CN112570579B

CN112570579B - Forming device and method for realizing pipe end necking thickening by accurately controlling temperature in different areas

Info

Publication number: CN112570579B
Application number: CN202011334936.XA
Authority: CN
Inventors: 范玉斌; 徐雪峰; 危立明; 肖洁; 徐佳俊
Original assignee: Nanchang Hangkong University
Current assignee: Nanchang Hangkong University
Priority date: 2020-11-25
Filing date: 2020-11-25
Publication date: 2022-07-08
Anticipated expiration: 2040-11-25
Also published as: CN112570579A

Abstract

The invention discloses a forming device and a method for realizing the thickening of a pipe end necking by accurately controlling temperature in different areas, which relate to the technical field of pipe plastic processing, wherein the forming device comprises a push head, a cooler, a necking die and a thickening die which are sequentially arranged according to the feeding direction of a pipe blank; the pushing head is used for pushing and extruding the tube blank under the driving of the power source; the necking die and/or the thickening die are/is provided with a heating structure, the necking die is used for necking and forming of the tube blank, and the thickening die is used for thickening and forming of the tube blank; the cooler is used for cooling the temperature of the pipe blank outside the necking die and the thickening die. The forming device and the forming method can realize free adjustment of the temperature of the necking area and the thickening area of the die, improve the material utilization rate, the product quality and the connection strength, reduce the manufacturing cost of the die, shorten the heating time of the die, are easier to clean after the die is divided into blocks, and are more convenient to take out the formed parts.

Description

Forming device and method for realizing pipe end necking thickening by accurately controlling temperature in different areas

Technical Field

The invention relates to the technical field of pipe plastic processing, in particular to a forming device and a method for realizing pipe end necking thickening by accurately controlling temperature by regions.

Background

The necking process is a forming method for reducing the diameter of the opening of a tube blank, is one of tube plastic processing technologies, and is widely applied to production and manufacturing of structural members in aerospace, national defense, light industry and the like. At present, the pipe necking formation neglects the pipe work hardening and the material thickness change after necking. Therefore, the radial direction of the reducing part is not obviously thickened after the pipe is formed, and other components are connected in the later stage in a welding or riveting mode. In addition, the wall thickness of the traditional airplane pull rod part is too thin at the pipe necking end, if the pipe is directly tapped, the pipe can be broken and fail, and the method of riveting the threaded sleeve after the pipe necking is adopted for manufacturing the traditional airplane pull rod part has the defects of unstable connection strength, higher manufacturing cost, short service life and the like. Therefore, in order to improve the reliability of the tie rod and reduce the manufacturing cost, research on a pipe necking and thickening forming process is urgently needed.

At present, the research on the thickening of the necking of the pipe at home and abroad mainly adopts a distribution forming method of thickening the pipe end firstly and necking the pipe end secondly, so that not only is the production cost increased and the production efficiency reduced, but also the difficulty of necking the thickened pipe end secondly is increased. Or the pipe is pushed into a female die heated to the forming temperature, the pipe sequentially passes through a supporting area, a reducing area and a thickening area along a female die cavity until the pipe touches the thickening area, the pipe starts to be stacked, the pipe is firstly reduced and then thickened, the female die sequentially consists of the supporting area, the reducing area and the thickening area from the direction of an inlet pipe opening, and the periphery of the die cavity is surrounded by 5 heating rod holes and a thermocouple hole which are communicated with the die cavity in parallel so as to control the temperature of the female die. The method has the advantages of high mold cost, heavy use and long time consumption for heating the mold, and can not realize the separate control of the temperature of different areas because the reducing area and the thickening area are integrated, so that too much material is accumulated in the reducing area, the unnecessary thickening of the wall thickness of the reducing area is caused, the material is wasted, the weight of parts is increased, the flowing of the material to the thickening area is hindered, and the wall thickness of the pipe blank thickening area is not increased enough.

In summary, how to provide a new scheme for thickening the pipe end necking is an urgent problem to be solved by the present invention.

Disclosure of Invention

The invention aims to provide a forming device and a forming method for realizing the thickening of a pipe end necking by accurately controlling the temperature by areas, which are used for solving the problems in the prior art.

