Hydrogenation reactor lower transition section and single-piece profiling forging forming method thereof

Abstract

The invention provides a hydrogenation reactor lower transition section and a single-piece profiling forging forming method thereof, and relates to the technical field of heavy pressure vessel manufacturing, the hydrogenation reactor lower transition section single-piece profiling forging forming method comprises the following steps: obtaining inner wall shape data of the hydrogenation reactor lower transition section, designing a reaming sleeve matched with the shape of the inner wall of the lower transition section of the hydrogenation reactor; the steel ingot is taken for preliminary forging, and a barrel-type pre-forged piece is obtained; and mounting a reaming sleeve, sleeving the cylindrical pre-forged piece on the reaming sleeve, performing single-piece profiling forging on the cylindrical pre-forged piece, and forming the lower transition section of the hydrogenation reactor under the constraint of the reaming sleeve. The size of the chambering sleeve is precisely matched with the inner diameter of the cylinder pre-forged piece and the final forming taper, precise constraint of the inner surface profile of the forging piece of the lower transition section of the hydrogenation reactor is achieved, the lower transition section of the hydrogenation reactor is directly formed under constraint of the chambering sleeve in combination with a single-piece profiling forging process, and efficient and precise forming of the lower transition section of the hydrogenation reactor is achieved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of heavy pressure vessel manufacturing, in particular to a hydrogenation reactor lower transition section and a single-piece profile forging forming method thereof. BACKGROUND

[0002] As a key equipment in the field of petroleum and chemical industry, the hydrogenation reactor lower transition section (such as shown in Figure 2 ) bears the important function of connecting the lower head and the cylinder section. This component has significant structural features: large diameter and small height, complex arc and step transition on the inner and outer diameters, and irregular geometric shape as a whole. In the related manufacturing process, there are mainly three kinds of forging methods, but all have obvious technical defects.

[0003] The first forging method is to straighten the forging piece into a straight circle (such as shown in Figure 3 ) according to the maximum wall thickness for forging. Although this method is simple to operate, it leads to extremely low material utilization and causes serious waste of raw materials.

[0004] The second forging method is to synthesize two transition sections into a lantern shape (such as shown in Figure 4 ) for profile forging. However, this method is limited: the number of special fixtures is limited and the size is fixed, and the equipment parameters such as the net clearance of the hydraulic press and the gap between the columns restrict the method to be only applicable to products within a specific size range, lacking process flexibility.

[0005] The third forging method is the process route of integrated forging with the cylinder (such as shown in Figure 5 ), which improves the material utilization to some extent, but is only applicable to transition section products with short length and small inner diameter arc. For most complex hydrogenation reactor lower transition sections, this process scheme is difficult to forge and difficult to implement. SUMMARY

[0006] The present application aims to solve the problems of low material utilization, lack of process flexibility or high forging difficulty when forging the hydrogenation reactor lower transition section.

[0007] To solve the above problems, the present application provides a hydrogenation reactor lower transition section and a single-piece profile forging forming method thereof.

[0008] In the first aspect, the present application provides a single-piece profile forging forming method of a hydrogenation reactor lower transition section, comprising the following steps: S1: obtaining the inner wall shape data of the hydrogenation reactor lower transition section, and designing a hole expanding sleeve compatible with the inner wall shape of the hydrogenation reactor lower transition section; S2: taking a steel ingot for preliminary forging to obtain a cylinder pre-forging piece; S3: install the reaming sleeve, put the cylindrical pre-forging on the reaming sleeve, and perform single-piece contour forging on the cylindrical pre-forging, so that the lower transition section of the hydrogenation reactor is formed under the constraint of the reaming sleeve.

[0009] Optionally, the step S2 comprises the following steps: S21: cutting off the water riser of the ingot by gas cutting, and then heating to a forging temperature; S22: sequentially performing upsetting punching, mandrel lengthening, mandrel reaming, and riser end upward flattening and edge opening operations on the ingot, so that the height of the ingot reaches the finished product height; S23: putting the reaming sleeve on the mandrel, and lengthening the cylindrical pre-forging to obtain a cylindrical pre-forging with a certain shape.

[0010] Optionally, in the step S3, the reaming sleeve is installed, and the cylindrical pre-forging is put on the reaming sleeve, comprising: putting the reaming sleeve on the mandrel, placing two mandrels, the distance between the two mandrels is 50 to 100 mm more than the length of the reaming sleeve, and then placing the mandrel with the reaming sleeve on the mandrel.

[0011] Optionally, in the step S3, the single-piece contour forging is performed on the cylindrical pre-forging, comprising: under the action of the water pressure machine, performing single-piece contour forging on the cylindrical pre-forging.

[0012] Optionally, the method further comprises the following steps: S4: air cooling treatment is performed on the formed lower transition section of the hydrogenation reactor.

[0013] Optionally, the method further comprises the following steps: S5: heat treatment is performed on the lower transition section of the hydrogenation reactor to improve the microstructure performance and mechanical properties thereof.

[0014] Optionally, the method further comprises the following steps: S6: machining and surface treatment are performed on the lower transition section of the hydrogenation reactor to meet the size precision and surface quality requirements.

[0015] Optionally, the step S1 further comprises: designing an outer contour forging die matched with the shape of the outer wall of the lower transition section of the hydrogenation reactor.

