Near-net forming method for oversize ring forging with conical section

Abstract

The invention relates to the technical field of forging forming, in particular to a near-net forming method of a super-huge ring forging with a conical cross section, which comprises the following steps of: carrying out inclined punching on a blank to obtain a conical ring blank; when it is judged that preparation of the conical ring blank does not reach the standard according to the characterization value of the wall thickness of the bottom end face, the preset single-time pressing amount is reduced or an alarm is given; the conical surface side of the inner hole of the conical ring blank reaching the standard is placed on a mandrel supporter rod, and the conical ring blank is downwards pressed and chambered through a forging hammer to obtain the chambered conical ring blank; after the broached conical ring blank is subjected to heat preservation for preset heat preservation time, a ring rolling machine conducts ring rolling at the preset main roller rotating speed, and a conical-section ring forge piece is obtained; when it is judged that preparation of the conical-section ring forge piece does not reach the standard according to the generatrix curvature characterization value, whether preparation of the conical-section ring forge piece reaches the standard or not is judged secondarily according to the hardness standard deviation; and cooling and packaging the up-to-standard ring forgings with the conical cross sections. According to the method, the preparation yield of the super-huge ring forgings with the conical sections is increased.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of forging forming, in particular to a near-net forming method of a super-large conical section ring forging. BACKGROUND

[0002] The super-large conical section ring forging is widely used in high-end equipment fields such as wind power, nuclear power and aerospace due to its excellent force transmission characteristics and spatial adaptability, for example, key components such as launch vehicle cone bottom connecting ring and large wind power flange. This kind of forging usually has characteristics such as large diameter-thickness ratio, long generatrix length and strict conical profile precision, and the forming precision directly affects the subsequent assembly reliability and equipment operation safety.

[0003] At present, the traditional forming process of the super-large conical section ring forging mainly adopts rectangular ring rolling process, which is the most widely used conventional method in the industry. The core process is "rectangular section blank preparation - overall ring rolling expansion - subsequent turning machining forming". However, due to the limitation of its own principle, the rectangular ring rolling process cannot adapt to the asymmetric special section requirements of the super-large conical ring, resulting in problems such as product organization performance degradation, low production efficiency and long process in actual production, which cannot meet the manufacturing requirements of near-net forming, high performance and high efficiency of high-end equipment.

[0004] Chinese patent application publication No. CN114309401A discloses a machine body outside free forging near-net forming method for large-diameter difference replacement ring forging, which comprises the following steps: hot charging of steel ingot, direct blanking, upsetting forming of conical blank, preforming of intermediate blank, forming of inner hole excess block, preforming of intermediate blank, forming of outer circular step, step blank hole expansion forming, furnace return cooling and supplementary heating, machine body outside forming of large end conical surface, and post-forging heat treatment adopting normalizing and high-temperature tempering heat treatment process.

[0005] It can be seen that the above technical solution does not consider the influence of the circumferential wall thickness of the super-large conical ring blank on the mandrel expansion, and does not consider the influence of the generatrix fluctuation of the super-large conical section ring forging on the forging precision, thereby causing the problem of poor yield of the prepared super-large conical section ring forging. SUMMARY

[0006] Therefore, the present application provides a near-net forming method of a super-large conical section ring forging to overcome the problem in the prior art that the influence of the circumferential wall thickness of the super-large conical ring blank on the mandrel expansion is not considered, and the influence of the generatrix fluctuation of the super-large conical section ring forging on the forging precision is not considered, thereby causing the problem of poor yield of the prepared super-large conical section ring forging.

[0007] To achieve the above-mentioned purpose, the present application provides a near-net forming method of a super-large conical section ring forging, comprising:

[0008] obtaining a plurality of circumferential wall thicknesses of the bottom end face of the conical ring blank, and obtaining a bottom end face wall thickness characteristic value of the conical ring blank;

[0009] When it is determined that the preparation of the conical ring blank does not meet the preset standard according to the bottom end face wall thickness characteristic value of the conical ring blank, a preset single pressing amount of subsequent pressing and expanding is reduced based on a difference between the first preset bottom end face wall thickness characteristic value and the bottom end face wall thickness characteristic value.

