CN219724502U - Core mould, core and pipe casting mould - Google Patents

Abstract

The utility model relates to a core mould, a core and a pipe fitting casting mould, wherein the core mould comprises a core upper mould and a core lower mould, and a core cavity at least comprises a group of first pipe section cavities and second pipe section cavities; an upper parting surface of the upper core die is provided with an upper core cavity, an upper turning part is formed at the joint of the upper second pipe section cavity and the upper first pipe section cavity, an upper convex part is arranged on the inner wall surface of the upper turning part, and the upper convex part protrudes out of the inner wall surface of the upper turning part and extends to the upper parting surface; a lower parting surface of the lower core die is provided with a lower core cavity, and a connection part of the lower second pipe section cavity and the lower first pipe section cavity is provided with a lower turning part; the inner wall surface of the lower turning part is provided with a convex lower convex part which protrudes out of the inner wall surface of the lower turning part and extends to the lower parting surface; after the upper convex part and the lower convex part are in butt joint, core concave forming parts are formed on two sides of the core parting surface. The adaptability of the core and the pipe casting mould is improved, the pipe casting waste products are reduced, and the production cost of enterprises is reduced.

Description

Core mould, core and pipe casting mould

Technical Field

The utility model relates to the technical field of dies, in particular to a core die, a core and a pipe casting die.

Background

The pipe products shown in fig. 10, including main pipe bodies and branch pipe bodies which are connected with each other, generally adopt a casting technology to process pipe blanks due to the complex structure. When the pipe fitting is cast and formed, as the connecting part of the main pipe body and the branch pipe body is provided with the transition and turning part, the sand mould at the mould closing part of the casting mould corresponding to the connecting part is low in strength, and the impact of molten iron is easy to generate in casting, so that the positions of the connecting part are provided with a plurality of dirty holes, the casting is sanded, the phenomenon of air leakage and water leakage of casting products occurs, the rejection rate is high, and the production cost is high.

The existing die is unreasonable in structure, so that the existing die needs to be improved.

Disclosure of Invention

The utility model aims to solve the technical problems of providing a core die, a core and a pipe casting die, which overcome the defects in the prior art, improve the yield of products and reduce the production cost.

In order to solve the technical problems, the technical scheme of the utility model is as follows:

the core die comprises a core upper die and a core lower die which are in butt joint to form a core cavity, wherein the core cavity at least comprises a group of first pipe section cavities and second pipe section cavities which are communicated with each other;

the upper parting surface of the upper core die is provided with an upper core cavity, and the upper core cavity comprises a first pipe section upper cavity and a second pipe section upper cavity; forming an upper turning part at the joint of the upper cavity of the second pipe section and the upper cavity of the first pipe section, wherein an upper convex part is arranged on the inner wall surface of the upper turning part, protrudes out of the inner wall surface of the upper turning part and extends to the upper parting surface;

a lower parting surface of the lower core die is provided with a lower core cavity, and the lower core cavity comprises a lower first pipe section cavity and a lower second pipe section cavity; the joint of the second pipe section lower cavity and the first pipe section lower cavity is provided with a lower turning part; the inner wall surface of the lower turning part is provided with a convex lower convex part which protrudes out of the inner wall surface of the lower turning part and extends to the lower parting surface;

after the upper convex part and the lower convex part are in butt joint, core concave forming parts are formed on two sides of the core parting surface.

As a preferable technical scheme, the inner side wall of the closed end of the cavity on the first pipe section is provided with a second insert upper mounting groove;

the inner side wall of the closed end of the first pipe section lower cavity is provided with a second embedded block lower mounting groove;

the mounting groove under the second embedded block and the mounting groove on the second embedded block are in butt joint to form a cylindrical second embedded block mounting groove, an embedded block is mounted in the second embedded block mounting groove, and the embedded block is formed by processing heat insulation materials.

As an optimized technical scheme, one end of the cavity on the second pipe section is communicated with the cavity on the first pipe section, the other end of the cavity is closed, and a first insert upper mounting groove is formed in the inner wall surface of the closed end of the cavity on the second pipe section;

one end of the second pipe section lower cavity is communicated with the first pipe section lower cavity, the other end of the second pipe section lower cavity is closed, and a first insert lower mounting groove is formed in the inner wall surface of the closed end of the second pipe section lower cavity;

the mounting groove forms cylindric first slug mounting groove after the butt joint of mounting groove on first slug under the first slug, installs the slug in the first slug mounting groove, and the slug is made by thermal-insulated material.