[0016] Optionally, the step S3 further comprises: after the cylindrical pre-forging is put on the reaming sleeve, the outer contour forging die is put on the cylindrical pre-forging, single-piece contour forging is performed on the cylindrical pre-forging, and the lower transition section of the hydrogenation reactor is formed under the joint constraint of the reaming sleeve and the outer contour forging die.

[0017] In a second aspect, the application provides a lower transition section of a hydrogenation reactor, which is formed by the single-piece contour forging forming method of the lower transition section of the hydrogenation reactor as described above.

[0018] The hydrogenation reactor lower transition section and the one-piece profiled forging forming method thereof have the following beneficial effects: the short conical expansion sleeve is designed by acquiring the inner wall shape data of the hydrogenation reactor lower transition section, the size of the short conical expansion sleeve is accurately matched with the inner diameter of the cylinder pre-forging and the final forming taper, the inner surface profile of the hydrogenation reactor lower transition section forging is accurately constrained, the hydrogenation reactor lower transition section is directly formed under the constraint of the short conical expansion sleeve combined with the one-piece profiled forging process, and the efficient and precise forming of the hydrogenation reactor lower transition section is realized; the inner wall shape is accurately controlled through the short conical expansion sleeve, the subsequent machining allowance is avoided, the material utilization rate is significantly improved, compared with the traditional method of straightening the forging according to the maximum wall thickness to form a straight circle, the material can be fully utilized, the raw material utilization rate is significantly improved, and the production cost is reduced; the one-piece forging mode breaks through the size limitation of the traditional process on the product, can adapt to the production needs of hydrogenation reactors of different specifications, compared with the method of profiled forging of two transition sections into a lantern shape, the product size range of the hydrogenation reactor lower transition section is not limited by the size of the special fixture, the clearance of the water pressure machine, the column gap and other factors, and the application range is wider. BRIEF DESCRIPTION OF DRAWINGS

[0019] Figure 1 The flow chart of the one-piece profiled forging forming method of the hydrogenation reactor lower transition section of the embodiment of the application is shown in the figure. Figure 2 The cross-sectional view of the hydrogenation reactor lower transition section of the background technology is shown in the figure. Figure 3 The cross-sectional view of the straight circle of the forging according to the maximum wall thickness of the background technology is shown in the figure. Figure 4 The cross-sectional view of the forging of two transition sections synthesized into a lantern shape of the background technology is shown in the figure. Figure 5 The cross-sectional view of the forging integrally forged with the cylinder of the background technology is shown in the figure. Figure 6 The cross-sectional view of the expansion sleeve of the embodiment of the application is shown in the figure. Figure 7 The operation flow chart of the preliminary forging of the steel ingot of the embodiment of the application is shown in the figure. Figure 8 The structure diagram of the expansion sleeve on the mandrel of the embodiment of the application is shown in the figure. In the figure: 1, expansion sleeve; 2, cylinder pre-forging; 3, mandrel; 4, mandrel; 5, press anvil; 6, operating machine. DETAILED DESCRIPTION

[0020] In order to make the above objectives, characteristics and advantages of the present application more apparent, comprehensible and easier to understand, specific embodiments of the present application will be described in detail below with reference to the accompanying drawings. Although some embodiments of the present application are shown in the drawings, it should be understood that the present application can be implemented in various forms, and should not be interpreted as being limited to the embodiments set forth herein, but rather, these embodiments are provided in order to more thoroughly and completely understand the present application. It should be understood that the drawings and embodiments of the present application are only for exemplary purposes, and are not intended to limit the scope of protection of the present application.

[0021] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description of the application herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application; As used herein, the term "includes" and its variants are open-ended, meaning "includes but is not limited to"; the term "based on" means "based, at least in part, 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"; the term "optionally" means "may optionally be present" or "may be absent". Related terms will be defined in the description below.

[0022] The embodiment of the present application provides a lower transition section of a hydrogenation reactor and a single-piece profile forging forming method thereof.

[0023] As shown in Figure 1 An embodiment of the present application provides a single-piece profile forging forming method of a lower transition section of a hydrogenation reactor, comprising the following steps: S1: Obtain the inner wall shape data of the lower transition section of the hydrogenation reactor, and design a hole expanding sleeve 1 that is adapted to the inner wall shape of the lower transition section of the hydrogenation reactor, as shown in Figure 6 ; S2: Take a steel ingot for preliminary forging to obtain a cylindrical pre-forged piece 2; S3: Install the hole expanding sleeve 1, and sleeve the cylindrical pre-forged piece 2 on the hole expanding sleeve 1, and perform single-piece profile forging on the cylindrical pre-forged piece 2, and under the constraint of the hole expanding sleeve 1, the lower transition section of the hydrogenation reactor is formed.

[0024] Specifically, as shown in Figure 6As shown, the reaming sleeve 1 refers to an annular die with a taper matching the curvature of the inner wall of the target component, which can be formed by numerical control machining. The taper angle is determined according to the change rate of the inner diameter of the transition section, and is used to provide continuous inner wall support during forging. The cylindrical pre-forging piece 2 refers to an approximately cylindrical blank formed by preliminary forging, which can be prepared by upsetting and piercing, core rod drawing and other processes. The wall thickness can be controlled within 1.2-1.5 times of the target size to provide a machining allowance for subsequent profile forging. Single-piece profile forging refers to a forging process for independently forming a single transition section. The axial pressure can be applied by a hydraulic press to make the pre-forging piece deform radially under the constraint of the reaming sleeve 1.

