阅读说明：本技术 一种减薄三通背部堆积的加工方法 (Processing method for thinning tee joint back accumulation ) 是由 孔令洋 叶小敏 赵友全 何涛 叶敏 于 2021-08-03 设计创作，主要内容包括：本发明公开一种减薄三通背部堆积的加工方法,包括使用一模具、两芯棒和一拉伸机,该所述模具内具有夹持空间；所述加工方法包括：步骤S1：将管坯夹持于所述夹持空间内；步骤S2：通过拉伸机驱动两所述芯棒,对所述管坯的两端进行拉伸；所述管坯的两端呈倾斜设置和/或所述芯棒的承口处的侧壁设置缺口槽。本发明提高了管材利用率以及减少产品背部多余堆积,减少三通管件重量的同时,仍能满足产品标准,提升产品市场竞争力。(The invention discloses a processing method for thinning tee joint back accumulation, which comprises the steps of using a die, two core rods and a stretcher, wherein a clamping space is arranged in the die; the processing method comprises the following steps: step S1: clamping the tube blank in the clamping space; step S2: driving the two core rods through a stretcher to stretch two ends of the tube blank; the two ends of the tube blank are obliquely arranged and/or the side wall of the socket of the core rod is provided with a notch groove. The invention improves the utilization rate of the pipe, reduces the redundant accumulation on the back of the product, reduces the weight of the three-way pipe, can meet the product standard and improves the market competitiveness of the product.)

1. A processing method for thinning tee joint back accumulation is characterized in that a die, two core rods and a stretcher are used, and a clamping space is arranged in the die;

the processing method comprises the following steps:

step S1: clamping the tube blank in the clamping space;

step S2: driving the two core rods through a stretcher to stretch two ends of the tube blank;

the two ends of the tube blank are obliquely arranged and/or the side wall of the socket of the core rod is provided with a notch groove.

2. The processing method for back stacking of thinned tees as claimed in claim 1, further comprising:

step S3: clamping the stretched tube blank on a clamp, and cutting off the closed end part of the middle head of the tube blank;

step S4: shaping the cut tube blank;

the gap groove faces to one side of the tube blank, which is far away from the middle head.

3. The method for processing back accumulation of thinned tees as claimed in claim 1, wherein the inclination angle of the end of said tube blank is 10 to 20 °.

4. The processing method for back stacking of thinned tees according to claim 1, wherein the mandrel comprises a rod body and a mandrel which are connected with each other, the rod body and the mandrel are coaxially arranged, an annular step is formed between the rod body and the mandrel, the side wall of the rod body is provided with the notch groove or the side wall of the mandrel is provided with the notch groove, and one end of the notch groove extends to the annular step.

5. The method of claim 4, wherein the notch groove has a depth not greater than the distance between the outer circumference of the rod and the outer circumference of the core print.

6. The method of claim 5, wherein the core head has a guide bevel on the outer periphery of the end portion.

7. The method of claim 5, wherein the sidewall of the rod is provided with the notch groove, and the depth of the notch groove is equal to the distance between the outer circumference of the rod and the outer circumference of the core print.

8. The method for processing back stacking of thinned tees of claim 7, wherein said head of said notched groove extends to said annular step.

9. The method for processing a thinned tee back pack according to claim 6, wherein the sidewall of the core print is provided with the notch groove, and the depth of the notch groove is smaller than the distance between the outer periphery of the rod body and the outer periphery of the core print.

10. The method for processing back stacking of thinned tees of claim 9, wherein said notched slot has a leading end extending to said guide ramp and a trailing end extending to said annular step.

Technical Field

The invention relates to the technical field of tee joint machining, in particular to a machining method for thinning back accumulation of a tee joint.

Background

The three-way pipe is a standard pipe fitting which is very important in pipe engineering and design, and the using amount is large in the construction of the pipe engineering. The common processing technology of the three-way pipe is to perform blanking, stretching, cutting, shaping, subsequent treatment (polishing, cleaning and drying), inspection and packaging on a copper pipe.

Wherein, tensile is the axial compensation expansion branch pipe through metal material, and raw and other materials can flow to the tee bend back along with axial extruded power and produce and pile up during because of axial compensation, and the terminal surface of the tensile raw and other materials of tee bend is straight in the trade at present, so the back of tee bend pile up can more than european standard EN 1254-1: 1998, the thickness of the wall is 1.5-2 times, and the accumulated material cannot be removed, which not only causes serious material waste, but also causes the unit price of the product to rise and lacks of market competitiveness.

