Integrated forging of conical shell section and folded end of hydrogenation reactor and its preparation method

Abstract

This invention provides an integrated forging of a conical shell section and a folded end for a hydrogenation reactor, and its preparation method, relating to the field of petrochemical equipment manufacturing technology. The preparation method includes taking a steel ingot, pre-drawing it, pressing the jaws, and gas-cutting the nozzle end to obtain a first billet; upsetting the first billet and forging it with a wide anvil and large reduction for lengthening and compaction to press a tail step into the first billet, obtaining a second billet; placing the second billet in an upsetting stencil for partial upsetting, and using a flat hammer and an electric rotary table to perform unidirectional rotational forging of the second billet, gradually transforming the outer contour of the second billet from a cylinder to a stepped cone, obtaining a third billet; punching a blind hole at the center of the surface of the third billet on the side away from the upsetting stencil, demolding and removing the material, and forging the stepped cone of the third billet to the cone surface to obtain the integrated forging of the conical shell section and the folded end for a coal liquefaction hydrogenation reactor.

Description

Technical Field

[0001] This invention relates to the field of petrochemical equipment manufacturing technology, and more specifically, to an integrated forging of a conical shell section and a folded end of a hydrogenation reactor and its preparation method. Background Technology

[0002] As a key piece of equipment in the petrochemical industry, the coal liquefaction hydrogenation reactor presents significant challenges to forging manufacturing due to its unique structure. One end of the reactor consists of a conical shell and a folded end. Due to the significant structural differences between the conical shell and the folded end forgings, the dimensional difference between the two ends is large, and the taper is usually above 25°, making integral forging impossible using traditional manufacturing processes.

[0003] In related technologies, the overall structure of the coal liquefaction hydrogenation reactor is decomposed into three independent components: a large conical shell section, a small conical shell section, and a folded end, which are forged separately. Figure 1 As shown, subsequent welding assembly is a segmented forging method that not only requires large steel ingots exceeding 67 tons, resulting in low material utilization, but also significantly extends the manufacturing cycle. More seriously, multi-segment welding increases the number of welds, raising manufacturing costs and creating potential safety hazards during equipment operation. Especially in the high-temperature, high-pressure coal liquefaction reaction environment, stress concentration and corrosion are more likely to occur in the weld area, affecting the equipment's service life and safety. Summary of the Invention

[0004] The present invention aims to solve the problems of increased safety hazards, stress concentration and corrosion in the weld area, and short equipment life caused by the increased number of welds in multi-stage welded coal liquefaction hydrogenation reactors.

[0005] To address the aforementioned problems, this invention provides an integrated forging of a conical shell section and a folded end for a hydrogenation reactor, and a method for preparing the same.

[0006] In a first aspect, the present invention provides a method for preparing an integrated forging of a conical shell section and a folded end of a hydrogenation reactor, comprising the following steps:

[0007] S1: After heating and heat preservation, the steel ingot is pre-drawn, the jaws are pressed and the nozzle end is cut by gas cutting to obtain the first billet;

[0008] S2: After heating and holding the first billet, it is upsetting and then forged with a wide anvil and large reduction to elongate and compact it, pressing out a tail step on the first billet to obtain the second billet;

[0009] S3: After heating and keeping the second billet warm, it is placed in the upsetting stencil for local upsetting. The upper flat hammer and the electric rotary table work together to perform unidirectional rotation and edge forging of the second billet, so that the outer contour of the second billet gradually changes from a cylindrical shape to a stepped cone, thus obtaining the third billet.

[0010] S4: After the third billet is heated and kept warm, a blind hole is punched in the center of the surface of the third billet on the side away from the upsetting stencil. The billet is then demolded and the material is removed. The stepped cone of the third billet is forged to the cone surface to obtain an integrated forging of the small section of the cone shell of the coal liquefaction hydrogenation reactor and the folded end.

[0011] Optionally, the height-to-diameter ratio of the first billet is ≤2.5.

[0012] Optionally, the diameter of the tail step of the second billet is not greater than the minimum inner diameter of the upsetting stencil, and the height of the tail step of the second billet is the same as the height of the inner hole step of the upsetting stencil.

[0013] Optionally, in step S1, the steel ingot is heated to 1200-1300℃ and held for ≥7h.

[0014] Optionally, in step S2, the first billet is heated to 1200-1300℃ and held for ≥17h.

[0015] Optionally, in step S3, the second billet is heated to 1200-1300℃ and held for ≥11 hours.

[0016] Optionally, in step S4, the third billet is heated to 1200-1300℃ and held for ≥16 hours.

[0017] Optionally, the step of punching a blind hole at the center of the surface of the third blank on the side away from the upsetting stencil includes: using a first punch to press out a blind hole at the center of the surface of the third blank on the side away from the upsetting stencil, throwing wood chips into the blind hole and burning the wood chips, and fixing a second punch in the blind hole to continue pressing out the blind hole.

[0018] Optionally, the size of the first punch is smaller than that of the second punch, and the outer surface of the second punch is coated with lubricant.

[0019] Secondly, the present invention provides an integrated forging of a conical shell section and a folded end of a hydrogenation reactor, which is manufactured using the preparation method of the integrated forging of a conical shell section and a folded end of a hydrogenation reactor as described above.