[0010] The inner hole conical surface side of the conical ring blank is placed on a mandrel rod, and the conical ring blank is pressed and expanded by a corresponding preset single pressing amount by a forging hammer to obtain a conical ring blank after pressing and expanding.

[0011] After the conical ring blank after pressing and expanding is heat preserved for a preset heat preservation time, a ring rolling machine rolls the conical ring blank at a preset main roller speed to obtain a conical cross-section ring forge piece, a plurality of generatrix curvatures of the conical cross-section ring forge piece are collected, and a generatrix curvature characteristic value of the conical cross-section ring forge piece is obtained.

[0012] When it is determined that the preparation of the conical cross-section ring forge piece does not meet the preset standard according to the generatrix curvature characteristic value of the conical cross-section ring forge piece, whether the preparation of the conical cross-section ring forge piece meets the preset standard is determined again according to a hardness standard deviation of the conical cross-section ring forge piece to reduce a preset main roller speed of the next batch.

[0013] The conical cross-section ring forge piece meeting the preset standard is cooled and packaged.

[0014] Further, whether the preparation of the conical ring blank meets the preset standard is determined according to the bottom end face wall thickness characteristic value of the conical ring blank, wherein

[0015] If the bottom end face wall thickness characteristic value is less than the first preset bottom end face wall thickness characteristic value, it is determined that the preparation of the conical ring blank meets the preset standard.

[0016] If the bottom end face wall thickness characteristic value is greater than or equal to the first preset bottom end face wall thickness characteristic value and less than the second preset bottom end face wall thickness characteristic value, it is determined that the preparation of the conical ring blank does not meet the preset standard, and a preset single pressing amount of subsequent pressing and expanding is reduced based on a difference between the first preset bottom end face wall thickness characteristic value and the bottom end face wall thickness characteristic value.

[0017] If the bottom end face wall thickness characteristic value is greater than or equal to the first preset bottom end face wall thickness characteristic value and less than the second preset bottom end face wall thickness characteristic value, it is determined that the preparation of the conical ring blank does not meet the preset standard, and an alarm is issued.

[0018] Further, the process of obtaining the bottom end face wall thickness characteristic value of the conical ring blank comprises:

[0019] Several measuring points are selected at equal intervals along the circumference of the bottom end face of the conical ring blank, and the wall thickness value of each point is measured respectively.

[0020] Calculate the arithmetic mean of the wall thickness values ​​at several measurement points and the standard deviation of the wall thickness values ​​at several measurement points;

[0021] The ratio of the standard deviation to the arithmetic mean is denoted as the characterization value of the bottom end wall thickness of the conical ring blank.

[0022] Furthermore, several methods for reducing the preset single pressure amount are provided, and each method reduces the preset single pressure amount by a different amount.

[0023] Furthermore, the fabrication of the tapered cross-section ring forging is determined based on the generatrix curvature characterization value of the forging.

[0024] If the curvature characterization value of the generatrix is ​​less than the first preset curvature characterization value of the generatrix, then the preparation of the tapered cross-section ring forging is determined to meet the preset standard.

[0025] If the curvature characterization value of the busbar is greater than or equal to the first preset busbar curvature characterization value and less than the second preset busbar curvature characterization value, it is determined that the preparation of the tapered cross-section ring forging does not meet the preset standard, and the preparation of the tapered cross-section ring forging is determined a second time based on the hardness standard deviation of the tapered cross-section ring forging.

[0026] If the curvature characterization value of the busbar is greater than or equal to the second preset busbar curvature characterization value, it is determined that the preparation of the tapered cross-section ring forging does not meet the preset standard, and the preset main roll speed of the next batch is reduced according to the difference between the second preset busbar curvature characterization value and the busbar curvature characterization value.

