Forging forming method and tooling for large thin-walled drum parts
By using forging methods and die tooling, the quality and cost issues in the processing of large thin-walled drum-shaped parts were solved, enabling efficient and low-cost production of high-quality forgings that meet the technical requirements of marine clutches.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- CHONGQING CHANGZHENG HEAVY IND
- Filing Date
- 2023-11-14
- Publication Date
- 2026-08-04
AI Technical Summary
Existing technologies are insufficient to meet the high-quality processing requirements of large, thin-walled drum-shaped parts in marine clutches. Conventional casting processes have many defects and require a large amount of welding repairs, making it difficult to meet the JB/T4730 standard and the 850 MPa strength grade.
The forging method is adopted, and staged heating and multi-step forging are carried out using mold tooling. Special mold tooling parameters are designed, including forming mold, upper pad mold and punching tooling. Through five-stage heating process and finishing correction, near-net-shape forming and high-quality forging production are achieved.
It improved processing efficiency, reduced costs, obtained forgings with excellent internal quality, reduced machining allowance, shortened production cycle, and met the requirements of JB/T4730 standard and 850Mpa strength grade.
Smart Images
Figure CN117483621B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of parts processing technology, specifically to a forging method and tooling for large thin-walled drum-shaped parts. Background Technology
[0002] With the continuous development of my country's shipbuilding industry, the operating conditions of ships at sea are becoming increasingly complex. As the disengagement and reversing device of the ship's main propulsion gearbox, the clutch controls the disengagement and engagement of the ship's power output shaft, playing a crucial role in the ship's maneuverability and being a vital component supporting the ship's flexibility in complex operating conditions. Currently, with the increasing power of ship propulsion systems, marine clutches are becoming larger and larger, and the related technical requirements are also becoming more stringent. Large, thin-walled drum-shaped parts, as an important component of marine clutches, have been subject to higher standards in existing technical requirements regarding their internal and external defect control levels and strength requirements. For example, defect control needs to meet the JB / T4730 standard's Class I quality requirements for ultrasonic and magnetic particle testing, and tensile strength needs to reach a strength grade of 850 MPa. If the processing quality fails to meet these standards, it will directly affect the overall quality of the marine clutch.
[0003] In the machining of large, thin-walled drum-shaped parts, the commonly used method is casting. This method is simple to operate and has a low cost; however, the forming effect is poor, with many defects, a large amount of welding repair and rework, and the quality of the resulting castings often fails to meet requirements. Especially with the increasing technical requirements of marine clutches, conventional casting processes can no longer meet the current needs of parts machining. Summary of the Invention
[0004] The present invention aims to provide a forging method and tooling for large thin-walled drum-shaped parts, which can achieve high product processing quality, help improve processing efficiency, and reduce processing costs.
[0005] To achieve the above objectives, the basic solution provided by this invention is as follows:
[0006] Option 1
[0007] A forging method for large, thin-walled drum-shaped parts includes the following steps:
[0008] Step 1: Design the forging drawing based on the part dimensions;
[0009] Step 2: Design the die mold tooling according to the forging drawing; the die mold tooling includes a hollow forming die, an upper pad die, and a punching tooling.
[0010] Step 3: Determine the staged heating process parameters and the forging process parameters for each step;
[0011] Step 4: Perform forging and forming according to the steps to obtain the forging; the forging and forming process includes: Step 1: Forging a stepped shaft-shaped billet according to the weight and size requirements of the forging drawing; Step 2: Placing the billet into the forming mold and upsetting it downwards, so that the billet is turned upside down and completely covers the forming mold; Step 3: Placing the upper die on the surface of the billet and pressing it downwards until it is completely pressed into the billet body, then removing the upper die; Step 4: Placing the punching fixture in the center of the billet and punching holes downwards on both sides.
[0012] Furthermore, it also includes step 5, which involves finishing and correcting the forging.
[0013] Furthermore, when designing forging drawings, the draft angle and process allowance of thin-walled drum forgings are designed according to the outline drawing of thin-walled drum parts.
[0014] Furthermore, determining the staged heating process parameters includes setting a five-stage heating process.