[0025] In this embodiment, the beneficial effects of the lower transition section of the hydrogenation reactor and the single-piece profile forging forming method of the present application are as follows: by obtaining the inner wall shape data of the lower transition section of the hydrogenation reactor, a suitable reaming sleeve 1 is designed, as shown in Figure 6 The short conical reaming sleeve 1 precisely matches the inner diameter of the cylindrical pre-forging piece 2 and the final forming taper, accurately constrains the inner surface profile of the lower transition section of the hydrogenation reactor, and directly forms the lower transition section of the hydrogenation reactor under the constraint of the short conical reaming sleeve 1 in combination with the single-piece profile forging process, achieving efficient and precise forming of the lower transition section of the hydrogenation reactor. The inner wall shape is accurately controlled by the short conical reaming sleeve 1, avoiding subsequent machining allowance, significantly improving material utilization, and compared with the traditional method of straightening the forging according to the maximum wall thickness to form a straight circle, the method can fully utilize the material, significantly improve the utilization rate of raw materials, and reduce the production cost. The single-piece forging mode breaks through the size limitation of traditional process, and can adapt to the production needs of different specifications of the lower transition section of the hydrogenation reactor. Compared with the method of profile forging of two transition sections into a lantern shape, the method can not be limited by the size of the special fixture, the clearance of the hydraulic press, and the column gap, and can not be limited by the size range of the lower transition section of the hydrogenation reactor, and has a wider application range.

[0026] Optionally, step S2 comprises the following steps: S21: cutting off the water riser of the ingot by gas cutting, and then heating to a forging temperature; S22: as shown in Figure 7 The ingot is sequentially subjected to upsetting and piercing, core rod drawing, mandrel reaming, and riser end upward flattening and edge opening operations to make the height of the ingot reach the finished product height, and ensure the installation adaptability of the inner wall of the ingot after trimming with the reaming sleeve 1; S23: as shown in Figure 8 The short conical reaming sleeve 1 is sleeved on the mandrel 3, and the cylindrical pre-forging piece 2 is sleeved on the short conical reaming sleeve 1 for drawing to obtain a cylindrical pre-forging piece 2 with a certain shape.

[0027] Specifically, the gas cutting off the water riser refers to removing the riser part formed at the top of the ingot due to casting by a flame cutting method, and specifically, an oxyacetylene cutting device can be used to achieve this operation, which can directly remove the invalid metal part and reduce material loss in the subsequent forging process. Upsetting and piercing refers to piercing a central through hole after forming a pie-shaped blank by axial compression of the ingot, and specifically, an upper and lower anvil can be used in cooperation with a punch to achieve this operation, which provides an initial hole type for subsequent hole expansion forging. Core rod lengthening refers to radially compressing the steel ingot blank with a central hole on the core rod, and specifically, a lower V anvil support can be used in cooperation with a rotating core rod to achieve this operation, and then placed on a horse frame 4, which can control the axial elongation rate and improve the wall thickness uniformity. The horse lever hole expansion refers to gradually expanding the inner diameter of the steel ingot blank by rotating forging while the blank is sleeved on the horse lever 3, and specifically, a horse frame 4 with adjustable span can be used in cooperation with different diameter horse levers 3 to achieve this operation, which can accurately adjust the inner diameter size of the cylindrical pre-forging piece 2. The riser end upward flat opening refers to planar finishing the riser end face of the forged blank and forming an end profile, and specifically, an angle anvil plate can be used in cooperation with local forging to achieve this operation, which can directly make the ingot height meet the product requirements.

[0028] In this optional embodiment, the steel ingot blank processing process is optimized by a staged forging process: after the water riser is removed by gas cutting, the ingot is heated to a forging temperature range with good plasticity, at which time the material deformation resistance is significantly reduced. The upsetting and piercing process forms a pie-shaped blank with a central hole, providing a geometric basis for subsequent hole expansion. During the core rod lengthening process, the core rod acts as an internal support to effectively constrain the inner wall shape of the blank, while simultaneously achieving coordinated control of wall thickness thinning and height extension through axial compression. In the horse lever hole expansion stage, the inner diameter size is gradually expanded by rotating forging, and size precision control is achieved by replacing different diameter horse levers 3. The riser end upward flat opening operation ensures the flatness of the end face while directly reaching the finished product height, avoiding material loss caused by multiple finishing in traditional processes. Finally, the short conical hole expansion sleeve 1 guides the lengthening deformation, allowing the cylindrical pre-forging piece 2 to form a taper transition matching the target product during radial expansion. Through process integration optimization, key processes such as upsetting and piercing, core rod lengthening, and horse lever hole expansion are completed in a single heating cycle, reducing the number of heating times and improving size control precision. In particular, the introduction of the riser end upward flat opening process allows the blank height to reach the finished product requirements in one step, reducing at least one finishing process compared to traditional processes. The initial wall thickness of the blank is effectively reduced, reducing the forging deformation and significantly reducing the equipment load demand. Material utilization is improved, reducing material loss compared to traditional straight circle sub-forging processes. The forming size precision is high, meeting the size matching requirements of subsequent profiled forging. The staged forging process effectively controls the metal flow in each deformation process, avoiding cracks caused by local excessive deformation.