[0020] The beneficial effects of the integrated forging of the conical shell section and the folded end of the hydrogenation reactor of the present invention and its preparation method are as follows: It successfully achieves integrated forging of the conical shell section and the folded end, integrating the structure that originally required two separate forgings into a single integral part. This eliminates the butt weld between the conical shell section and the folded end in traditional processes, effectively solving the problems of material waste and weld safety hazards caused by traditional segmented manufacturing. It can improve the pressure-bearing capacity of the equipment while increasing material utilization, raising the ingot utilization rate by approximately 20%, reducing manufacturing costs, shortening the manufacturing cycle, and reducing the number of welds to improve equipment safety, reliability, and service life. It also avoids the heat treatment deformation and inspection costs associated with the welding process between the conical shell section and the folded end. The precise conical surface transition is formed through rotary forging, making the material distribution more consistent with the stress requirements. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structure of the coal liquefaction hydrogenation reactor in the background technology of this invention;

[0022] Figure 2 This is a flowchart illustrating the preparation method of an integrated forging of a small conical shell section and a folded end for a hydrogenation reactor according to an embodiment of the present invention.

[0023] Figure 3 This is a schematic diagram of the structure in step three of embodiment 1 of the present invention, in which the second billet is placed in the upsetting stencil for local upsetting;

[0024] Figure 4 This is a schematic diagram of the structure of the second billet being upset using a flat cover plate and a flat hammer in step three of embodiment 1 of the present invention;

[0025] Figure 5 This is a schematic diagram of the structure of the second billet undergoing unidirectional rotary forging in step three of embodiment 1 of the present invention;

[0026] Figure 6 This is a schematic diagram of the structure of the third blank in step four of embodiment 1 of the present invention, in which a blind hole is pressed by a first punch;

[0027] Figure 7 This is a schematic diagram of the structure of the third blank in step four of embodiment 1 of the present invention, in which a second punch is used to press a blind hole;

[0028] Figure 8 This is a schematic diagram of the structure of the third blank in step four of embodiment 1 of the present invention, in which the blind hole is pressed by the second punch;

[0029] Figure 9 This is a schematic diagram of the structure in step four of embodiment 1 of the present invention, showing the third billet being removed from the upsetting die.

[0030] Figure 10 This is a schematic diagram of the structure of the third billet being forged to a conical surface in step four of embodiment 1 of the present invention;

[0031] Figure 11 This is a schematic diagram of the integrated forging of the conical shell section and the folded end of the hydrogenation reactor prepared in Embodiment 1 of the present invention.

[0032] Explanation of reference numerals in the attached figures:

[0033] 1. Large section of conical shell; 2. Small section of conical shell; 3. Folded edge end; 4. Electric rotary table; 5. Rotary table cover plate; 6. Flat cover plate; 7. Flat hammer head; 8. Upsetting die; 9. Large platform; 10. First punch; 11. Second punch; 12. Demolding pad; 13. Upper flat anvil; 14. Support ring; 15. Robotic arm; 16. Lower V-anvil. Detailed Implementation

[0034] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Although some embodiments of the present invention are shown in the drawings, it should be understood that the present invention can be implemented in various forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the present invention. It should be understood that the accompanying drawings and embodiments of the present invention are for illustrative purposes only and are not intended to limit the scope of protection of the present invention.

[0035] Unless otherwise defined, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used in this invention's description is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0036] The term "comprising" and its variations as used herein are open-ended, meaning "including but not limited to"; the term "based on" means "at least partially based on"; the term "one embodiment" means "at least one embodiment"; the term "another embodiment" means "at least one additional embodiment"; the term "some embodiments" means "at least some embodiments"; and the term "optionally" means "optional embodiments". Definitions of other terms will be given in the following description. It should be noted that the concepts of "first" and "second" mentioned in this invention are used to distinguish different objects, not to describe a specific order or hierarchy. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include one or more of that feature.

[0037] In related technologies, the conical shell and folded edge of a coal liquefaction hydrogenation reactor have complex structures and large dimensional differences. Traditional forging processes require the conical shell to be manufactured separately into a large section 1, a small section 2, and the folded edge 3. This segmented forging leads to cumbersome procedures, low material utilization, and the need for welding to connect the components, increasing the number of welds and directly impacting equipment safety and service life. Figure 1 The structural separation manufacturing method shown not only requires the consumption of 67 tons of steel ingots, but also has the drawback of a manufacturing cycle of several months.

[0038] To address the problems existing in the aforementioned related technologies, embodiments of the present invention provide an integrated forging of a small section of a hydrogenation reactor cone shell and a folded end, and a method for preparing the same.

[0039] like Figure 2 As shown, an embodiment of the present invention provides a method for preparing an integrated forging of a conical shell segment and a folded end of a hydrogenation reactor, comprising the following steps:

[0040] S1: After heating and heat preservation, the steel ingot is pre-drawn, the jaws are pressed and the nozzle end is cut by gas cutting to obtain the first billet;

[0041] S2: After heating and holding the first billet, it is upsetting and then forged with a wide anvil and large reduction to elongate and compact it, pressing out a tail step on the first billet to obtain the second billet;

[0042] S3: After the second billet is heated and kept warm, it is placed in the upsetting tray 8 for local upsetting. The upper flat hammer head 7 and the electric rotary table 4 work together to perform unidirectional rotation and edge forging of the second billet, so that the outer contour of the second billet gradually forms a stepped cone from a cylindrical shape, and the third billet is obtained.