[0015] Furthermore, the five-stage heating process includes: controlling the raw material to be kept at 500°C; heating up to 850°C; keeping at 850°C; heating up to 1230°C; keeping at 1230°C, and starting forging.
[0016] Furthermore, after the forging process begins, the holding time for subsequent forging heat cycles is set at 0.8–1.2 h / 100 mm based on the billet thickness.
[0017] The working principle and advantages of this solution are as follows:
[0018] This solution utilizes a die-casting fixture for die forging, resulting in dimensionally precise forgings. High-quality forming of large, thin-walled drum-shaped parts can be achieved through simple finishing and correction. This solution overcomes the limitations of conventional casting processes by employing forging technology to process large, thin-walled drum-shaped parts. It eliminates casting defects such as porosity, pores, and dendrite segregation at the source, resulting in forgings with excellent internal quality. Furthermore, this solution has lower operating costs, uses a simple die-casting fixture, and produces dimensionally accurate forgings, effectively reducing machining allowances and shortening the manufacturing cycle. This solution achieves high product quality, contributing to improved processing efficiency and reduced processing costs.
[0019] In particular, firstly, compared with conventional forging processes, this solution chooses to forge using a die-casting fixture, resulting in lower forging costs and higher forging quality. Specifically, in the die-casting process designed in this solution, on the one hand, near-net-shape forgings can be obtained through die-casting fixture forging, reducing machining allowances and material consumption; on the other hand, in die-casting, the forging deformation of various parts of large, thin-walled drum-shaped parts can be uniformly controlled, resulting in forgings with good microstructure; in addition, the die-casting fixture has a simple structure, low manufacturing cost, strong versatility and commonality with other forgings, and high overall cost-effectiveness.
[0020] Secondly, this solution overcomes the design challenges of using die-casting molds in the forging production of large, thin-walled drum-shaped parts, enabling die-casting molds to achieve good results in large-sized, heavy parts. Specifically, large, thin-walled drum-shaped parts, which are components of marine clutches, often have length, width, and height dimensions reaching several meters and weights reaching tons; moreover, their structures include thin-walled structures. This makes die-casting molds prone to the following difficulties—first, the selection of design parameters for the draft angles inside and outside the die-casting mold. If the draft angle is too large, it is easy to cause difficulties in upsetting the forging and reverse edge formation, making it difficult to forge the height dimension; if the draft angle is too small, it will lead to difficulty in demolding after the reverse edge is formed. Secondly, the selection of the design parameters for the fillet radius of the die is crucial. If the fillet radius is too large, the forging deformation force requirement is high, making it difficult to form the material and achieve the required forging dimensions. If the fillet radius is too small, it will lead to forging defects such as folding and cracking in certain areas. Thirdly, the forging dimensions are large and the operation is complex. The design of the die and tooling must fully consider the forging operation processability. At the same time, it is necessary to comprehensively consider the optimal process combination between the difficulty of the forging operation and production efficiency and the reduction of the machining amount of the forging.
[0021] To address the aforementioned challenges, this solution simulates the forging process and features targeted parameter design for the forming die, upper die, and punching fixture. These parameters are innovatively combined and applied to the forging production of large, thin-walled drum-shaped parts. The designed die shape meets the processing requirements, facilitates demolding, and minimizes forging defects. Furthermore, by using the die fixture in separate steps, this solution reduces operational complexity, better ensures the uniformity and controllability of deformation during forging, results in superior forging processability, and produces high-quality forgings.
[0022] Option 2
[0023] Forging tooling for large thin-walled drum-shaped parts, for the forging method for large thin-walled drum-shaped parts as described in Scheme 1; including a die tooling; the die tooling includes a hollow forming die, an upper pad die and a punching tooling.
[0024] Furthermore, the inclination of the inner wall of the molded die is 3° to 5°.
[0025] Furthermore, the inclination of the outer cylindrical surface of the punching fixture is 5° to 7°.
[0026] Furthermore, the upper edges of the inner and outer walls of the molded die and the upper edges of the outer wall of the upper pad mold are both rounded; and the rounded corner size is R30 to R50.