Disclosure of Invention

Aiming at the problems in the existing three-way pipe processing, the processing method for thinning the back accumulation of the three-way pipe is provided, the utilization rate of the pipe is improved, the redundant accumulation of the back of the product is reduced, the weight of the three-way pipe is reduced, meanwhile, the product standard can be still met, and the market competitiveness of the product is improved.

The specific technical scheme is as follows:

a processing method for thinning tee back accumulation comprises the following steps: using a die, two core rods and a stretching machine, wherein the die is internally provided with a clamping space;

the processing method comprises the following steps:

step S1: clamping the tube blank in the clamping space;

step S2: driving the two core rods through a stretcher to stretch two ends of the tube blank;

the two ends of the tube blank are obliquely arranged and/or the side wall of the socket of the core rod is provided with a notch groove.

The processing method for back accumulation of the thinned tee joint comprises the following steps:

step S3: clamping the stretched tube blank on a clamp, and cutting off the closed end part of the middle head of the tube blank;

step S4: shaping the cut tube blank;

the gap groove faces to one side of the tube blank, which is far away from the middle head.

In the processing method for thinning tee joint back accumulation, the inclination angle of the end part of the tube blank is 10-20 degrees.

In the processing method for thinning tee joint back accumulation, the core rod comprises a rod body and a core head which are connected with each other, the rod body and the core head are coaxially arranged, an annular step is formed between the rod body and the core head, the side wall of the rod body is provided with the notch groove or the side wall of the core head is provided with the notch groove, and one end of the notch groove extends to the annular step.

In the processing method for thinning tee joint back accumulation, the depth of the notch groove is not more than the distance between the periphery of the rod body and the periphery of the core print.

In the processing method for thinning tee back accumulation, the periphery of the end part of the core print is provided with a guide inclined plane.

In the processing method for thinning tee joint back accumulation, the side wall of the rod body is provided with the notch groove, and the depth of the notch groove is equal to the distance between the periphery of the rod body and the periphery of the core print.

In the processing method for thinning the back accumulation of the tee joint, the head of the notch groove extends to the annular step.

In the processing method for thinning tee joint back accumulation, the side wall of the core print is provided with the notch groove, and the depth of the notch groove is smaller than the distance from the periphery of the rod body to the periphery of the core print.

In the processing method for back accumulation of the thinning tee joint, the head end of the notch groove extends to the guide inclined plane, and the tail end of the notch groove extends to the annular step.

Compared with the prior art, the technical scheme has the positive effects that:

the invention improves the utilization rate of the pipe, reduces the redundant accumulation on the back of the product, reduces the weight of the three-way pipe, can meet the product standard and improves the market competitiveness of the product.

Drawings

FIG. 1 is a schematic structural diagram of a tube blank in a first embodiment, a fourth embodiment and a fifth embodiment of a processing method for reducing tee back stacking according to the invention;

FIG. 2 is a schematic structural diagram of a cutting of a raw material pipe blank into a pipe blank in a first embodiment, a fourth embodiment and a fifth embodiment of the processing method for reducing the back accumulation of the tee joint;

FIG. 3 is a schematic view showing the structure of tube blank drawing in the first embodiment of the processing method for reducing the back accumulation of the tee joint of the present invention;

FIG. 4 is a schematic structural view of a stretched tubular blank in a first embodiment, a fourth embodiment and a fifth embodiment of a method of reducing tee back pack in accordance with the present invention;

FIG. 5 is a schematic structural diagram of a shaped product in the first, fourth and fifth embodiments of a processing method for thinning tee back stacking according to the present invention;

FIG. 6 is a schematic view showing the structure of the raw material pipe blank and the pipe blanks of the second and third embodiments of the method for reducing tee back pack in accordance with the present invention;

FIG. 7 is a schematic drawing of the tube blank drawing in a second embodiment of a method of reducing tee back buildup in accordance with the present invention;

FIG. 8 is a schematic drawing of the tube blank drawing in a third embodiment of a method of reducing tee back buildup in accordance with the present invention;

FIG. 9 is a schematic structural view of a mandrel used in a second embodiment of a method of forming a back pack of thinned tees in accordance with the present invention;

FIG. 10 is a schematic structural view of a mandrel used in a third embodiment of a method of forming a back pack of thinned tees in accordance with the present invention;