[0043] S4: After the third billet is heated and kept warm, a blind hole is punched in the center of the surface of the third billet on the side away from the upsetting stencil 8. The billet is demolded and the material is taken out. The stepped cone of the third billet is forged to the cone surface to obtain an integrated forging of the small section of the cone shell of the coal liquefaction hydrogenation reactor and the folded end.

[0044] In this embodiment, the integrated forging of the conical shell segment and the folded edge end was successfully achieved. This integrates the structure, which originally required two separate forgings, into a single integral part. This eliminates the butt weld between the conical shell segment and the folded edge end in traditional processes, effectively solving the material waste and weld safety hazards caused by traditional segmented manufacturing. It improves the equipment's pressure-bearing capacity while increasing material utilization, raising the ingot utilization rate by approximately 20%, reducing manufacturing costs, shortening the manufacturing cycle, and reducing the number of welds to improve equipment safety, reliability, and service life. It also avoids the heat treatment deformation and inspection costs associated with welding the conical shell segment and the folded edge end. The precise conical surface transition is formed through rotary forging, making the material distribution more consistent with stress requirements.

[0045] Specifically, pre-drawing treatment refers to improving the uniformity of the internal structure of the steel ingot through axial extension. This can be achieved by alternating drawing in multiple passes, providing a material basis for subsequent large deformation forging. Wide anvil high reduction forging (KD) utilizes the sufficient plasticity of the steel ingot under prolonged high-temperature conditions, enabling forging with a wide anvil and high reduction rate on limited equipment. Using upper and lower V-shaped wide anvils improves the surface plasticity of the forging and increases the triaxial compressive stress state in the core, effectively forging together internal defects in the steel ingot. Typically, 135° upper and lower V-shaped wide anvils are used, with an anvil-to-width ratio generally between 0.4 and 0.8, optimally 0.6, and a reduction rate of around 20%. KD forging results in a larger and more uniform central deformation zone, which is beneficial for forging together core defects and avoids eccentricity. Upsetting die 8 refers to a constraint die with an internal stepped bore, specifically cast from a high-temperature alloy. Its function is to restrict radial material flow and guide axial compressive deformation. Unidirectional rotary forging refers to the billet being intermittently rotated in one direction under the drive of an electric rotary table 4, while simultaneously being radially extruded with a flat hammer head 7. This can be achieved by setting an index value of 5 to 10 degrees per revolution. This operation causes the billet above the upsetting duct plate 8 to widen, thereby constructing a stepped cone.

[0046] After high-temperature homogenization, the steel ingot undergoes pre-drawing to eliminate casting defects and form an initial shape suitable for subsequent processing. During the wide-anvil, high-reduction forging stage, the material is densified under three-dimensional compressive stress, and the precise forming of the tail step provides a positioning reference for subsequent processes. In the local upsetting process, the constraint of the inner hole of the stencil on the lower part of the billet and the free upsetting at the upper part create differential deformation. Combined with rotary open-edge forging, the material expands along a spiral trajectory, gradually forming a conical structure with transition steps. In the final punching process, the progressive punching of the blind hole and the conical surface forming are carried out simultaneously. By controlling the ratio of axial shrinkage to radial expansion of the metal, a seamless transition between the conical shell and the folded edge is achieved.

[0047] Optionally, the large section 1 of the conical shell can be manufactured by stepping cylinder expansion. When using stepping cylinder expansion, the forging process parameters, such as heating temperature, upsetting ratio, reduction amount, and mandrel size, can be reasonably adjusted according to its specific structural dimensions and performance requirements to ensure the quality and performance of the large section 1 of the conical shell.

[0048] Optionally, the height-to-diameter ratio of the first billet is ≤2.5.

[0049] In this optional embodiment, by optimizing the billet geometry parameters, the causes of upsetting instability are fundamentally eliminated, avoiding the decrease in production efficiency and material waste caused by repeated corrections. This effectively solves the problem of uneven material flow caused by billet instability in the upsetting process, improves the density of the internal structure of the forging, and reduces auxiliary operations in the forging process, thereby increasing material utilization.

[0050] Specifically, the height-to-diameter ratio refers to the ratio of the billet's height to its diameter, which can be achieved by adjusting the forging deformation during the pre-drawing process. During pre-drawing, by controlling the reduction and the number of forging passes, the billet maintains a reasonable diameter increase while extending axially, thus ensuring that the final height-to-diameter ratio does not exceed 2.5. This parameter setting effectively reduces the risk of the billet bending or folding during the subsequent upsetting process.

[0051] When the height-to-diameter ratio exceeds 2.5, the billet is prone to longitudinal instability during upsetting, leading to disordered metal flow paths and internal defects. By limiting the height-to-diameter ratio to below 2.5, the billet can achieve more uniform radial expansion during upsetting, forming a stable metal flow pattern. This geometric control, in conjunction with the subsequent wide-anvil, large-reduction forging process, ensures the controllability of forging deformation and provides a uniformly structured billet foundation for subsequent processes.

[0052] Optionally, the diameter of the tail step of the second billet is not greater than the minimum inner diameter of the upsetting stencil 8, and the height of the tail step of the second billet is the same as the height of the inner hole step of the upsetting stencil 8.

