Precise roll forging-die forging composite forming process for engineering machinery movable arm

Abstract

The invention discloses a precision roll forging-die forging composite forming process for a movable arm of engineering machinery, which comprises the following steps of: carrying out two-pass roll forging on a heated metal blank to obtain an intermediate blank with a required shape, bending and die forging to obtain a formed product, and directly entering the bending and die forging forming procedures of the intermediate blank without secondary heating; a workpiece extends in the axis direction of the workpiece through two-pass roll forging machining, the surface of the workpiece is extruded through a profiled groove in a two-pass roll forging die, and the workpiece is rolled into the needed section shape and size. According to the method, the heated metal blank with the circular cross section is subjected to two-pass roll forging to be manufactured into the blank for the subsequent forming procedure, the intermediate blank with the good shape, size and surface quality is obtained, the quality of the movable arm forge piece is effectively improved, and the defects that the forge piece is folded and cannot be fully filled due to the shape problem of the manufactured blank are overcome; and continuous local deformation is achieved in the roll forging process, so that the metal flow direction is consistent with the shape of the intermediate blank, the metallographic structure is uniform and compact, and forgings with good mechanical performance can be obtained easily.

Description

Technical Field

[0001] The invention relates to the technical field of forming a movable arm of an engineering machinery, and in particular to a precision roll forging-die forging composite forming process for a movable arm of an engineering machinery. Background Art

[0002] The boom is an important component of the working device of the construction machinery and is also the main load-bearing component. The production quality and mechanical properties of the boom directly affect the working performance of the entire construction machinery. At present, the production method of the boom for construction machinery at home and abroad is mainly free forging billet-die forging. Its shape is as follows Figure 1 As shown, the overall structure is a relatively long non-cylindrical flat arm-shaped structure, the thickness in the middle is less than the thickness at both ends, the thickness at one end is greater than the other end, and there is a corresponding groove structure on the outer surface, with at least two separated grooves.

[0003] like Figure 2 As shown in the figure, the free forging-die forging process uses free forging in the billet making stage, and the heated round billet is free forged. After billet making, it is transferred and heated again. After reaching the required forming temperature, it is pressed and bent, die forged, and then trimmed and heat treated. This process has the following disadvantages: 1) The free forging process has slow forging speed, low production efficiency, low material utilization rate, loud noise during forging, great pollution to the production environment, poor working environment, inaccurate shape and size control, poor surface quality, affecting the quality of subsequent product molding, high technical requirements for operators, and difficult to achieve automation; 2) It requires two-fire heating and needs to be reheated after billet making, which increases the difficulty of heating control and easily leads to increased oxidation and decarburization, increased internal stress, and grain growth, which increases energy consumption and cost and reduces production efficiency. Summary of the invention

[0004] The purpose of the present invention is to overcome the defects of the current free forging and two-fire heating processes, and to provide a precision roll forging-die forging composite forming process for an engineering machinery boom. The boom intermediate billet roll forging process of the present invention performs two-pass billet roll forging on a circular billet with a circular cross-section after heating, and then directly enters the press bending and die forging process without the need for secondary heating, which can effectively reduce the number of processes and improve production efficiency.

[0005] A precision roll forging-die forging composite forming process for a boom of an engineering machinery comprises the following steps: performing two roll forgings on a heated circular cross-section metal blank to obtain an intermediate blank of a desired shape, and then performing press bending and die forging to form a formed product; the intermediate blank directly enters the subsequent press bending and die forging forming steps without secondary heating; through the two-pass roll forging process, the workpiece is extended in the axial direction thereof, and the grooves on the two-pass roll forging dies extrude the workpiece surface, and the workpiece is rolled to form the desired cross-sectional shape and size.

[0006] The intermediate blank comprises two small cylindrical sections with circular cross sections and three large cylindrical sections with circular cross sections, and the diameter of the small cylindrical section is smaller than the diameter of the large cylindrical section.

[0007] Wherein, the small cylindrical section and the large cylindrical section are connected via a conical structure.

[0008] The grooves on the two roll forging dies respectively correspond to the outer shapes of the workpiece after roll forging.

[0009] Among them, after the metal billet is roll-forged once on the first-pass roll-forging die, it is turned 90 degrees along its axial direction and roll-forged twice on the second-pass roll-forging die.

[0010] Among them, the central angle of the front end transition section of the deformation zone of the single-pass roll forging die and the second-pass roll forging die is greater than the central angle of the rear end transition section of the deformation zone.

