CN220195956U

CN220195956U - Pipe drawing equipment

Info

Publication number: CN220195956U
Application number: CN202320836329.6U
Authority: CN
Inventors: 岳学明; 冯橹铭; 王春光; 岳胜亚
Original assignee: Zhejiang Hailiang Co Ltd
Current assignee: Zhejiang Hailiang Co Ltd
Priority date: 2023-04-12
Filing date: 2023-04-12
Publication date: 2023-12-19
Anticipated expiration: 2033-04-12

Abstract

The utility model discloses a pipe drawing device, which belongs to the field of pipe processing devices and can reduce the residual stress of pipe. In the drawing process of the pipe stock, the pipe stock sequentially passes through the diameter reducing structure and the diameter expanding structure, so that the pipe stock is firstly subjected to diameter reducing once and then subjected to diameter expanding once, and residual stress is counteracted.

Description

Pipe drawing equipment

[ field of technology ]

The utility model relates to the field of pipe material processing equipment, in particular to pipe material drawing equipment.

[ background Art ]

At present, the pipe material is processed and molded in a mode generally comprising the following steps: firstly, raw materials are melted and cast into a tube blank, and the tube blank is drawn, so that the inner diameter of the tube is adjusted, and the wall thickness is reduced. The adjustment of the inner diameter of the pipe material is two, namely diameter expansion and diameter reduction, wherein the diameter reduction is the inner diameter of the pipe material, after the inner diameter of the pipe material is reduced, the pipe material has residual stress, and the pipe material is easy to crack. In order to reduce the residual stress, the conventional method is to anneal the drawn pipe material, but the annealing treatment requires longer time and more cost, and red oxidation spots and patterns often appear on the surface of the annealed pipe material, which belongs to defective products and cannot be sold.

[ utility model ]

The utility model aims to solve the technical problem of overcoming the defects of the prior art and providing pipe drawing equipment which can reduce the residual stress of the pipe.

In order to solve the technical problems, the utility model adopts the following technical scheme:

the pipe drawing equipment comprises an outer die and an inner die, wherein a through hole is formed in the outer die, the inner die penetrates through the through hole, the inner die is positioned in the pipe when the pipe is drawn, and the inner die comprises a diameter-reducing structure and a diameter-expanding structure in the drawing direction of the pipe so that the pipe is firstly reduced in diameter and then expanded in diameter in the drawing process.

On the basis of the scheme, the minimum dimension of the diameter-reducing structure is D1, the maximum dimension of the diameter-reducing structure is D2, the maximum dimension of the diameter-expanding structure is D3, and D3 is larger than D1 and smaller than D2.

On the basis of the scheme, the dimensional difference between the D3 and the D1 is not more than 2% of the D1. The maximum size of the expanding structure is slightly larger than the size of the sizing section, so that the inner diameter of the pipe material cannot be changed obviously.

On the basis of the scheme, in the drawing direction of the pipe, the diameter reducing structure comprises a guide section, a sizing section and a first transition section connected between the guide section and the sizing section, the minimum size of the sizing section is D1, the maximum size of the guide section is D2, and the sizing section and the guide section are of cylindrical structures.

On the basis of the scheme, the inner wall of the through hole comprises a sizing bearing and a transition belt, the sizing bearing and the sizing section form a sizing gap, a transition gap is formed between the transition belt and the first transition section, the sizing gap and the transition gap are spliced to form a drawing gap for changing the inner diameter of a pipe material, the diameter expanding structure penetrates through the sizing bearing, the size of the sizing bearing is D4, and D1 is smaller than D4.

On the basis of the scheme, the diameter reducing structure and the diameter expanding structure are integrally formed.

On the basis of the scheme, the inner die further comprises a first core head and a second core head which are connected with each other, the diameter-reducing structure is arranged on the first core head, and the diameter-expanding structure is arranged on the second core head.

On the basis of the scheme, the first core is provided with the first connecting piece, the second core is provided with the second connecting piece, and the first core is connected with the second core through the cooperation of the first connecting piece and the second connecting piece.