[0053] In this optional embodiment, by establishing a geometric constraint relationship between the tail step and the inner hole of the upsetting stencil 8, the positioning error caused by the assembly gap is eliminated, allowing the tail step to be inserted into the stencil, and the billet to maintain a stable spatial posture during the high-temperature plastic deformation stage. This effectively solves the problem of uneven metal flow caused by dimensional mismatch during local upsetting, avoids crack defects caused by stress concentration at the step, and improves the forming accuracy of the material during the rotary forging stage, reducing subsequent machining allowances.

[0054] Specifically, the diameter of the tail step refers to the outer diameter of the cylindrical protrusion formed at the end of the billet after forging with a wide anvil and large reduction. This dimension can be controlled by machining or hot forging processes, for example, by adjusting the cavity size of the forging die. The height of the tail step refers to the axial extension length of the protrusion, which can be achieved by measuring the depth of the inner hole step of the upsetting stencil 8 and matching the forging parameters. The minimum inner diameter of the upsetting stencil 8 refers to the diameter of the narrowest part of the inner hole step structure of the upsetting stencil 8, and its value can be a fixed parameter designed according to the forging dimensions.

[0055] In the partial upsetting process, when the second billet is placed into the upsetting stencil 8, the diameter of the tail step is constrained within the minimum diameter range of the inner hole of the upsetting stencil 8, enabling the billet to be accurately positioned axially. When the step height matches the step height of the inner hole of the upsetting stencil 8, the end face of the billet forms surface contact with the bottom surface of the step in the inner hole of the upsetting stencil 8. During the subsequent rotary forging process, the axial pressure borne by the billet is evenly transmitted to the stencil through the contact surface, preventing the billet from tilting or shifting due to height differences. The dual matching relationship of diameter and height ensures the stable positioning of the billet within the stencil, providing a precise reference plane for unidirectional rotary forging.

[0056] Optionally, in step S1, the steel ingot is heated to 1200-1300℃ and held for ≥7h.

[0057] In this optional embodiment, by increasing the lower limit of the temperature and extending the holding time, for example, holding at 1250°C for 8 hours, the temperature difference between the core and surface of the steel ingot is reduced from 200°C in conventional methods to less than 80°C, thereby significantly improving material uniformity. This effectively eliminates the temperature gradient during the initial heating stage of the steel ingot, resulting in more uniform metal flow during subsequent forging and avoiding grain boundary embrittlement caused by localized overheating or undercooling, thus providing a fundamental guarantee for the overall forming quality of the integrated forging.

[0058] Specifically, the ingot heating temperature range refers to the temperature interval controlled during the initial heating stage, such as using a resistance furnace or gas furnace for gradient heating, to achieve austenitization of the entire ingot. This temperature range can prevent abnormal grain growth and eliminate dendritic segregation formed during casting. The holding time ≥7h refers to the duration of isothermal maintenance of the ingot at the target temperature, for example, by real-time monitoring of the furnace temperature distribution using thermocouples to ensure the temperature difference between the core and surface is controlled within a reasonable range. This duration allows for sufficient heat conduction within the ingot, eliminating residual stress caused by cross-sectional temperature differences.

[0059] In the initial heating stage, the steel ingot is uniformly heated to the range of 1200-1300℃, for example, in stages at a rate of 50-80℃ per hour to reach the target temperature. At this temperature, the carbides inside the steel ingot are fully dissolved, and the material's plasticity is significantly improved. The holding time is set to ≥7 hours, for example, using a multi-zone temperature-controlled furnace, and adjusting the heating zone power to ensure that the temperature deviation of different parts of the steel ingot does not exceed ±10℃. This process results in a uniform austenitic structure in the cross-section of the steel ingot, providing stable material flow properties for the subsequent pre-drawing process, while avoiding the risk of forging cracks caused by core temperature lag.

[0060] Optionally, in step S2, the first billet is heated to 1200-1300℃ and held for ≥17h.

[0061] In this optional embodiment, by increasing the lower limit of the temperature and extending the holding time, the segregated elements in the billet core can diffuse sufficiently. For example, the width of the sulfur segregation band can be reduced from the original 3 mm to less than 0.5 mm. This effectively prevents forging cracks caused by the temperature difference between the billet core and surface, and improves the uniformity of material flow during the tail step forming process. After compaction, the proportion of the internal porous defect area of ​​the billet can be reduced to less than 0.02%, providing a dense processing matrix for subsequent local upsetting processes. At the same time, this combination of heating parameters avoids abnormal grain growth, ensuring that the forging can obtain a uniform fine-grained structure in subsequent heat treatment.

[0062] Specifically, heating to 1200-1300℃ refers to placing the billet in a heating furnace until it reaches this temperature range as a whole. This can be achieved using a resistance furnace or gas-fired radiant heating. This temperature range allows for the full formation of austenite within the steel ingot. Holding time of no less than 17 hours refers to the duration for which the billet is maintained at the target temperature. This can be achieved through a closed-loop furnace temperature control system. This duration ensures sufficient heat transfer within the material.