In order to achieve the purpose, the invention provides the following scheme:

the invention provides a forming device for realizing the thickening of a pipe end necking by accurately controlling temperature in different areas, which comprises a push head, a cooler, a necking die and a thickening die, wherein the cooler, the necking die and the thickening die are sequentially arranged in the feeding direction of a pipe blank; the push head is used for pushing and extruding the tube blank under the driving of a power source; the necking die and/or the thickening die are/is provided with a heating structure, the necking die is used for necking and forming of the tube blank, and the thickening die is used for thickening and forming of the tube blank; the cooler is used for cooling the temperature of the pipe blank outside the necking die and the thickening die.

Optionally, the power source is a universal experiment machine, and the push head is mounted at the top of the universal experiment machine.

Optionally, the thickening mold is mounted at the bottom of the universal testing machine and is located right below the pushing head; the necking die is arranged above the thickening die, and the cooler is arranged above the necking die.

Optionally, a heat insulation plate is arranged between the necking die and the thickening die.

Optionally, the heating structure is a heating rod.

Optionally, the necking die and/or the thickening die are provided with thermocouples for measuring the die temperature.

Optionally, the cooler is a water cooler, a circulating water tank is arranged in the water cooler, a water inlet and a water outlet which are communicated with the circulating water tank are arranged on the side wall of the water cooler, and the water inlet and the water outlet are both connected with a hose.

Meanwhile, the invention provides a forming method for realizing the thickening of the necking of the pipe end by accurately controlling the temperature in different areas based on the forming device, which mainly comprises the following steps:

the method comprises the following steps: taking raw materials for the tube blank, cleaning the tube blank, ensuring that the surface of the end opening of the tube blank is smooth and has no burrs, and the outer surface of the tube blank has no impurities;

step two: installing a mold, namely installing a push head, a thickening mold, a necking mold and a cooler in place on a universal testing machine in sequence;

step three: pretreating the mould, namely introducing cooling liquid into a cooler to avoid the temperature rise of the tube blank outside the reducing area and the thickening area; simultaneously starting a heating device to heat the necking die and the thickening die, and enabling the temperature of the necking die to be lower than that of the thickening die, so that material accumulation of the tube blank in a thickening area is ensured, and the wall thickness is increased;

step four: and (3) performing a test, putting the processed pipe blank into a heated necking die and a heated thickening die through a cooler, preheating to enable the pipe blank to reach a necking temperature, starting a pushing head to axially and slowly feed, enabling the pipe blank to sequentially pass through the necking die and the thickening die to realize necking formation, after the pipe blank is subjected to necking, continuously preheating in the thickening die, and after the temperature of a thickening region of the pipe blank reaches a thickening temperature, continuously feeding until the end face of the pipe blank is contacted with a thickening surface of the thickening die, and preventing the end face of the pipe blank from continuously moving downwards so as to finish thickening deformation of the necking of the pipe blank.

Optionally, in the first step, after the pipe blank is cleaned, a layer of lubricant is coated on the outer surface of the pipe blank.

Optionally, a die correction step is further included between the second step and the third step, the axial center holes of the cooler, the necking die and the thickening die are adjusted to be aligned, the axial center of the tube blank is adjusted to be aligned with the axial center of the cooler, and the tube blank is prevented from being bent due to the deviation of the axial hole during forming.

Compared with the prior art, the invention has the following technical effects:

the forming device and the method for realizing the necking thickening of the pipe end by accurately controlling the temperature in the areas by areas can realize the free adjustment of the temperature of the necking area and the thickening area of the die. Compared with the prior art, the necking thickening female die is divided into the independent necking die and the thickening die, and the independent heating devices are respectively configured, so that the temperature difference between the necking area and the thickening area can be manually set, the temperatures of the necking area and the thickening area are both at the optimal necking temperature and thickening temperature, the problems that materials are accumulated too much in the necking area, waste is caused, the material flow is blocked, and the weight of parts is reduced can be effectively solved, the strength of a tube blank in the necking area and the utilization rate of the materials are improved, the working efficiency is improved, the energy is saved, and the practicability is high.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.