[0027] The working principle and advantages of this solution are as follows: The die-casting fixture includes different types of components, which can meet the forming requirements of different structural features of large, thin-walled drum-shaped parts. It is easy to use, can be mass-produced efficiently, and has good economic benefits. Furthermore, the die-casting fixture designed in this solution has special dimensions. The set angle can ensure the effective completion of steps such as upsetting and reverse edge forming of the forging, ensuring accurate forming of the forging and easy demolding. The set rounded corners can ensure smooth forming of each step and reduce the occurrence of forging defects. The overall fixture dimensions are precisely designed, which can assist in completing high-quality forging. Attached Figure Description
[0028] Figure 1 This is a schematic diagram of the method flow of the forging and forming method and tooling embodiment of the present invention for large thin-walled drum-shaped parts;
[0029] Figure 2 This is a contour drawing of a thin-walled drum-shaped part, representing an embodiment of the forging method and tooling for large thin-walled drum-shaped parts according to the present invention.
[0030] Figure 3 This is a forging drawing of an embodiment of the forging method and tooling for large thin-walled drum-shaped parts according to the present invention;
[0031] Figure 4 This is a schematic diagram of the forming mold structure of the forging method and tooling embodiment of the present invention for large thin-walled drum-shaped parts;
[0032] Figure 5 This is a schematic diagram of the upper die structure of the forging method and tooling embodiment of the present invention for large thin-walled drum-shaped parts;
[0033] Figure 6 This is a schematic diagram of the punching fixture structure of the forging method and tooling embodiment of the present invention for large thin-walled drum-shaped parts;
[0034] Figure 7 This is a schematic diagram of the blank structure of the stepped shaft shape in the forging method and tooling embodiment of the present invention for large thin-walled drum-shaped parts;
[0035] Figure 8 This is a schematic diagram of step 2, which involves loading the blank into the forming mold, in an embodiment of the forging and forming method and tooling for large thin-walled drum-shaped parts according to the present invention.
[0036] Figure 9This is a schematic diagram of the downward upsetting step in step 2 of the forging method and tooling embodiment of the present invention for large thin-walled drum-shaped parts;
[0037] Figure 10 This is a schematic diagram of the blank reverse flanging and complete wrapping of the forming mold step in step 2 of the forging method and tooling embodiment of the present invention for large thin-walled drum-shaped parts.
[0038] Figure 11 This is a schematic diagram of step 3, pressing in the upper die, in the forging method and tooling embodiment of the present invention for large thin-walled drum-shaped parts.
[0039] Figure 12 This is a schematic diagram of the punching step in step 4 of the forging method and tooling embodiment of the present invention for large thin-walled drum-shaped parts. Detailed Implementation
[0040] The following detailed explanation illustrates the specific implementation methods:
[0041] The basic implementation examples are as follows: Figure 1 The forging method for large, thin-walled drum-shaped parts includes the following steps:
[0042] Step 1: Design the forging drawing based on the part dimensions.
[0043] When designing the forging drawing, the draft angle and process allowance of the thin-walled drum-shaped forging are designed according to the outline drawing of the thin-walled drum-shaped part. In this embodiment, the part is selected as a thin-walled drum-shaped part in a high-power marine clutch, and the outline drawing of the thin-walled drum-shaped part is attached. Figure 2 As shown, its outer diameter is approximately 2500 mm, its height is approximately 800 mm, its wall thickness is approximately 100 mm, and its total weight is approximately 7 tons. Furthermore, the thin-walled drum-shaped part in this embodiment is designed with a strength grade of 850 MPa and uses medium-carbon alloy steel such as 35CrMo or 42CrMo as raw material. Such large parts are conventionally formed using casting processes, but the forming effect is poor, with many defects, a large amount of welding repair and rework, and the quality of the castings often fails to meet requirements.
[0044] The forging drawing obtained from the outline drawing of the corresponding thin-walled drum-shaped part is shown in the attached figure. Figure 3 As shown.