As the preferable technical scheme, at least two groups of core lower cavities are arranged on the lower parting surface of the core lower die, the first pipe section lower cavities of the two groups of core lower cavities are coaxial and communicated, and a fracture line forming groove is arranged on the inner wall surface of the communicating position.

As the preferable technical scheme, the upper core die is provided with an upper weight-reducing part, and the lower core die is provided with a lower weight-reducing part.

As a preferable technical scheme, the longitudinal section of the first pipe section cavity is elliptical, and the radial dimension of the first pipe section cavity in the direction parallel to the parting surface of the core is larger than the dimension of the first pipe section cavity in the direction perpendicular to the parting surface.

The core is prepared from the core die and at least comprises one pipe core module, wherein the pipe core module comprises a first pipe core and a second pipe core, a transition part is formed at the joint of the first pipe core and the second pipe core, two pipe concave parts are arranged at the transition part, and the two pipe concave parts are oppositely arranged; the concave part of the pipe fitting extends to two sides of the parting surface of the core;

as the preferable technical scheme, the pipe fitting core module comprises at least two pipe fitting core modules, wherein the first pipe section cores of the two pipe fitting core modules are coaxial and communicated, and a fracture line forming protrusion is arranged on the outer wall of the communicating position.

As a preferable technical scheme, the outer ends of the first pipe section core and the second pipe section core are provided with openings.

The pipe casting die comprises an outer die and a core; the core is the core, the outer die is provided with at least one pipe molding cavity, the core is positioned in the pipe molding cavity, and the core and the pipe molding cavity jointly enclose a pipe casting chamber;

each pipe fitting forming cavity comprises a first pipe section forming cavity and a second pipe section forming cavity which are respectively used for forming a main pipe body and a branch pipe body of the pipe fitting; the longitudinal section of the first pipe section forming cavity is elliptical, and the radial dimension of the first pipe section forming cavity parallel to the pipe joint surface is larger than the radial dimension of the first pipe section forming cavity perpendicular to the pipe joint surface.

By adopting the technical scheme, the structure of the core mould, the core and the pipe casting mould is improved, and the part corresponding to the position of the parting surface on the inner wall of the pipe product can be thickened locally, so that pipe casting waste products are reduced, the production cost of enterprises is reduced, and the carbon emission is reduced.

Drawings

In order to more clearly illustrate the embodiments of the utility model or the technical solutions of the prior art, the drawings which are used in the description of the embodiments or the prior art will be briefly described, it being obvious that the drawings in the description below are only some embodiments of the utility model, and that other drawings can be obtained according to these drawings without inventive faculty for a person skilled in the art.

FIG. 1 is an exploded view of a core mold;

FIG. 2 is a schematic view of the structure of the upper core mold;

FIG. 3 is an enlarged view of a portion of area A of FIG. 2;

FIG. 4 is a schematic view of the structure of the lower core mold;

FIG. 5 is an enlarged partial view of region B of FIG. 2;

FIG. 6 is a schematic perspective view of the core in a first view angle state;

FIG. 7 is a schematic perspective view of the core in a second view angle state;

FIG. 8 is a schematic view of the structure of a pipe casting die;

FIG. 9 is a schematic structural view of a pipe casting;

fig. 10 is a schematic structural view of a pipe.

In the figure:

1-core upper die; 11-upper weight-reduction portion; 12-a first positioning molding part; 13-mounting slots on the first slug; 14-upper convex part; 15-a first pipe section upper cavity; 16-a second pipe section upper cavity; 17-a mounting groove on the second slug; 18-upper parting surface; 19-upper corner;

2-a core lower die; 21-lower weight-reduction portion; 22-a second positioning and forming part; 23-a first pipe section lower cavity; 24-a second pipe section lower cavity; 25-a second slug lower mounting groove; 26-lower convex part; 27-a breaking line forming groove; 28-lower parting surface; 29-a lower curve; 210-a first slug lower mounting groove;

3-core; 31-a first pipe section core; 32-a second pipe segment core; 33-opening; 34-breaking line forming protrusions; 35-positioning a support; 36-a pipe fitting concave part;

4-heating holes;

5-an insert;

6-outer die; 61-pouring gate; 62-inner flow passage; 63-riser; 64-exhaust port; 65-pipe parting surfaces; 66-a first tube segment forming cavity; 67-second tube segment forming cavity.