[0029] Optionally, in step S3, the short conical expansion sleeve 1 is installed, and the cylindrical pre-forging 2 is sleeved on the expansion sleeve 1, including: sleeving the short conical expansion sleeve 1 on the mandrel 3, placing two horse stands 4, the distance between the two horse stands 4 is 50 to 100 mm more than the length of the short conical expansion sleeve 1, and then placing the mandrel 3 sleeved with the short conical expansion sleeve 1 on the horse stands 4.

[0030] Specifically, the short conical expansion sleeve 1 refers to a forging auxiliary tool matched with the shape of the inner wall of the lower transition section of the hydrogenation reactor, which can be realized by a steel sleeve with a taper consistent with the arc of the product inner diameter, and the conical structure can guide the cylindrical pre-forging 2 to form the target inner wall profile during forging. The horse stand 4 refers to a load-bearing structure for supporting the mandrel 3, which can be realized by a steel structure support with adjustable support point position, and the distance between the two horse stands 4 can be adjusted to adapt to expansion sleeves 1 of different lengths. The distance between the two horse stands 4 is 50 to 100 mm more than the length of the short conical expansion sleeve 1, which refers to the principle of spacing the horse stands 4, and the specific range can be realized by measuring the length of the expansion sleeve 1 and adding a certain amount of margin, which can ensure that the two ends of the mandrel 3 have operating space while maintaining overall support stability.

[0031] In this optional embodiment, during installation, the axis of the short conical expansion sleeve 1 and the mandrel 3 is strictly centered through the sleeve joint operation, realizing the axial and radial fixation of the expansion sleeve 1 in the cylindrical pre-forging 2, ensuring that the center line of the conical surface of the expansion sleeve 1 coincides with the axis of the cylindrical pre-forging 2, and avoiding eccentric load during forging. The spacing between the two horse stands 4 is set by reserving an expansion space of 50 to 100 mm, which not only leaves enough movement gap for the operating arm of the forging equipment, but also makes the support point of the horse stand 4 always within the effective length range of the expansion sleeve 1. This spacing design allows the mandrel 3 to undergo a small amount of elastic deformation during forging, thereby reducing the risk of rigid impact of the equipment by absorbing part of the forging stress, and at the same time allowing the same group of horse stands 4 to adapt to expansion sleeves 1 of different lengths, breaking through the limitations of traditional fixed spacing horse stands 4 on product size. By dynamically adjusting the spacing of the horse stands 4 and setting a scientific margin range, the equipment versatility is improved while ensuring support stability. This effectively solves the stability and equipment adaptability problems during the installation of the expansion sleeve 1, ensuring that the expansion sleeve 1 and the mandrel 3 remain coaxial and centered during forging, avoiding forming errors caused by improper support. The adjustable spacing allows the same forging equipment to be compatible with multiple specifications of products, reducing the frequency of tool replacement and improving the flexibility of the production line. The reserved spacing margin allows the equipment components to absorb the forging impact energy by allowing a small amount of deformation, reducing the risk of fatigue damage, and prolonging the service life of the key components.

[0032] Optionally, in step S3, the cylindrical pre-forging 2 is subjected to single-piece profile forging, including: under the action of a hydraulic press, the cylindrical pre-forging 2 is subjected to single-piece profile forging.

[0033] Specifically, the hydraulic press refers to a heavy forging equipment that utilizes liquid pressure to transfer energy, and can be implemented by a four-column hydraulic press. The worktable size of the four-column hydraulic press matches the diameter of the cylindrical pre-forging piece 2, and the pressure output range covers the tonnage required for forming, such as Figure 8 As shown, the press anvil plate 5 of the hydraulic press contacts the outer wall of the cylindrical pre-forging piece 2. The equipment generates a continuous and stable pressure through a hydraulic system to ensure uniform plastic deformation of the pre-forging piece under the constraint of the hole expanding sleeve 1; the operating machine 6 is an auxiliary equipment that works with the forging press equipment such as the hydraulic press, and is used to clamp the mandrel 3. Among them, single piece copying forging refers to a shape copying forming process for a single pre-forging piece, which can be implemented by matching a copying die system of a short conical hole expanding sleeve 1. During the forging process, the inner wall of the pre-forging piece is precisely fitted with the outer surface of the short conical hole expanding sleeve 1, and the precise copying of the complex curved surface is realized.

[0034] In this optional embodiment, the pressure control system of the hydraulic press forms a linkage mechanism with the short conical hole expanding sleeve 1. During the forging process, the press anvil plate 5 of the hydraulic press applies axial pressure to the cylindrical pre-forging piece 2 according to the preset program, and the pressure value is dynamically adjusted according to the deformation resistance of different parts of the cylindrical pre-forging piece 2. The long stroke characteristic of the hydraulic press allows the overall forming of the short axial size of the transition section to be completed in one clamping, avoiding shape deviation caused by multiple forging. The hydraulic press used has the characteristics of continuous adjustable pressure and adaptive stroke length, which can realize one-time forming of complex curved surfaces and significantly reduce the frequency of manual intervention. The shape deviation problem caused by uneven pressure distribution during the forming process of thick-walled pre-forging pieces is effectively solved, and the orderly flow of metal materials under the constraint of the hole expanding sleeve 1 is ensured. Through the coordinated optimization of equipment and process, the fitting degree of the inner wall curved surface of the transition section after forming and the hole expanding sleeve 1 reaches the design requirement, and the subsequent machining allowance is greatly reduced. At the same time, the negative impact of the insufficient stroke of traditional forging equipment on the forming quality of short axial size workpieces is overcome, and the consistency of product size precision is significantly improved.