[0045] Step 2: Design the die-casting fixture based on the forging drawing; the die-casting fixture includes a hollow forming die (as shown in the attached image). Figure 4 (as shown), upper mold (as attached) Figure 5 (as shown) and punching fixtures (as attached) Figure 6 (As shown).
[0046] Step 3: Determine the staged heating process parameters and the forging process parameters for each step.
[0047] The determination of the phased heating process parameters includes setting a five-stage heating process. Specifically, the five-stage heating process includes: holding the raw material at 500℃ for 4–6 hours; increasing the temperature to 850℃ at a rate of 60–80℃ / hour; holding at 850℃ for 6–8 hours; increasing the temperature to 1230℃ at the maximum furnace power; and holding at 1230℃ for 10 hours to begin forging. After the start of forging, the holding time for subsequent forging passes is set at 0.8–1.2 hours / 100mm based on the billet thickness. Using a phased heating method allows for setting appropriate heating methods for different process steps, resulting in higher heating quality.
[0048] Step 4: Perform forging and forming processes according to the steps to obtain the forging.
[0049] The forging process includes:
[0050] Step 1: According to the weight and dimensional requirements of the forging drawing, forge a blank in the shape of a stepped shaft. The diameter of the small end of the stepped shaft is designed based on the inner hole size of the forming die (-30 to 50 mm), while the large end of the stepped shaft is designed with a height-to-diameter ratio of 1.7 to 2.2 based on the material weight. (See attached diagram.) Figure 7 As shown.
[0051] Step 2: First, coat the surface of the molding die with a layer of graphite emulsion and preheat it to 300-400℃. Then, load the blank into the molding die, as shown in the attached figure. Figure 8 As shown. The large end of the stepped shaft is rolled downwards and then upset to form the entire shape, facilitating the downward flow of the stepped shaft-shaped billet material, as shown in the attached diagram. Figure 9 As shown, this causes the blank to be flipped in the opposite direction and completely wrapped around the forming mold, as attached. Figure 10 As shown.
[0052] Step 3: Apply a layer of graphite emulsion to the surface of the upper mold pad, and preheat to 300-400℃, as shown in the attached image. Figure 11 As shown, the upper die is aligned and placed on the surface of the billet. After forging downwards until it is fully pressed into the billet body, the billet is clamped and rotated 180° using a forging manipulator. The upper die can then easily fall off under the lubrication of the graphite emulsion.
[0053] Step 4: Using a forging manipulator, clamp the billet and rotate it 180° again. Place the punching fixture in the center of the billet and punch holes downwards on both sides to obtain a hollow forging. This process ensures that the central part of the billet is fully forged and deformed, as shown in the attached diagram. Figure 12 As shown.
[0054] By implementing the forging process with the aforementioned division of labor, this solution effectively reduces the difficulty of production operations, fully utilizes the functions of each die and tooling, and makes it easier to ensure the uniformity and controllability of deformation during the forging process. This results in better forging processability and superior forging quality. Furthermore, auxiliary operations such as coating, preheating, and flipping in each step ensure higher die forging efficiency and more reliable forging operations.
[0055] Step 5: Finish and straighten the forging.
[0056] This embodiment also provides a forging forming fixture for large thin-walled drum-shaped parts, used in a forging forming method for large thin-walled drum-shaped parts as described above; including a die fixture; the die fixture includes a hollow forming die, an upper pad die, and a punching fixture.
[0057] Specifically, in this embodiment, the forming mold has an outer diameter of 2100mm, an inner diameter of 700mm, and a height of 500mm, with an inner wall inclination of 3-5°. The punching tool has a diameter of 200mm and an outer surface inclination of 5-7°. The upper edges of the inner and outer walls of the forming mold and the upper edge of the outer wall of the upper pad mold are all rounded; and the rounded corner size is R30-R50. Under the above dimensional conditions, the set inclination angle ensures the effective completion of steps such as upsetting and reverse edge forming of the forging, ensuring accurate forging and easy demolding; the set rounded corners ensure smooth forming of each step and reduce the likelihood of forging defects. The overall tooling dimensions are precisely designed, which helps to complete high-quality forging.