[0063] During the upsetting and wide-anvil large-reduction drawing and compaction process in step S2, the billet needs to withstand severe plastic deformation. When the temperature is controlled at 1200-1300℃, the material flow stress is significantly reduced; for example, the yield strength of carbon steel at 1250℃ can be reduced by more than 80% compared to room temperature. After the holding time reaches more than 17 hours, the temperature gradient of the billet section can be controlled within 10℃ / m, eliminating the surface tensile stress concentration caused by the core-surface temperature difference. Under these conditions, when forming the tail step, the material flow lines are uniformly distributed along the axial direction, avoiding folding defects caused by differences in local deformation resistance.

[0064] Optionally, in step S3, the second billet is heated to 1200-1300℃ and held for ≥11 hours.

[0065] In this optional embodiment, by extending the holding time to homogenize the temperature field, the core-to-surface temperature difference is compressed to within 50°C, significantly improving the metal flow compatibility. This effectively eliminates forging cracks and folding defects caused by temperature gradients, improving the uniformity of equivalent strain distribution during the stepped cone forming process to the required level. The material maintains stable high-temperature plasticity during rotary forging, and the grain size grade of the transition zone at the folded edge is controlled to be above ASTM level 5, meeting the internal quality requirements of the coal liquefaction hydrogenation reactor for the forging.

[0066] Specifically, heating to 1200-1300℃ means controlling the material within the austenitic phase region. This can be achieved using a resistance furnace or a gas furnace with stepped heating, and real-time monitoring of the furnace temperature distribution via thermocouples. This temperature range keeps the material in a highly ductile state while preventing excessive grain coarsening. Holding time ≥11 hours refers to the minimum time threshold determined through heat conduction simulation calculations. This can be achieved using a segmented temperature control process, with a rapid initial heating to the target temperature followed by a isothermal stage. This duration ensures that the temperature difference between the core and surface of the billet is less than a critical value, eliminating thermal stress concentration.

[0067] Before local upsetting, the billet is uniformly heated to the austenitic single-phase region, eliminating internal residual stress through thermal diffusion. When the temperature gradient is controlled to be less than 5°C per millimeter, the material flow stress is reduced below the plastic deformation threshold. During unidirectional rotary forging, as the metal flows radially, the uniform temperature field ensures a consistent distribution of deformation resistance, preventing local strain from exceeding limits. The holding time setting is verified through finite element thermo-mechanical coupling simulation. When the core temperature reaches 98% of the target value, the material anisotropy index decreases to the allowable range of the process.

[0068] Optionally, in step S4, the third billet is heated to 1200-1300℃ and held for ≥16 hours.

[0069] In this optional embodiment, by precisely controlling the heating temperature and holding time, the material is fully softened and homogenized at high temperatures, providing the necessary conditions for subsequent punching and conical surface forming. This effectively solves the problem of internal cracks caused by insufficient material plasticity during blind hole punching, eliminates local deformation defects caused by temperature gradients, and ensures the structural continuity of the integrated forging of the conical shell segment and the folded end. After punching, the hole wall surface is smooth and crack-free, the metal flow lines in the transition area of ​​the conical surface are uniformly distributed, and the overall mechanical properties of the forging meet the high-temperature and high-pressure requirements of the coal liquefaction hydrogenation reactor.

[0070] Specifically, heating the third billet to 1200-1300℃ refers to heating the material to the austenitizing temperature range. This can be achieved using a resistance furnace or a gas furnace with controlled temperature control, ensuring a uniform transformation of the material's internal structure. This temperature range avoids excessive grain growth that could degrade mechanical properties while ensuring sufficient high-temperature plasticity. Holding time ≥16 hours refers to the duration the billet remains at the target temperature. This is achieved by monitoring the core-surface temperature difference using thermocouples, starting the timer once the core temperature reaches the set value. This duration is designed to eliminate residual forging stress and ensure overall billet temperature uniformity, preventing deformation or cracking caused by localized temperature differences during punching.

[0071] Before punching blind holes, the billets need to undergo a heating and holding process. When the temperature reaches 1200-1300℃, the austenite grains inside the material diffuse fully, the atomic migration ability is enhanced, and the plasticity is significantly improved. The holding time is extended to more than 16 hours, so that the temperature gradient between the core and the surface of the billet approaches zero, eliminating the differences in microstructure caused by uneven temperature. Under this condition, the metal flow resistance is reduced, and stress concentration is less likely to occur in the hole wall area, thereby avoiding crack initiation. At the same time, the uniform temperature distribution keeps the metal flow lines in the transition area between the conical shell and the flange end continuous, ensuring the overall structural integrity of the forging.

[0072] Optionally, the step of punching a blind hole at the center of the surface of the third blank on the side away from the upsetting stencil 8 includes: using a first punch 10 to press out a blind hole at the center of the surface of the third blank on the side away from the upsetting stencil 8, throwing wood chips into the blind hole and burning the wood chips, and fixing a second punch 11 in the blind hole to continue pressing out the blind hole.

[0073] In this optional embodiment, a dimensional gradient is created through staged punching. Combined with the physical expansion and chemical lubrication effects of combustion, this results in more uniform material flow, a more reasonable distribution of stamping load, and effectively eliminates the risk of cracking at the punching edge. This achieves gradient control of material deformation during punching, solving the problem of uneven stress distribution on the hole wall during blind hole forming. The gas pressure and lubrication layer generated by combustion reduce the contact friction between the punch and the blank, avoiding difficulties in demolding caused by punch jamming. The step-by-step stamping process optimizes the metal flow path through dimensional transitions, significantly improving the dimensional accuracy of blind holes.