[0027] Furthermore, the process of obtaining the generatrix curvature characterization value of the tapered cross-section ring forging includes:

[0028] Along the outer circle of the tapered cross-section ring forging, a number of corresponding contour curves of generatrices are uniformly selected at preset intervals in the circumferential direction.

[0029] Obtain the curvature values ​​of several contour curves at the same axial position, and calculate the standard deviation of curvature at that axial position;

[0030] Obtain the largest standard deviation of curvature corresponding to all axial positions, and denot it as the generatrix curvature characterization value of the tapered cross-section ring forging.

[0031] Furthermore, the preparation of the tapered cross-section ring forging is determined a second time based on the standard deviation of its hardness, to determine whether the forging meets the preset standard.

[0032] If the hardness standard deviation is less than the preset hardness standard deviation, then the preparation of the tapered cross-section ring forging is determined to meet the preset standard.

[0033] If the hardness standard deviation is greater than or equal to the preset hardness standard deviation, it is determined that the preparation of the tapered cross-section ring forging does not meet the preset standard, and the preset heat preservation time of the next batch is increased according to the difference between the preset hardness standard deviation and the hardness standard deviation.

[0034] The hardness standard deviation is the standard deviation of several hardnesses of the tapered cross-section ring forging.

[0035] Furthermore, the increase in the preset heat preservation time for the next batch is positively correlated with the hardness standard deviation offset value, wherein the hardness standard deviation offset value is the difference between the preset hardness standard deviation and the hardness standard deviation.

[0036] Furthermore, the oblique punching includes a primary oblique punching and a secondary punching performed sequentially, wherein the primary oblique punching uses an oblique punch with a preset cone angle to form a preliminary conical inner hole in the blank, and the secondary punching uses a straight punch.

[0037] Furthermore, before the ring rolling machine rolls the ring at a preset main roller speed, the mandrel of the ring rolling machine is used to drive the expanded conical ring blank close to the main roller of the ring rolling machine. Then, the conical roller of the ring rolling machine is brought into contact with the expanded conical ring blank and the axial position of the conical roller is kept fixed.

[0038] Compared with the prior art, the beneficial effect of the present invention is that by immediately collecting the circumferential wall thickness of the bottom end face of the conical ring billet after oblique punching and calculating the wall thickness characterization value, the present invention realizes the quantitative evaluation of the initial quality of the billet, especially the degree of punching eccentricity. When the wall thickness uniformity does not meet the standard but has not yet been scrapped, the single pressing amount of the subsequent pressing and expanding process can be adaptively reduced, thereby improving the geometric accuracy of the ring billet.

[0039] Furthermore, this invention constructs a multi-dimensional qualification judgment system that is more in line with engineering practice by correlating mechanical performance indicators (hardness) with geometric dimensional indicators (generatrix curvature). When the generatrix curvature of a ring component slightly exceeds the standard, it is not immediately scrapped, but its hardness uniformity is tested. If the hardness uniformity is good, it indicates that the internal structure of the product is uniform, meeting the usage requirements and improving material utilization and production economy. If the hardness is also uneven, the heat treatment holding time of the next batch is automatically increased, thereby achieving precise optimization of heat treatment process parameters and ensuring the reliability of the final product performance. Attached Figure Description

[0040] Figure 1 This is a flowchart of a near-net-shape forming method for an extra-large tapered cross-section ring forging according to an embodiment of the present invention;

[0041] Figure 2 This is a flowchart illustrating how to determine whether the preparation of a conical ring blank meets a preset standard, according to an embodiment of the present invention.

[0042] Figure 3 This is a flowchart illustrating how the fabrication of a tapered cross-section ring forging conforms to a preset standard based on the generatrix curvature characterization value of the forging, as described in an embodiment of the present invention.