[0035] Optionally, it further includes the steps of: S4: air cooling treatment is performed on the formed lower transition section of the hydrogenation reactor.

[0036] Specifically, air cooling treatment refers to the process of slowly cooling the high-temperature forged piece in the natural environment, which can be implemented by placing the forged piece on the ground of the workshop or a special cooling rack. This treatment utilizes the heat exchange between air and the surface of the forged piece to keep the temperature gradient within a controllable range, avoiding the concentration of organizational stress caused by sudden cooling rate.

[0037] In this optional embodiment, after the single-piece die forging process is completed, the formed transition section is still in a high-temperature state, at which point the entire forging is uniformly cooled by air cooling. Due to the low natural convection heat dissipation rate of air, the temperature difference between the surface and the core of the forging is controlled within a small range, thereby reducing the lattice distortion caused by thermal stress. In this process, the austenite structure inside the forging gradually transforms into a stable ferrite-pearlite mixed structure, and the residual stress is released through plastic deformation. This cooling method avoids the risk of quenching cracks that may be caused by forced cooling methods such as water cooling or oil cooling, and provides a uniform initial organizational basis for subsequent heat treatment processes. It effectively solves the problem of uneven internal stress distribution in the forged part after forming due to improper cooling, controls the phase transformation behavior during cooling, and improves the uniformity of the internal structure of the forging, providing a stable organizational structure basis for subsequent heat treatment, thereby ensuring that the tensile strength and impact toughness of the transition section meet the use requirements.

[0038] Optionally, it also includes the steps of: S5: heat treating the lower transition section of the hydrogenation reactor to improve its organizational performance and mechanical properties.

[0039] Specifically, heat treatment refers to a process of optimizing the material properties of the forging through temperature control and time regulation, which can be achieved by using one or a combination of normalizing, quenching, and tempering. Normalizing is used to refine the grains and eliminate residual stress during forging, quenching is used to harden the material through rapid cooling, and tempering is used to adjust the toughness of the material and stabilize the internal structure. This step forms a uniform microstructure inside the material through phase transformation and reorganization, thereby improving the anti-deformation ability of the forging in high-temperature and high-pressure environments.

[0040] In some specific embodiments, after the air cooling process is completed, the formed lower transition section of the hydrogenation reactor is placed in a heat treatment furnace and heated and held according to a predetermined temperature curve. For example, in the austenitizing stage, the material is heated above the critical temperature and held for a certain time to allow the carbide to fully dissolve; then it is rapidly cooled through a quenching medium to form a martensite structure to enhance hardness; finally, it is tempered at a temperature below the critical temperature and slowly cooled to eliminate internal stress and balance the strength and toughness of the material. This process controls the phase transformation of the material in stages, so that the grain size and distribution inside the forging reach an optimized state, thereby meeting the anti-creep and anti-fatigue performance requirements of the hydrogenation reactor.

[0041] In this optional embodiment, by increasing the heat treatment step, actively intervening in the evolution of the material microstructure, not only the local stress formed in the forging process is eliminated, but also the strength and toughness of the material are improved through phase transformation control, overcoming the defects of traditional methods prone to cracks or deformation under complex working conditions. The problem of insufficient organization and mechanical properties of the lower transition section of the hydrogenation reactor after forging is solved, the internal grain structure of the material is more dense and uniform, and the residual stress is significantly reduced, thereby improving the creep resistance and long-term service stability of the forged piece under high temperature and high pressure environment, effectively prolonging the service life of the component.

[0042] Optionally, it further comprises the steps of: S6: machining and surface treatment are performed on the lower transition section of the hydrogenation reactor to meet the size accuracy and surface quality requirements.

[0043] Specifically, machining refers to removing the excess amount after forging forming through cutting or grinding process, which can be realized by turning, milling or grinding equipment, and is used to accurately control the inner and outer diameter of the transition section and the step height to ensure that the geometric parameters meet the design standards. Surface treatment refers to improving the surface state through physical or chemical methods, which can be realized by sandblasting, polishing or chemical passivation process, and is used to eliminate processing marks and improve surface finish and corrosion resistance.

[0044] In some specific embodiments, after forging forming, the machining process first positions the reference surface of the transition section, precisely cuts the inner and outer contours through numerical control machine tools, gradually removes the forging excess amount and corrects the size deviation, so that the diameter, arc and step height of the transition section meet the drawing requirements. Subsequently, the surface treatment process performs sandblasting treatment on the machined workpiece, removes the surface oxidation layer and microscopic burrs by high-speed sand impact, and further reduces the surface roughness by mechanical polishing to finally form a uniform and dense surface state.