Detailed Description

As shown in fig. 1, the core mold comprises a core upper mold 1 and a core lower mold 2, which are butted to form a core cavity for molding a core 3. The core cavity at least comprises a group of first pipe section cavities and second pipe section cavities which are communicated with each other; four groups may also be included as shown in fig. 1.

The upper core die 1 and the lower core die 2 are respectively provided with a heating hole 4 for realizing the heating of a core die, and the core 3 is manufactured by using a precoated sand core manufacturing machine. The number of the heating holes 4 can be set according to the actual needs of the hole diameters, the distribution and the like of the upper core die 1 and the lower core die 2, for example, ten heating holes 4 are arranged on the upper core die 1 and the lower core die 2.

As shown in fig. 2 and 3, the upper parting surface 18 of the upper core mold 1 is provided with an upper core cavity, and the upper core cavity includes a first pipe section upper cavity 15 and a second pipe section upper cavity 16. One end of the first pipe section upper cavity 15 forms an upper half sand injection port, and the other end is closed; the inner side wall of the closed end of the first pipe section upper cavity 15 is provided with a second embedded block upper mounting groove 17. If the first pipe section upper cavities 15 of the two or more groups of core upper cavities are coaxial and communicated, an upper half sand shooting port is arranged at the outer end of one of the first pipe section upper cavities 15 positioned at the end, and the outer end of the other first pipe section upper cavity 15 positioned at the end is closed and provided with a second insert upper mounting groove 17. The same set of core upper cavities may include one, two or more second pipe segment upper cavities 16; one end of the second pipe section upper cavity 16 is communicated with the first pipe section upper cavity 15, the other end of the second pipe section upper cavity is closed, and a first insert upper mounting groove 13 is formed in the inner wall surface of the closed end of the second pipe section upper cavity 16.

The second pipe section upper cavity 16 is not coaxial with the first pipe section upper cavity 15, and the axes of the second pipe section upper cavity 16 and the first pipe section upper cavity 15 have an included angle smaller than or equal to 90 degrees, so that an upturned part 19 is formed at the joint of the second pipe section upper cavity 16 and the first pipe section upper cavity 15. Wherein, the second pipe section upper cavity 16 is communicated with the first pipe section upper cavity 15, two upper turning parts 19 are formed, and the two upper turning parts 19 are positioned at two sides of the second pipe section upper cavity 16. An upper convex part 14 is arranged on the inner wall surface of the upper turning part 19, the upper convex part 14 protrudes out of the inner wall surface of the upper turning part 19 and is matched with the outline of the inner wall surface, the upper convex part extends along the inner wall surface of the upper turning part 19, and the two ends of the upper convex part extend into the second pipe section upper cavity 16 and the first pipe section upper cavity 15 respectively; the upper protrusion 14 extends to an upper parting plane 18.

The upper core die 1 is further provided with upper weight-reducing parts 11, and the number, shape and the like of the upper weight-reducing parts 11 are selected and arranged according to design requirements. Optimally, the upper weight-reducing parts 11 are symmetrically arranged on the upper core die 1 relative to the overturning axis of the upper core die 1, so that the overturning stability of the core die is improved. In the prior art, the core die is square, the peripheral heights are consistent, and because the core die is formed by processing an integral casting or a steel piece, the integral weight is heavy, so that the die assembly load of equipment is overlarge, the die assembly is slow, the overturning difficulty is high after the die assembly is slow, and the production efficiency of the core is reduced. Through the upper weight reduction part 11 arranged on the upper core die 1, the weight of the periphery of the upper core die 1 is reduced, so that the heating efficiency of the upper core die 1 is improved, the equipment load is reduced, the motor load of the equipment is reduced, the electricity consumption is reduced, and the production cost is reduced.

As shown in fig. 4 and 5, the lower parting surface 28 of the lower core mold 2 is provided with lower core cavities, and the number and positions of the lower core cavities correspond to those of the upper core cavities. The core lower cavity comprises a first pipe section lower cavity 23 and a second pipe section lower cavity 24. The first pipe section lower cavity 23 is butted with the first pipe section upper cavity 15 to form a first pipe section cavity; the second tube segment lower cavity 24 interfaces with the second tube segment upper cavity 16 to form a second tube segment cavity.

