A die manufacturing method for realizing finish rolling of a complex profiled section ring

Abstract

The application provides a die manufacturing method for realizing finish rolling of a complex profiled section ring, and belongs to the technical field of die manufacturing for ring rolling forming, and comprises the following steps: constructing a profile of a die for rolling; obtaining time sequence information of first contact of a blank and a die profile groove at different longitudinal positions in a rolling process, and dividing different structures on the die profile groove into different levels of wear areas according to the time sequence information; formulating a hardness distribution scheme of different areas; and manufacturing a rolling die with differentiated hardness distribution. According to the difference in the sequence of contact of the die profile groove with the blank at different longitudinal positions in the rolling process and the severity of wear, the material hardness at different longitudinal positions of the die is actively designed to be different, and the hardness of the part first contacting the ring is ensured to be the highest and the most wear-resistant, so that the problem of loss of die precision and early failure caused by local excessive wear is solved from the root of the structure design.

Description

Technical Field

[0001] This invention belongs to the field of tooling and die manufacturing technology for ring rolling forming, and specifically relates to a die manufacturing method for realizing the refined rolling of complex irregular cross-section rings. Background Technology

[0002] Ring rolling is an advanced plastic forming technology that uses ring rolling equipment to continuously apply pressure to a ring-shaped billet, reducing wall thickness, increasing diameter, and shaping the cross-sectional profile. With the increasing demands for complexity and dimensional accuracy in the cross-sectional shapes of ring parts in high-end equipment such as aero-engine casings, wind turbine bearing rings, and nuclear power plant sealing rings, the refined rolling of ring parts with irregular cross-sections (such as flanges, grooves, steps, and conical surfaces) has become a mainstream trend. During the rolling process, the grooves of the drive roll and mandrel directly participate in the shaping of the irregular profile of the ring part, and their geometric accuracy and surface integrity determine the final cross-sectional profile and surface quality of the ring part.

[0003] Currently, most ring rolling dies are made of homogeneous high-alloy hot-work die steel or cold-rolled tool steel, achieving roughly uniform hardness through overall quenching and tempering. For rolling complex irregular cross-section rings, the die groove has an undulating shape along the ring's axial direction (i.e., the die's longitudinal direction). In actual rolling, the billet is usually initially rectangular or a simple shape, not filling the groove in one step. When the billet is bitten in, certain specific protruding parts on the groove (such as the bosses or sharp edges of the forming flange) always come into contact with the billet first, resulting in friction and compression. The concave bottom of the groove or areas not involved in large deformation come into contact later or even only slightly. This difference in contact timing causes the parts that come into contact first to endure severe friction, high pressure, and thermal shock for a long time, making them highly susceptible to abrasive wear, adhesive wear, and plastic deformation, becoming the source of die failure. Once the wear in this area exceeds the limit, the overall cavity accuracy of the die is lost, and even if the rest of the parts are intact, it cannot continue to be used for finishing rolling.

[0004] To address this issue, existing technologies often employ nitriding, carburizing, or plating treatments on the entire mold surface, or the use of higher-grade, solid hard materials. However, while increasing overall hardness can alleviate wear, it severely sacrifices mold toughness, making the root of the groove or stress concentration areas prone to fatigue cracks or even fracture. If lower overall hardness is used to ensure toughness, the first contact area will wear prematurely, resulting in poor precision retention. Existing combined roll technology, although capable of segmental replacement, often has uniform hardness across segments, failing to design differentiated hardness distribution based on contact sequence and wear patterns. This fails to fundamentally reconcile the contradiction between "wear resistance of the most easily worn areas" and "overall mold fracture resistance."

[0005] Therefore, there is an urgent need for a structural design method that can achieve directional differential configuration of material hardness at different longitudinal positions of the die groove for the contact characteristics of rolling complex irregular cross-section rings. This would allow the area that first contacts the billet to have the highest hardness and strongest wear resistance, while the remaining areas would maintain relatively low hardness to ensure overall service reliability. This would simultaneously extend the die life and stabilize the ring accuracy under refined rolling conditions. Summary of the Invention

[0006] The purpose of this invention is to solve the problem of mold precision loss and premature failure caused by localized excessive wear, as mentioned above.

[0007] To achieve the above objectives, the present invention provides the following technical solution: a method for manufacturing a mold for refining the rolling of complex irregular cross-section ring parts, comprising: Based on the complex irregular cross-sectional profile of the target ring, the groove profile of the rolling die is constructed; Based on the finite element simulation or analytical kinematic analysis of the ring rolling process, the timing information of the first contact between the billet and the die groove at different longitudinal positions during the rolling process is obtained, and the different structures on the die groove are divided into different wear zones according to the timing information. Analyze the wear degree of the different wear zones identified above, and formulate hardness distribution schemes for different regions; Different processes are used to manufacture rolling dies with differentiated hardness distributions based on the hardness distribution schemes of different regions.

