A tee pipe fitting forging die and a precision forging process forming method thereof

Abstract

This invention relates to the field of forging technology, specifically a precision forging process for a tee pipe fitting, comprising the following steps: selecting a bar stock of appropriate diameter and sawing it into segments of a certain length, then flattening and chamfering the ends; cleaning and drying the bar stock; heating the bar stock in an oven; spraying lubricant; placing the bar stock in a high-temperature resistance furnace for heating; removing the bar stock from the resistance furnace with tongs and placing it into a pre-forging mold until the blank is pre-formed into the shape of a tee fitting and then ejecting it; placing the pre-forged part into a final forging mold for forging, and removing it after shaping; placing the final forged part into a trimming mold for punching off the flash, and then removing it. This invention has the advantages of small material feed rate, small flash after precision forging, high material utilization rate, complete metal flow lines in the forging, minimal damage to the mold, and long mold service life.

Description

Technical Field

[0001] This invention relates to the field of forging technology, and in particular to a forging die for a tee pipe fitting and its precision forging process. Background Technology

[0002] Forging is a processing method that uses forging machinery to apply pressure to metal billets, causing them to undergo plastic deformation to obtain forgings with specific mechanical properties, shapes, and dimensions. Forging can eliminate defects such as casting porosity generated during the smelting process, optimize the microstructure, and preserve complete metal flow lines. In the field of machining, components that perform important functions are often made from forgings. Tee fittings are a commonly used type of pipe fitting, and their application in production and construction is gradually increasing. Currently, the forming of existing tee fittings mainly involves directly placing the bar stock into the final forging cavity for forming, or first flattening the bar stock and then forging it. Both of these processes result in a large forging material ratio, high forming difficulty, incomplete metal flow lines, significant damage to the die, and a short die lifespan. Summary of the Invention

[0003] To solve the above-mentioned technical problems, the present invention adopts the following technical solution.

[0004] Design a pre-forging die for a tee pipe fitting, including a pre-forging die, a final forging die, and a trimming die. The pre-forging die includes an upper die assembly and a lower die assembly arranged opposite each other. The upper die assembly includes a top plate, an upper die frame, and an upper die core connected sequentially from top to bottom. An upper groove is provided at the top center of the upper die frame, and an upper pad block is provided in the upper groove. An installation groove communicating with the upper groove is provided at the bottom of the upper die frame. The upper groove and the installation groove are stepped, with the upper groove being smaller at the top and the lower groove being larger at the bottom. The top of the upper die core is embedded in the installation groove and abuts against the upper pad block.

[0005] The lower mold assembly includes a base plate, a lower mold frame, and a lower mold core connected sequentially from bottom to top. A lower groove is provided at the middle of the bottom of the lower mold frame, and a lower pad is provided in the lower groove. A stepped groove with a larger upper section and a smaller lower section is provided on the upper surface of the lower mold frame, which communicates with the lower groove. The bottom end of the lower mold core is embedded in the stepped groove and abuts against the lower pad. A mold cavity for receiving the blank is provided on the upper surface of the lower mold core, and the mold cavity is correspondingly provided with the upper mold core.

[0006] A first through hole and a second through hole are respectively opened on the base plate and the lower pad block, and the second through hole is connected to the bottom of the mold cavity. A T-shaped ejector rod is provided in the mold cavity and the second through hole. The horizontal section of the T-shaped ejector rod is located at the bottom of the mold cavity, and the vertical section is located in the second through hole. A T-shaped ejector rod is provided in the second through hole and the first through hole. The horizontal section of the T-shaped ejector rod is located at the bottom of the second through hole, and the vertical section is located in the first through hole and extends to the bottom of the first through hole.

[0007] The final forging die includes an upper die and a lower die, and the trimming die includes a trimming female die and a trimming male die.

[0008] Preferably, the bottom end of the upper mold core is an upwardly convex arc surface, and the bottom end surface of the upper mold core is connected to the side surface by an arc surface.

[0009] Preferably, the mold cavity is composed of an integrally formed upper mold cavity and a lower mold cavity, the inner diameter of the upper mold cavity is larger than the inner diameter of the lower mold cavity, and a draft angle of 1-3° is provided between the two.

[0010] Preferably, the top plate and the upper mold frame, as well as the bottom plate and the lower mold core, are fixed together by fixing bolts.