[0043] Figure 4 This is a flowchart illustrating a secondary determination, based on the hardness standard deviation of the tapered cross-section ring forging, of whether the preparation of the tapered cross-section ring forging conforms to a preset standard, according to an embodiment of the present invention. Detailed Implementation

[0044] To make the objectives and advantages of the present invention clearer, the present invention will be further described below with reference to embodiments; it should be understood that the specific embodiments described herein are merely for explaining the present invention and are not intended to limit the present invention.

[0045] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0046] It should be noted that the data in this embodiment are all derived from a comprehensive analysis and evaluation of historical test data and corresponding historical test results from the three months prior to this test. Those skilled in the art will understand that the method described in this invention can determine the above-mentioned parameters in the following ways: selecting the value with the highest proportion based on the data distribution as the preset standard parameter; using weighted summation to obtain the value as the preset standard parameter; substituting each historical data point into a specific formula and using the value obtained by that formula as the preset standard parameter; or other selection methods, as long as the method described in this invention can clearly define different specific situations in the single-item judgment process through the obtained values.

[0047] Please see Figure 1 , Figure 2 , Figure 3 as well as Figure 4 The flowcharts shown are respectively: a near-net-shape forming method for extra-large conical cross-section ring forgings according to an embodiment of the present invention; a flowchart for determining whether the preparation of the conical ring blank meets the preset standard according to an embodiment of the present invention; a flowchart for determining whether the preparation of the conical cross-section ring forging meets the preset standard according to an embodiment of the present invention; and a flowchart for determining whether the preparation of the conical cross-section ring forging meets the preset standard according to an embodiment of the present invention.

[0048] This invention provides a near-net-shape forming method for extra-large tapered cross-section ring forgings, comprising:

[0049] Step S1: The billet is fed into a heating furnace and heated from 800°C to 1250°C at a rate of 10°C / min.

[0050] Step S2: The hydraulic press uses a φ990mm×φ550mm (cone angle 45°) angled punch to punch the blank at an angle, obtaining a single-punched semi-finished product with dimensions of φ1480mm×T300mm. The single-punched semi-finished product is then punched a second time with a φ550mm straight punch to obtain a conical ring blank. Several circumferential wall thicknesses of the bottom end face of the conical ring blank are collected to obtain the characterization value of the bottom end face wall thickness of the conical ring blank.

[0051] Step S3: If the preparation of the conical ring blank does not meet the preset standard based on the characterization value of the bottom end face wall thickness of the conical ring blank, reduce the preset single pressing amount of the subsequent pressing and expanding hole or issue an alarm.

[0052] Step S4: After the conical ring blank that meets the preset standard is kept in the furnace at 1250℃, the inner conical surface of the conical ring blank is placed on the frame bar. The conical ring blank is pressed down with a preset single pressing amount of 50mm by a forging hammer to expand the hole, and the expanded conical ring blank is obtained. In this process, the conical ring blank is flattened by 10mm after each circumferential rotation.

[0053] Step S5: After the expanded conical ring blank is kept at a preset temperature for 24 minutes, the ring rolling machine rolls it at a preset main roller speed of 700 RPM to obtain a conical cross-section ring forging. The curvature of several generatrices of the conical cross-section ring forging is collected, and the generatrice curvature characterization value of the conical cross-section ring forging is obtained.

[0054] Step S6: If the preparation of the tapered cross-section ring forging does not meet the preset standard based on the generatrix curvature characterization value of the tapered cross-section ring forging, a second determination is made based on the hardness standard deviation of the tapered cross-section ring forging to determine whether the preparation of the tapered cross-section ring forging meets the preset standard, or the preset main roller speed of the next batch is reduced.

[0055] Step S7: Cool and package the tapered cross-section ring forging that meets the preset standards.