FIG. 11 is a schematic view of the structure of a stretched tubular blank in the second and third embodiments of a method of reducing tee back buildup in accordance with the present invention;

in the drawings: 1. a pipe blank; 11. a mold; 12. a core rod; 13. a first clamping space; 14. a second clamping space; 15. a raw material pipe blank; 16. a clamping cylinder; 17. a clamp; 18. cutting the motor; 19. A saw blade; 21. bellmouths at two ends; 22. a middle head; 23. the stretched tube blank; 31. a rod body; 32. A core print; 33. an annular step; 34. a first rod body wall; 35. a second rod body wall; 36. a first core wall; 37. a second core head wall; 38. a guide slope; 41. a water outlet end core rod; 42. a water plugging end core rod; 51. a first annular arc surface; 52. a second arc-shaped surface.

Detailed Description

The invention is further described with reference to the following drawings and specific examples, which are not intended to be limiting.

FIG. 1 is a schematic structural diagram of a tube blank in a first embodiment, a fourth embodiment and a fifth embodiment of a processing method for reducing tee back stacking according to the present invention, FIG. 2 is a schematic structural diagram of a raw material tube blank cut into a tube blank in a first embodiment, a fourth embodiment and a fifth embodiment of a processing method for reducing tee back stacking according to the present invention, FIG. 3 is a schematic structural diagram of tube blank stretching in a first embodiment of a processing method for reducing tee back stacking according to the present invention, FIG. 4 is a schematic structural diagram of a stretched tube blank in a first embodiment, a fourth embodiment and a fifth embodiment of a processing method for reducing tee back stacking according to the present invention, FIG. 5 is a schematic structural diagram of a reshaped product in a first embodiment, a fourth embodiment and a fifth embodiment of a processing method for reducing tee back stacking according to the present invention, FIG. 6 is a schematic structural view of a raw material pipe blank and pipe blanks of a second embodiment and a third embodiment of a method of manufacturing a thinned three-way back accumulation of the present invention, FIG. 7 is a schematic structural view of drawing a pipe blank of a second embodiment of a method of manufacturing a thinned three-way back accumulation of the present invention, FIG. 8 is a schematic structural view of drawing a pipe blank of a third embodiment of a method of manufacturing a thinned three-way back accumulation of the present invention, FIG. 9 is a schematic structural view of a mandrel bar of a second embodiment of a method of manufacturing a thinned three-way back accumulation of the present invention, FIG. 10 is a schematic structural view of a mandrel bar of a third embodiment of a method of manufacturing a thinned three-way back accumulation of the present invention, FIG. 11 is a schematic structural view of drawn pipe blanks of a second embodiment and a third embodiment of a method of manufacturing a thinned three-way back accumulation of the present invention, as shown in fig. 1 to 11, a preferred embodiment of the method for processing the back accumulation of the thinned tee is shown, which uses a die 11, two mandrels 12 and a stretcher, wherein the die 11 has a holding space therein.

Further, as a preferred embodiment, the processing method includes:

step S1: clamping the tube blank 1 in a clamping space;

step S2: the two mandrils 12 are driven by a stretcher to stretch the two ends of the tube blank 1;

the two ends of the tube blank 1 are obliquely arranged and/or the side wall of the socket of the mandril 12 is provided with a gap groove 2.

Further, as a preferred embodiment, the processing method further includes:

step S3: clamping the stretched tube blank 1 on a clamp, and cutting off the closed end part of the middle head of the tube blank;

step S4: shaping the cut tube blank 1;

preferably, the stretcher is provided with a pressurizing device.

Preferably, the tube blank 1 is a copper tube blank.

Preferably, the clamping space in the mold 11 comprises: the clamping device comprises a first clamping space 13 and a second clamping space 14, wherein the first clamping space 13 penetrates through the die 11 along the length direction, the second clamping space 14 is located in the middle of the first clamping space 13, one end of the second clamping space 14 is communicated with the middle of the first clamping space 13, and the other end of the second clamping space 14 extends to the side wall of the die 11.

Preferably, the tube blank 1 is clamped in the first clamping space 13.

Preferably, the two core rods 12 are a water outlet end core rod 41 and a water plugging end core rod 42 respectively.

The first embodiment:

the invention discloses a processing method for thinning tee joint back accumulation, wherein the inclination angle of the end part of a tube blank 1 is 10-20 degrees.