[0008] The die manufacturing method for refining the rolling of complex irregular cross-section rings provided by the present invention also has the following technical features: the rolling die includes at least a drive roller and / or a core roller, and the die has a longitudinal axis, which corresponds to the axial direction of the ring.

[0009] The mold manufacturing method for refining the rolling of complex irregular cross-section rings provided by the present invention also has the following technical feature: the groove profile has profile areas with different radial depths in the longitudinal direction, and the different radial profile areas correspond to the irregular cross-section of the ring.

[0010] The die manufacturing method for achieving refined rolling of complex irregular cross-section ring parts provided by the present invention also has the following technical features: the different wear zones include a high wear zone, a low wear zone, and a non-wear zone. The high wear zone is the local area in the longitudinal direction of the die groove that first experiences continuous friction and high-pressure contact with the billet. The low wear zone is the local area that experiences delayed contact or less pressure release compared to the high wear zone. The non-wear zone is the area where the billet and the die groove do not experience wear during the rolling process.

[0011] The mold manufacturing method for achieving refined rolling of complex irregular cross-section ring parts provided by the present invention also has the following technical feature: the hardness distribution scheme of the different regions is respectively a first hardness value corresponding to the high wear area, a second hardness value corresponding to the low wear area, and a third hardness value corresponding to the non-wear area, wherein the first hardness value > the second hardness value ≥ the third hardness value.

[0012] The mold manufacturing method for achieving refined rolling of complex irregular cross-section ring parts provided by the present invention also has the following technical features: the first hardness value is Rockwell hardness HRC 60~65, the second hardness value is Rockwell hardness HRC 50~55, and the third hardness value is Rockwell hardness HRC 45~50.

[0013] The mold manufacturing method for refining the rolling of complex irregular cross-section rings provided by the present invention also has the following technical features: the different processes adopted according to the hardness distribution scheme of different regions include a combination of one or more processes selected from material composite process, gradient heat treatment process and segmented combination process.

[0014] The mold manufacturing method for achieving refined rolling of complex irregular cross-section ring parts provided by the present invention also has the following technical features: the material composite process includes local surface strengthening treatment along the longitudinal direction based on a single metal matrix to form a hardened layer with a hardness higher than that of the matrix. The local surface strengthening treatment includes one or more treatment methods selected from laser quenching, induction hardening, welding of high-hardness wear-resistant alloys, laser cladding, thermal spraying, boronizing or nitriding.

[0015] The mold manufacturing method for refining the rolling of complex irregular cross-section ring parts provided by the present invention also has the following technical features: the gradient heat treatment process includes using additive manufacturing technology to form an integrated mold along the longitudinal direction, and by adjusting the powder material composition or process parameters, a continuous gradient change or step change in hardness is achieved.

[0016] The mold manufacturing method for achieving refined rolling of complex irregular cross-section ring parts provided by the present invention also has the following technical features: the segmented assembly process includes pre-preparing multiple annular roller segments or arc segments with different material hardness, and then assembling them into an integral mold by welding, mechanical connection or thermal assembly.

[0017] Beneficial effects: The mold manufacturing method provided in this application addresses the differences in the sequence of contact between the mold groove and the blank and the severity of wear at different longitudinal positions during the rolling process. By actively designing different material hardnesses at different longitudinal positions of the mold, it ensures that the part that contacts the ring first has the highest hardness and is the most wear-resistant. This solves the problem of mold precision loss and early failure caused by localized excessive wear from the root of structural design.

[0018] The die manufactured using this method has its initial contact area made of the hardest material, effectively resisting wear, plastic deformation, and thermomechanical fatigue. The die's precision retention time is significantly increased, reducing die change frequency and downtime losses. Enhanced shape retention results in minimal fluctuations in the profile, dimensional tolerances, and surface quality of irregularly shaped ring parts during mass production, truly achieving refined rolling. The non-initial contact area maintains excellent toughness with medium or low hardness, preventing overall die brittle fracture and significantly improving service reliability and safety. This method allows for flexible selection of different manufacturing schemes based on existing manufacturing conditions, implementing high-alloy or reinforced treatments only on critical areas, saving valuable materials and demonstrating outstanding overall economic benefits. This method is applicable to ring rolling dies of various cross-sectional shapes, including drive rolls, core rolls, and guide rolls. Attached Figure Description

[0019] To more clearly illustrate the technical solutions of the embodiments of this disclosure, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram showing the longitudinal contact state between the ring blank and the rolling die, as well as the hardness distribution along the longitudinal direction of the die groove in an embodiment of the present invention.