[0045] In this optional embodiment, by integrating machining and surface treatment, a complete machining chain is formed after single-piece profile forging, realizing systematic correction of size error and directional elimination of surface defects. The size tolerance problem caused by thermal deformation of the forged piece is solved, and the influence of surface micro-cracks on equipment sealing is avoided, so that the inner and outer contour accuracy and surface finish of the transition section meet the assembly and operation requirements of the hydrogenation reactor under high pressure working conditions.

[0046] Optionally, step S1 further comprises: Designing an outer profile forging die that is compatible with the shape of the outer wall of the lower transition section of the hydrogenation reactor.

[0047] Specifically, the outer profiled forging die refers to a forming die matched with the outer geometric profile of the transition section, which can be realized by numerical control machining or three-dimensional scanning reverse modeling technology, and the inner surface shape thereof is complementary to the curvature and step features of the outer part of the transition section. The outer wall shape matching refers to that the die cavity and the outer surface of the transition section form a continuous contact surface, which can be realized by a segmented die cavity structure, and each segment of the die cavity corresponds to a different curvature region of the outer wall of the transition section, so as to ensure that the metal flow direction is consistent with the product outer profile during the forging process.

[0048] In the optional embodiment, after the cylindrical pre-forging piece 2 is sleeved on the short conical hole expanding sleeve 1, the outer profiled forging die is sleeved on the outside of the pre-forging piece to form a bidirectional constraint structure expanding from inside to outside. During the forging process, the radial pressure applied by the hydraulic press makes the pre-forging piece metal subjected to the bidirectional force of the outer expansion of the inner sleeve and the inner contraction of the outer sleeve, so as to force the metal to flow along the gap between the cavities formed by the inner and outer dies. Through the synchronous constraint of the inner and outer die surfaces, the wall thickness of the pre-forging piece is controlled within the distance between the inner and outer surfaces, and the step and curvature features of the outer wall are accurately formed in one piece through the cavity limiting of the outer profiled forging die. Through the physical limiting action of the outer profiled forging die, the outer wall forming process is converted into the die cavity filling behavior, and the shape deviation caused by manual intervention is eliminated. The curvature forming precision of the outer wall of the transition section can be effectively controlled, the subsequent machining allowance caused by the shape deviation of the outer wall is avoided, the material scrap caused by the size out-of-tolerance of the outer profile during the forging process is reduced, and the near-net forming of the complex outer wall structure is realized.

[0049] Optionally, step S3 further comprises: After the cylindrical pre-forging piece 2 is sleeved on the short conical hole expanding sleeve 1, the outer profiled forging die is sleeved on the cylindrical pre-forging piece 2, the cylindrical pre-forging piece 2 is profiled forged in one piece, and the lower transition section of the hydrogenation reactor is formed under the common constraint of the short conical hole expanding sleeve 1 and the outer profiled forging die sleeve.

[0050] Specifically, the outer profiled forging die refers to a forging die matched with the shape of the outer wall of the lower transition section of the hydrogenation reactor, which can be realized by a numerically controlled machining steel die, and the inner surface profile thereof is completely consistent with the curvature and step structure of the outer wall of the target product, which is used to limit the metal flow direction of the outer wall of the forging piece. The short conical hole expanding sleeve 1 refers to a cylindrical forging auxiliary tool with a specific taper, which can be made of high-temperature resistant alloy steel, and the outer surface taper thereof is matched with the tapered structure of the inner wall of the target product, which is used to maintain the geometric shape of the inner wall of the forging piece during the forging process. The common constraint refers to a closed forging space formed by the inner and outer dies, which can be realized by adjusting the assembly gap of the inner and outer dies, so that the metal material is simultaneously subjected to the shape limitation of the inner and outer surfaces during the axial compression, and the wall thickness deviation caused by unilateral constraint is avoided.

[0051] In this optional embodiment, during the forging process, the cylindrical preform 2 is sleeved on the outer surface of the short conical reaming sleeve 1, and at this time the outer profiled forging die is sleeved on the outside of the preform to form a double-layer die structure. When the hydraulic press applies axial pressure, the preform metal undergoes plastic deformation between the rigid contact surfaces of the inner and outer dies. The inner profile of the outer profiled forging die forces the metal to fill the recessed area of the stepped portion along the predetermined path, while the taper surface of the short conical reaming sleeve 1 continuously counteracts the tendency of the metal to flow inward. Through the synchronous constraint action of the inner and outer dies, the free flow of the metal in the radial direction is effectively inhibited, ensuring the uniformity of the wall thickness of the stepped transition area, and improving the forming accuracy of the arc-shaped structure.

[0052] In some specific embodiments, the outer profiled forging die can be designed as a split structure, for example composed of two semicircular die segments, to facilitate quick demolding after forging is completed. The taper angle of the short conical reaming sleeve 1 can be adjusted according to the actual arc of the inner wall of the product, for example using a gradual taper angle of 5° to 15° to adapt to the forming needs of transition sections of different specifications.

[0053] This optional embodiment controls the metal deformation process in two directions through the cooperative constraint of the inner and outer dies, without relying on subsequent large amount of cutting to directly obtain forgings that meet the accuracy requirements of the inner and outer profiles. It realizes synchronous and precise control of the shape of the inner and outer walls of the lower transition section of the hydrogenation reactor, solves the problems of wall thickness deviation and insufficient step forming caused by traditional single-sided constraint, significantly reduces the subsequent machining allowance, and improves the material utilization rate.