[0011] Preferably, the bottom of the upper mold core and the top of the lower mold frame are respectively provided with inner countersunk holes, and fastening bolts are provided in the inner countersunk holes. The upper mold core and the upper mold frame, as well as the lower mold frame and the lower mold core, are respectively fixed by fastening bolts.

[0012] Preferably, a top hole is provided at the center of the top plate.

[0013] Preferably, mounting holes are provided on both sides of the upper mold frame and the lower mold frame.

[0014] This invention also provides a precision forging method for a tee pipe fitting, comprising the following steps:

[0015] S1: Cutting: Select a bar of appropriate diameter and cut it into sections of a certain length. Use a CNC lathe to flatten and chamfer the two ends of the sections.

[0016] S2: Cleaning: Place the bar segments in an alkaline water tank for 300 seconds, clean water for 60 seconds, running water tank for 60 seconds, pickling tank for 120 seconds, clean water for 60 seconds, running water tank for 60 seconds, and hot water tank for 120 seconds in sequence, then take them out and blow them dry.

[0017] S3: First heating: Place the bar stock in the oven and heat for 20 minutes, maintaining the heating temperature at 130°C, then remove it;

[0018] S4: Spraying: Place the heated bar segment on the spraying frame, and spray the lubricant onto the segment using a spray gun filled with water-based glass lubricant. At the same time, rotate the spraying frame to ensure uniform coating.

[0019] S5: Secondary heating: After spraying, the bar segments are arranged on the material rack, and the temperature inside the high-temperature resistance furnace is heated to 1050°C. Then, the bar segments are placed into the resistance furnace and kept at that temperature for 40 minutes.

[0020] S6: Pre-forging: Use tongs to remove the bar stock from the resistance furnace and place it into the pre-forging mold. Select 900T forging energy and strike precisely until the billet is pre-formed into the shape of a tee and then ejected.

[0021] S7: Final forging: The pre-forged part is placed into the final forging mold, forged, and then removed after forming;

[0022] S8: Trimming: Place the forging after final forging into the trimming die to punch off the flash, and then remove it after completion;

[0023] Preferably, the pre-forging die and the final forging die are heated to 100°C-200°C during forging.

[0024] The beneficial effects of this invention are as follows:

[0025] 1. This invention uses fixing bolts and fastening bolts to assemble the upper and lower mold groups separately, which facilitates the assembly and disassembly of the mold. At the same time, by setting upper and lower pads, and by removing the upper and lower mold cores, the upper and lower pads can be easily removed, preventing deformation of the upper and lower mold groups, which would cause poor fit between the parts and lead to long-term wear and mold damage, thereby improving the service life of the mold.

[0026] 2. By setting the bottom end face of the upper die core to an arc shape, and by using an arc transition between the bottom end face and the side face, as well as the shape setting of the die cavity, it can better match the shape of the forging. Moreover, it can maintain the complete metal flow line of the forging in subsequent processing, and the formed product has small flash and high material utilization.

[0027] 3. The present invention uses pre-forging of fixed-length round bars. The pre-forged billet is similar in shape to the finished product. Compared with the finished product, the material ratio is smaller. After precision forging, the product has small flash, high material utilization, complete metal flow lines in the forging, less damage to the mold, and long mold service life. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the overall structure of the pre-forging die in this invention;

[0029] Figure 2 This is a schematic diagram of the cross-sectional structure of a pre-forging die;

[0030] Figure 3 This is a schematic diagram of the structure of the upper module of the pre-forging die;

[0031] Figure 4 This is a bottom view of the upper module structure in a pre-forging die;

[0032] Figure 5 This is a schematic diagram of the lower module of the pre-forging die;

[0033] Figure 6 This is a top view of the lower module of the pre-forging die.

[0034] Figure 7 This is a schematic diagram of the final forging die;

[0035] Figure 8 This is a schematic diagram of the upper die structure of the final forging die;

[0036] Figure 9 This is a schematic diagram of the lower die structure of the final forging die;

[0037] Figure 10 and Figure 11 This is a schematic diagram of the edge-cutting mold;

[0038] Figure 12 It is a comparison diagram of the metal flow lines of the bar stock before and after pre-forging;

[0039] Figure 13 This is a process flow diagram of the forming method for tee pipe fittings;