On the basis of the scheme, the first core head is detachably arranged on the second core head; alternatively, the second core print is removably mounted on the first core print.

The utility model has the beneficial effects that:

the utility model discloses a pipe drawing device which is used for drawing a pipe material to change the inner diameter, the outer diameter and the wall thickness of the pipe material. The pipe material is made of metal, so that after the pipe material is reduced in diameter, tensile stress, namely residual stress, which has the tendency of outwards expanding the pipe material, is generated, and after the diameter reduction pass, the diameter expansion pass is arranged to offset the residual stress, so that the residual stress is eliminated in an annealing mode. Therefore, the time required for carrying out the annealing process can be reduced, the production efficiency of the pipe material is improved, the pipe material is not required to be transported for many times, the scrapped pipe material in the transportation process is reduced, the yield of the pipe material is improved, and meanwhile, the production cost of the pipe material can be reduced.

The minimum size of the diameter-reducing structure is D1, the maximum size of the diameter-reducing structure is D2, the maximum size of the diameter-expanding structure is D3, and D3 is larger than D1 and smaller than D2. After the pipe material is subjected to the reducing pass, the inner diameter size of the pipe material is D1, and the purpose of the diameter-expanding structure is to reduce residual stress, so that the diameter-expanding structure is only required to be larger than D1, and if D2 is the diameter of the pipe material is larger than the size before being processed.

The dimensional difference between the D3 and the D1 is not more than 2% of the D1. The maximum size of the expanding structure is slightly larger than the size of the sizing section, so that the inner diameter of the pipe material cannot be changed obviously. In the drawing process, the inner die needs to pass through the outer die, and the size of the expanding structure is not beneficial to the matching with the outer die if the size is too large.

These features and advantages of the present utility model will be disclosed in detail in the following detailed description and the accompanying drawings.

[ description of the drawings ]

The utility model is further described with reference to the accompanying drawings:

FIG. 1 is a schematic diagram of a drawing apparatus in a tube drawing process according to an embodiment of the present utility model;

FIG. 2 is a schematic view of an inner mold according to an embodiment of the present utility model;

FIG. 3 is a schematic diagram of a drawing apparatus according to an embodiment of the present utility model;

FIG. 4 is a schematic view of another internal mold according to an embodiment of the present utility model;

FIG. 5 is a schematic diagram illustrating connection between a first core print and a second core print according to an embodiment of the present utility model;

fig. 6 is a schematic diagram illustrating connection between a first core print and another second core print according to an embodiment of the present utility model.

Reference numerals:

the outer die 100, the through hole 110, the bearing 111 and the transition band 112;

the inner die 200, the diameter reducing structure 210, the guide section 211, the sizing section 212, the first transition section 213, the diameter expanding structure 220, the second transition section 221, the cylindrical section 2211, the round platform section 2212, the first core bit 230, the opening 231, the second core bit 240, the second core bit body 241, the connecting piece 242 and the locking piece 243;

sizing gap 300, transition gap 310.

[ detailed description ] of the utility model

The technical solutions of the embodiments of the present utility model will be explained and illustrated below with reference to the drawings of the embodiments of the present utility model, but the following embodiments are only preferred embodiments of the present utility model, and not all embodiments. Based on the examples in the implementation manner, other examples obtained by a person skilled in the art without making creative efforts fall within the protection scope of the present utility model.

The appearances of the phrases such as "exemplary," "some embodiments," and the like in the following text are meant to be "serving as examples, embodiments, or illustrative," and any embodiment described as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments. In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the present utility model, it will be appreciated by those skilled in the art that the present disclosure may be practiced without some of these specific details.

Referring to fig. 1 to 6, the embodiment of the utility model discloses a pipe drawing device, which comprises an outer die 100 and an inner die 200, wherein a through hole 110 is formed in the outer die 100, the inner die 200 penetrates through the through hole 110, the inner die 200 is positioned in the pipe when the pipe is drawn, and the inner die 200 comprises a diameter reducing structure 210 and a diameter expanding structure 220 in the drawing direction of the pipe so as to reduce the diameter of the pipe before expanding the diameter of the pipe in the drawing process.