[0021] Wherein, 1: core roller; 2: blank; 3: drive roller. Detailed Implementation

[0022] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. However, it should be noted that these embodiments are not intended to limit the present invention. Equivalent changes or substitutions in function, method, or structure made by those skilled in the art based on these embodiments are all within the protection scope of the present invention.

[0023] In the description of the embodiments of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting the invention.

[0024] Furthermore, the terms "first," "second," "third," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0025] The terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to the internal connection between two components. Those skilled in the art will understand the specific meaning of these terms in this invention based on the specific circumstances.

[0026] This invention provides a method for manufacturing a die for refining the rolling of complex irregular cross-section ring parts. The die is used to achieve, for example... Figure 1 The manufacturing of the complex irregular cross-section ring shown involves a groove on the outer periphery of the drive roller that matches the inner cross-section of the ring. The groove has two protruding forming platforms in the longitudinal direction (axial direction of the ring), as well as adjacent transition fillet areas and groove areas. The initial blank is a rectangular cross-section ring. Rolling simulation shows that when the mandrel and drive roller are closed, the top edge of the forming platform on the drive roller contacts the inner surface of the blank first. During subsequent continuous rotational rolling, this area endures intense radial pressure and tangential friction for a long time, resulting in the highest interface temperature. The bottom of the groove and the non-forming chamfered area contact later, and the contact pressure is significantly lower.

[0027] The method includes: Based on the complex irregular cross-sectional profile of the target ring, the groove profile of the rolling die is constructed; Based on the finite element simulation or analytical kinematic analysis of the ring rolling process, the timing information of the first contact between the billet and the die groove at different longitudinal positions during the rolling process is obtained, and the different structures on the die groove are divided into different wear zones according to the timing information. Analyze the wear degree of the different wear zones identified above, and formulate hardness distribution schemes for different regions; Different processes are used to manufacture rolling dies with differentiated hardness distributions based on the hardness distribution schemes of different regions.

[0028] In some embodiments, the rolling die includes at least a drive roller and / or a core roller, and the die has a longitudinal axis that corresponds to the axial direction of the ring.

[0029] In some embodiments, the groove profile has profiled areas with different radial depths in the longitudinal direction, and the different radial profiled areas correspond to the irregular cross-section of the ring.

[0030] In some embodiments, the different wear zones include a high wear zone, a low wear zone, and a non-wear zone. The high wear zone is the local area in the longitudinal direction of the die groove where continuous friction and high-pressure contact occur first with the billet. The low wear zone is the local area where the contact or release pressure is less delayed compared to the high wear zone. The non-wear zone is the area where the billet and the die groove do not experience wear during the rolling process.

[0031] In some embodiments, the hardness distribution scheme of the different regions is a first hardness value corresponding to the high wear area, a second hardness value corresponding to the low wear area, and a third hardness value corresponding to the non-wear area, wherein the first hardness value > the second hardness value ≥ the third hardness value.

[0032] In some embodiments, the first hardness value is a Rockwell hardness of HRC 60~65, the second hardness value is a Rockwell hardness of HRC 50~55, and the third hardness value is a Rockwell hardness of HRC 45~50.

[0033] In some embodiments, the different processes adopted according to the hardness distribution scheme of different regions include a combination of one or more processes selected from material composite process, gradient heat treatment process and segmented combination process.

[0034] In some embodiments, the material composite process includes a local surface strengthening treatment along the longitudinal direction based on a single metal matrix to form a hardened layer with a hardness higher than that of the matrix. The local surface strengthening treatment includes one or more treatment methods selected from laser hardening, induction hardening, welding of high-hardness wear-resistant alloys, laser cladding, thermal spraying, boronizing, or nitriding.

[0035] In some embodiments, the gradient heat treatment process includes using additive manufacturing technology to form an integrated mold along the longitudinal direction, and by adjusting the powder material composition or process parameters, to achieve a continuous gradient change or step-like change in hardness.

[0036] In some embodiments, the segmented assembly process includes pre-preparing multiple annular roller segments or arc segments with different material hardness, and then assembling them into an integral mold through welding, mechanical connection or thermal assembly.

[0037] In some embodiments, such as Figure 1As shown, region A is the high-wear zone, with a surface hardness set at HRC 62~64; region B is the low-wear zone, with a surface hardness set at HRC 62~64; and region C is the non-wear zone, with a hardness set at HRC 48~50. The drive base is made of hot-work die steel H13 forgings, which are rough-machined and then tempered to a hardness of HRC 48~50 (the hardness of region C). Then, at the locations corresponding to regions A and B, different compositions of nickel-based wear-resistant alloys are clad using laser cladding. Region A is clad with a nickel-based alloy reinforced with tungsten carbide particles, with a cladding layer thickness of 2.5mm, which is then precision ground to the required dimensions, achieving a surface hardness of HRC 63; region B is clad with a low-carbon nickel-based alloy, with a hardness controlled at HRC 53.

