Design and upsetting method of oversize blank for reducing upsetting power of free forging
By designing a drum-shaped blank structure, the stress state during upsetting is changed, which solves the problem of insufficient upsetting force for ultra-large volume blanks and achieves efficient forming and quality improvement.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- WUHAN UNIV OF TECH
- Filing Date
- 2026-03-30
- Publication Date
- 2026-06-05
AI Technical Summary
Existing forging technology cannot effectively reduce the upsetting force of ultra-large volume blanks, resulting in insufficient forging press force and difficulty in meeting the forming requirements of large volume forgings.
The blank is designed as a drum shape with large diameters at the top and bottom and small diameters in the middle. The drum shape structure is used to change the triaxial stress state of the metal during upsetting, converting axial compressive stress into radial tensile stress. The law of least resistance guides the metal to flow preferentially along the short axis, optimizing the stress state and reducing the upsetting force.
By controlling the upsetting force within the equipment load, the equipment performance requirements are reduced, the forming quality is improved, instability and crack defects are reduced, and efficient forming of ultra-large volume blanks is achieved.
Smart Images
Figure CN122142215A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of metal forging, and specifically relates to a design and upsetting method for ultra-large volume blanks that reduces the upsetting force energy during free forging. Background Technology
[0002] Upsetting is a fundamental process commonly used in metal forging. It is mainly used to axially compress and radially expand the billet, breaking up segregated and hard phases and eliminating internal porosity through large deformation, resulting in a uniform microstructure in the forging. Upsetting is often combined with drawing; repeated upsetting and drawing can further increase the deformation of the forging, resulting in an even more uniform microstructure.
[0003] For small-volume (mass) forgings, since the required upsetting and drawing forces are within the capacity range of the enterprise's free forging press, the blank design range is wide and the upsetting and drawing process is easy to achieve.
[0004] For large-volume (mass) forgings, the main limitation to increasing the blank volume is the diameter of the ingot, because the height-to-diameter ratio of the ingot in the initial upsetting process must be less than 3. For this reason, a series of tool and die designs have been developed to fix the position of the ingot and avoid tilting during the upsetting process. Nevertheless, the maximum height-to-diameter ratio of the material provided for large-volume ingots does not exceed 3.3. At the same time, shrinkage cavities will appear in the axial direction of many metal and alloy ingots, and the ingot diameter cannot be increased indefinitely, thus limiting the upper limit of the material volume (mass) required for integral forgings.
[0005] With the rapid development of marine engineering equipment and marine transportation equipment, the requirements for the volume of integral forgings are becoming increasingly larger. Therefore, a process has emerged where several uniformly forged round blanks are stacked together, the contact gaps between the upper and lower layers are first sealed by welding, then heated, and finally upset to completely eliminate the original contact gaps, forming a metallurgically bonded, integral, ultra-large volume (mass) blank. This process of stacking round blanks + welding + heating + upset can produce ultra-large volume (mass) blanks that were previously impossible to achieve. However, the force capacity of existing forging presses is beginning to be insufficient to meet the force requirements for upseting ultra-large volume (mass) blanks. If a slender blank design (height-to-diameter ratio of 3.3) is used, anti-tilting dies are required, which only increases the upset force; if a short and thick blank design (height-to-diameter ratio of around 2) is used, the increased cross-sectional area will also significantly increase the upset force.
[0006] Therefore, how to reduce the upsetting force energy of free forging when upsetting ultra-large volume blanks, so as to simultaneously meet the force energy and total volume requirements of forging press, is a common problem faced by blank upsetting in many engineering applications. Summary of the Invention
[0007] The purpose of this application is to provide a design method for ultra-large volume blanks that reduces the upsetting force energy of free forging, and an upsetting method for ultra-large volume blanks that reduces the upsetting force energy of free forging based on the above design method. This application designs the blank into a waist drum shape, which not only reduces the upsetting force energy of free forging but also improves the forming quality.
[0008] The technical solution adopted in this invention is A method for designing ultra-large volume blanks to reduce the upsetting force during free forging involves designing the blank as a drum shape with large diameters at the top and bottom and a small diameter in the middle. This drum-shaped structure alters the triaxial stress state of the metal during upsetting, converting axial compressive stress into radial tensile stress. Under the law of least resistance, the metal is guided to flow preferentially along the short axis, and it is ensured that the outward deformation of the blank's middle section during upsetting does not exceed the dimensions of the blank's two ends. This allows the required upsetting force to vary with the cross-sectional area of the blank's middle section, thus enabling the upsetting of ultra-large volume blanks with a smaller upsetting force.