FIG. 1 is a schematic view of the overall structure of a forming device for realizing the thickening of a necking of a pipe end by accurately controlling temperature in different areas according to the invention;

FIG. 2 is a top view of a cooler in a forming apparatus of the present invention;

FIG. 3 is an isometric view of a cooler in a forming apparatus of the present invention;

FIG. 4 is an isometric view of the necking die of the present invention;

FIG. 5 is an isometric view of the insulation sheeting of the present invention;

FIG. 6 is an isometric view of a thickening mold of the present invention;

wherein the reference numerals are: 1. the device comprises a push head, a pipe blank 2, a hose 3, a nut 4, a cooler 5, a necking die 6, a heat insulation plate 7, a thickening die 8, a screw rod 9, a screw rod 14, a screw rod 28, a screw hole 10, a screw hole 15, a heating rod 11, a thermocouple 12, a universal experiment machine 13, a positioning hole 16, a positioning hole 20, a positioning hole 24, a positioning hole 17, a water inlet 18, a water outlet 19, a circulating water tank 21, a heating rod hole 30, a necking die cavity 22, a thermocouple hole 23, a thermocouple hole 27, a heat insulation plate thickening die cavity 25, a thickening face 29, and a thickening die cavity 31.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

The invention aims to provide a forming device and a forming method for realizing the thickening of a pipe end necking by accurately controlling the temperature by areas, which can realize the free adjustment of the temperature of a necking area and a thickening area of a die, improve the material utilization rate, the product quality and the connection strength, reduce the manufacturing cost of the die, shorten the heating time of the die, ensure that the die is easier to clean after being partitioned, and more conveniently take a formed piece.

In order to make the aforementioned objects, features and advantages of the present invention comprehensible, embodiments accompanied with figures are described in further detail below.

The first embodiment is as follows:

as shown in fig. 1 to 6, this embodiment provides a forming apparatus for realizing the increase of the necking thickness of the pipe end by accurately controlling the temperature in different areas. The universal experiment machine 13 is used as a main power source and generates extrusion force for pushing the push head 1 to form the tube blank 2. A threaded hole 15 at the top of the universal experimental machine 13 is used for fixing the push head 1, a water inlet 17 and a water outlet 18 of the cooler 5 are respectively connected with the hose 3, the screw 9 is used for connecting the cooler 5 and the necking die 6, the heating device comprises a heat insulation plate 7 and a thickening die 8, a threaded hole 10 at the bottom of a universal experiment machine 13 is used for fixing the thickening die 8, a pushing head 1 is used for feeding a tube blank 2, a cooler 5 is used for cooling the temperature of the tube blank outside a necking die 6 and the thickening die 8, the necking die 6 is used for realizing necking forming of the tube blank 2, the thickening die 8 is used for realizing thickening forming of the tube blank 2, the heat insulation plate 7 is used for isolating temperature transfer between the necking die 6 and the thickening die 8,

heating rod holes

21 and 30 are used for placing a heating rod 11,

thermocouple holes

23 and 27 are used for placing a thermocouple 12, the heating rod 11 is used for heating the necking die 6 and the thickening die 8, and the thermocouple 12 is used for measuring the temperature of the necking die 6 and the thickening die 8.

The embodiment also provides a forming method for realizing the thickening of the necking of the pipe end by accurately controlling the temperature in different areas, which is implemented by adopting the forming device. The forming method specifically comprises the following steps:

the method comprises the following steps: 2 unloading of tubular product, under the prerequisite that satisfies the manufacture requirement, use the pipe cutting machine to cut the pipe of certain length, the required terminal surface of the pipe that the cutting is good is perpendicular with the hollow shaft, clearance pipe base internal and external surface, guarantees that the port surface is level and smooth and burr-free, and pipe surface is impurity-free, prevents burr and impurity entering inner mould cavity and damages the grinding apparatus, increases the frictional force of pipe and die cavity, is difficult for the pipe throat bodiness and takes shape, smears the even emollient of one deck on pipe surface.

