Forging forming method and die for variable-cross-section thin-wall revolving body product

Abstract

The invention provides a variable-cross-section thin-wall revolving body product forging forming method and die. The method comprises the steps that a blank is put into a furnace to be heated, and a first forging die is assembled on a first forging press after being preheated; an upper punch of the first forging die ascends, and the heated blank is placed in a first cavity; the upper punch is pressed downwards, and the blank is forged into a required shape; the upper punch ascends again, and the lower ejector rod ejects the forge piece out and enters the furnace again for heat compensation; a second forging die is preheated and then assembled on a second forging press, the forge piece obtained after heat compensation is placed in a lower die, and an upper die moves downwards to be closed to press the forge piece; the left punch and the right punch move to the stop position, so that the forge piece is completely formed; and the left punch and the right punch are withdrawn, the upper die ascends to expose a formed product, the product is taken out, and flashes are polished cleanly. Compared with the prior art, more materials are saved, the mold utilization rate is better, comprehensive benefits are higher, continuity of a product flow line can be better achieved, and the service performance of a product is improved.

Description

Technical Field

[0001] The invention relates to the technical field of forging products of complex shapes, and in particular to a forging method and a die for a variable-section thin-walled body of revolution product. Background Art

[0002] For thin-walled rotating parts with variable cross-sections and skins in the middle, the traditional manufacturing process is to use straight rods for cutting. This manufacturing process not only wastes a lot of raw materials and increases machining hours, but also cuts off the product flow line, which is not conducive to the service performance of the product. Another manufacturing process is to thicken the thin-walled section and then forge it. The purpose of thickening is to reduce the cross-sectional changes, and the metal flow is stable, which is conducive to forming; at the same time, the thick-section material is relatively less affected by the friction of the mold during the flow process; in addition, the thick-section material has a large heat capacity and is not easy to lose temperature. The rheological stress and other characteristics of the material during the deformation process remain relatively stable, which is conducive to forming. Thickening the section also wastes materials and also invests in molds, and the overall benefits are not high. In order to improve the economic benefits of product manufacturing, while achieving the continuity of product flow lines and improving the service performance of products, it is necessary to further improve the plan to achieve the forming of thin-walled rotating parts with variable cross-sections. Summary of the invention

[0003] The purpose of the present invention is to provide a solution that can better realize the forging of variable-section thin-walled rotating body products in view of the shortcomings of the above-mentioned background technology.

[0004] In order to achieve the above object, the present invention provides a forging method for a thin-walled rotating body with a variable cross-section, comprising the following steps:

[0005] S1, putting the blank into the furnace for heating, and at the same time preheating the first forging die and assembling it on the first forging press;

[0006] S2, starting the first forging press to raise the upper punch of the first forging die, and placing the heated blank into the first cavity of the first forging die;

[0007] S3, the first forging press drives the upper punch to press down, forging the blank into a desired shape, completing the first forging;

[0008] S4, the upper punch rises again, and the lower ejector of the first forging die ejects the forging and puts it back into the furnace for reheating;

[0009] S5, preheating the second forging die and assembling it on the second forging press, placing the forged piece after the supplementary heating into the lower die of the second forging die, and moving the upper die of the second forging die downward to close the die and press the forged piece;

[0010] S6, the left punch and the right punch of the second forging die move until they reach the stop position, so that the forging is completely formed;

[0011] S7, withdraw the left punch and the right punch, move the upper die upward to expose the formed product, take out the product and grind the flash clean.

[0012] Furthermore, in S3, when the upper punch presses down from the center of the blank, the initial thickness of the blank is a preset value, and the blank gradually thickens during the subsequent upward flow until it contacts the end face of the upper punch, and the blank becomes thicker as the upper punch descends.

[0013] Furthermore, the maximum stroke limit of the upper punch pressing down in S3 ensures the preset thickness of the forging and the smoothness of the surface.

[0014] Furthermore, during the downward pressing process of the upper punch in S3, the blank flows downward until it fills the entire gap between the lower punch and the first cavity, forming a preset forging shape.

[0015] Further, in S5, the upper die and the lower die are closed and opened from the top and bottom directions, and in S6, the left punch and the right punch are pressed and reset from the left and right directions.

[0016] Furthermore, before S5, the second cavities of the upper die and the lower die and the left punch and the right punch are evenly coated with graphite lubricant.

[0017] Furthermore, the preheating temperature in S5 is 300-400°C.