The tube drawing apparatus is used for drawing a tube to change the inner diameter, outer diameter and wall thickness of the tube.

In the prior art, after the tube material is drawn, the mechanical property, the surface state and the surface hydrophilicity of the tube material are qualified, but the residual stress is higher, and the general situation is 6-8 kgf/mm ² However, the tube stock may be used with a requirement of less than 5kgf/mm ² . The residual stress of the pipe material after annealing can be reduced to 3-4.5 kgf/mm by adopting the traditional stress relief annealing method ² But the surface of the annealed tube stock is oftenRed oxidation spots and patterns appear, which belong to defective products and cannot be sold.

When the pipe drawing equipment is used for drawing the pipe, the process comprises the following steps: annealing/casting-diameter reduction-diameter expansion-annealing-secondary drawing-sawing; or annealing/casting-reducing-expanding-sawing.

In the prior art, the typical drawing process is: annealing/casting-diameter reduction-annealing-secondary drawing-annealing-sawing; or annealing/casting-reducing-annealing-sawing.

When the pipe drawing equipment is used for drawing pipe, the outer die 100 can clamp the inner die 200 to limit the movement of the inner die 200, so that the pipe can move relative to the outer die 100 and the inner die 200, and the pipe can sequentially pass through the diameter reducing structure 210 and the diameter expanding structure 220, so that the pipe is firstly subjected to diameter reduction once and then subjected to diameter expansion once. The pipe material is made of metal, so that after the pipe material is reduced in diameter, tensile stress, namely residual stress, which has the tendency of outwards expanding the pipe material, is generated, and after the diameter reduction pass, the diameter expansion pass is arranged to offset the residual stress, so that the residual stress is eliminated in an annealing mode. Therefore, the time required for carrying out the annealing process can be reduced, the production efficiency of the pipe material is improved, the pipe material is not required to be transported for many times, the scrapped pipe material in the transportation process is reduced, the yield of the pipe material is improved, and meanwhile, the production cost of the pipe material can be reduced.

The following table shows the properties of the tube drawn by the tube drawing apparatus of the present application:

as shown in the table, the same type of tube blank was used as the raw material and processed with different processing targets, and after the traveling core head of the present application was used, the residual stress of each formed tube blank was less than 5kgf/mm ² 。

The minimum dimension of the diameter-reducing structure 210 is D1, the maximum dimension of the diameter-reducing structure 210 is D2, the maximum dimension of the diameter-expanding structure 220 is D3, D3 is greater than D1 and less than D2, and the dimension difference between D3 and D1 is not more than 2% of D1. After the pipe material is subjected to the reducing pass, the inner diameter dimension is D1, and the purpose of the expanding structure 220 is to reduce the residual stress, so that the expanding structure 220 only needs to be larger than D1, and if D2, the inner diameter of the pipe material is larger than the dimension before being processed. The maximum dimension of the expanded diameter structure 220 is slightly larger than the size of the sizing section 212 so that no significant change in the inside diameter of the tubing occurs. In the drawing process, the inner mold 200 needs to pass through the outer mold 100, the size of the expanding structure 220 is too large to be beneficial to matching with the outer mold 100, and the size of the expanding structure 220 is too small, so that the effect of eliminating stress is not obvious. Preferably, D3 is 0.5% to 1.5% greater than D1.

In the drawing direction of the pipe, the reducing structure 210 comprises a guide section 211, a sizing section 212 and a first transition section 213 connected between the two sections, the sizing section 212 is of a size D1, the guide section 211 is of a size D2, the sizing section 212 and the guide section 211 are of a cylindrical structure, the inner wall of the through hole 110 comprises a sizing bearing 111 and a transition belt 112, the sizing bearing 111 and the sizing section 212 form a sizing gap 300, a transition gap 310 is formed between the transition belt 112 and the transition section, the sizing gap 300 and the transition gap 310 are spliced to form a drawing gap for changing the inner diameter of the pipe, the diameter expanding structure 220 passes through the sizing bearing 111, the size of the sizing bearing 111 is D4, and the D1 is smaller than D4.