[0058] This embodiment provides a forging method and tooling for large, thin-walled drum-shaped parts. The forging process achieves high product quality, improves processing efficiency, and reduces processing costs. Furthermore, the designed mold tooling structure is simple, and the forgings obtained through mold forging are dimensionally accurate, effectively reducing machining allowances and shortening the production cycle.
[0059] The above descriptions are merely embodiments of the present invention. Commonly known structures and characteristics of the solutions are not described in detail here. Those skilled in the art are aware of all common technical knowledge in the field prior to the application date or priority date, are aware of all existing technologies in that field, and have the ability to apply conventional experimental methods prior to that date. Those skilled in the art can, under the guidance of this application, improve and implement this solution in combination with their own capabilities. Some typical known structures or methods should not be obstacles for those skilled in the art to implement this application. It should be noted that those skilled in the art can make several modifications and improvements without departing from the structure of the present invention. These should also be considered within the scope of protection of the present invention, and will not affect the effectiveness of the implementation of the present invention or the practicality of the patent.
Claims
1. A method of forging forming for large thin-walled drum parts, characterized in that, Includes the following steps: Step 1: Design the forging drawing based on the part dimensions; Step 2: Design the die-casting tooling according to the forging drawing; the die-casting tooling includes a hollow forming die, an upper pad die, and a punching tooling; the inclination of the inner wall of the forming die is 3-5°. Step 3: Determine the staged heating process parameters and the forging process parameters for each step; Step 4: Perform forging and forming processes according to the steps to obtain the forging; The forging process includes: Step 1, forging a stepped shaft-shaped billet according to the weight and size requirements of the forging drawing; the small end diameter of the stepped shaft is designed by subtracting 30-50mm from the inner hole size of the forming mold; Step 2, coating the surface of the forming mold with a layer of graphite emulsion, preheating it to 300-400℃, placing the billet into the forming mold, rotating downwards to press the large end of the stepped shaft, and then upsetting the whole piece so that the billet is reversed and completely wrapped around the forming mold; Step 3, aligning the upper pad mold and placing it on the surface of the billet, forging downwards until it is completely pressed into the billet body, and then removing the upper pad mold; Step 4, placing the punching fixture in the center of the billet and punching holes downwards on both sides.
2. The forging method for large, thin-walled drum-shaped parts according to claim 1, characterized in that, It also includes step 5, which involves finishing and correcting the forging.
3. The forging method for large, thin-walled drum-shaped parts according to claim 1, characterized in that, When designing forging drawings, the draft angle and process allowance of thin-walled drum forgings are designed according to the outline drawing of thin-walled drum parts.
4. The forging method for large, thin-walled drum-shaped parts according to claim 1, characterized in that, The determination of the phased heating process parameters includes setting a five-stage heating process.
5. The forging method for large, thin-walled drum-shaped parts according to claim 4, characterized in that, The five-stage heating process includes: holding the raw material at 500°C; raising the temperature to 850°C; holding the temperature at 850°C; raising the temperature to 1230°C; holding the temperature at 1230°C, and starting forging.
6. The forging method for large, thin-walled drum-shaped parts according to claim 5, characterized in that, After forging begins, the holding time for subsequent forging heats is set at 0.8–1.2 h / 100 mm based on the billet thickness.
7. A forging tooling for large, thin-walled drum-shaped parts, characterized in that, Forging method for large thin-walled drum-shaped parts as described in any one of claims 1-6; It includes a mold tooling; the mold tooling includes a hollow forming mold, an upper pad mold, and a punching tooling.
8. The forging tooling for large, thin-walled drum-shaped parts according to claim 7, characterized in that, The inclination of the inner wall of the molded die is 3° to 5°.
9. The forging tooling for large, thin-walled drum-shaped parts according to claim 7, characterized in that, The outer circular surface inclination of the punching fixture is 5° to 7°.
10. The forging tooling for large, thin-walled drum-shaped parts according to claim 7, characterized in that, The upper edges of the inner and outer walls of the molded die and the upper edges of the outer wall of the upper pad mold are both rounded; and the rounded corner size is R30 to R50.