[0056] It should be noted that the data in this embodiment are all results obtained through preliminary experiments before this test using the method described in this invention. Each preset value can be adjusted according to the specific application, as long as the method described in this invention can clearly define different specific situations in the single-item judgment process through the acquired values. The preset values ​​set in this embodiment are all obtained from preliminary experiments, including the correction coefficients, which were also selected through experimental verification.

[0057] Specifically, before the ring rolling mill rolls the ring at a preset main roller speed, the mandrel of the ring rolling mill drives the expanded conical ring blank close to the main roller of the ring rolling mill. Then, the conical roller of the ring rolling mill contacts the expanded conical ring blank and keeps the axial position of the conical roller fixed. The main roller speed is 700 RPM, and the mandrel feed adopts segmented ring rolling. In the first stage, the mandrel-main roller spacing is 463.5-440mm, and the feed is 0.4mm / s. In the second stage, the mandrel-main roller spacing is 440mm-343.5mm, and the feed is 2mm / s. In the third stage, the mandrel-main roller spacing is 343.5mm-276.5mm, and the feed is 1.4mm / s. In the fourth stage, the mandrel-main roller spacing is 276.5mm-130mm, and the feed is 0.8mm. In the fifth stage, the mandrel-main roller spacing is 130mm-124.5mm, and the feed is 0.4mm.

[0058] Specifically, the fabrication of the conical ring blank is determined based on the characterization value of the bottom end wall thickness, indicating whether the fabrication meets the preset standard.

[0059] If the bottom end wall thickness characterization value is less than the first preset bottom end wall thickness characterization value of 0.005, then the preparation of the conical ring blank is determined to meet the preset standard;

[0060] If the bottom end face wall thickness characterization value is greater than or equal to the first preset bottom end face wall thickness characterization value and less than the second preset bottom end face wall thickness characterization value by 0.01, then it is determined that the preparation of the conical ring blank does not meet the preset standard, and the preset single pressing amount of the subsequent pressing hole expansion is reduced according to the difference between the first preset bottom end face wall thickness characterization value and the bottom end face wall thickness characterization value.

[0061] If the bottom end face wall thickness characterization value is greater than or equal to the first preset bottom end face wall thickness characterization value and less than the second preset bottom end face wall thickness characterization value, then it is determined that the preparation of the conical ring blank does not meet the preset standard, and an alarm is issued.

[0062] Specifically, the first preset bottom end face wall thickness characterization value ranges from [0.003, 0.008], and the second preset bottom end face wall thickness characterization value ranges from [0.008, 0.015]. Preferably, the first preset bottom end face wall thickness characterization value is 0.005, and the second preset bottom end face wall thickness characterization value is 0.01.

[0063] Specifically, the bottom end face wall thickness characterization value reflects the circumferential wall thickness uniformity of the billet. The smaller the ratio, the higher the uniformity. If the wall thickness characterization value is less than the first preset bottom end face wall thickness characterization value, it indicates that the billet wall thickness fluctuation is minimal (excellent uniformity), which meets the high requirements of near-net-shape forming for the geometric accuracy of the billet. If the wall thickness characterization value is greater than or equal to the second preset bottom end face wall thickness characterization value, it indicates that the wall thickness fluctuation is significant (poor uniformity), which is prone to stress concentration, cracks, or poor ellipticity during hole expansion.

[0064] Specifically, the process of obtaining the characterization value of the bottom end wall thickness of the conical ring blank includes:

[0065] Several measuring points are selected at equal intervals along the circumference of the bottom end face of the conical ring blank, and the wall thickness value of each point is measured respectively.

[0066] Calculate the arithmetic mean of the wall thickness values ​​at several measurement points and the standard deviation of the wall thickness values ​​at several measurement points;

[0067] The ratio of the standard deviation to the arithmetic mean is denoted as the characterization value of the bottom end wall thickness of the conical ring blank.

[0068] Specifically, several methods for reducing the preset single pressure amount are provided, among which,

[0069] If the wall thickness deviation value is less than the first preset wall thickness deviation value, the preset single pressing amount is reduced to the corresponding value using the first adjustment coefficient of 0.96.