[0011] Among them, the processing accuracy of the intermediate billet formed by two-pass roll forging is within 5mm.

[0012] Among them, in the press-bending process step, when the press-bending is positioned, one end of the long deformation zone of the intermediate blank is matched with the press-bending die for positioning, and the other end is released.

[0013] The transfer of the metal blank and the connection between different roll forging passes are automated by using a roll forging manipulator.

[0014] Among them, a medium frequency heating furnace is used to heat the metal billet to the required temperature.

[0015] The roll forging blank making process for the boom of the engineering machinery of the present invention adopts a composite process of precision roll forging-die forging and single-fire heating. In the blank making stage, the workpiece is continuously partially formed by roll forging. After blank making, it does not need to be heated again and directly enters the bending and die forging forming process. After that, the edge trimming and heat treatment are performed, and the workpiece is shipped after passing the inspection and packaging process. The present invention changes the two-fire heating into one-fire heating, reduces the process, improves the boom production efficiency, material utilization rate and product quality, reduces the equipment investment cost, reduces energy consumption, and conforms to the concept of green development.

[0016] The engineering machinery boom roll forging process of the present invention performs two roll forgings on a heated metal billet with a circular cross section to form a billet for a subsequent forming process, thereby obtaining an intermediate billet with good shape, size and surface quality, effectively improving the quality of boom forgings, and avoiding defects such as folding and insufficient filling of forgings caused by billet shape problems; the continuous local deformation during the roll forging process makes the metal flow direction consistent with the shape of the intermediate billet, and the metallographic structure is uniform and dense, which is conducive to obtaining forgings with good mechanical properties.

[0017] Compared with the original process of heating twice before and after billet making, no heating is required after billet making, which can significantly reduce the difficulty of heating control, reduce oxidation and decarburization, reduce internal stress, avoid excessive grain growth, reduce energy consumption and cost, and improve production efficiency; since the beat of the roll forging machine is stable and the temperature consistency of the roll forging billet is good, it is conducive to obtaining an intermediate billet with stable dimensions, reducing the probability of defects such as insufficiency and folding in the subsequent forming of the product due to unstable billet shape; due to the improved billet making accuracy, compared with the original free-end billet making, the material utilization rate of this process can be increased by 30%. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of a hot forging of a typical engineering machinery boom product to be processed by the present invention.

[0019] Figure 2 The present invention is a schematic diagram of free forging blank-die forging forming of an engineering machinery boom under the prior art.

[0020] Figure 3 The present invention is a forming process flow chart of the engineering machinery boom roll forging.

[0021] Figure 4 , Figure 5 It is a cross-sectional view and a front schematic view of a cylindrical metal blank of the present invention.

[0022] Figure 6 It is a schematic diagram of a cylindrical metal blank and a first pass workpiece and a second pass workpiece designed by the present invention.

[0023] Figure 7 , Figure 8 They are respectively a front view and an axonometric view of a single-pass roll forging of the present invention.

[0024] Fig. 9 , Fig.10 They are respectively the front view and the axonometric view of the two-pass roll forging of the present invention.

[0025] Fig.11 It is a schematic diagram of the deformation process of a cylindrical metal blank of the present invention from being subjected to two-pass roll forging to an intermediate blank.

[0026] Fig.12 , Fig.13 They are cross-sectional schematic diagrams of the two middle deformation zones of the intermediate blank.

[0027] Fig.14 Schematic diagram of the front wall angle and the rear wall angle of the roll forging die of the present invention.

[0028] Fig.15 It is a schematic diagram of a blank having a tapered transition section formed after a single roll forging in the process of the present invention.

[0029] Fig.16 It is a schematic diagram of the cooperation between the forging and the die in the press bending process of the present invention.

[0030] Fig.17 It is a schematic diagram of a press-bent forging obtained by the press-bending process of the present invention.

[0031] Fig.18 It is a schematic diagram of a final forging obtained by the final forging process of the present invention. DETAILED DESCRIPTION

[0032] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0033] The engineering machinery boom processed by the present invention has a shape as follows Figure 1 As shown, the overall structure is a relatively long non-cylindrical flat arm-shaped structure, which is in a certain degree of bending state as a whole, not a straight arm, with a thickness in the middle less than that at both ends, and a thickness at one end greater than that at the other end. The outer surface has a corresponding groove structure, and the groove structure includes at least two separated grooves, such as Figure 1 shown.