Preferably, both ends of the tube blank 1 are inclined at 10-20 degrees.

Preferably, the section of the tube blank 1 is isosceles trapezoid, and the back of the tee joint is machined on the shorter side of the tube blank 1.

Preferably, one side of the long end of the tube blank 1 is located on the side of the first clamping space 13 away from the second clamping space 14, and one side of the short end of the tube blank 1 is located on the side of the first clamping space 13 close to the second clamping space 14.

The processing method for obliquely arranging the end part of the tube blank 1 comprises the following steps: cutting the red copper raw material pipe blank into pipe blanks with the bevel angle of 10-20 degrees and the specified length size by using bevel blanking equipment.

Preferably, the raw material tube blank 15 of red copper is held by a clamp cylinder 16 and a jig 17, and the raw material tube blank 15 of red copper is cut by driving a saw blade 19 by a cutting motor 18.

In step S1, a die with a corresponding dimension is selected, and under a set forming condition, the tube blank 15 is loaded into the die 11, so that the long end of the bevel opening of the tube blank 1 is placed towards the middle branch direction of the tee;

in step S2, adjusting the pressure of a pressure cylinder of the water stretcher to 10-15MPA, closing the upper and lower dies, extruding the core rods 12 at two ends, and expanding a tee blank;

in step S3, the three-way blank is placed into a notching fixture of the upper and lower type, and the middle branch of the three-way blank is notched by a notching tool, so as to ensure that the end surface of the middle branch is flat and the length of the middle bell mouth meets the drawing requirement, thereby obtaining a three-way pipe fitting;

the processing method further comprises the following steps: polishing, cleaning, drying, inspecting and warehousing, namely adding the tee pipe fitting into polishing and cleaning equipment for polishing, cleaning and drying, inspecting the inner diameter, length and inner and outer surfaces of each socket of the tee pipe fitting according to the requirements of a drawing, and then packaging and warehousing the tee pipe fitting.

According to the invention, by utilizing the characteristics that one end of the manufactured bevel blank has more raw materials and the other end has less raw materials, and placing the end with less raw materials at the back side of the product, the problem of more back accumulation during the stretching of the tee joint is solved, and the blanking angle needs to be controlled within the range of 10-20 degrees each time.

Preferred embodiment one, the 22CB specification tee produced in this embodiment, includes the steps of:

step 1) blanking, calculating blanking specification according to the forming size of a three-way pipe fitting, and blanking a soft (M2) TP2 coil pipe with the specification of phi 23.5mm multiplied by 0.68 mm through a chipless blanking machine, wherein the blanking length is 96+1mm, the short end is 84+1mm, the single-side inclination is 14 degrees, and the specific shape of a tube blank 1 is shown in figure 1;

step 2) forming, namely taking a die with a corresponding size, putting the tube blank 1 into the die 11 for pressing, stretching and forming, stretching and extruding in a 100-ton oil press, adjusting the water injection pressurization pressure to be 10-15MPA during extrusion, controlling the total length of an extrusion end to be 55+1mm, controlling the calibers of bellmouths 21 at two ends to be phi 22.07-22.18mm, and controlling the stretching height straight-line segment of a middle head 22 to be 16+1 mm;

step 3), cutting, namely clamping the stretched tube blank 23 on a clamp, cutting off the closed end part of the middle head 2 to form a middle bell mouth, wherein the length of the middle bell mouth is 16+0.5mm, and the figure is 4;

step 4) shaping, namely expanding the opening of the cut product through an upper die and a lower die until the calibers of the bellmouths meet the requirements of a drawing, and adjusting the lengths of the pipe fittings to ensure that the calibers of the three bellmouths are within the range of phi 22.07-22.18mm, the total length of the pipe fittings is 55+1mm, and the lengths of the three bellmouths are 15.4+0.5mm, as shown in figure 5;

step 5), polishing, cleaning and drying, namely adding the three-way pipe fitting into polishing and cleaning equipment for polishing, cleaning and drying;

and 6) inspecting and warehousing, inspecting the inner diameter, length size and surface of the bell mouth according to the requirements of a drawing, and packaging and warehousing.