[0018] The present invention also provides a forging die for a variable-section thin-walled body of revolution product, which adopts a forging method for a variable-section thin-walled body of revolution product as described above, and is characterized in that it comprises a first forging die and a second forging die;

[0019] The first forging die comprises an upper punch, a lower punch, a bottom die, a lower ejector and an ejector sleeve; the bottom die is provided with a first cavity for accommodating a blank, the size of the first cavity matches the blank, and the upper part of the first cavity gradually widens from bottom to top, the top of the bottom die and the outer ring position of the end face of the upper punch are both provided with step surfaces to limit the upper punch, the ejector sleeve is used to limit and guide the upper punch, the lower punch is pre-placed at the bottom of the bottom die, the bottom of the bottom die and the outer ring position of the end face of the lower punch are also provided with step surfaces to limit the lower punch and maintain a preset coaxiality, and the lower ejector is used to eject the forging from the first cavity;

[0020] The second forging die comprises an upper die, a lower die, a left punch and a right punch; the upper die and the lower die are arranged opposite to each other in upper and lower layers, the left punch and the right punch are arranged opposite to each other on the left and right sides, the upper die and the lower die are both provided with a second cavity for accommodating the forging, and the inner surface of the second cavity is provided with a shape matching the cross-sectional change protrusions at various locations of the product, the left punch and the right punch are used to press the forging from both sides so that the thickness of the middle skin position of the forging reaches a preset value, and at the same time the forging is extruded into shape, and corresponding cross-sectional change protrusions are formed on the surface.

[0021] Furthermore, the lower punch is provided with a top hole, and the lower ejector rod can extend from the top hole into the first cavity.

[0022] Furthermore, the upper die and the lower die are also provided with stop blocks, and the stop blocks are used to limit the left punch and the right punch.

[0023] The above scheme of the present invention has the following beneficial effects:

[0024] The present invention provides a method and die for forging a thin-walled rotating body with a variable cross-section. Through the combination of a first forging die and a second forging die, the blank can be forged twice, so that the blank is finally formed into a thin-walled rotating body with a variable cross-section and a preset size. Compared with the existing direct cutting and thickening forging methods, the forging method and die for the thin-walled rotating body with a variable cross-section provided by the two embodiments saves more materials, has a better die utilization rate, and has a higher comprehensive benefit. It can also better realize the continuity of the product flow line and improve the service performance of the product.

[0025] Other beneficial effects of the present invention will be described in detail in the subsequent specific implementation section. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a schematic diagram of the product of the present invention;

[0027] Figure 2 It is a schematic diagram of the first forging die and forging of the present invention;

[0028] Figure 3 It is a schematic diagram of the second forging die and product of the present invention.

[0029] [Description of Reference Numerals]

[0030] 1-upper punch; 2-lower punch; 3-bottom die; 4-lower ejector pin; 5-top sleeve; 6-upper die; 7-lower die; 8-left punch; 9-right punch; 10-stop block. DETAILED DESCRIPTION

[0031] In order to facilitate the understanding of the present application, the present application will be described more comprehensively with reference to the relevant drawings below. The preferred embodiments of the present application are provided in the drawings. However, the present application can be implemented in many other different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the understanding of the disclosure of the present application more thorough and comprehensive.

[0032] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it can be directly on the other element or indirectly on the other element. When an element is referred to as being "connected to" another element, it can be directly connected to the other element or indirectly connected to the other element.

[0033] It should be understood that the terms "length", "width", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0034] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the features. In the description of this application, the meaning of "plurality" is two or more, unless otherwise clearly and specifically defined.

[0035] Unless defined otherwise, 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.

[0036] Embodiment 1:

[0037] Embodiment 1 of the present invention provides a method for forging a thin-walled rotating body with a variable cross-section. Figure 1 The figure shows a forging according to the setting of the thin-walled rotating body with variable cross-section. The characteristics of the thin-walled rotating body with variable cross-section are that there are cross-section change bulges at A, B, C, and D. The forging is designed with bulges according to the characteristics of the thin-walled rotating body with variable cross-section. Among them, the bulge at A is the largest, and it is most difficult to gather materials there. According to calculations and simulations, direct forging metal flow to this place will form folding defects. E is the middle skin position. The thinnest part of the overall design of the forging is 10mm, and the wall thickness of most areas is ≤20mm, which is a typical thin-walled part.