[0074] Specifically, the first punch 10 refers to the punching tool used for pre-pressing to form the initial blind hole. It can be implemented using a cylindrical punch with a smaller diameter, smaller than the second punch 11. Because the large solid punch has a large diameter difference between its two ends, and its small end has a small diameter and high height, it cannot be effectively fixed to the blank for punching. Therefore, the small punch is used first to press down, pressing the blank to form a blind hole, thus fixing the large solid punch. This design reduces the deformation resistance of the initial punch, preventing cracks in the blank due to localized stress concentration. The wood chip combustion refers to the process of igniting wood chips after they are placed into the blind hole; pine wood chips can be used as fuel. The expansion of the combustion gases widens the gap between the hole walls, while residual carbides form a temporary lubricating layer on the hole walls. The second punch 11 refers to the punching tool used for final pressing, specifically a stepped punch coated with a graphite-based lubricant. Its size is larger than that of the first punch by 10. By gradually increasing the size of the blind hole, the lubricant can reduce the frictional resistance between the blank and the die during the stamping process.

[0075] In the pre-pressing stage, a small-sized first punch is used to form the initial blind hole, and excessive material deformation is avoided by controlling the stamping depth. In the combustion stage, the gas pressure released by the combustion of wood chips is used to create an expansion gap between the hole wall and the punch, and the carbonized layer acts as a temporary lubricant to reduce the resistance of subsequent stamping. In the final pressing stage, a large-sized second punch coated with lubricant is used for secondary stamping. The blind hole is precisely formed through step-by-step dimensional transition, and the expansion gap and the lubricating layer work together to ensure smooth demolding of the punch.

[0076] Optionally, the size of the first punch 10 is smaller than the size of the second punch 11, and the outer surface of the second punch 11 is coated with lubricant.

[0077] In this optional embodiment, staged punching establishes a guiding reference with a small punch, eliminates hole wall defects through a combustion cleaning process, and then completes the final forming with a lubricated large punch, effectively avoiding surface damage caused by a single punching operation. Simultaneously, the dimensional difference between the two punches in the staged operation creates a progressive deformation path, which is more conducive to effective punch fixation compared to direct large deformation punching. This solves the problem of scratches on the forging surface caused by excessive friction during punching and avoids dimensional deviations caused by the punch sticking to the hole wall. Staged punching combined with the hole wall cleaning process significantly improves the smoothness of the final blind hole inner wall while ensuring consistency between the punching position and the design dimensions. The application of lubricant effectively reduces energy loss during the punching process, extends the service life of the punch, and facilitates subsequent punch removal.

[0078] Specifically, the first punch 10 refers to the tool used for initial punching, which can be implemented using a cylindrical punch with a smaller diameter to reduce punching resistance by decreasing the initial contact area. The second punch 11 refers to the tool used for final shaping, which can be implemented using a stepped punch with a larger diameter than the first punch 10 to control material flow through staged hole expansion. Wood chip combustion refers to the oxidation reaction process that takes place inside the blind hole, which can be implemented using pine wood chips as the combustion material, utilizing the gas pressure generated by combustion to clean the hole wall surface. Lubricant refers to the coating material that reduces the coefficient of friction, which can be implemented using graphite-based lubricating grease, forming an isolation layer by covering the punch surface.

[0079] After the third blank is heated to the set temperature, a smaller diameter first punch 10 is used for initial punching. At this stage, the punching resistance is low and the material deformation is controllable. The initial blind hole formed provides a positioning reference for subsequent processing. After the first punching is completed, wood chips are put into the hole and ignited. The instantaneous high-temperature gas generated during combustion can remove the oxide layer on the hole wall, while locally heating the hole wall material to improve plasticity. Subsequently, a larger diameter second punch 11 is used. The lubricant pre-coated on its surface continuously reduces the direct contact between the punch and the hole wall during the punching process, avoiding micro-cracks on the forging surface caused by frictional heat. During the staged punching process, the guide hole formed by the first punch 10 can constrain the movement trajectory of the second punch 11, ensuring the dimensional accuracy of the final blind hole.

[0080] In some specific embodiments, the diameter of the first punch 10 can be approximately 30% to 50% smaller than that of the second punch 11, for example, using a φ200mm first punch 10 in conjunction with a φ300mm second punch 11. The amount of wood chips filling can be controlled to 60% to 80% of the blind hole volume, and the burning time can be maintained at 10 to 20 seconds. The coating thickness of the lubricant can be maintained in the range of 0.1 to 0.3mm, and the coating area covers the entire working surface of the second punch 11.

[0081] Another embodiment of the present invention provides an integrated forging of a conical shell section and a folded end of a hydrogenation reactor, which is manufactured using the preparation method of the integrated forging of a conical shell section and a folded end of a hydrogenation reactor as described above.

[0082] In this embodiment, an integrated forging process is used to achieve integral forming, avoiding the multiple heating, processing, and welding steps required for separate forging, while reducing material waste and the risk of weld defects. This solves the problem that the conical shell section and the folded edge end of the coal liquefaction hydrogenation reactor cannot be forged integrally due to their complex shape and large dimensional differences, achieving integrated forming of the conical shell and the folded edge end. This reduces the manufacturing cycle and the number of welds, improves ingot utilization, and lowers manufacturing costs.