The first transition section 213 is in a truncated cone shape, one end of the first transition section 213 connected with the guide section 211 is D2, and one end of the first transition section 213 connected with the sizing section 212 is D1. The first transition section 213 of the truncated cone shape does not damage the inner wall of the tube during the drawing process, and allows the inner diameter of the tube to be gradually changed.

Referring to fig. 2 and 4, in an embodiment of the present utility model, the diameter-reducing structure 210 and the diameter-expanding structure 220 are integrally formed based on the above embodiment. The inner mold 200 is a moving core, and the moving core is provided with a diameter reducing part and a diameter expanding part at the same time, so that the processing can be completed through one drawing pass without carrying out a diameter reducing step and then a diameter expanding step, thereby eliminating the need of making a head twice to reduce the loss, and the hardness of the tube material between the two drawing passes is increased, thereby being unfavorable for the diameter expanding step of the second time.

In this embodiment, the diameter-enlarging structure 220 is disposed at one end of the sizing section 212 far from the first transition section 213, so as to ensure that the pipe material passes through the sizing section 212 long enough to be fully processed.

The expanding structure 220 is a convex rib surrounding the outer side wall of the sizing section 212, the side wall of the convex rib in the radial direction of the sizing section 212 is an arc surface, the contact surface between the convex rib and the inner wall of the pipe material is an arc surface, and the expanding structure 220 is formed by extending outwards from the outer side wall of the sizing section 212 along the radial direction of the outer side wall, so that the inner wall of the pipe material can be protected in the drawing process.

Alternatively, the diameter-expanding structure 220 is a columnar structure, a second transition section 221 is arranged between the diameter-expanding structure 220 and the sizing section 212, the second transition section 221 is in a shape of a circular table, one end of the second transition section 221 connected with the sizing section 212 is D1, and one end of the second transition section 221 connected with the diameter-expanding structure 220 is D3. The inner diameter of the tube material gradually increases when passing through the second transition section 221, so that the influence on the quality of the tube material caused by obvious dimensional change of the inner wall of the tube material in a short time is avoided. The second transition section 221 in the shape of a truncated cone does not damage the inner wall of the tube during drawing, and the inner diameter of the tube can be gradually changed.

Referring to fig. 5 and 6, in another embodiment of the present utility model, the inner mold 200 further includes a first core tip 230 and a second core tip 240 connected to each other, the diameter-reducing structure 210 is disposed on the first core tip 230, and the diameter-expanding structure 220 is disposed on the second core tip 240, unlike the above-described embodiment.

Preferably, the first core print 230 and the second core print 240 are detachably connected, so that the second core print 240 can be replaced, and the second core print 240 is selected appropriately according to factors such as the size of the pipe material.

The second core 240 includes a second core body 241 and a connecting piece 242 disposed on the second core body 241, the first core 230 is provided with an opening 231 through which the connecting piece 242 passes, the connecting piece 242 passes through the opening 231 and cooperates with a locking piece 243 to clamp the first core 230 between the second core body 241 and the locking piece 243, after cooperating with the connecting piece 242, the locking piece 243 does not shake relatively between the first core 230 and the second core 240, so as to ensure the quality of the pipe material, the size of the locking piece 243 is smaller than the minimum size of the second core 240, and the size of the locking piece 243 is smaller, so that the inner wall of the pipe material is not contacted to wear.

Wherein, the connecting piece 242 is a columnar structure, one end of the connecting piece 242 far away from the second core head body 241 is provided with an external thread, the locking piece 243 is a nut matched with the external thread, and the nut can apply a force towards the second core head 240 to the first core head 230 in the process of being matched with the connecting piece 242 so as to ensure the overall stability of the inner mold 200. The direction of the force applied to the first core print 230 during drawing is the axial direction of the opening 231, and the force in the circumferential direction of the opening 231 is required to separate the connecting piece 242 from the nut, so that the first core print 230 and the second core print 240 are not separated during drawing of the tube.

