uses an eccentric valve body forging process for oil wells. After forming a blank in the blank forming step, a first eccentric body, including a protrusion and a middle part, is formed by forging in the first eccentric step. The axes of the protrusion and the middle part of the first eccentric body are offset. In the second eccentric step, the protrusion is limited by the first die, and the axis position of the protrusion remains fixed. During the forging process, the axis of the middle part moves away from the axis of the protrusion under the forging of the press, which expands the eccentric distance between the axes and forms a second eccentric body with a larger eccentricity. Since the height of the first die is fixed, the eccentric distance between the axes of the middle part is constant under the drive of the press, thus ensuring the accuracy of eccentricity and improving processing efficiency. After the second eccentric step, the valve body blank is formed by shaping and cooling in the blank forming step. Through shaping and cooling in the blank forming stage, the dimensional accuracy of the valve body can be further improved, making the manufactured valve body more in line with the design requirements.

[0042] 2. In the forging method of the eccentric valve body for oil production tree provided by the present invention, in the secondary eccentric step, the first mold is set on the anvil of the forging equipment, the press upsets and drives the middle part to approach the lower anvil surface until it contacts the lower anvil surface and then stops forging.

[0043] This method for forging the eccentric valve body of the oil wellhead utilizes a technique where a first die is placed on the anvil, and forging of the middle section is stopped once it contacts the anvil. This allows for better control of deformation during the forging process, resulting in a more precise valve body. By gradually driving the middle section towards the downward anvil face, the eccentricity generated during forging can be effectively controlled, along with better control over the filling of the billet, thereby improving machining accuracy and reducing machining errors. This method is simple to operate and easy to master. Attached Figure Description

[0044] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0045] Figure 1 This is a schematic diagram of the valve body blank provided in an embodiment of the present invention;

[0046] Figure 2 This is a schematic diagram of the structure of the first eccentric body formed after one eccentricity in an embodiment of the present invention.

[0047] Figure 3 This is a top view of the structure in the secondary eccentrication step provided in an embodiment of the present invention;

[0048] Figure 4 This is a schematic diagram of the structure of the second mold provided in an embodiment of the present invention;

[0049] Figure 5 This is a schematic diagram of the structure for raising the upset in a single eccentric step provided in an embodiment of the present invention;

[0050] Figure 6 This is a schematic diagram of the structure of the first mold provided in an embodiment of the present invention;

[0051] Figure 7 This is a schematic cross-sectional view of the first mold provided in an embodiment of the present invention;

[0052] Explanation of reference numerals in the attached figures:

[0053] 1-First eccentric body; 11-Protrusion; 12-Middle part;

[0054] 2-First mold;

[0055] 3-Valve body blank;

[0056] 4-Second mold. Detailed Implementation

[0057] The technical solution of the present invention will now be clearly and completely described with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. 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.

[0058] In the description of this invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing the invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0059] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connection," "linking," and "connection" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0060] Furthermore, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0061] Example

[0062] like Figures 1 to 3 As shown, this embodiment provides a forging method for an eccentric valve body for a pre-works tree, including the following steps:

[0063] Billet forming: A metal material is provided, and the metal material is forged into a billet;

[0064] First eccentricity: The first eccentric body 1 is formed by forging at both ends of the billet. The first eccentric body 1 has a protrusion 11 and a middle part 12. The axis of the protrusion 11 and the axis of the middle part 12 are not collinear.

[0065] Secondary eccentricity: A pair of first molds 2 are set up, the protrusion 11 is limited and installed on the first molds 2, and the middle part 12 is forged so that under the limitation of the first molds 2, the axis of the middle part 12 moves in a direction away from the axis of the protrusion 11 to form a second eccentric body;

[0066] Blank forming: The second eccentric body is shaped and cooled to form valve body blank 3.