[0034] The movable arm roll forging process of the embodiment of the present invention is to firstly process a metal blank 100 (diameter 280 mm, length 1272 mm, such as Figure 4-Figure 5 The heated metal blank 100 with a circular cross section is then subjected to two roll forging passes through a roll forging machine to be transformed into an intermediate blank 120; the intermediate blank 110 is then subjected to a press bending and forming die forging process to be formed through the press bending and die forging forming process. Fig.11 As shown, the shape and structure after bending are as follows Fig.14 As shown, after die forging, Fig.15 As shown, the flash can then be removed before other subsequent processing.

[0035] In the embodiment of the present application, by heating the metal billet before entering the roll forging, the metal plasticity can be improved, the deformation resistance can be reduced, and the forgeability of the metal can be increased, so that the metal is easy to flow and form, and the roll forging can obtain good post-forging structure and mechanical properties.

[0036] Among them, the blank is made after the metal blank is roll forged twice, which is done in a single roll forging die (see Figure 7 , Figure 8 After the first roll forging of the workpiece is completed, the workpiece is turned 90 degrees along the axial direction and the second roll forging die (see Fig. 9 , Fig.10The workpiece is rolled in the axial direction by roll forging, and the groove on the roll forging die squeezes the workpiece surface to roll the workpiece into the required cross-sectional shape and size.

[0037] The roll forging process for the engineering machinery boom of the present invention performs two roll forgings on a heated metal billet with a circular cross section to form a billet for the subsequent process, which can effectively improve the quality of the boom forgings, obtain an intermediate billet with good shape, size and surface quality, and avoid defects such as folding and insufficiency of the forgings caused by billet shape problems. Moreover, the continuous local deformation during the roll forging process makes the metal flow direction consistent with the shape of the intermediate billet, and the metallographic structure is uniform, dense, and has good mechanical properties, which is conducive to obtaining forgings with good mechanical properties; it can reduce the number of processes and improve production efficiency; since the beat of the roll forging machine is stable and the temperature consistency of the roll forging billet is good, it is conducive to obtaining forging products with stable dimensions.

[0038] In an embodiment of the present invention, the intermediate blank 120 has two small cylindrical sections with circular cross-sections, namely, a first small cylindrical section 21 and a second small cylindrical section 22, which serve as deformation zones of the workpiece and are relatively deformed in diameter, and three large cylindrical sections with circular cross-sections, namely, a first large cylindrical section 23, a second large cylindrical section 24, and a third large cylindrical section 25. The diameters of the small cylindrical sections are smaller than the diameters of the large cylindrical sections, wherein the small cylindrical sections are connected to the large cylindrical sections via a conical structure. Therefore, before roll forging the metal blank, the corresponding roll forging die should be designed. On the premise that the original blank size and the intermediate blank forging drawing are known, the blank roll forging die is designed according to the blank roll forging groove design process. In the embodiment of the present application, the two-pass roll forging dies each have a first-pass roll forging groove 200 and a second-pass roll forging groove 300, each corresponding to the shape of the workpiece after roll forging in its process. See. Fig.12 as well as Fig.13 As shown, the cross-sectional shapes of the first small cylindrical segment 21 and the second small cylindrical segment 22 are respectively shown. It can be seen that the two deformation zones have good roundness and regular shapes without defects such as burrs and folds.

[0039] Wherein, the one-pass roll forging die and the two-pass roll forging die are both composed of two dies, such as Figure 7 , Figure 8 as well as Fig. 9 , Fig.10 As shown, by rolling the cylindrical metal material relative to each other, it undergoes one roll forging and two roll forgings, as shown in FIG. Fig.11 The corresponding shape deformation of the blank is achieved as shown.

[0040] A preferred embodiment is that the center angle of the front transition section of the deformation zone of the first-pass roll forging die and the second-pass roll forging die is greater than the center angle of the rear transition section of the deformation zone, see Fig.14 In order to meet the shape and size requirements, taking the one-pass roll forging module as an example, the first front wall 202 on the one-pass roll forging die is designed to have a central angle greater than the first rear wall 201, and the second front wall 204 has a central angle greater than the second rear wall 203. The design of the second pass roll forging die is similar and will not be repeated. Fig.15 The position of the corresponding conical transition structure of the final formed workpiece is shown as Fig.15 As shown, the first tapered transition portion 31, the second tapered transition portion 32, the third tapered transition portion 33 and the fourth tapered transition portion 34 on the corresponding formed workpiece. In the implementation of the present application, the machining accuracy of the intermediate blank formed by two-pass roll forging can be within 5mm.