[0070] If the wall thickness deviation value is greater than or equal to the first preset wall thickness deviation value and less than the second preset wall thickness deviation value, then the preset single downward pressure amount is reduced to the corresponding value using the second adjustment coefficient of 0.94.

[0071] If the wall thickness deviation value is greater than or equal to the second preset wall thickness deviation value, then the preset single downward pressure amount is reduced to the corresponding value using the third adjustment coefficient of 0.92;

[0072] The wall thickness deviation value is the difference between the first preset bottom end wall thickness characterization value and the bottom end wall thickness characterization value.

[0073] Specifically, the fabrication of the tapered cross-section ring forging is determined to meet a preset standard based on the generatrix curvature characterization value of the forging.

[0074] If the curvature value of the busbar is less than the first preset curvature value of the busbar by 0.0003 mm -1 If the preparation of the tapered cross-section ring forging is deemed to meet the preset standard, then the preparation of the ring forging is deemed to meet the preset standard.

[0075] If the busbar curvature characterization value is greater than or equal to the first preset busbar curvature characterization value and less than the second preset busbar curvature characterization value by 0.0006 mm... -1 If the preparation of the tapered cross-section ring forging does not meet the preset standard, the preparation of the tapered cross-section ring forging will be determined a second time based on the hardness standard deviation of the tapered cross-section ring forging.

[0076] If the curvature characterization value of the busbar is greater than or equal to the second preset busbar curvature characterization value, it is determined that the preparation of the tapered cross-section ring forging does not meet the preset standard, and the preset main roll speed of the next batch is reduced according to the difference between the second preset busbar curvature characterization value and the busbar curvature characterization value.

[0077] Specifically, the range of the first preset busbar curvature characterization value is [0.00025mm]. -1 , 0.000550mm -1 The first preset busbar curvature characterization value ranges from [0.00055mm]. -1 0.00085mm -1 Preferably, the first preset busbar curvature characterization value is 0.0003 mm. -1 The second preset busbar curvature characterization value is 0.0006 mm. -1 .

[0078] Specifically, the curvature characterization value reflects the accuracy of the conical ring profile. For key structural components such as extra-large wind turbine towers, there are extremely high requirements for roundness and straightness of the busbar. The curvature characterization value essentially quantifies the non-straightness of the busbar.

[0079] Specifically, the process of obtaining the generatrix curvature characterization value of the tapered cross-section ring forging includes:

[0080] Along the outer circle of the tapered cross-section ring forging, a number of corresponding contour curves of generatrices are uniformly selected at preset intervals in the circumferential direction.

[0081] Obtain the curvature values ​​of several contour curves at the same axial position, and calculate the standard deviation of curvature at that axial position;

[0082] Obtain the largest standard deviation of curvature corresponding to all axial positions, and denot it as the generatrix curvature characterization value of the tapered cross-section ring forging.

[0083] Specifically, the preparation of the tapered cross-section ring forging is determined twice based on the standard deviation of its hardness, to determine whether the forging meets the preset standard.

[0084] If the hardness standard deviation is less than the preset hardness standard deviation of 18HB, then the preparation of the tapered cross-section ring forging is determined to meet the preset standard.

[0085] If the hardness standard deviation is greater than or equal to the preset hardness standard deviation, it is determined that the preparation of the tapered cross-section ring forging does not meet the preset standard, and the preset heat preservation time of the next batch is increased according to the difference between the preset hardness standard deviation and the hardness standard deviation.

[0086] The hardness standard deviation is the standard deviation of several hardnesses of the tapered cross-section ring forging.

[0087] In this embodiment, the preset hardness standard deviation is 18HB. The 50 alternating load tests of the wind turbine main shaft bearing show that when the hardness standard deviation is less than 18HB, the fatigue life deviation of each part of the ring blank is less than 10%, and there is no risk of local early failure. However, the above value is not limited to this, and those skilled in the art can also adjust the value according to actual needs.