[0067] Specifically, in this embodiment, after the billet is formed through the billet forming step, a first eccentric body 1, including a protrusion 11 and a middle part 12, is formed by forging in the first eccentric step. The axes of the protrusion 11 and the middle part 12 of the first eccentric body 1 are misaligned. In the second eccentric step, the protrusion 11 is limited by the first mold 2, and the axis position of the protrusion 11 remains fixed. During the forging process, the axis of the middle part 12 moves away from the axis of the protrusion 11 under the forging pressure of the press, which expands the eccentric distance between the axes and forms a second eccentric body with a larger eccentricity. Since the height of the first mold 2 is fixed, the eccentric distance between the axes of the middle part 12 is constant under the drive of the press, thereby ensuring the accuracy of the eccentricity. Through the combination of the first and second eccentric processes, the surface and interior of the metal billet can be compacted during the forging process, thereby improving the density of the parts. After the second eccentric step, the valve body blank 3 to be processed is formed by shaping and cooling in the blank forming step. Through the shaping and cooling in the blank forming stage, the dimensional accuracy of the valve body can be further improved, making the manufactured valve body more in line with the design requirements.

[0068] like Figures 4 to 5 As shown, the forging method for the eccentric valve body of the wellhead provided in this embodiment includes the following steps in one eccentric step:

[0069] Marking and material separation: symmetrical markings are made at the same distance from the two end faces on the upper end face of the blank, and the protrusion 11 is chamfered and rounded.

[0070] Secondary forging: Second molds 4 are respectively fitted at both ends of the billet, and the billet is upsetting upright. Under the drive of the press, the two second molds 4 approach each other to drive the two ends of the billet to fill the inner cavity of the second molds 4.

[0071] like Figure 3 , Figures 6 to 7 As shown in this embodiment, the forging method for an eccentric valve body used in oil production trees includes a second eccentric step. In this step, the first mold 2 is placed on the anvil of the forging equipment. The press upsets the material and drives the intermediate part 12 closer to the lower anvil surface until it contacts the surface, at which point the forging stops. Specifically, in this embodiment, by setting the first mold 2 on the anvil and forging the intermediate part 12 until it contacts the anvil, the deformation during forging can be better controlled, resulting in higher dimensional accuracy of the forged valve body. By gradually driving the intermediate part 12 closer to the lower anvil surface, the eccentric distance generated during forging can be effectively controlled, and the filling of the billet can be better controlled, thereby improving machining accuracy and reducing machining errors. This method is simple to operate and easy to master.

[0072] The forging method for the eccentric valve body of the wellhead provided in this embodiment further includes the following steps after the secondary eccentric step:

[0073] Three-stage forging: The first mold 2 is removed, the second mold 4 is installed, and the second eccentric body is erected and upset again. Specifically, in this embodiment, after the second eccentric body is upset again, the second mold 4 is removed and precision forging is performed. Through the third forging, the second eccentric body can be forged again, further improving the dimensional accuracy of the valve body; using the second mold 4 for extrusion allows the metal billet to bond more tightly during the forging process, thereby improving the density of the valve body.

[0074] The forging method for the eccentric valve body of the oil wellhead provided in this embodiment further includes a primary forging step in the billet forming step, which includes the following steps:

[0075] First upsetting: Stand the billet upright and upset it to a height of 520mm;

[0076] First drawing: The billet after the first upsetting is first drawn into a square with a side length of 560mm, and then drawn into a columnar billet with a height of 580mm and a length of 910mm.

[0077] Secondary upsetting: Upsetting the billet after the first drawing to a height of 520mm.

[0078] Specifically, in this embodiment, by performing a single drawing and a second upsetting operation, the shape and size of the metal billet can be better controlled, thereby improving the precision and shape accuracy during the forging process; through the upsetting process of the billet, a denser microstructure can be formed inside the metal, improving the mechanical properties of the valve body.

[0079] The forging method for the eccentric valve body of the oil wellhead provided in this embodiment further includes the following steps in the billet forming step:

[0080] First shaping: The blank is drawn out and squared into a cube of 470*500*1074mm, and both ends are flattened.