[0054] Another embodiment of the present application provides a hydrogenation reactor lower transition section made by the single-piece profiled forging forming method of the hydrogenation reactor lower transition section as described above.

[0055] Specifically, the single-piece profiled forging forming method refers to the operation process of obtaining the inner wall shape data of the target piece, designing the short conical reaming sleeve 1, and sleeving the cylindrical preform 2 on the die for single forming forging. Plastic deformation can be realized by using a water pressure machine to drive the forging die. This process directly forms the target geometric profile through die constraint. The short conical reaming sleeve 1 refers to a conical forging auxiliary tool that matches the curvature of the inner wall of the transition section, which can be realized by using a numerically controlled machining high-strength alloy steel die. This die realizes deformation control during forging by accurately matching the curvature of the inner wall. The outer profiled forging die refers to a forming die that matches the stepped structure of the outer wall of the transition section, which can be realized by using a split combined structure. This die, together with the short conical reaming sleeve 1, forms a two-way constraint system.

[0056] In this embodiment, the problem of serious raw material waste in the traditional forging process is effectively solved, the machining allowance of the blank is reduced through accurate matching of the profiling die; the limitation of product size range by lantern forging is overcome, so that different specifications of the transition section can be produced in single piece; the wall thickness distribution of the blank is optimized, the deformation resistance in the forging process is reduced, and thus the forming quality and process stability are improved.

[0057] The application will be further described in conjunction with specific embodiments.

[0058] In embodiment 1, a single-piece profiling forging forming method for the lower transition section of a hydrogenation reactor is used to manufacture a lower transition section of a hydrogenation reactor with a length of 1150 mm, an inner diameter of the large-end Φ5810 mm, a wall thickness of the large-end 328 mm, an inner diameter of the small-end Φ5193 mm, an outer diameter of the small-end 5625 mm, and a net weight of 55T, which comprises the following steps: 1. The design size of the lower transition section of the hydrogenation reactor is counted, the inner wall shape data is obtained by drawing a graph using CAD, and a hole expanding sleeve 1 that is adapted to the inner wall shape of the lower transition section of the hydrogenation reactor is designed.

[0059] 2. According to the design size of the lower transition section of the hydrogenation reactor, the size of the hole expanding sleeve 1 and the forging process requirement, a forging allowance is added, a forging part drawing is drawn, the weight of the forging part is calculated, and thus the steel ingot type 225TT / 1 used for the forging part is determined; The water gap of the steel ingot body (including the knife edge) is 150, and the water gap is cut off; First fire: heated to a forging temperature of 1250±10℃, and kept for ≥40H; the water gap end is upset to H (height)=2200mm, Φ (diameter)=3570mm, the punching hole diameter is 1400mm, and the punching burr is cleaned; Second fire: heated to a temperature of 1250±10℃, and kept for ≥8H, the core rod is lengthened to 2400mm (shaping); Third fire: heated to a temperature of 1250±10℃, and kept for ≥8H, the mandrel is expanded to an inner diameter of 2400mm and an outer diameter of 4170mm; Fourth fire: heated to a temperature of 1250±10℃, and kept for ≥8H, the water gap end is flattened upward to H=2200, the upper anvil is rotated to open the edge to H=1500, so that the height of the steel ingot reaches the finished product height, and a cylindrical pre-forging part 2 is obtained; Fifth fire: the hole expanding sleeve 1 is sleeved on the mandrel 3, the cylindrical pre-forging part 2 is sleeved on the hole expanding sleeve 1, the heating temperature is 1250±10℃, the temperature is kept for ≥7H, lengthening is performed, and the hole expanding sleeve is removed; Sixth fire: heated to a temperature of 1250±10℃, and kept for ≥7H, the water gap end is flattened upward to H=1800mm, and the edge is opened to H=1650mm; The seventh fire: the reaming sleeve 1 is sleeved on the mandrel 3, the cylindrical preformed piece 2 is sleeved on the reaming sleeve 1, the heating temperature is 1250±10℃, the temperature is kept for ≥7H, the reaming is performed to form the product, and the lower transition section of the hydrogenation reactor is formed.

[0060] 4. The formed lower transition section of the hydrogenation reactor is subjected to air cooling treatment.

[0061] 5. After being cooled to room temperature, the lower transition section is placed into a heat treatment furnace to perform normalizing + tempering heat treatment process, so as to improve the organizational performance.

[0062] 6. The lower transition section is subjected to machining operations such as turning and milling, and is subjected to surface sand blasting treatment, so as to reach the design size precision and surface roughness requirements.

[0063] In the comparative example 1, the lower transition section of the hydrogenation reactor is forged by using the traditional straight circle method, the weight of the forged piece is calculated to be 166.8T, and the ingot type is determined to be 278T.

[0064] Forging deformation process: The ingot body (including the knife edge) is air-cut to 150, and all the risers are air-cut.