[0083] Specifically, the integrated forging process refers to the hot-working forming of the conical shell segment and the folded end as a single structure. This can be achieved through multi-stage hot working control, including pre-drawing and compaction, local upsetting, unidirectional rotary forging, and step-by-step blind hole punching. This process eliminates the need for separate forging, reducing subsequent welding processes. Multi-stage hot working control refers to achieving plastic deformation of the material through a combination of forging steps under different temperature conditions. This can be achieved through heating and holding, wide anvil large reduction forging, and the coordinated operation of the electric rotary table 4, ensuring the elimination of internal defects and the formation of irregular structures in the forging. This control method avoids crack defects caused by localized stress concentration by adjusting the deformation amount in stages. Unidirectional rotary forging refers to the method of unidirectional rotary forging of the billet using the upper flat hammer 7 and the electric rotary table 4. This can be achieved through stepped reduction and continuous rotation, gradually forming a stepped conical outer contour from the cylindrical billet. This forging method ensures a smooth transition of the conical surface through uniform plastic deformation. The step-by-step blind hole punching process refers to the method of forming blind holes by pressing punches of different sizes into the center of the blank in stages. Specifically, it can be achieved by using wood chip burning to assist demolding and applying lubricant to reduce punching resistance and improve forming accuracy. This process avoids hole wall cracking caused by large deformation in a single punching operation through step-by-step punching.

[0084] During the preparation process, after the steel ingot is pre-drawn and compacted to eliminate internal porosity defects, it is locally upsetting to form a tail step to adapt to the mold constraint. Subsequently, it undergoes unidirectional rotary forging under the drive of an electric rotary table 4, gradually transitioning the outer contour of the billet from a cylindrical shape to a stepped conical structure. Further, on the center of the surface of the stepped conical billet away from the upsetting die 8, a step-by-step blind hole punching process is used to complete the conical surface forming. In the first punching, the expansion of gas generated by burning wood chips assists in demolding. During the second punching, a larger punch combined with a lubricant coating process is used to ensure the accuracy of the blind hole forming. Thus, the irregular structure of the conical shell segment and the folded edge end is directly formed through integrated forging, eliminating the need for separate manufacturing and subsequent welding.

[0085] The present invention will be further described below with reference to specific embodiments.

[0086] Example 1: Preparation method of an integrated forging of a conical shell section and a folded end of a hydrogenation reactor.

[0087] 1. Heat the double-vacuum steel ingot in the furnace to 1250℃ and hold for ≥7 hours. Pre-draw the ingot body to Φ1250mm~L=3170mm, press the jaws, and cut 160mm (including the cutting edge) at the sprue end. The weight of the discarded material at the sprue end after pre-drawing is equivalent to the weight of 150mm of the original ingot body at the sprue end. After sprue cutting, the length of the first billet is Φ1250mm~L=3010mm, and the height-to-diameter ratio needs to be controlled ≤2.5.

[0088] 2. The first billet is heated to 1250℃ and held for ≥17 hours, then upset to H=1000mm~Φ2150mm; it is then drawn to Φ1200mm~L=3200mm using a wide V-anvil. During the drawing process, the reduction rate of each of the first four passes is ≥20%. After each of the first four passes, the billet is rotated 90° to compact the loose material and shrinkage cavities. Subsequent passes finish the billet to a diameter of Φ1200mm. Then, the billet is cut from the riser side using a flat upper and low V-anvil 16, pressing out the tail step. Finally, the entire jaw is cut with gas to obtain the second billet. The tail step size should be sufficient to allow insertion into the minimum inner diameter of the upsetting die, and its height should be equal to the height of the inner step of the upsetting die 8.

[0089] 3. Heat the second billet to 1250℃ and hold for ≥11 hours. Place the second billet in the local upsetting tray 8 for local upsetting. Figure 3 As shown: the partial upsetting tray 8 is placed on the rotary table cover plate 5 of the electric rotary table 4, and upsetting is performed using the flat cover plate 6 and the flat hammer head 7, as shown. Figure 4 As shown, after upsetting to H=1400mm, the flat cover plate 6 is lifted away. The electric rotary table 4 rotates in coordination with the flat hammer head 7 to perform unidirectional rotary forging, widening the billet above the upsetting die 8 and gradually forming a taper. The reduction is controlled to ≤100mm. The forging is completed to H=700mm. Figure 5 As shown, the third blank is obtained.

[0090] IV. The heating temperature for the third billet is selected as 1250±10℃, and the holding time is ≥16H. After the third billet is removed, it is placed in the partial upsetting stencil 8, with a large platform 9 placed below the stencil 8 for support. First, a small solid first punch 10 is used to press it down, with a pressing amount of 250mm to 300mm, which is the blind hole depth. Figure 6 As shown, this is mainly because a large solid second punch 11 is needed for punching later. However, due to the large diameter difference between the two ends of the large solid second punch 11, and the small end having a small diameter and a high height, it cannot be effectively fixed on the third blank for punching. Therefore, a small solid first punch 10 is used to press down first, pressing a blind hole into the third blank, thus fixing the large solid second punch 11. After punching is completed, the small punch is lifted away, and the large solid punch is placed in the hole of the third blank, as shown. Figure 7 As shown (where after the first punch 10 punches the blind hole, wood chips are thrown into the blind hole and burned to act as a lubricant; before using the second punch 11 in this firing, its outer surface needs to be evenly coated with molybdenum disulfide lubricant to facilitate its subsequent removal). The punching depth is H=1230mm, as shown. Figure 8As shown in the diagram. Because the third blank fills the cavity in the die after punching, and the strong extrusion force prevents its removal, the third blank needs to be placed on the demolding pad 12. Then, the upper anvil 13, controlled by the hammer, presses down on the support ring 14, thereby removing the third blank. (See schematic diagram). Figure 9 As shown.