[0041] In a preferred embodiment, in the bending process step, during the bending positioning, one end of the intermediate blank 120 close to the first large cylindrical section 23 is matched with the bending die for positioning, and the other end is released for bending. An example of the cooperation between the forging and the die in the bending process is as follows: Fig.16 As shown, the left side is positioned and the right side is released; in the bending process, the axis of the blank is squeezed and bent, as shown in Fig.17 shown.

[0042] Take a circular cross-section metal billet with a diameter of 280 mm and a length of 1272 mm, such as Figure 4 , 5 As shown, carbon structural steel is used as the material for the purpose of illustrating the process flow of the present invention.

[0043] During production, before the secondary precision roll forging, the metal blank is heated to the required temperature, such as about 1200℃, by a medium frequency heating furnace, and then sent to the roll forging machine for two passes of roll forging. The intermediate blank of the boom is formed by the first two passes of roll forging. The workpiece is extended in the axial direction by the two passes of roll forging. The groove on the roll forging die is rotated to extrude the workpiece surface to form the required shape on the surface of the workpiece. Finally, it is die forged to form the required groove structure on the outer surface, and the whole is formed, such as Fig.18 As shown, it is finally completed after trimming and heat treatment, and finally shipped out after testing and packaging.

[0044] Since the beat of the roll forging machine is stable and the temperature of the roll forging blank is consistent, such a process is conducive to obtaining an intermediate blank with stable shape, size and surface quality, avoiding defects such as folding and insufficiency of forgings caused by billet shape problems, and is conducive to automation. In addition, the continuous local deformation during the roll forging process of the roll forging machine makes the direction of the metal fiber consistent with the shape of the forging, and the metallographic structure is uniform, dense, and has high mechanical properties, which is conducive to obtaining forgings with good mechanical properties.

[0045] The basic principles and main features of the present invention and the advantages of the present invention are shown and described above. It is obvious to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or basic features of the present invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is therefore intended that all changes falling within the meaning and range of equivalent elements of the claims are included in the present invention.

[0046] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. The precision roll forging-die forging composite forming process of engineering machinery boom is characterized by: The heated metal billet with a circular cross-section is subjected to two passes of roll forging to obtain an intermediate billet of the desired shape, which is then subjected to press bending and die forging to form a formed product. The intermediate billet directly enters the subsequent press bending and die forging forming process without secondary heating; through the two-pass roll forging process, the workpiece is extended in the axial direction, and the grooves on the two-pass roll forging dies extrude the workpiece surface to roll the workpiece into the desired cross-sectional shape and size.

2. According to claim 1, the engineering machinery boom precision roll forging-die forging composite forming process is characterized in that: The intermediate blank comprises two small cylindrical sections with circular cross sections and three large cylindrical sections with circular cross sections, wherein the diameter of the small cylindrical section is smaller than the diameter of the large cylindrical section.

3. According to claim 2, the engineering machinery boom precision roll forging-die forging composite forming process is characterized in that: The small cylindrical section and the large cylindrical section are connected via a conical structure.

4. According to claim 1, the engineering machinery boom precision roll forging-die forging composite forming process is characterized in that: The grooves on the two-pass roll forging dies respectively correspond to the outer shapes of the workpiece after roll forging.

5. According to claim 1, the precision roll forging-die forging composite forming process for engineering machinery boom is characterized in that: After the metal billet is roll forged once on the first-pass roll forging die, it is turned 90 degrees along its axial direction and roll forged twice on the second-pass roll forging die.

6. The precision roll forging-die forging composite forming process for engineering machinery boom according to claim 1 is characterized in that: The central angle of the front end transition section of the deformation zone of the one-pass roll forging die and the two-pass roll forging die is greater than the central angle of the rear end transition section of the deformation zone.

7. The precision roll forging-die forging composite forming process for engineering machinery boom according to claim 1 is characterized in that: The machining accuracy of the intermediate billet formed by two-pass roll forging is within 5mm.

8. The precision roll forging-die forging composite forming process for engineering machinery boom according to claim 1 is characterized in that: In the press-bending process step, during press-bending positioning, one end of the long deformation zone of the intermediate blank is matched with the press-bending die for positioning, and the other end is released.

9. The precision roll forging-die forging composite forming process for engineering machinery boom according to claim 1 is characterized in that: The transfer of the metal blank and the connection between different roll forging passes are automated by using a roll forging manipulator.

10. The precision roll forging-die forging composite forming process for engineering machinery boom according to claim 1 is characterized in that: A medium frequency heating furnace is used to heat the metal billet to the required temperature.

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