[0009] Preferably, the specific shape of the blank is determined by several key dimensional parameters, and the method for determining these key dimensional parameters is as follows: first, based on the maximum force of the forging press... The diameter D of the upper and lower ends of the blank is determined based on the properties of the blank material, where the maximum force of the forging press is... The properties of the blank material are known and obtained experimentally. Then, the middle diameter d, height H, and radius R of the blank are determined based on the blank volume V, the blank height-to-diameter ratio k, and the diameters of the upper and lower ends of the blank D. Among these, the blank volume V is known, the blank height-to-diameter ratio k is selected according to the situation, and the diameters of the upper and lower ends of the blank D are obtained by calculation.
[0010] Preferably, the formula for calculating the diameter D at the top and bottom of the blank is: (1) in, This refers to the flow stress of the raw material during the upsetting process.
[0011] Preferably, the height-to-diameter ratio of the blank is... k takes values from 1.6 to 2.5.
[0012] Preferably, the method for determining the middle diameter d, height H, and radius R of the blank based on the blank volume V, the blank height-to-diameter ratio k, and the diameters at the top and bottom of the blank D is as follows: First, establish the functional relationship between the middle diameter d, height H, radius R, volume V, height-to-diameter ratio k, and diameters at the top and bottom of the blank based on the cross-sectional arc calculation equation of the drum-shaped structure, the volume calculation equation of the drum-shaped structure, and the height-to-diameter ratio; then, use the bisection method to iteratively calculate and solve the function to obtain the middle diameter d, height H, and radius R of the blank.
[0013] Preferably, based on the calculation equation of the cross-sectional arc of the drum-shaped structure, the geometric constraint relationships of the upper and lower end diameters D, the middle diameter d, the height H, and the arc radius R of the blank are obtained: (2) Based on the volume calculation equation for the drum-shaped structure, the functional relationship between the blank volume V and the blank's central diameter d, blank height H, and blank arc radius R is obtained: (3) Based on the height-to-diameter ratio, the geometric constraint relationship between the mid-section diameter d and the height H of the blank is obtained: (4) Combining equations (2) to (4), we can obtain the functional relationships between the blank's middle diameter d, blank height H, blank arc radius R, blank volume V, blank height-to-diameter ratio k, and blank upper and lower end diameter D.
[0014] Preferably, the method of using the bisection method to iteratively calculate and solve the function to obtain the blank's central diameter d, blank height H, and blank arc radius R is as follows: Based on the functional relationship in equation (3), combined with equation (2) and equation (4), the blank's central diameter d is taken as the only variable. The bisection method is used in combination with numerical integration to iteratively calculate and solve the blank's central diameter d. After obtaining the numerical solution of d, the blank height H and blank arc radius R are calculated and obtained using equation (2) and equation (4).
[0015] Preferably, the method of iteratively calculating and solving the diameter d of the middle part of the blank using the bisection method combined with numerical integration involves inputting the known blank volume V, the blank height-to-diameter ratio k, the diameters D of the upper and lower ends of the blank, and the set precision. and maximum number of iterations back: S1) Initialize the iteration interval and iteration counter: Set the lower bound of the iteration. upper bound of iteration The iteration count n=0; S2) Calculate the midpoint of the interval : = ; S3) Calculate the midpoint of the interval Corresponding blank volume :
[0016] S4) Adjust the iteration interval: like If d is too small, update the left endpoint: ;like If d is too large, update the right endpoint: Increment the iteration count n by 1; S5) Determine the iteration termination condition: Calculate volume error If volume error Or iteration count n The output result is as follows. Otherwise, continue iterating and repeating steps S2 to S5.
[0017] Preferably, the accuracy is set. Set the initial lower bound for iteration. Initial iteration upper bound .
[0018] A method for upsetting ultra-large volume blanks to reduce the upsetting force energy of free forging is provided. The blanks are obtained by the above-mentioned design method for ultra-large volume blanks to reduce the upsetting force energy of free forging. The downsetting speed is controlled by variable speed during upsetting, thereby improving the forming quality while reducing the upsetting force energy of free forging.