[0081] The forging method for eccentric valve bodies used in oil wells provided in this embodiment involves heating the billet before the first forging, first shaping, second forging, and second eccentric steps. The heating temperature is 1200℃-1240℃, and the holding time is 1.5±0.5h. Specifically, in this embodiment, considering the control of large deformation and the difficulty of forging, the product is heated four times. The purpose of heating before these forming steps is to ensure that the metal billet reaches a sufficient deformation temperature, thereby facilitating the forming process. At the same time, appropriate heating temperature and holding time can improve forging efficiency and reduce the possibility of defects occurring during forging.

[0082] The forging method for the eccentric valve body of the oil well provided in this embodiment involves marking the upper end face of the billet using a narrow anvil in the marking and material distribution step. The distance between the marking and the end face of the billet on the same side is 150mm, and the marking depth is 35mm. The protrusion 11 is shaped to the end face radius R≤20mm.

[0083] In the forging method for the eccentric valve body of the oil wellhead provided in this embodiment, the upsetting height of the billet is 880mm in the secondary forging step.

[0084] The forging method for the eccentric valve body of the wellhead provided in this embodiment further includes the following steps after the secondary forging step:

[0085] Secondary shaping: The blank after secondary forging is demolded and shaped so that the middle part of the blank is 12mm wide and 630mm high.

[0086] The forging method for the eccentric valve body of the oil wellhead provided in this embodiment involves preheating the first mold 2 and the second mold 4 before use. The preheating temperature is 250℃-350℃, and the preheating time lasts for 1.5-2.5 hours. The purpose of preheating the molds is to reduce thermal stress, improve the forming quality and precision of the valve body, and also to prevent mold deformation or thermal cracking.

[0087] In the forging method for the eccentric valve body of the oil well tree provided in this embodiment, in the secondary eccentric step, the first mold 2 is raised and placed on the anvil, with a raising height of 15mm-20mm.

[0088] The forging method for the eccentric valve body for oil wells provided in this embodiment involves shaping the middle 12 positions of the billet to a width of 508mm and a height of 620mm after the middle 12 positions of the billet contact the lower anvil surface in the secondary eccentric step.

[0089] The forging method for the eccentric valve body of the oil wellhead provided in this embodiment, in the three forging steps, the upsetting height of the upsetting billet is 965mm when the second mold 4 is set and the billet is erected.

[0090] The eccentric valve body forging method for oil wellheads provided in this embodiment involves air-cooling the billet after three forgings to a surface temperature of 700°C-750°C, then placing it in a furnace at a temperature ≤500°C for furnace cooling. After furnace cooling to below 200°C, the billet is removed and air-cooled again. By controlling the post-forging cooling, internal stress in the billet can be eliminated, preventing cracks from forming in the valve body billet.

[0091] The forging method for the eccentric valve body of the oil wellhead provided in this embodiment has an initial forging temperature of 1200℃-1240℃ and a final forging temperature of ≥850℃. Such forging temperatures enable the metal billet to reach a relatively ideal plastic state, which is beneficial for forming operations and shape control.

[0092] The forging method for eccentric valve bodies used in oil wells provided in this embodiment has a single-process forging ratio greater than or equal to 1.8 and a total forging ratio greater than or equal to 4. In the forging method for eccentric valve bodies used in oil wells provided in this embodiment, by controlling the forging ratio, the metal billet can achieve higher forming quality during the forging process, thereby improving the dimensional accuracy and performance of the valve body.

[0093] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

Claims

1. A method for forging an eccentric valve body for a pre-works tree, characterized in that, Includes the following steps: Billet forming: A metal material is provided, and the metal material is forged into a billet; First eccentricity: A first eccentric body (1) is formed by forging at both ends of the billet. The first eccentric body (1) has a protrusion (11) and a middle part (12). The axis of the protrusion (11) is not collinear with the axis of the middle part (12). Secondary eccentricity: A pair of first molds (2) are set up, the protrusion (11) is limited and installed on the first mold (2), and the middle part (12) is forged so that under the limitation of the first mold (2), the axis of the middle part (12) moves in a direction away from the axis of the protrusion (11) to form a second eccentric body; Blank forming: The second eccentric body is shaped and cooled to form a valve body blank (3); The first eccentric step includes the following steps: Marking and material distribution: symmetrical markings are made at the same distance from the two end faces on the upper end face of the blank, and the protrusion (11) is chamfered and rounded. Secondary forging: Second molds (4) are respectively fitted on both ends of the billet, and the billet is upsetting. Under the drive of the press, the two second molds (4) approach each other to drive the two ends of the billet to fill the inner cavity of the second molds (4); In the secondary eccentric step, the first mold (2) is placed on the anvil of the forging equipment, the press upsets and drives the middle part (12) to approach the lower anvil surface until it contacts the lower anvil surface and then stops forging; in the secondary eccentric step, the first mold (2) is raised and placed on the anvil surface, with a raising height of 15mm-20mm.