[0091] After the billet is removed, the manipulator 15 holds the straight end of the second punch 11 and places it on the lower V-anvil 16. The upper flat anvil 13, based on the billet feed rate and pressing amount, forges the stepped area formed in the upsetting die 8 during local upsetting to the conical surface. After each forging cycle, the pressing is gradually performed with the same feed rate, such as... Figure 10 As shown.

[0092] During the rotation of the straight end of the second punch 11 by the manipulator 15, the manipulator 15 needs to apply force to the second punch 11; however, during the pressing down of the upper flat anvil 13, the manipulator 15 does not apply force to the second punch 11, but only plays a fixing role. As a result, the second punch 11 is loosened and falls off due to the horizontal component force and the effect of lubricant on the punch during the pressing of the taper by the upper flat anvil 13.

[0093] The conical shell section and the folded end can be forged separately into a single forging, resulting in an integrated forging of the conical shell section and the folded end of the hydrogenation reactor, such as... Figure 11 As shown, reducing weld seams can also reduce the size of steel ingots, which has significant advantages in terms of cycle time, economy, and quality.

[0094] Compared to separate forging, integrated forging results in the following weight differences: the conical shell section weighs 31.83T, the flanged end forging weighs 7.72T, and the total forging weight is 39.55T. These two forgings can be produced using a 67T forging machine. However, the integrated forging weight is only 23.97T, effectively reducing forging allowance (machining work) and reducing the forging weight by 15.58T. The required ingot weight also needs to be reduced accordingly. Since the ingot shape is not continuous, if forged separately, the next size after 67T in our factory is 62T. The 62T ingot is even lighter than the 67T, and considering waste and heat loss, the remaining material weight is insufficient for separate forging. Integrated forging of the conical shell section and flanged end allows for a reduction in ingot size. Separate forging does not allow for a reduction in ingot size.

[0095] While the present invention has been disclosed above, its scope of protection is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention, and all such changes and modifications will fall within the scope of protection of the present invention.

Claims

1. A method for manufacturing a hydroprocessing reactor conical shell segment and flanged end integrated forging, characterized in that, Includes the following steps: S1: After heating and heat preservation, the steel ingot is pre-drawn, clamped, and gas-cut at the sprue end to obtain the first billet; the height-to-diameter ratio of the first billet is ≤2.5; S2: After heating and holding the first billet, it is upsetting and then forged with a wide anvil and large reduction to elongate and compact it, pressing out a tail step on the first billet to obtain the second billet; S3: After heating and heat preservation, the second billet is placed in an upsetting stencil for local upsetting. The upper flat hammer and the electric rotary table work together to perform unidirectional rotational forging of the second billet, so that the outer contour of the second billet gradually forms a stepped cone from a cylindrical shape, thus obtaining the third billet; the diameter of the tail step of the second billet is not greater than the minimum inner diameter of the upsetting stencil, and the height of the tail step of the second billet is the same as the height of the inner hole step of the upsetting stencil; S4: After the third billet is heated and kept warm, a blind hole is punched in the center of the surface of the third billet on the side away from the upsetting stencil. The billet is demolded and the material is taken out. The stepped cone of the third billet is forged to the cone surface to obtain an integrated forging of the small section of the hydrogenation reactor cone shell and the folded end. The step of punching a blind hole at the center of the surface of the third blank on the side away from the upsetting stencil includes: using a first punch to press out a blind hole at the center of the surface of the third blank on the side away from the upsetting stencil; throwing wood chips into the blind hole and burning the wood chips; and fixing a second punch in the blind hole to continue pressing out the blind hole.

2. The method for preparing the integrated forging of the conical shell section and the folded end of the hydrogenation reactor according to claim 1, characterized in that, The steel ingot mentioned in step S1 is heated to 1200-1300℃ and held for ≥7h.

3. The method for preparing the integrated forging of the conical shell section and the folded end of the hydrogenation reactor according to claim 1, characterized in that, In step S2, the first billet is heated to 1200-1300℃ and held for ≥17h.

4. The method for preparing the integrated forging of the conical shell section and the folded end of the hydrogenation reactor according to claim 1, characterized in that, In step S3, the second billet is heated to 1200-1300℃ and held for ≥11h.

5. The method for preparing the integrated forging of the conical shell section and the folded end of the hydrogenation reactor according to claim 1, characterized in that, In step S4, the third billet is heated to 1200-1300℃ and held for ≥16h.

6. The method for preparing the integrated forging of the conical shell section and the folded end of the hydrogenation reactor according to claim 1, characterized in that, The size of the first punch is smaller than that of the second punch, and the outer surface of the second punch is coated with lubricant.

7. An integrated forging of a conical shell section and a folded end for a hydrogenation reactor, characterized in that, It is manufactured using the method described in any one of claims 1-6 for the integrated forging of the conical shell section and the folded end of the hydrogenation reactor.

Images