Comparative example one (comparative example Using conventional processing techniques as a comparison to the procedure of example one)

The tee fitting produced in this example was of size 22CB comprising the steps of:

step 1), blanking, calculating blanking specification according to the forming size of a three-way pipe fitting, and blanking a soft (M2) TP2 coil pipe with the specification of phi 23.5mm multiplied by 0.68 mm through a chipless blanking machine, wherein the blanking length is 96+1mm, and the specific shape of a raw material pipe blank 15 is shown in figure 6;

step 2) forming, namely taking a die with a corresponding size, putting the tube blank 1 into the die 11 for pressing, stretching and forming, and performing stretching and extrusion in a 100-ton oil press, wherein the total length of an extrusion end is 55+1mm, the mouth diameter phi of bellmouths 21 at two ends is 22.07-22.18mm, the length of the bellmouths 21 at two ends is 15.4-16mm, and the stretching height straight line segment of the middle head 22 is 16+1mm, which is shown in figure 4;

step 3), cutting, namely clamping the stretched tube blank 23 on a clamp, cutting off the closed end part of the middle head of the stretched tube blank to form a middle bell mouth, wherein the length of the middle bell mouth is 16+0.5mm, and the step 4 is shown in the figure;

step 4) shaping, namely expanding the opening of the cut product through an upper die and a lower die until the calibers of the bellmouths meet the requirements of a drawing, and adjusting the lengths of the pipe fittings to ensure that the calibers of the three bellmouths are within the range of phi 22.07-22.18mm, the total length of the pipe fittings is 55+1mm, and the lengths of the three bellmouths are 15.4+0.5mm, as shown in figure 5;

step 5), polishing, cleaning and drying, namely adding the three-way pipe fitting into polishing and cleaning equipment for polishing, cleaning and drying;

and 6) inspecting and warehousing, inspecting the inner diameter, length size and surface of the bell mouth according to the requirements of a drawing, and packaging and warehousing.

The following comparison chart of the tee joint processing technology can be obtained by combining the comparison of the preferred embodiment I and the comparative example I

Second embodiment:

the invention discloses a processing method for thinning tee back accumulation, wherein the step S3 comprises the following steps: and clamping the stretched tube blank 1 on a clamp, and cutting off the closed end part of the middle head 22 and the edges of the two end bell mouths 21. Preferably, the end sockets 21 are flush.

Further, as a preferred embodiment, the notch groove 2 is directed toward the side of the tube blank 1 away from the intermediate head 22. Preferably, the relief groove 2 is located on a side of the mandrel 12 remote from the second clamping space 14.

Further, as a preferred embodiment, the core rod 12 includes a rod 31 and a core head 32 connected to each other, the rod 31 and the core head 32 are coaxially disposed, an annular step 33 is formed between the rod 31 and the core head 32, a side wall of the rod 31 is provided with the notch groove 2 or a side wall of the core head 32 is provided with the notch groove 2, and one end of the notch groove 2 extends to the annular step 33.

Further, as a preferred embodiment, the depth of the notch groove 2 is not greater than the distance between the outer periphery of the rod 31 and the outer periphery of the core print 32.

Further, as a preferred embodiment, the outer periphery of the end of the core print 32 has a guide bevel 38.

Further, as a preferred embodiment, the side wall of the rod 31 is provided with a notch 2, and the depth of the notch 2 is equal to the distance between the outer periphery of the rod 31 and the outer periphery of the core print 32.

Further, as a preferred embodiment, the head of the notch groove 2 extends to the annular step 33.

Preferably, the cutaway groove 2 includes: first stick body wall 34 and second stick body wall 35, first stick body wall 35 is the bottom surface of this breach groove 2, and first stick body wall 34 is the arc setting along the circumference of core print 32, and first stick body wall 34 flushes mutually with the perisporium of core print 32, and second stick body wall 35 is the side of this breach groove 2, and second stick body wall 35 is the crooked setting along the axial of stick body 31, and the notch of second stick body wall 35 is towards core print 32.

Preferably, the radius of the first rod body wall 35 is equal to the radius of the core print 32.

In the present invention, a notch groove 2 is formed at the socket of a mandrel bar 12, and excess raw material is introduced into the notch groove 2 by the flow of the raw material during water expansion and drawing.

The structure of the invention can be formed at one time, is convenient for automatic production, does not need to carry out inner boring to remove the accumulation, and avoids the back of the product from being wrinkled.