The inner wall of the opening 231 is also provided with an internal thread, and the external thread on the connecting piece 242 can be matched with the internal thread, so that the second core body 241 does not shake relative to the core body in the radial direction of the through hole 110, and in addition, the assembling direction of the connecting piece 242 and the through hole 110 is limited by the matching of the internal thread and the external thread.

The second core print body 241 further includes a second transition section 221 connected between the expanding structure 220 and the connecting piece 242, and the inner diameter of the pipe material gradually increases when passing through the second transition section 221, so as to avoid that the quality of the pipe material is affected due to obvious dimensional change of the inner wall of the pipe material in a short time.

As shown in fig. 5, the outer sidewall of the second transition section 221 tapers from the connecting piece 242 toward the expanding structure 220, and the dimension of the end of the second transition section 221 connected to the expanding structure 220 is D3. The outer side wall of the second transition section 221 may be a conical surface or an arc surface, preferably, the outer side wall of the second transition section 221 is an arc surface, and forms a second core body 241 close to a sphere with the diameter-expanding structure 220.

Alternatively, as shown in fig. 6, the second transition section 221 includes a cylindrical section 2211 and a circular truncated cone section 2212, one end of the cylindrical section 2211 is connected with the connecting piece 242, the other end of the cylindrical section 2211 is connected with the circular truncated cone section 2212, the other end of the circular truncated cone section 2212 is connected with the diameter expanding structure 220, the size of the cylindrical section 2211 is D1, the size of one end of the circular truncated cone section 2212 connected with the cylindrical section 2211 is D5, and the D5 is slightly smaller than D1, so that the edge part of the circular truncated cone section 2212 does not scratch the inner wall of the pipe in the process of leaving the sizing section 212, and the size of one end of the circular truncated cone section 2212 connected with the diameter expanding structure 220 is D3.

While the utility model has been described in terms of embodiments, it will be appreciated by those skilled in the art that the utility model is not limited thereto but rather includes the drawings and the description of the embodiments above. Any modifications which do not depart from the functional and structural principles of the present utility model are intended to be included within the scope of the appended claims.

Claims

1. The pipe drawing equipment comprises an outer die and an inner die, wherein a through hole is formed in the outer die, the inner die penetrates through the through hole, and the inner die is positioned in the pipe when the pipe is drawn.

2. A tube drawing apparatus as claimed in claim 1, wherein the minimum dimension of the diameter reducing structure is D1, the maximum dimension of the diameter reducing structure is D2, the maximum dimension of the diameter expanding structure is D3, and D3 is greater than D1 and less than D2.

3. A tube drawing apparatus as claimed in claim 2, wherein the dimensional difference between D3 and D1 is no more than 2% of D1.

4. A pipe drawing apparatus according to claim 2, wherein in the drawing direction of the pipe, the reducing structure comprises a guide section, a sizing section and a first transition section connected therebetween, the sizing section having a minimum dimension D1, the guide section having a maximum dimension D2, and the sizing section and the guide section having a cylindrical structure.

5. A pipe drawing apparatus according to claim 4, wherein the inner wall of the through hole comprises a bearing and a transition zone, the bearing and the sizing section form a sizing gap, the transition zone and the first transition section form a transition gap, the sizing gap and the transition gap are spliced to form a drawing gap for changing the inner diameter of the pipe, the diameter expanding structure passes through the bearing, the bearing has a dimension D4, and the D1 is smaller than the D4.

6. A tube drawing apparatus as claimed in claim 1, wherein the reducing structure and the expanding structure are integrally formed.

7. A tube drawing apparatus as claimed in claim 1, wherein the inner die further comprises a first core head and a second core head connected to each other, the diameter reducing structure is provided on the first core head, and the diameter expanding structure is provided on the second core head.

8. A tube drawing apparatus as claimed in claim 7, wherein the first core is provided with a first connector and the second core is provided with a second connector, and the first core is connected to the second core by the cooperation of the first connector and the second connector.

9. A tube drawing apparatus as claimed in claim 7, wherein the first core print is removably mounted on the second core print; alternatively, the second core print is removably mounted on the first core print.