[0065] The first fire: the heating temperature is selected to be 1250±10℃, the temperature is kept for ≥45H, the water end is upset to H=2200mm, Φ3880mm, the punching is 1400mm, and the punching burrs are cleaned; The second fire: the heating temperature is selected to be 1250±10℃, the temperature is kept for ≥8H, the mandrel is reamed to Φ inner diameter 2400mm Φ outer diameter 4440mm; The third fire: the heating temperature is selected to be 1250±10℃, the temperature is kept for ≥8H, the double-face flattening is to H=1800; The fourth fire: the heating temperature is selected to be 1250±10℃, the temperature is kept for ≥8H, the mandrel is reamed to Φ inner diameter 2800mm Φ outer diameter 4920mm; The fifth fire: the heating temperature is selected to be 1250±10℃, the temperature is kept for ≥7H, the double-face flattening is to H=1510; The sixth fire: the heating temperature is selected to be 1250±10℃, the temperature is kept for ≥7H, the mandrel is reamed to form the product; The product of the lower transition section of the hydrogenation reactor is subjected to air cooling treatment; After being cooled to room temperature, the lower transition section is placed into a heat treatment furnace to perform normalizing + tempering heat treatment process, so as to improve the organizational performance; The lower transition section is subjected to machining operations such as turning and milling, and is subjected to surface sand blasting treatment, so as to reach the design dimensional accuracy and surface roughness requirements. The raw material utilization rate of the hydrogenation reactor lower transition section forged by the method of Example 1 is 55 / 225 x 100% = 24.45%, and the ingot type of the traditional straight circle method of Comparative Example 1 is 278T / 1, the raw material utilization rate is 55 / 278 x 100% = 19.79%, and the raw material utilization rate of Example 1 is increased by 4% compared with the traditional method of Comparative Example 1.

[0066] Although the present application is disclosed as above, the protection scope of the present application is not limited to this. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present application, and these changes and modifications shall fall within the protection scope of the present application.

Claims

1. A method of single piece profiled forging of a lower transition section of a hydrogenation reactor, characterized in that, The method comprises the following steps: S1: obtaining the inner wall shape data of the lower transition section of the hydrogenation reactor, and designing a reaming sleeve (1) matched with the inner wall shape of the lower transition section of the hydrogenation reactor; S2: taking a steel ingot for preliminary forging to obtain a cylindrical pre-forging piece; S3: installing the reaming sleeve (1), sleeving the cylindrical pre-forging piece (2) on the reaming sleeve (1), and performing single-piece contour forging on the cylindrical pre-forging piece (2) under the constraint of the reaming sleeve (1) to form the lower transition section of the hydrogenation reactor.

2. The method of claim 1, wherein the lower transition piece of the hydrogenation reactor is formed by a single piece of a forging process, and the lower transition piece is formed by a single piece of a forging process. Step S2 comprises the following steps: S21: cutting off the riser of the steel ingot by gas cutting, and then heating to a forging temperature; S22: sequentially performing upsetting punching, core rod lengthening, mandrel reaming, and riser end upward flattening and edge opening operations on the steel ingot to make the height of the steel ingot reach the finished product height; S23: sleeving the reaming sleeve (1) on the mandrel (3), and lengthening the cylindrical pre-forging piece (2) sleeved on the reaming sleeve (1) to obtain the cylindrical pre-forging piece (2) with a certain shape.

3. The method of claim 1, wherein the lower transition piece of the hydrogenation reactor is formed by a single piece of a forging process. In step S3, the installation of the reaming sleeve (1) and the sleeving of the cylindrical pre-forging piece (2) on the reaming sleeve (1) comprise: sleeving the reaming sleeve (1) on the mandrel (3), placing two mandrels (4), the distance between the two mandrels (4) being 50-100 mm more than the length of the reaming sleeve (1), and then placing the mandrel (3) sleeved with the reaming sleeve (1) on the mandrels (4).

4. The method of claim 1, wherein the lower transition piece of the hydrogenation reactor is formed by a single piece of a forging process. In step S3, the single-piece contour forging of the cylindrical pre-forging piece (2) comprises: under the action of a water press, performing single-piece contour forging on the cylindrical pre-forging piece (2).

5. The method of claim 1, wherein the lower transition piece of the hydrogenation reactor is formed by a single piece of a forging process. Further comprising steps: S4: performing air cooling treatment on the formed lower transition section of the hydrogenation reactor.

6. The method of claim 5, wherein the lower transition piece is formed by a single piece of forging. Further comprising steps: S5: performing heat treatment on the lower transition section of the hydrogenation reactor to improve the microstructure performance and mechanical performance thereof.

7. The method of claim 6, wherein the lower transition piece is formed by a single piece of forging. Further comprising steps: S6: performing machining and surface treatment on the lower transition section of the hydrogenation reactor to meet the requirements of dimensional accuracy and surface quality.

8. The method of claim 1, wherein the lower transition piece of the hydrogenation reactor is formed by a single piece of a forging process. Step S1 further comprises: designing an outer contour forging die matched with the outer wall shape of the lower transition section of the hydrogenation reactor.

9. The method of claim 8, wherein the lower transition piece is formed by a single piece of forging. Step S3 further comprises: after the cylindrical pre-forging piece (2) is sleeved on the reaming sleeve (1), sleeving the outer contour forging die on the cylindrical pre-forging piece (2), performing single-piece contour forging on the cylindrical pre-forging piece (2) under the joint constraint of the reaming sleeve (1) and the outer contour forging die, and forming the lower transition section of the hydrogenation reactor.

10. A lower transition section for a hydrogenation reactor, characterized in that The lower transition section of the hydrogenation reactor is formed by the single-piece contour forging forming method according to any one of claims 1-9.

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