[0040] The numbers in the diagram are: 1 Top plate, 2 Upper mold frame, 3 Mounting hole, 4 Upper mold core, 5 Lower mold core, 6 Lower mold frame, 7 Fixing bolt, 8 Base plate, 9 Lower pad, 10 T-shaped ejector pin one, 11 T-shaped ejector pin two, 12 First through hole, 13 Second through hole, 14 Lower groove, 15 Mold cavity, 16 Stepped groove, 17 Blank, 18 Mounting groove, 19 Upper groove, 20 Upper pad, 21 Ejector hole, 22 Fastening bolt, 23 Inner countersunk hole, 24 Upper mold, 25 Lower mold, 26 Male mold, 27 Female mold, 28 Lower mold cavity, 29 Upper mold cavity. Detailed Implementation

[0041] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0042] Example 1

[0043] A pre-forging die for a tee pipe fitting, such as Figures 1 to 11 As shown, it includes an upper module and a lower module arranged opposite to each other. The upper module includes a top plate 1, an upper mold frame 2, and an upper mold core 4 connected sequentially from top to bottom. An upper groove 19 is provided at the middle of the top of the upper mold frame 2. An upper pad 20 is provided in the upper groove 19. There are two upper pads 20. An installation groove 18 communicating with the upper groove 19 is provided at the bottom of the upper mold frame 2. The upper groove 19 and the installation groove 18 are in a stepped shape with the upper groove being smaller and the lower groove being larger. The top of the upper mold core 4 is embedded in the installation groove 18 and abuts against the upper pad 20.

[0044] The lower mold assembly includes a base plate 8, a lower mold frame 6, and a lower mold core 5 connected sequentially from bottom to top. A lower groove 14 is provided at the bottom center of the lower mold frame 6, and a lower pad block 9 is provided in the lower groove 14. A stepped groove 16 with a larger upper part and a smaller lower part is provided on the upper surface of the lower mold frame 6, which communicates with the lower groove 14. The bottom end of the lower mold core 5 is embedded in the stepped groove 16 and abuts against the lower pad block 9. A mold cavity 15 for accommodating the blank 17 is provided on the upper surface of the lower mold core 5, and the mold cavity 15 is correspondingly provided with the upper mold core 4.

[0045] The top plate 1 is fixed to the upper mold frame 2 and the bottom plate 8 is fixed to the lower mold core 5 by fixing bolts 7. The bottom of the upper mold core 4 and the top of the lower mold frame 6 are respectively provided with inner countersunk holes 23, and fastening bolts are provided in the inner countersunk holes 23. The upper mold core 4 and the upper mold frame 2, and the lower mold frame 6 and the lower mold core 5 are respectively fixed by fastening bolts 22. Loosening the fixing bolt 7 and tightening the fastening bolt 22 facilitates the disassembly and assembly of the upper and lower dies, making assembly convenient. During long-term use, the upper pad 20 and lower pad 9 are prone to deformation due to the impact of forging. If they are not replaced in time, it will affect the forming of the forging and cause damage to the die. A top hole 21 is provided at the center of the top plate 1. The upper die core 4 can be removed from the upper die frame 2 by tightening the fastening bolt 22. A top rod can be inserted into the top hole 21 to push the upper pad 20 out of the upper groove 19, facilitating the replacement of the upper pad 20. Similarly, the lower die core 5 can be removed from the lower die frame 6 by tightening the fastening bolt 22, and the lower pad 9 can be removed from the lower groove 14, facilitating the replacement of the lower pad 9. This prevents the deformation of the upper pad 20 and lower pad 9 from affecting the precision of the forging and also prevents loose fit between the components of the upper and lower dies, which could cause long-term wear and die damage. Both fastening bolt 22 and fixing bolt 7 are internal hex bolts.

[0046] Mounting holes 3 are provided on both sides of the upper mold frame 2 and the lower mold frame 6. The mold can be fixed on the drive device through the mounting holes 3.

[0047] The bottom end of the upper die core 4 is an upward-convex arc surface, and the bottom surface of the upper die core 4 transitions to the side surface through an arc surface. The die cavity 15 is composed of an integrally formed upper die cavity 29 and a lower die cavity 28. The inner diameter of the upper die cavity 29 is larger than the inner diameter of the lower die cavity 28, and a 1-3° draft angle is provided between the two to facilitate the demolding of the blank 17. The shape of the upper die core 4 and the die cavity 15 can better match the shape of the forging, and can maintain the complete metal flow line of the forging in subsequent processing. Moreover, the formed product has small flash and high material utilization.