The longitudinal section of the first pipe section cavity is elliptical, and the radial dimension of the first pipe section cavity in the direction parallel to the parting surface of the core is larger than the dimension of the first pipe section cavity in the direction perpendicular to the parting surface; namely, as shown in fig. 1, the dimension of the longitudinal section of the first pipe section cavity in the X direction is smaller than that in the Y direction, and casting deformation caused by extrusion of equipment in casting is eliminated.

One end of the first pipe section lower cavity 23 forms a lower half sand injection port, and the other end is closed; a second insert lower mounting groove 25 is provided on the inside wall of the closed end of the first tube section lower cavity 23. If the first pipe section lower cavities 23 of the two or more groups of core lower cavities are coaxial and communicated, a lower half sand injection port is arranged at the outer end of the first pipe section lower cavity 23 positioned at one end, and the outer end of the first pipe section lower cavity 23 positioned at the other end is closed and provided with a second insert lower mounting groove 25.

When the lower parting surface 28 is provided with a plurality of groups of core lower cavities, the communicating part of the two first pipe section lower cavities 23 which are communicated with each other is provided with a fracture line forming groove 27, and the fracture line forming groove 27 extends along the circumferential direction of the first pipe section lower cavity 23 and can be distributed on the inner wall surface of the first pipe section lower cavity 23 in a dot shape, a strip shape and the like. In the prior art, clay sand is usually used as a breaking line on an outer die, and the convex clay sand is easily added into castings to generate waste products due to low strength of the sand mold under the impact of high-temperature molten iron, so that the inventor creatively proposes that the convex breaking line is added on the core 3, and the core 3 is high in strength and is not easy to bring molten iron into a cavity, so that the waste rate is low, the breaking effect is good, and the manual water gap breaking is reduced.

The same set of core lower cavities may include one, two or more second tube segment lower cavities 24; one end of the second pipe section lower cavity 24 is communicated with the first pipe section lower cavity 23, the other end of the second pipe section lower cavity is closed, and a first insert lower mounting groove 210 is formed in the inner wall surface of the closed end of the second pipe section lower cavity 24.

The first slug lower mounting groove 210 forms a cylindrical first slug mounting groove after interfacing with the first slug upper mounting groove 13, and the second slug lower mounting groove 25 forms a cylindrical second slug mounting groove after interfacing with the second slug upper mounting groove 17. The first insert mounting groove and the second insert mounting groove are internally provided with the inserts 5, and the inserts 5 can be disc-shaped, or spliced by two semi-disc shapes or other shapes. The inserts 5 are each made of a heat insulating material. When the core 3 is manufactured by heating, the end parts of the core 3 can be made to be open, so that the material consumption of the core 3 can be reduced, the exhaust mode of the core 3 in the pipe casting process is improved, the exhaust speed is increased, the air holes in the pipe are reduced, and the yield of the pipe is improved.

The second pipe section lower cavity 24 is not coaxial with the first pipe section lower cavity 23, so the joint of the second pipe section lower cavity 24 and the first pipe section lower cavity 23 is provided with a lower turning part 29. Wherein, the second pipe section lower cavity 24 is communicated with the first pipe section lower cavity 23, two downward turning parts 29 are formed, and the two downward turning parts 29 are positioned at two sides of the second pipe section lower cavity 24. The inner wall surface of the lower turning part 29 is provided with a convex lower convex part 26, the lower convex part 26 protrudes out of the inner wall surface of the lower turning part 29, and two ends of the lower convex part 26 extend into the second pipe section lower cavity 24 and the first pipe section lower cavity 23 respectively; the lower protrusion 26 extends to a lower parting plane 28. After the upper convex part 14 and the lower convex part 26 are butted, core concave forming parts are formed on two sides of the core parting surface, so that defects such as dirty holes and sand holes at the casting parting surface can be reduced.

The lower core mold 2 is further provided with lower weight-reducing parts 21, and the number, shape, etc. of the lower weight-reducing parts 21 are selected and set according to design requirements. Optimally, the plurality of lower weight-reducing parts 21 are symmetrically arranged with the turning center of the core lower die 2, thereby improving the turning stability.

In order to achieve the cooperation of the core 3 and the outer mold, the first pipe section cavity and the second pipe section cavity are further provided with a first positioning forming part 12, a second positioning forming part 22 and the like, respectively, for forming end supports, inner supports and the like of the core 3, which are the prior art.