2. The forging method for the eccentric valve body of the wellhead according to claim 1, characterized in that, Following the second eccentricity step, the following steps are also included: Three forging processes: Remove the first mold (2), install the second mold (4), and stand the second eccentric body upright and upsetting it again.

3. The forging method for the eccentric valve body of the wellhead according to claim 1, characterized in that, The billet forming step also includes a primary forging step, which includes the following steps: One-time upsetting: The billet is stood upright and upset to a height of 520mm; First drawing: The billet after the first upsetting is first drawn into a square with a side length of 560mm, and then drawn into a columnar billet with a cross-section of a regular octagon with a height of 580mm and a length of 910mm. Secondary upsetting: The billet after the first drawing is upset to a height of 520mm.

4. The forging method for the eccentric valve body of the wellhead according to claim 3, characterized in that, The blank forming step also includes the following steps: First shaping: The blank is drawn out and squared into a cube of 470*500*1074mm, and both ends are flattened.

5. The forging method for the eccentric valve body for the wellhead as described in claim 4, characterized in that, Before the first forging, first shaping, second forging and second eccentric steps, the billet is heated to a temperature of 1200℃-1240℃ and held for 1.5±0.5h.

6. The forging method for the eccentric valve body of the wellhead according to claim 1, characterized in that, In the marking and material distribution process, a narrow anvil is used to mark the upper end face of the blank. The distance between the mark and the end face of the blank on the same side is 150mm, and the mark depth is 35mm. The protrusion (11) is shaped to the end face radius R≤20mm.

7. The forging method for the eccentric valve body of the wellhead according to claim 1, characterized in that, In the secondary forging, the upsetting height of the billet is 880 mm.

8. The forging method for the eccentric valve body for a pre-works tree according to claim 7, characterized in that, After the secondary forging, the following steps are also included: Secondary shaping: The blank after secondary forging is demolded and the middle part (12) of the blank is shaped to a width of 510mm and a height of 630mm.

9. The forging method for the eccentric valve body of the wellhead according to claim 1, characterized in that, The first mold (2) and the second mold (4) are preheated before use. The preheating temperature is 250℃-350℃ and the preheating time lasts for 1.5-2.5 hours.

10. The forging method for the eccentric valve body of the wellhead according to claim 1, characterized in that, In the second eccentric step, after the middle part (12) of the billet contacts the lower anvil, the middle part (12) of the billet is shaped to a width of 508mm and a height of 620mm.

11. The forging method for the eccentric valve body of the wellhead according to claim 2, characterized in that, In the three forging steps, the second mold (4) is set up and the billet is upset, and the upset height of the billet is 965mm.

12. The forging method for the eccentric valve body of the wellhead according to claim 2, characterized in that, In the blank forming step, after the three forgings, the blank is air-cooled to a surface temperature of 700°C-750°C and then placed in a furnace with a furnace temperature of ≤500°C for furnace cooling. After the furnace temperature drops below 200°C, the blank is taken out and air-cooled again.

13. The forging method for the eccentric valve body for a production tree according to claim 12, characterized in that, The initial forging temperature is 1200℃-1240℃, and the final forging temperature is ≥850℃.

14. The forging method for the eccentric valve body for a pre-works tree according to claim 13, characterized in that, The single-process forging ratio is ≥1.8, and the total forging ratio of processes is ≥4.

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