[0048] A first through hole 12 and a second through hole 13 are respectively opened on the base plate 8 and the lower pad block 9, and the second through hole 13 is connected to the bottom of the mold cavity 15. A T-shaped ejector rod 10 is provided in the mold cavity 15 and the second through hole 13. The horizontal section of the T-shaped ejector rod 10 is located at the bottom of the mold cavity 15, and the vertical section is located in the second through hole 13. A second T-shaped ejector rod 11 is provided in the second through hole 13 and the first through hole 12. The horizontal section of the second T-shaped ejector rod 11 is located at the bottom of the second through hole 13, and the vertical section is located in the first through hole 12 and extends to the bottom of the first through hole 12. An upward force is applied to the second T-shaped ejector rod 11. A hydraulic cylinder can be connected to the bottom of the second T-shaped ejector rod 11 to apply the upward force, so that the second T-shaped ejector rod 11 transmits the upward force to the first T-shaped ejector rod 10, and then to the forging through the first T-shaped ejector rod 10, thereby facilitating the ejection of the forged tee connector.

[0049] The final forging die includes an upper die 24 and a lower die 25, and the trimming die includes a trimming female die 27 and a trimming male die 26.

[0050] Example 2

[0051] A precision forging process for a tee pipe fitting, such as Figures 12-13 As shown, it includes the following steps:

[0052] S1: Blanking: Select a bar of appropriate diameter and cut it into sections of a certain length. Use a CNC lathe to flatten and chamfer the two ends of the sections and remove the saw marks at both ends to prevent the blank from cracking along the saw marks during pre-forging.

[0053] S2: Cleaning: Place the bar segments in an alkaline water tank for 300 seconds, clean water for 60 seconds, running water tank for 60 seconds, pickling tank for 120 seconds, clean water for 60 seconds, running water tank for 60 seconds, and hot water tank for 120 seconds. Remove and dry. The cleaned product has a clean surface and will not damage the protective layer of lubricant during heating, thus better preventing product oxidation.

[0054] S3: First heating: Place the bar stock in the oven and heat for 20 minutes, maintaining the heating temperature at 130°C, then remove it;

[0055] S4: Spraying: Place the heated material section on the spraying frame, and use a spray gun filled with water-based glass lubricant to spray the lubricant onto the material section while rotating the spraying frame to ensure uniform coating.

[0056] S5: Secondary heating: Arrange the sprayed bar segments on the material rack, heat the temperature in the high-temperature resistance furnace to 1050°C, and then put the bar segments into the resistance furnace to maintain the temperature at 1050°C for 40 minutes to ensure that the internal and external temperatures of the bar segments are uniform and the same.

[0057] S6: Pre-forging: During pre-forging, graphite emulsion is sprayed onto the mold, the bar stock in the resistance furnace is taken out with tongs and placed into the pre-forging mold, and 900T of forging energy is selected for precise striking until the billet is pre-formed into the shape of a tee and then ejected.

[0058] S7: Final forging: The pre-forged part is placed into the final forging mold, forged, and then removed after forming;

[0059] S8: Trimming: Place the forging after final forging into the trimming die to punch off the flash, and then remove it after completion;

[0060] The pre-forging die and the final forging die are heated to 100°C-200°C during forging.

[0061] In practical use, the upper and lower molds are first assembled and installed using fixing bolts 7 and fastening bolts 22. Then, the entire mold is installed on the drive device through the mounting hole 3. A round bar of a fixed length is placed into the mold cavity 15 of the lower mold core 5. The drive device is started so that the upper mold core 4 forges the bar in the mold cavity 15. After forming, the blank 17 is ejected by T-shaped ejector pin 2 11 and T-shaped ejector pin 10. Then, it is placed into the final forging mold for final forging. Finally, it is placed into the trimming mold for punching and trimming the flash. The entire tee part is then precision forged.