[0019] The beneficial effects of this invention are: During the upsetting and plastic forming process of metal materials, the radial frictional resistance of the upper and lower end faces of the blank is relatively large, resulting in "dead zones" at the upper and lower ends of the blank. Due to the effect of the "dead zones" at the upper and lower ends, the metal in the middle of the blank in the height direction is forced to bulge outward. This application utilizes this phenomenon and designs the blank as a waist drum shape, which not only optimizes the stress state and controls the upsetting force within the equipment load, reducing the equipment performance requirements, but also guides the orderly flow of metal, reduces instability and crack defects, and improves the forming quality. Attached Figure Description
[0020] Figure 1 This is a schematic diagram of the key dimensional parameters of the drum-shaped blank in this application.
[0021] Figure 2 This is a schematic diagram showing the dimensions of the drum-shaped blank in the embodiments of this application.
[0022] Figure 3 This is a diagram showing the forming result of a simulated drum-shaped blank after upsetting in an embodiment of this application.
[0023] Figure 4 This is a schematic diagram showing the change in pressing speed over time when upsetting a waisted drum-shaped blank in an embodiment of this application.
[0024] Figure 5 This is a schematic diagram illustrating the change of upsetting force over time during upsetting of a waisted drum-shaped blank in an embodiment of this application. Detailed Implementation
[0025] The present application will be further described below with reference to the accompanying drawings and embodiments. The features and performance of the present application will be further described in detail below with reference to the embodiments.
[0026] Example 1 This embodiment discloses a design method for ultra-large volume blanks that reduces the upsetting force during free forging. The blank is designed as a drum shape with large diameters at the top and bottom and a small diameter in the middle. The drum shape changes the triaxial stress state of the metal during upsetting, converting axial compressive stress into radial tensile stress. Under the law of least resistance, the metal is guided to flow preferentially along the short axis, and it is ensured that the deformation of the blank bulging outward during upsetting in the middle does not exceed the dimensions of the two ends of the blank. This makes the required upsetting force change with the cross-sectional area of the middle of the blank, thereby upsetting ultra-large volume blanks with a smaller upsetting force. During the upsetting and plastic forming process of metal materials, the radial frictional resistance of the upper and lower end faces of the blank is relatively large, resulting in "dead zones" at the upper and lower ends of the blank. Due to the effect of the "dead zones" at the upper and lower ends, the metal in the middle of the blank in the height direction is forced to bulge outward. This application utilizes this phenomenon and designs the blank as a waist drum shape, which not only optimizes the stress state and controls the upsetting force within the equipment load, reducing the equipment performance requirements, but also guides the orderly flow of metal, reduces instability and crack defects, and improves the forming quality.
[0027] like Figure 1 As shown, the specific shape of the blank is determined by several key dimensional parameters, and the method for determining these key dimensional parameters is as follows: I. Based on the maximum force capacity of the forging press The diameter D of the upper and lower ends of the blank is determined based on the properties of the blank material. The formula for calculating the diameter D at the top and bottom of the blank is: (1) in, The flow stress of the blank material during the upsetting process; the maximum force of the forging press. The known flow stress of raw material in the upsetting process Obtained through experiments.
[0028] II. Determine the mid-section diameter d, height H, and radius R of the blank based on the blank volume V, height-to-diameter ratio k, and top and bottom diameters D: 1. Based on the calculation equations for the cross-sectional arc of the drum-shaped structure, the volume calculation equation of the drum-shaped structure, and the height-to-diameter ratio, establish the functional relationships between the blank's mid-section diameter d, blank height H, blank arc radius R, blank volume V, blank height-to-diameter ratio k, and blank upper and lower end diameters D: Based on the calculation equation of the cross-sectional arc of the drum-shaped structure, the geometric constraint relationships of the upper and lower end diameters D, the middle diameter d, the height H, and the arc radius R of the blank are obtained: (2) Based on the volume calculation equation for the drum-shaped structure, the functional relationship between the blank volume V and the blank's central diameter d, blank height H, and blank arc radius R is obtained: (3) Based on the height-to-diameter ratio, the geometric constraint relationship between the mid-section diameter d and the height H of the blank is obtained: (4) Combining equations (2) to (4), we can obtain the functional relationships between the blank's middle diameter d, blank height H, blank arc radius R, blank volume V, blank height-to-diameter ratio k, and blank upper and lower end diameter D.
[0029] Among them, the blank volume V is known, the blank height-to-diameter ratio k is selected according to the situation, and the blank upper and lower diameters D are obtained by calculation.