The core 3 is used in a pipe casting process, and as shown in fig. 6 and 7, at least comprises one pipe core module, each pipe core module comprises a first pipe section core 31 and a second pipe section core 32, and the first pipe section core 31 and the second pipe section core 32 are hollow structures and are mutually communicated. If the core 3 comprises a plurality of pipe core modules, two first pipe segment cores 31 of two adjacent pipe core modules are coaxial and communicated, and break line forming protrusions 34, such as two break line forming protrusions 34, are arranged on the outer wall at the communication position, and the two break line forming protrusions 34 are respectively adjacent to the inner cavity forming positions of the two pipes. Preferably, the plurality of breaking line forming projections 34 are located on the same side of the parting plane of the core 3, so that the breaking line forming grooves 27 forming the breaking line forming projections 34 can be located on the core upper die 1 or the core lower die 2 at the same time.

The first pipe section core 31 and the second pipe section core 32 are communicated but not coaxial, so that a transition part is formed at the joint of the two pipe section cores, the transition part is provided with two pipe fitting concave parts 36, and the two pipe fitting concave parts 36 are symmetrically arranged relative to the second pipe section core 32; and each tube recess 36 extends to both sides of the parting plane of the core 3.

The ends of the first 31 and second 32 segment cores each have an opening 33 and have a locating support 35 that mates with the outer mold. The positioning support 35 is a conventional art and will not be described in detail here.

The longitudinal section of the first tube segment core 31 is elliptical, and its radial dimension parallel to the core parting plane is greater than its radial dimension perpendicular to the core parting plane.

The pipe casting mould comprises an outer mould 6 and a core 3, the structure of the core 3 being as described above and not repeated here. The outer mold 6 has a structure as shown in fig. 8 and 9 and has at least one pipe molding cavity, and the core 3 is located in the pipe molding cavity and encloses a pipe casting chamber together with the pipe molding cavity. Each tube forming cavity includes a first tube segment forming cavity 66 and a second tube segment forming cavity 67 for forming the main and branch tube bodies of the tube, respectively. One, two or more second tube segment forming cavities 67 may be provided, depending on the actual design requirements. The core 3 and the pipe molding cavity together form a casting cavity, and the outer mold 6 is also provided with a gate 61, an inner runner 62, a riser 63, an exhaust port 64 and the like, which are the prior art.

In long-term practice, the inventors have found that if the cross section of the first pipe section forming cavity 66 is designed to be circular, the wall thickness of the pipe is uneven due to extrusion of equipment during casting; in order to solve this technical problem, the inventors innovatively proposed to design the longitudinal section of the first pipe section forming cavity 66 to be elliptical, the radial dimension of the first pipe section forming cavity 66 parallel to the pipe parting surface 65 being larger than the radial dimension thereof perpendicular to the pipe parting surface 65, i.e., the dimension of the first pipe section forming cavity 66 in the X direction being smaller than the dimension in the Y direction.

The core mould, the core and the pipe casting mould are suitable for casting pipe products such as 90-degree elbows, 45-degree elbows, 22.5-degree elbows, 11.25-degree elbows, positive tee joints, reducing elbows and the like.

The foregoing has shown and described the basic principles, main features and advantages of the present utility model. It will be understood by those skilled in the art that the present utility model is not limited to the embodiments described above, and that the above embodiments and descriptions are merely illustrative of the principles of the present utility model, and various changes and modifications may be made without departing from the spirit and scope of the utility model, which is defined in the appended claims. The scope of the utility model is defined by the appended claims and equivalents thereof.

Claims (10)

1. The core die comprises a core upper die (1) and a core lower die (2), and a core cavity is formed after the core upper die and the core lower die are in butt joint, wherein the core cavity at least comprises a group of first pipe section cavities and second pipe section cavities which are communicated with each other; the method is characterized in that:

an upper parting surface (18) of the upper core die (1) is provided with an upper core cavity, and the upper core cavity comprises a first pipe section upper cavity (15) and a second pipe section upper cavity (16); an upper turning part (19) is formed at the joint of the second pipe section upper cavity (16) and the first pipe section upper cavity (15), an upper convex part (14) is arranged on the inner wall surface of the upper turning part (19), and the upper convex part (14) protrudes out of the inner wall surface of the upper turning part (19) and extends to the upper parting surface (18);