[0088] Specifically, the increase in the preset heat preservation time for the next batch is positively correlated with the hardness standard deviation offset value. The positive correlation can be linear or non-linear. The linear slope of the linear positive correlation is not specifically limited. It can be understood that the larger the hardness standard deviation offset value, the greater the increase in the preset heat preservation time. The hardness standard deviation offset value is the difference between the preset hardness standard deviation and the hardness standard deviation.

[0089] The technical solution of the present invention has been described above with reference to the preferred embodiments shown in the accompanying drawings. However, it will be readily understood by those skilled in the art that the scope of protection of the present invention is obviously not limited to these specific embodiments. Without departing from the principles of the present invention, those skilled in the art can make equivalent changes or substitutions to the relevant technical features, and the technical solutions after these changes or substitutions will all fall within the scope of protection of the present invention.

Claims

1. A near-net-shape forming method for an extra-large conical cross-section ring forging, characterized in that, include: The billet is punched at an angle to obtain a conical ring billet. Several circumferential wall thicknesses of the bottom end face of the conical ring billet are collected, and the characterization value of the bottom end face wall thickness of the conical ring billet is obtained. When it is determined that the preparation of the conical ring blank does not meet the preset standard based on the bottom end face wall thickness characterization value, the preset single pressing amount of the subsequent pressing hole expansion is reduced based on the difference between the first preset bottom end face wall thickness characterization value and the bottom end face wall thickness characterization value. The inner conical surface of the conical ring blank is placed on a frame bar, and the conical ring blank is pressed down with a forging hammer to expand the hole with a corresponding preset single pressing amount to obtain the expanded conical ring blank. After the expanded conical ring blank is kept at a preset temperature for a preset time, the ring rolling mill rolls the ring at a preset main roller speed to obtain a conical cross-section ring forging. The curvature of several generatrices of the conical cross-section ring forging is collected, and the generatrice curvature characterization value of the conical cross-section ring forging is obtained. When the curvature characterization value of the tapered cross section ring forging indicates that the preparation of the tapered cross section ring forging does not meet the preset standard, the standard deviation of the hardness of the tapered cross section ring forging is used to make a second determination on whether the preparation of the tapered cross section ring forging meets the preset standard, so as to reduce the preset main roll speed of the next batch. The tapered cross-section ring forgings that meet the preset standards are cooled and packaged.

2. The near-net-shape forming method for extra-large conical cross-section ring forgings according to claim 1, characterized in that, The quality of the conical ring blank's preparation is determined based on the characterization value of the bottom end wall thickness. This characterization determines whether the preparation of the conical ring blank meets the preset standard. If the bottom end wall thickness characterization value is less than the first preset bottom end wall thickness characterization value, then the preparation of the conical ring blank is determined to meet the preset standard; If the bottom end face wall thickness characterization value is greater than or equal to the first preset bottom end face wall thickness characterization value and less than the second preset bottom end face wall thickness characterization value, then it is determined that the preparation of the conical ring blank does not meet the preset standard, and the preset single pressing amount of the subsequent pressing hole expansion is reduced according to the difference between the first preset bottom end face wall thickness characterization value and the bottom end face wall thickness characterization value. If the bottom end face wall thickness characterization value is greater than or equal to the first preset bottom end face wall thickness characterization value and less than the second preset bottom end face wall thickness characterization value, then it is determined that the preparation of the conical ring blank does not meet the preset standard, and an alarm is issued.

3. The near-net-shape forming method for extra-large conical cross-section ring forgings according to claim 2, characterized in that, The process of obtaining the characterization value of the bottom end face wall thickness of the conical ring blank includes: Several measuring points are selected at equal intervals along the circumference of the bottom end face of the conical ring blank, and the wall thickness value of each point is measured respectively. Calculate the arithmetic mean of the wall thickness values ​​at several measurement points and the standard deviation of the wall thickness values ​​at several measurement points; The ratio of the standard deviation to the arithmetic mean is denoted as the characterization value of the bottom end wall thickness of the conical ring blank.