[0038] The forging is Figure 2The first forging die shown in the figure performs the first forging, and the first forging die specifically includes an upper punch 1, a lower punch 2, a bottom die 3 and a lower ejector 4. Among them, the bottom die 3 is provided with a first cavity for accommodating the blank (bar), the size of the first cavity matches the blank, and the upper part of the first cavity gradually widens from bottom to top and outward, so that when the upper punch 1 presses down from the center of the blank, the initial thickness of the blank formed is the same as that at F shown in the figure. In the subsequent process of the blank flowing upward, due to the friction resistance on the surface of the first cavity, it will gradually thicken until it reaches G and then contacts the end face of the upper punch 1. As the upper punch 1 descends, the blank is roughened to fill G. It can be understood that due to the early thickening of the blank, the cross-sectional changes at G and F are within the safe roughening range, and the blank will hardly produce forging defects.

[0039] It should be noted that in this embodiment, the top of the bottom die 3 and the outer ring position of the end face of the upper punch 1 are both provided with step surfaces, and the upper punch 1 is limited by the mutual contact of the step surfaces, limiting the maximum distance of the upper punch 1 pressed downward. In addition, the preset thickness at G and the smoothness of the transition with F can be maintained.

[0040] At the same time, a top sleeve 5 can be further provided on the top of the bottom die 3. The top sleeve 6 is used to further limit and guide the upper punch 1, so as to ensure that the upper punch 1 can perform stamping operations more reliably and accurately.

[0041] It should be noted that during the forging process, the lower punch 2 is pre-placed at the bottom of the bottom die 3, and there is also a gap of preset thickness between it and the inner wall of the first cavity, and this gap is ensured by the coaxiality of the lower punch 2 and the first cavity. Therefore, in this embodiment, step surfaces are also set at the bottom of the bottom die 3 and the outer ring position of the end face of the lower punch 2, and the lower punch 2 is limited by the mutual contact of the step surfaces to ensure this coaxiality. During the downward pressing process of the upper punch 1, the blank will also flow downward until it fills all the gaps downward to form a preset forging shape.

[0042] In addition, a top hole is also provided on the lower punch 2, and the lower ejector rod 4 can extend into the first cavity from the top hole, so when the upper punch 1 is forged and raised to reset, the lower ejector rod 4 can eject the forged forging out of the die. It should be noted that another purpose of forging is to partially form the blank in advance, reduce the subsequent forming pressure, and reduce the turbulence of the subsequent flow.

[0043] When the forging is finally formed, Figure 3The second forging die shown in the figure is used for the second forging. The second forging die specifically includes an upper die 6, a lower die 7, a left punch 8 and a right punch 9. The upper die 6 and the lower die 7 are arranged opposite to each other on the upper and lower sides, and the left punch 8 and the right punch 9 are arranged opposite to each other on the left and right sides. The upper die 6 and the lower die 7 are both provided with a second cavity for accommodating the forging, and the inner surface of the second cavity is provided with a shape matching the cross-sectional variation protrusions at various locations of the product, so that the variable cross-sectional thin-walled rotating body product after the final forming has a preset cross-sectional variation protrusion.

[0044] When the upper die 6 and the lower die 7 are closed, the left punch 8 and the right punch 9 press against the forging from both sides respectively, so that the thickness of the middle skin-connecting position (at E) of the forging reaches the preset value, and the forging is extruded and formed, and the corresponding cross-sectional change protrusion is formed on the surface. Among them, the upper die 6 and the lower die 7 are also provided with a stop block 10, and the stop block 10 is used to limit the left punch 8 and the right punch 9, so that the left punch 8 and the right punch 9 will not move after moving to the corresponding position, ensuring that the thickness of the middle skin-connecting position of the forging reaches the preset value.

[0045] It should be noted that since the product is a thin-walled product, in order to prevent the loss of temperature of the forging and the large friction resistance during the forging process, the second cavity of the upper die 6 and the lower die 7 and the left punch 8 and the right punch 9 are evenly coated with a layer of graphite lubricant before the second forging, and the second forging die is fully preheated, and the preheating temperature is within the tolerable range of the die. In one specific case, the second forging die is made of H13 steel, and the preheating temperature is 300-400°C. It is worth mentioning that the second forging adopts the horizontal stamping method, which can make the flow of the billet more uniform, thereby better ensuring the forging quality of the product, the accuracy of the convexity of the cross-sectional changes, and the continuity of the streamline.