a lower parting surface (28) of the lower core die (2) is provided with a lower core cavity, and the lower core cavity comprises a first lower pipe section cavity (23) and a second lower pipe section cavity (24); the joint of the second pipe section lower cavity (24) and the first pipe section lower cavity (23) is provided with a lower turning part (29); the inner wall surface of the lower turning part (29) is provided with a convex lower convex part (26), and the lower convex part (26) protrudes out of the inner wall surface of the lower turning part (29) and extends to the lower parting surface (28);

after the upper convex part (14) and the lower convex part (26) are butted, core concave forming parts are formed on two sides of the core parting surface.

2. The core mold of claim 1, wherein: the inner side wall of the closed end of the first pipe section upper cavity (15) is provided with a second insert upper mounting groove (17);

the inner side wall of the closed end of the first pipe section lower cavity (23) is provided with a second insert lower mounting groove (25);

the second embedding block lower mounting groove (25) and the second embedding block upper mounting groove (17) are in butt joint to form a cylindrical second embedding block mounting groove, the embedding block (5) is mounted in the second embedding block mounting groove, and the embedding block (5) is formed by processing heat insulation materials.

3. The core mold of claim 1, wherein: one end of the second pipe section upper cavity (16) is communicated with the first pipe section upper cavity (15), the other end of the second pipe section upper cavity is closed, and a first insert upper mounting groove (13) is formed in the inner wall surface of the closed end of the second pipe section upper cavity (16);

one end of the second pipe section lower cavity (24) is communicated with the first pipe section lower cavity (23), the other end of the second pipe section lower cavity is closed, and a first insert lower mounting groove (210) is formed in the inner wall surface of the closed end of the second pipe section lower cavity (24);

the first embedding block lower mounting groove (210) is in butt joint with the first embedding block upper mounting groove (13) to form a cylindrical first embedding block mounting groove, the first embedding block mounting groove is internally provided with the embedding block (5), and the embedding block (5) is made of heat insulation materials.

4. The core mold of claim 1, wherein: at least two groups of core lower cavities are arranged on a lower parting surface (28) of the core lower die (2), first pipe section lower cavities (23) of the two groups of core lower cavities are coaxial and communicated, and a fracture line forming groove (27) is formed in the inner wall surface of the communicating position.

5. The core mold of claim 1, wherein: the upper core die (1) is provided with an upper weight-reducing part (11), and the lower core die (2) is provided with a lower weight-reducing part (21).

6. The core mold of claim 1, wherein: the longitudinal section of the first pipe section cavity is elliptical, and the radial dimension of the first pipe section cavity in the direction parallel to the parting surface of the core is larger than the dimension of the first pipe section cavity in the direction perpendicular to the parting surface.

7. The core, its characterized in that: the core mould of claim 1, at least comprising one pipe core module, wherein the pipe core module comprises a first pipe core (31) and a second pipe core (32), a transition part is formed at the joint of the first pipe core and the second pipe core, two pipe concave parts (36) are arranged at the transition part, and the two pipe concave parts (36) are oppositely arranged; and the pipe fitting concave parts (36) extend to two sides of the core parting surface.

8. The cartridge of claim 7, wherein: the pipe fitting core module comprises at least two pipe fitting core modules, wherein first pipe section cores (31) of the two pipe fitting core modules are coaxial and communicated, and fracture line forming protrusions (34) are arranged on the outer wall of the communicating position.

9. The cartridge of claim 7, wherein: the outer ends of the first pipe section core (31) and the second pipe section core (32) are respectively provided with an opening (33).

10. The pipe casting mould comprises an outer mould (6) and a core (3); the method is characterized in that: the core (3) is a core according to claims 7-9, the outer mold (6) is provided with at least one pipe molding cavity, the core (3) is positioned in the pipe molding cavity, and the core and the pipe molding cavity together enclose a pipe casting chamber;

each pipe forming cavity comprises a first pipe section forming cavity (66) and a second pipe section forming cavity (67) which are respectively used for forming a main pipe body and a branch pipe body of the pipe; the longitudinal section of the first pipe section forming cavity (66) is elliptical, and the radial dimension of the first pipe section forming cavity (66) parallel to the pipe joint surface (65) is larger than the radial dimension of the first pipe section forming cavity perpendicular to the pipe joint surface (65).