4. The near-net-shape forming method for extra-large conical cross-section ring forgings according to claim 3, characterized in that, Several methods for reducing the preset single pressure amount are provided, and each method reduces the preset single pressure amount by a different amount.

5. The near-net-shape forming method for extra-large conical cross-section ring forgings according to claim 4, characterized in that, The fabrication of the tapered cross-section ring forging is determined based on the generatrix curvature characterization value. This determines whether the fabrication meets the preset standards. If the curvature characterization value of the generatrix is ​​less than the first preset curvature characterization value of the generatrix, then the preparation of the tapered cross-section ring forging is determined to meet the preset standard. If the curvature characterization value of the busbar is greater than or equal to the first preset busbar curvature characterization value and less than the second preset busbar curvature characterization value, it is determined that the preparation of the tapered cross-section ring forging does not meet the preset standard, and the preparation of the tapered cross-section ring forging is determined a second time based on the hardness standard deviation of the tapered cross-section ring forging. If the curvature characterization value of the busbar is greater than or equal to the second preset busbar curvature characterization value, it is determined that the preparation of the tapered cross-section ring forging does not meet the preset standard, and the preset main roll speed of the next batch is reduced according to the difference between the second preset busbar curvature characterization value and the busbar curvature characterization value.

6. The near-net-shape forming method for extra-large tapered cross-section ring forgings according to claim 5, characterized in that, The process of obtaining the generatrix curvature characterization value of the tapered cross-section ring forging includes: Along the outer circle of the tapered cross-section ring forging, a number of corresponding contour curves of generatrices are uniformly selected at preset intervals in the circumferential direction. Obtain the curvature values ​​of several contour curves at the same axial position, and calculate the standard deviation of curvature at that axial position; Obtain the largest standard deviation of curvature corresponding to all axial positions, and denote it as the generatrix curvature characterization value of the tapered cross-section ring forging.

7. The near-net-shape forming method for extra-large tapered cross-section ring forgings according to claim 6, characterized in that, The preparation of the tapered cross-section ring forging is determined twice based on the standard deviation of its hardness to determine whether it meets the preset standard. If the hardness standard deviation is less than the preset hardness standard deviation, then the preparation of the tapered cross-section ring forging is determined to meet the preset standard. If the hardness standard deviation is greater than or equal to the preset hardness standard deviation, it is determined that the preparation of the tapered cross-section ring forging does not meet the preset standard, and the preset heat preservation time of the next batch is increased according to the difference between the preset hardness standard deviation and the hardness standard deviation. The hardness standard deviation is the standard deviation of several hardnesses of the tapered cross-section ring forging.

8. The near-net-shape forming method for extra-large tapered cross-section ring forgings according to claim 7, characterized in that, The increase in the preset heat preservation time for the next batch is positively correlated with the hardness standard deviation offset value, wherein the hardness standard deviation offset value is the difference between the preset hardness standard deviation and the hardness standard deviation.

9. The near-net-shape forming method for extra-large tapered cross-section ring forgings according to claim 1, characterized in that, The oblique punching includes a first oblique punching and a second punching performed sequentially. The first oblique punching uses an oblique punch with a preset cone angle to form a preliminary conical inner hole in the blank. The second punching uses a straight punch.

10. The near-net-shape forming method for extra-large tapered cross-section ring forgings according to claim 1, characterized in that, Before the ring rolling machine rolls the ring at a preset main roller speed, the mandrel of the ring rolling machine is used to drive the expanded conical ring blank close to the main roller of the ring rolling machine. Then, the conical roller of the ring rolling machine is brought into contact with the expanded conical ring blank and the axial position of the conical roller is kept fixed.

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