[0046] During the first forging process, Figure 2 The dashed line in the middle is the original billet (bar), which is formed after forging. Figure 2The solid line shape in the figure. The blank is put into the furnace for heating, and the first forging die is preheated and assembled on the first forging press. The first forging press is started to raise the upper punch 1, and the heated blank is placed in the first cavity. The blank can be supported by the lower punch 2 in a preset position. The first forging press drives the upper punch 1 to press down and forge the blank into the desired shape. Then the upper punch 1 rises again, and the lower ejector 4 ejects the forging and re-enters the furnace for reheating. Then, a layer of graphite lubricant is evenly applied to the second cavity and the punch of the second forging die, and they are preheated and assembled on the multi-directional second forging press. The reheated forging is placed in the lower die 7, and the upper die 6 moves downward to close the die to press the forging, and the left punch 8 and the right punch 9 move until they reach the stop position, at which time the forging is completely formed. The left punch 8 and the right punch 9 are withdrawn, and then the upper die 6 moves upward to expose the formed product, the product is taken out and the flash is polished clean to obtain the desired variable-section thin-walled rotating body product.

[0047] Embodiment 2:

[0048] Based on the same inventive concept, embodiment 2 of the present invention provides a forging die for a thin-walled rotating body product with a variable cross-section, including a first forging die and a second forging die. Among them, the first forging die is used for the first forging of the blank, including an upper punch 1, a lower punch 2, a bottom die 3, a lower ejector 4 and a top sleeve 5. The bottom die 3 is provided with a first cavity for accommodating the blank, the size of the first cavity matches the blank, and the upper part of the first cavity gradually widens from bottom to top, so that the initial thickness of the blank formed during the pressing process of the upper punch 1 from the center of the blank reaches a preset value. The lower part of the first cavity is of equal width or slightly widened from top to bottom. The top of the bottom die 3 and the outer ring position of the end face of the upper punch 1 are both provided with step surfaces, and the upper punch 1 is limited by the mutual contact of the step surfaces. The top sleeve 5 is connected to the top of the bottom die 3 or to the upper punch 1, and is used to further limit and guide the upper punch 1, ensuring that the upper punch 1 can perform the stamping operation more reliably and accurately. The lower punch 2 is pre-placed at the bottom of the bottom die 3, and the bottom of the bottom die 3 and the outer ring position of the end face of the lower punch 2 are also provided with step surfaces, and the lower punch 2 is limited by the mutual contact of the step surfaces to maintain the preset coaxiality. The lower punch 2 is also provided with a top hole, and the lower ejector 4 can extend into the first cavity from the top hole, so that when the upper punch 1 is forged and raised and reset, the lower ejector 4 can eject the forged forging out of the die.

[0049] The second forging die is used for the second forging of the forging, and adopts the form of multiple die forging, including an upper die 6, a lower die 7, a left punch 8 and a right punch 9. Among them, the upper die 6 and the lower die 7 are arranged in two layers opposite to each other, and the left punch 8 and the right punch 9 are arranged on the left and right sides. The upper die 6 and the lower die 7 are both provided with a second cavity for accommodating the forging, and the inner surface of the second cavity is provided with a shape matching the cross-sectional change protrusions at various locations of the product. The left punch 8 and the right punch 9 press against the forging from both sides respectively, so that the thickness of the middle skin position of the forging reaches the preset value, and at the same time, the forging is extruded and formed, and the corresponding cross-sectional change protrusions are formed on the surface. The upper die 6 and the lower die 7 are also provided with a stop block 10, and the left punch 8 and the right punch 9 are limited by the stop block 10, so that the left punch 8 and the right punch 9 will not move after moving to the corresponding position, ensuring that the thickness of the middle skin position of the forging reaches the preset value.

[0050] Therefore, this embodiment can perform two forging processes on the blank through the combination of the first forging die and the second forging die, so that the blank is finally formed into a variable cross-section thin-walled body of revolution product with a preset shape and size. Compared with the existing direct cutting and thickening forging methods, the forging forming method and die of the variable cross-section thin-walled body of revolution product provided by the two embodiments saves more materials, has a better die utilization rate, and has a higher comprehensive benefit, and can better realize the continuity of the product flow line and improve the service performance of the product.