The third embodiment:

the invention discloses a processing method for thinning tee back accumulation, wherein the step S3 comprises the following steps: and clamping the stretched tube blank 1 on a clamp, and cutting off the closed end part of the middle head 22 and the edges of the two end bell mouths 21. Preferably, the end sockets 21 are flush.

Further, as a preferred embodiment, the notch groove 2 is directed toward the side of the tube blank 1 away from the intermediate head 22. Preferably, the relief groove 2 is located on a side of the mandrel 12 remote from the second clamping space 14.

Further, as a preferred embodiment, the core rod 12 includes a rod 31 and a core head 32 connected to each other, the rod 31 and the core head 32 are coaxially disposed, an annular step 33 is formed between the rod 31 and the core head 32, a side wall of the rod 31 is provided with the notch groove 2 or a side wall of the core head 32 is provided with the notch groove 2, and one end of the notch groove 2 extends to the annular step 33.

Further, as a preferred embodiment, the depth of the notch groove 2 is not greater than the distance between the outer periphery of the rod 31 and the outer periphery of the core print.

Further, as a preferred embodiment, the outer periphery of the end of the core print 32 has a guide bevel 38.

Further, as a preferred embodiment, the side wall of the core print 32 is provided with a notch groove 2, and the depth of the notch groove 2 is smaller than the distance between the outer periphery of the rod 31 and the outer periphery of the core print 32.

Further, as a preferred embodiment, the head end of the notch 2 extends to the guiding slope 38, and the tail end of the notch 2 extends to the annular step 33. Preferably, the head of the cut-out groove 2 has a first circular arc surface 51 transition with the guide ramp 38, and the head of the cut-out groove 2 has a second circular arc surface 52 transition with the first circular arc surface 51.

Preferably, the cutaway groove 2 includes: a first core wall 36 and a second core wall 37, wherein the first core wall 36 is a bottom surface of the notch groove 2, the first core wall 36 is disposed in an arc shape along a circumferential direction of the core 32, the second core wall 37 is a side surface of the notch groove 2, and the second core wall 37 extends to the guide slope 38.

Preferably, the second core head wall 37 is inclined or curved to facilitate the introduction of the material.

Preferably, the second core head wall 37 transitions via the second arc-shaped surface 52 and the first circular arc surface 51 in this order into the guide ramp 38.

Preferably, the radius of the first core wall 36 is less than the radius of the core 32.

In the present invention, a notch groove 2 is formed at the socket of a mandrel 31, and excess raw material is introduced into the notch groove 2 by the flow of the raw material during water expansion and drawing.

The structure of the invention can be formed at one time, is convenient for automatic production, does not need to carry out inner boring to remove the accumulation, and avoids the back of the product from being wrinkled.

The fourth embodiment:

the structure of this embodiment is substantially the same as that of the second embodiment, except that: the inclination angle of the end of the tube blank 1 is 10-20 degrees.

Preferably, both ends of the tube blank 1 are inclined at 10-20 degrees.

Preferably, the section of the tube blank 1 is isosceles trapezoid, and the back of the tee joint is machined on the longer side of the tube blank 1.

Preferably, one side of the long end of the tube blank 1 is located on the side of the first clamping space 13 away from the second clamping space 14, and one side of the short end of the tube blank 1 is located on the side of the first clamping space 13 close to the second clamping space 14.

Fifth embodiment:

the structure of this embodiment is substantially the same as that of the third embodiment, except that: the inclination angle of the end of the tube blank 1 is 10-20 degrees.

Preferably, both ends of the tube blank 1 are inclined at 10-20 degrees.

Preferably, the section of the tube blank 1 is isosceles trapezoid, and the back of the tee joint is machined on the longer side of the tube blank 1.

Preferably, one side of the long end of the tube blank 1 is located on the side of the first clamping space 13 away from the second clamping space 14, and one side of the short end of the tube blank 1 is located on the side of the first clamping space 13 close to the second clamping space 14.

The invention improves the utilization rate of the pipe, reduces the redundant accumulation on the back of the product, reduces the weight of the three-way pipe, can meet the product standard and improves the market competitiveness of the product.

The invention adopts the three-way bevel connection stretching process, so that the redundant accumulation of the back of the three-way pipe blank is reduced, the short end material length of raw materials is reduced through the bevel connection design, the back accumulation of products is reduced, the single weight of the same product can be reduced by about 8-15%, and the competitiveness of the product is greatly improved.

While the invention has been described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes in form and detail may be made therein without departing from the spirit and scope of the invention.