Step two: the device is fixed by firstly connecting the push head 1 with a threaded hole 15 at the top of the universal experiment machine 13 through a screw 14 in a threaded manner. And then the hose 3 is sleeved on a water inlet 17 and a water outlet 18 of the cooler 5, and the water inlet 17 and the water outlet 18 are both communicated with a circulating water tank 19 in the cooler. After the screw rod 9 passes through the

positioning holes

16, 20, 24 and 26, the bottom end of the screw rod is connected with the screw cap 4, and the cooler 5, the necking die 6, the heat insulation plate 7 and the thickening die 8 are fixed together. Finally, the thickened die 8 is connected with the threaded hole 10 at the bottom of the universal experiment machine 13 through a screw 28 at the bottom.

Step three: and (3) correcting the die, adjusting the alignment of the shaft center holes of the cooler 5, the necking die 6, the heat insulation plate 7 and the thickening die 8, and adjusting the alignment of the shaft center of the tube blank 2 and the shaft center of the cooler 5 to prevent the tube blank 2 from being bent due to shaft hole deviation during forming.

Step four: the cooler 5 is filled with cooling liquid, the water inlet 17 and the water outlet 18 are both connected with plastic hoses, the cooling liquid flows in from the water inlet 17, flows out from the water outlet 18 after passing through the circulating water tank 19, and takes away the heat of the tube blank 2 in the supporting area, so that the temperature rise of the tube blank outside the necking area and the thickening area is avoided, the strength of the tube blank is reduced, and buckling is generated; the heating rod 11 and the thermocouple 12 are respectively inserted into the

heating rod holes

21 and 30 and the

thermocouple holes

23 and 27, then the heating rod is electrified, the heating rod 11 starts to heat the necking die 6 and the thickening die 8, the thermocouple 12 can accurately measure the temperatures of the necking die 6 and the thickening die 8 in real time, and the temperatures of the necking die 6 and the thickening die 8 are ensured to be in respective preset temperature ranges, so that the temperature of the necking die 6 is lower than that of the thickening die 8, the material accumulation of the tube blank 2 in a thickening area is easier, and the wall thickness is increased.

Step five: and (3) performing a test, namely putting the processed pipe blank 2 into a heated necking die 6 and a heated thickening die 8 through a cooler 5, preheating for 5 minutes, and after the pipe blank 2 reaches the necking temperature. The axial slow feeding of the push head 1 is controlled by a universal experiment machine 13, and the tube blank passes through a necking cavity 22, a heat insulation plate thickening cavity 25 and a thickening cavity 31 in sequence to realize necking forming; after the pipe blank is reduced, the pipe blank is continuously preheated in the thickening mould for 2 minutes, after the temperature of the thickening area of the pipe blank 2 reaches the thickening temperature, the pipe blank is continuously fed until the end surface of the pipe blank 2 is contacted with the thickening surface 29 of the thickening mould 8, and the end surface of the pipe blank 2 cannot continuously move downwards, so that the thickening deformation of the pipe is realized.

Therefore, the forming device and the forming method for realizing the necking thickening of the pipe end by accurately controlling the temperature in different areas have the advantages that:

1. compared with the prior art, the necking thickening female die is divided into an independent necking die and a thickening die, two symmetrical heating rod holes and a thermocouple hole which are vertical to a cavity are arranged around the cavities of the necking die and the thickening die, the forming temperatures of the necking die and the thickening die are respectively controlled by two independent temperature control systems, an insulating plate is arranged between the two dies, and the temperature transfer between the dies is isolated, so that the forming temperatures of a necking area and a thickening area are accurately and reasonably controlled;

2. the temperature difference between the necking area and the thickening area can be manually set, so that the temperatures of the necking area and the thickening area are both at the optimal necking temperature and the optimal thickening temperature, the phenomenon that too much material is accumulated in the necking area to cause waste, the material flow is hindered, the weight of parts is reduced, and the strength of the tube blank in the necking area and the utilization rate of the material are improved;

3. because the strength of the tube blank in the reducing area is improved, the tube blank can bear more forming load when being formed, and the obstruction of the material flowing from the reducing area to the thickening area is reduced, so that more materials can be accumulated in the thickening area, the wall thickness of the thickening area is increased, the quality and the connection strength of a product are further improved, the machining allowance is reduced, and the machining difficulty is reduced;