[0062] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method of precision forging process forming of a tee fitting, based on a tee fitting forging die, characterized in that, The three-way pipe forging die comprises a pre-forging die, a finish-forging die and a trimming die, the pre-forging die comprises an upper die set and a lower die set arranged oppositely, the upper die set comprises a top plate (1), an upper die frame (2) and an upper die core (4) connected in sequence from top to bottom, an upper groove (19) is formed in the middle position of the top of the upper die frame (2), an upper pad (20) is arranged in the upper groove (19), an installation groove (18) is formed in the bottom of the upper die frame (2) and communicates with the upper groove (19), the upper groove (19) and the installation groove (18) are in a stepped shape of small top and large bottom, and the top end of the upper die core (4) is embedded in the installation groove (18) and abuts against the upper pad (20); the lower die set comprises a bottom plate (8), a lower die frame (6) and a lower die core (5) connected in sequence from bottom to top, a lower groove (14) is formed in the middle position of the bottom of the lower die frame (6), a lower pad (9) is arranged in the lower groove (14), a stepped groove (16) of large bottom and small top is formed in the upper surface of the lower die frame (6) and communicates with the lower groove (14), the bottom end of the lower die core (5) is embedded in the stepped groove (16) and abuts against the lower pad (9), a die cavity (15) for accommodating a blank (17) is formed in the upper surface of the lower die core (5), and the die cavity (15) is arranged correspondingly to the upper die core (4); first and second through holes (12) and (13) are formed in the bottom plate (8) and the lower pad (9) and communicate with each other, the second through hole (13) communicates with the bottom of the die cavity (15), a T-shaped ejector pin I (10) is arranged in the die cavity (15) and the second through hole (13), the horizontal section of the T-shaped ejector pin I (10) is located at the bottom of the die cavity (15), and the vertical section is located in the second through hole (13), a T-shaped ejector pin II (11) is arranged in the second through hole (13) and the first through hole (12), the horizontal section of the T-shaped ejector pin II (11) is located at the bottom of the second through hole (13), the vertical section is located in the first through hole (12) and extends below the first through hole (12), the bottom end of the upper die core (4) is an upwardly protruding arc surface, and the bottom end surface of the upper die core (4) is transitioned to the side surface through a circular arc surface; The method comprises the following steps: S1: blanking: select a rod of appropriate diameter and saw it into a length of material segment, and use a numerical control lathe to perform a flat end chamfer on the two end faces of the material segment; S2: cleaning: sequentially place the rod segment in an alkali water tank for cleaning for 300s, in clean water for 60s, in a running water tank for 60s, in an acid pickling tank for 120s, in clean water for 60s, in a running water tank for 60s, in a hot water tank for 120s, and then take out and dry; S3: first heating: place the rod segment in an oven and heat for 20min, and keep the heating temperature at 130°C, and then take out; S4: spraying: place the heated rod segment on a spraying frame, use a spray gun filled with water-based glass lubricant to spray the lubricant on the material segment, and rotate the spraying frame to ensure uniform coating; S5: secondary heating: the sprayed rod section is arranged on the rack, the temperature in the high-temperature resistance furnace is heated to 1050 DEG C, then the rod section is put into the resistance furnace, and is kept for 40 min; S6: pre-forging: the rod in the resistance furnace is taken out by the fire tongs, and is put into the pre-forging die, the forging energy of 900T is selected, accurate striking is carried out, until the blank (17) is preformed into the shape of the tee joint, and then is ejected; S7: finish forging: the pre-forging piece is put into the finish forging die, and is forged, and is taken out after forming; S8: edge cutting: the forged piece after finish forging is put into the edge cutting die, and is punched to cut the flash, and is taken out after finishing.

2. The method of precision swaging of a tee fitting according to claim 1, wherein: The mold cavity (15) is composed of an integrally formed upper mold cavity (29) and lower mold cavity (28), the inner diameter of the upper mold cavity (29) is larger than that of the lower mold cavity (28), and a 1-3° mold opening slope is arranged between the two.

3. The method of precision swaging of a tee fitting according to claim 2, wherein: The top plate (1) and the upper mold frame (2) and the bottom plate (8) and the lower mold core (5) are fixed together by fixing bolts (7) respectively.

4. The method of precision swaging of a tee fitting according to claim 3, wherein: The bottom of the upper mold core (4) and the top of the lower mold frame (6) are respectively provided with inner counterbores (23), and fastening bolts (22) are arranged in the inner counterbores (23), and the upper mold core (4) and the upper mold frame (2) and the lower mold frame (6) and the lower mold core (5) are fixed by the fastening bolts (22) respectively.

5. The method of precision swaging of a tee fitting as defined in claim 4 wherein: A top piece hole (21) is arranged at the center position of the top plate (1).

6. The method of precision swaging of a tee fitting as defined in claim 5 wherein: Mounting holes (3) are arranged on both sides of the upper mold frame (2) and the lower mold frame (6).

7. The method of precision swaging of a tee fitting as defined in claim 1 wherein: The finish forging die comprises an upper die (24) and a lower die (25), and the edge cutting die comprises an edge cutting female die (27) and an edge cutting male die (26).

8. The method of precision swaging of a tee fitting as defined in claim 1 wherein: The pre-forging die and the finish forging die are heated to 100-200 DEG C during forging.

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