[0030] Among them, the height-to-diameter ratio of the blank The value of k ranges from 1.6 to 2.5, depending on the equipment condition and the company's circumstances.
[0031] 2. Using the bisection method, iterative calculations are performed to solve the function and obtain the blank's mid-section diameter d, blank height H, and blank arc radius R: A. Based on the functional relationship in equation (3), and combined with equations (2) and (4), the diameter d at the center of the blank is taken as the only variable, and the diameter d at the center of the blank is iteratively calculated using the bisection method combined with numerical integration: Input the known blank volume V, blank height-to-diameter ratio k, blank top and bottom diameters D, and the set precision. and maximum number of iterations back: S1) Initialize the iteration interval and iteration counter: Set the lower bound of the iteration. upper bound of iteration The iteration count n=0; S2) Calculate the midpoint of the interval : = ; S3) Calculate the midpoint of the interval Corresponding blank volume :
[0032] S4) Adjust the iteration interval: like If d is too small, update the left endpoint: ;like If d is too large, update the right endpoint: Increment the iteration count n by 1; S5) Determine the iteration termination condition: Calculate volume error If volume error Or iteration count n The output result is as follows. Otherwise, continue iterating and repeating steps S2 to S5.
[0033] Preferably, the accuracy is set. Set the initial lower bound for iteration. Initial iteration upper bound .
[0034] Setting a precision can make the solution more accurate, while setting a maximum number of iterations can avoid infinite iterations.
[0035] B. After obtaining the numerical solution of d, calculate the blank height H and blank radius R using equations (2) and (4): , .
[0036] Therefore, this application can accurately calculate the blank size, has strong process controllability, and reduces trial and error costs.
[0037] Example 2 This embodiment discloses a method for upsetting ultra-large volume blanks to reduce the upsetting force energy of free forging. The blank is obtained by the ultra-large volume blank design method for reducing the upsetting force energy of free forging in Embodiment 1 above. Furthermore, the downsetting speed is controlled by variable speed during upsetting, thereby improving the forming quality while reducing the upsetting force energy of free forging.
[0038] Taking titanium alloy TC4 as an example, its upsetting equipment can provide a maximum force of 14,000 tons, and its blank volume is 11.06 cubic meters. 3 The deformation resistance of the TC4 titanium alloy at 950℃ was tested through a hot compression experiment. The results were then used in practical engineering conditions. =30N / mm 2 Choose a blank height-to-diameter ratio of k=2.
[0039] Its key dimensional parameters are determined as follows: The diameter D of the upper and lower ends of the blank ; ; Input blank volume V The height-to-diameter ratio of the blank is k=2, and the diameters of the upper and lower ends of the blank are D. Precision Maximum number of iterations Then, set the lower bound for the iteration. upper bound of iteration The diameter d of the middle part of the blank was calculated iteratively by using the bisection method combined with numerical integration, and the diameter d of the middle part of the blank was found to be 1773 mm. Raw material radius R ; blank height H .
[0040] The key dimensional parameters were calculated as follows: Figure 2 As shown, finite element simulation verification was performed, and the final forming result is as follows. Figure 3 As shown, the downward pressure speed changes with time as follows: Figure 4 As shown, the upsetting force changes with time as follows: Figure 5 As shown, the final forging height is 1.7 meters, and the upsetting force is within the force limit.
[0041] The embodiments described above are some, but not all, of the embodiments of this application. The detailed description of the embodiments of this application is not intended to limit the scope of the claimed application, but merely to illustrate selected embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application.
Claims
1. A method for designing ultra-large volume blanks to reduce the roughing force energy during free forging, characterized in that: The blank is designed as a drum shape with large diameters at the top and bottom and small diameter in the middle. The drum shape changes the triaxial stress state of the metal during upsetting, converting axial compressive stress into radial tensile stress. Under the law of least resistance, the metal is guided to flow preferentially along the short axis. It is also ensured that the outward deformation of the blank during upsetting in the middle does not exceed the dimensions of the blank ends. This makes the required upsetting force change with the cross-sectional area of the blank in the middle, thus allowing for upsetting of ultra-large volume blanks with a smaller upsetting force.