[0051] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0052] The above embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

Claims

1. A method for forging a thin-walled rotating body with a variable cross-section, characterized in that: The steps include: S1, putting the blank into the furnace for heating, and at the same time preheating the first forging die and assembling it on the first forging press; S2, starting the first forging press to raise the upper punch (1) of the first forging die, and placing the heated blank into the first cavity of the first forging die; S3, the first forging press drives the upper punch (1) to press downward to forge the blank into a desired shape, thus completing the first forging; S4, the upper punch (1) rises again, and the lower ejector (4) of the first forging die ejects the forging and puts it back into the furnace for reheating; S5, preheating the second forging die and assembling it on the second forging press, placing the forged piece after the supplementary heating into the lower die (7) of the second forging die, and moving the upper die (6) of the second forging die downward to close the die and press the forged piece; S6, the left punch (8) and the right punch (9) of the second forging die move until they reach the stop position, so that the forging is completely formed; S7, the left punch (8) and the right punch (9) are withdrawn, the upper die (6) moves upward to expose the formed product, the product is taken out and the flash is polished clean.

2. A method for forging a thin-walled rotating body with a variable cross-section according to claim 1, characterized in that: In S3, when the upper punch (1) presses down from the center of the blank, the initial thickness of the blank is a preset value, and the blank gradually thickens as it flows upward until it contacts the end face of the upper punch (1). As the upper punch (1) descends, the blank becomes thicker.

3. The forging method of a variable cross-section thin-walled rotating body product according to claim 1, characterized in that: In S3, the maximum stroke limit of the upper punch (1) pressing down is used to ensure the preset thickness of the forging and the smoothness of the surface.

4. A method for forging a thin-walled rotating body with a variable cross-section according to claim 1, characterized in that: In S3, during the downward pressing process of the upper punch (1), the blank flows downward until it fills the entire gap between the lower punch 2 and the first cavity, forming a preset forging shape.

5. The forging method of a variable cross-section thin-walled rotating body product according to claim 1, characterized in that: In S5, the upper die (6) and the lower die (7) close and open the die from the top and bottom directions, and in S6, the left punch (8) and the right punch (9) press and reset from the left and right directions.

6. A method for forging a thin-walled rotating body with a variable cross-section according to claim 1, characterized in that: Before S5, the second cavities of the upper die (6) and the lower die (7) and the left punch (8) and the right punch (9) are evenly coated with graphite lubricant.

7. The forging method of a variable cross-section thin-walled rotating body product according to claim 1, characterized in that: The preheating temperature in S5 is 300-400°C.

8. A forging die for a thin-walled rotating body with a variable cross-section, using a forging method for a thin-walled rotating body with a variable cross-section as claimed in any one of claims 1 to 7, characterized in that: comprising a first forging die and a second forging die; The first forging die comprises an upper punch (1), a lower punch (2), a bottom die (3), a lower ejector rod (4) and an ejector sleeve (5); the bottom die (3) is provided with a first cavity for accommodating a blank, the size of the first cavity matches the blank, and the upper part of the first cavity gradually widens from bottom to top, the top of the bottom die (3) and the outer ring position of the end face of the upper punch (1) are both provided with step surfaces to limit the position of the upper punch (1), the ejector sleeve (5) is used to limit and guide the upper punch (1), the lower punch (2) is pre-placed at the bottom of the bottom die (3), the bottom of the bottom die (3) and the outer ring position of the end face of the lower punch (2) are also provided with step surfaces to limit the position of the lower punch (2) and maintain a preset coaxiality, and the lower ejector rod (4) is used to eject the forging from the first cavity; The second forging die comprises an upper die (6), a lower die (7), a left punch (8) and a right punch (9); the upper die (6) and the lower die (7) are arranged in an upper and lower layer opposite to each other, and the left punch (8) and the right punch (9) are arranged in a left and right side opposite to each other; the upper die (6) and the lower die (7) are both provided with a second cavity for accommodating the forging, and the inner surface of the second cavity is provided with a shape matching the cross-sectional variation protrusions at various locations of the product; the left punch (8) and the right punch (9) are used to press the forging from both sides so that the thickness of the middle skin position of the forging reaches a preset value, and at the same time, the forging is extruded and formed, and a corresponding cross-sectional variation protrusion is formed on the surface.

9. A forging die for a variable cross-section thin-walled rotating body product according to claim 8, characterized in that: The lower punch (2) is provided with a top hole, and the lower ejector rod (4) can extend from the top hole into the first cavity.

10. A forging die for a variable cross-section thin-walled rotating body product according to claim 8, characterized in that: The upper die (6) and the lower die (7) are also provided with a stop block (10), and the stop block (10) is used to limit the position of the left punch (8) and the right punch (9).

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