4. the structure of the female die is optimized, the die design is divided into blocks, the heating time of the die is greatly shortened, the working efficiency is improved, and the energy is saved; in addition, when necking thickening forming with different taper angles is carried out, only the middle necking die is needed to be replaced, so that the manufacturing cost of the die is reduced;

5. after the block is formed, the lubricating liquid is more conveniently and uniformly coated on the die cavity, so that the lubricating effect during forming is better, and the daily maintenance, cleaning and polishing of the die after the experiment is finished are more convenient;

6. compared with the traditional hydraulic cylinder feeding, the feeding of the universal testing machine can control the feeding speed and the feeding length more accurately, can directly observe the forming load borne by the tube blank in the forming process, and is greatly helpful for researching the necking thickening forming of the tube.

It will be evident to those skilled in the art that the invention is not limited to the details of the foregoing illustrative embodiments, and that the present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein, and any reference signs in the claims are not intended to be construed as limiting the claim concerned.

The principle and the implementation mode of the invention are explained by applying a specific example, and the description of the embodiment is only used for helping to understand the method and the core idea of the invention; meanwhile, for a person skilled in the art, according to the idea of the present invention, the specific embodiments and the application range may be changed. In view of the above, the present disclosure should not be construed as limiting the invention.

Claims

1. A precise forming method for realizing the thickening of the necking of a pipe end by controlling the temperature in different areas is implemented by adopting a forming device for realizing the thickening of the necking of the pipe end by controlling the temperature in different areas, and is characterized in that the forming device for realizing the thickening of the necking of the pipe end by controlling the temperature in different areas comprises a push head, a cooler, a necking die and a thickening die which are sequentially arranged according to the feeding direction of a pipe blank; the push head is used for pushing and extruding the tube blank under the driving of a power source; the necking die and/or the thickening die are/is provided with a heating structure, the necking die is used for necking and forming of the tube blank, and the thickening die is used for thickening and forming of the tube blank; the cooler is used for cooling the temperature of the pipe blank outside the necking die and the thickening die; the forming method for realizing the necking thickening of the pipe end by accurately controlling the temperature in different areas comprises the following steps:

step three: pretreating the mould, namely introducing cooling liquid into a cooler to avoid the temperature rise of the tube blank outside the reducing area and the thickening area; simultaneously starting a heating device to heat the necking die and the thickening die, and enabling the temperature of the necking die to be lower than that of the thickening die, so that material accumulation of the tube blank in a thickening area is ensured, and wall thickness increase is realized;

2. The method of claim 1, wherein the power source is a universal testing machine, and the pusher is mounted on the top of the universal testing machine.

3. The method for forming the tapered pipe end by accurately controlling the temperature in different areas according to claim 2, wherein the thickening die is arranged at the bottom of the universal testing machine and is positioned right below the push head; the necking die is arranged above the thickening die, and the cooler is arranged above the necking die.

4. The forming method for realizing the thickening of the necking of the pipe end by accurately controlling the temperature in the divided areas according to claim 1, wherein a heat insulation plate is arranged between the necking die and the thickening die.

5. The method of claim 1, wherein the heating structure is a heating rod.

6. The method of claim 1, wherein said necking die and/or said thickening die is equipped with a thermocouple for measuring die temperature.

7. The forming method for realizing the thickening of the necking of the pipe end by accurately controlling the temperature in different areas according to claim 1, wherein the cooler is a water cooler, a circulating water tank is arranged in the water cooler, a water inlet and a water outlet which are communicated with the circulating water tank are arranged on the side wall of the water cooler, and the water inlet and the water outlet are both connected with a hose.

8. The method for forming a tapered pipe end by controlling the temperature in a precise sub-area according to claim 1, wherein in the first step, after the pipe blank is cleaned, a layer of lubricant is coated on the outer surface of the pipe blank.

9. The forming method for realizing the necking and thickening of the pipe end by accurately controlling the temperature in different areas according to claim 1, wherein a mould correction step is further included between the second step and the third step, the axial center holes of the cooler, the necking mould and the thickening mould are adjusted to be aligned, the axial center of the pipe blank is adjusted to be aligned with the axial center of the cooler, and the bending phenomenon of the pipe blank caused by the deviation of the shaft hole during forming is prevented.