2. The method for designing ultra-large volume blanks to reduce the roughing force energy of free forging as described in claim 1, characterized in that, The specific shape of the blank is determined by several key dimensional parameters. The method for determining these key dimensional parameters is as follows: first, based on the maximum force of the forging press... The diameter D of the upper and lower ends of the blank is determined based on the properties of the blank material, where the maximum force of the forging press is... The properties of the blank material are known and obtained experimentally. Then, the middle diameter d, height H, and radius R of the blank are determined based on the blank volume V, the blank height-to-diameter ratio k, and the diameters of the upper and lower ends of the blank D. Among these, the blank volume V is known, the blank height-to-diameter ratio k is selected according to the situation, and the diameters of the upper and lower ends of the blank D are obtained by calculation.
3. The method for designing ultra-large volume blanks to reduce the roughing force energy of free forging as described in claim 2, characterized in that, The formula for calculating the diameter D at the top and bottom of the blank is: （1） in, This refers to the flow stress of the raw material during the upsetting process.
4. The method for designing ultra-large volume blanks to reduce the roughing force energy of free forging as described in claim 2, characterized in that: The height-to-diameter ratio of the blank k takes values from 1.6 to 2.
5.
5. The method for designing ultra-large volume blanks to reduce the roughing force energy of free forging as described in claim 2, characterized in that, The method for determining the mid-section diameter d, height H, and radius R of the blank based on the blank volume V, height-to-diameter ratio k, and upper and lower diameters D is as follows: First, establish the functional relationships between the mid-section diameter d, height H, radius R, volume V, height-to-diameter ratio k, and upper and lower diameters D of the blank based on the cross-sectional arc calculation equation, volume calculation equation, and height-to-diameter ratio of the drum-shaped structure. Then, use the bisection method to iteratively calculate and solve the functions to obtain the mid-section diameter d, height H, and radius R of the blank.
6. The method for designing ultra-large volume blanks to reduce the roughing force energy of free forging as described in claim 5, characterized in that: Based on the calculation equation of the cross-sectional arc of the drum-shaped structure, the geometric constraint relationships of the upper and lower end diameters D, the middle diameter d, the height H, and the arc radius R of the blank are obtained: （2） Based on the volume calculation equation for the drum-shaped structure, the functional relationship between the blank volume V and the blank's central diameter d, blank height H, and blank arc radius R is obtained: （3） Based on the height-to-diameter ratio, the geometric constraint relationship between the mid-section diameter d and the height H of the blank is obtained: （4） Combining equations (2) to (4), we can obtain the functional relationships between the blank's middle diameter d, blank height H, blank arc radius R, blank volume V, blank height-to-diameter ratio k, and blank upper and lower end diameter D.
7. The method for designing ultra-large volume blanks to reduce the roughing force energy of free forging as described in claim 6, characterized in that, The method of using the bisection method to iteratively calculate and solve the function to obtain the blank's central diameter d, blank height H, and blank arc radius R is as follows: Based on the functional relationship in equation (3), combined with equation (2) and equation (4), the blank's central diameter d is taken as the only variable. The bisection method is used in combination with numerical integration to iteratively calculate and solve the blank's central diameter d. After obtaining the numerical solution of d, the blank height H and blank arc radius R are calculated using equation (2) and equation (4).
8. The method for designing ultra-large volume blanks to reduce the roughing force energy of free forging as described in claim 7, characterized in that, The method of iteratively calculating the diameter d at the center of the blank using the bisection method combined with numerical integration involves inputting the known blank volume V, the blank height-to-diameter ratio k, the blank upper and lower diameters D, and a set precision. and maximum number of iterations back: S1) Initialize the iteration interval and iteration counter: Set the lower bound of the iteration. upper bound of iteration The iteration count n=0; S2) Calculate the midpoint of the interval : = ； S3) Calculate the midpoint of the interval Corresponding blank volume : S4) Adjust the iteration interval: like If d is too small, update the left endpoint: ;like If d is too large, update the right endpoint: Increment the iteration count n by 1; S5) Determine the iteration termination condition: Calculate volume error If volume error Or iteration count n The output result is as follows. Otherwise, continue iterating and repeating steps S2 to S5.
9. The method for designing ultra-large volume blanks to reduce the roughing force energy of free forging as described in claim 8, characterized in that: Setting precision Set the initial lower bound for iteration. Initial iteration upper bound .
10. A method for upsetting ultra-large volume blanks to reduce the upsetting force energy during free forging, characterized in that: The blank is obtained by the ultra-large volume blank design method for reducing the free forging upsetting force energy as described in any one of claims 1 to 9, and the downsetting speed is controlled by variable speed during upsetting, thereby reducing the free forging upsetting force energy while improving the forming quality.