[0038] Rolling production verification: After continuously rolling 80 ring parts, the die was inspected. The wear depth of the forming table of the uniform hardness drive roller (made of H13 and integrally quenched to HRC 54) reached 0.22mm, and the inner contour of the ring part exceeded the tolerance by 0.15mm, requiring repair. However, the wear depth of the drive roller of the present invention was only 0.06mm, and the inner contour of the ring part was kept within 0.07mm. The die life was increased by more than 1.5 times, and no cracks appeared.

[0039] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention. The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the technical principles of the present invention, and these improvements and modifications should also be considered within the protection scope of the present invention.

Claims

1. A method for manufacturing a die to achieve refined rolling of complex irregular cross-section ring parts, characterized in that, include: Based on the complex irregular cross-sectional profile of the target ring, the groove profile of the rolling die is constructed; Based on the finite element simulation or analytical kinematic analysis of the ring rolling process, the timing information of the first contact between the billet and the die groove at different longitudinal positions during the rolling process is obtained, and the different structures on the die groove are divided into different wear zones according to the timing information. Analyze the wear degree of the different wear zones identified above, and formulate hardness distribution schemes for different regions; Different processes are used to manufacture rolling dies with differentiated hardness distributions based on the hardness distribution schemes of different regions.

2. The die manufacturing method for achieving refined rolling of complex irregular cross-section ring parts according to claim 1, characterized in that, The rolling die includes at least a drive roller and / or a core roller, and the die has a longitudinal axis that corresponds to the axial direction of the ring.

3. The die manufacturing method for achieving refined rolling of complex irregular cross-section ring parts according to claim 1, characterized in that, The groove profile has profiled areas with different radial depths in the longitudinal direction, and the different radial profiled areas correspond to the irregular cross-section of the ring.

4. The die manufacturing method for achieving refined rolling of complex irregular cross-section ring parts according to claim 1, characterized in that, The different wear zones include a high wear zone, a low wear zone, and a non-wear zone. The high wear zone is the local area in the longitudinal direction of the die groove that first experiences continuous friction and high-pressure contact with the billet. The low wear zone is the local area that experiences delayed contact or less pressure release compared to the high wear zone. The non-wear zone is the area where the billet and the die groove do not experience wear during the rolling process.

5. The die manufacturing method for achieving refined rolling of complex irregular cross-section ring parts according to claim 4, characterized in that, The hardness distribution schemes for different regions are as follows: the first hardness value corresponding to the high wear zone, the second hardness value corresponding to the low wear zone, and the third hardness value corresponding to the non-wear zone, wherein the first hardness value > the second hardness value ≥ the third hardness value.

6. The die manufacturing method for achieving refined rolling of complex irregular cross-section ring parts according to claim 5, characterized in that, The first hardness value is a Rockwell hardness of HRC 60~65, the second hardness value is a Rockwell hardness of HRC 50~55, and the third hardness value is a Rockwell hardness of HRC 45~50.

7. The die manufacturing method for achieving refined rolling of complex irregular cross-section ring parts according to claim 1, characterized in that, The different processes adopted according to the hardness distribution scheme of different regions include one or more processes selected from material composite process, gradient heat treatment process and segmented combination process.

8. The die manufacturing method for achieving refined rolling of complex irregular cross-section ring parts according to claim 7, characterized in that, The material composite process includes using a single metal matrix as a base and performing local surface strengthening treatment along the longitudinal direction to form a hardened layer with a hardness higher than that of the matrix. The local surface strengthening treatment includes one or more treatment methods selected from laser hardening, induction hardening, welding of high-hardness wear-resistant alloys, laser cladding, thermal spraying, boronizing, or nitriding.

9. The die manufacturing method for achieving refined rolling of complex irregular cross-section ring parts according to claim 7, characterized in that, The gradient heat treatment process includes using additive manufacturing technology to form an integrated mold along the longitudinal direction, and by adjusting the powder material composition or process parameters, to achieve a continuous gradient change or step-like change in hardness.

10. The die manufacturing method for achieving refined rolling of complex irregular cross-section ring parts according to claim 7, characterized in that, The segmented assembly process includes pre-preparing multiple annular roller segments or arc segments with different material hardness, and then assembling them into an integral mold through welding, mechanical connection or thermal assembly.

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