Copper-nickel alloy single clamping and pressing type seamless tee joint forming device and method

Abstract

The invention discloses a copper-nickel alloy single compression type seamless tee joint forming device and method.The forming device comprises a tee joint forming die and a compression end forming die, a through hole is formed in the center of the bottom of a lower die plate of the tee joint forming die, and a left-right through round hole is formed between an upper die plate and the lower die plate after the upper die plate and the lower die plate are assembled. The forming clamping and pressing end mold comprises a fixing mold, a first clamping and pressing mold, a second clamping and pressing mold and a third clamping and pressing mold, the water expansion forming technology is utilized, the tee joint forming mold is adopted, a single clamping and pressing tee joint copper pipe is integrally formed, the three ends of a tee joint can be formed at the same time, and then the three clamping and pressing ends of the tee joint are formed at the same time in a mechanical forming mode. The copper-nickel alloy single-clamping-pressing type seamless tee joint is integrally formed. The integrally-formed tee joint is free of welding seams, welding and polishing procedures are omitted in the manufacturing process, large-scale production can be achieved, the manufacturing cost is reduced, the heat influence caused by welding is avoided, and the reject ratio of products can be greatly reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of metal material processing and manufacturing methods. The present invention relates to a method for manufacturing a copper-nickel alloy single-clip type seamless tee. Background Art

[0002] Copper-nickel alloy materials have excellent corrosion resistance, anti-fouling by marine organisms and good processing properties. They are ideal materials for seawater environments and are widely used in shipbuilding and marine engineering at home and abroad. In low-pressure pipeline systems, three-way pipe fittings are often used for connection, usually by welding or threading, which is costly and has low installation efficiency. Thin-walled compression fittings have the characteristics of low cost and convenient construction, and can be used for low-pressure seawater pipelines.

[0003] Stainless steel compression fittings are manufactured by forming the branch pipe and the main pipe separately and then welding them. Invention patent CN112917107A "A production process for equal-diameter tees of stainless steel compression fittings" introduces a production process for equal-diameter tees of stainless steel compression fittings. The production process includes: feeding, laser cutting, chamfering, water expansion forming, punching, high-frequency heating, drawing, flattening, pipe cleaning, bright solution annealing, polishing, installation of sealing rings, and pipe testing. The branch pipes in this invention patent need to be welded, and the process is complicated. The single compression tees in the prior art are all produced by mechanical forming, forming the main pipe and the branch pipe separately, and then welding them. The process is complicated, and welding will produce a heat-affected zone, which has a certain impact on the material around the weld. There is currently no public report on the manufacturing method of the copper-nickel alloy single compression seamless tee. Summary of the invention

[0004] In view of this, the present invention aims to overcome the problem of complex single-clip press type tee forming process, and provide a copper-nickel alloy single-clip press type seamless tee forming device and method with simple process, high yield and low cost.

[0005] A copper-nickel alloy single-clip seamless tee forming device, the forming device includes a forming tee mold and a forming crimping end mold, the forming tee mold includes an upper mold, a lower mold, a punch and a pressure plate, wherein a through hole is provided at the bottom center of the lower mold, and the height of the through hole is the same as the height of the lower mold; a circular hole that passes through the left and right is formed in the middle after the upper mold and the lower mold are clamped, and the circular hole is perpendicular to the through hole; the forming crimping end mold includes a fixed mold, a first crimping mold, a second crimping mold and a third crimping mold, a flat-end tee pipe is placed in a mold cavity of the fixed mold, and the first crimping mold, the second crimping mold and the third crimping mold are respectively located at a flat first interface, a flat second interface and a flat third interface of the flat-end tee pipe.

[0006] Furthermore, the punch is divided into a left punch and a right punch, and the pressure plate is divided into a left pressure plate and a right pressure plate. The left punch is fixedly connected to the left pressure plate, and the right punch is fixedly connected to the right pressure plate. The left punch and the right punch are respectively located at the axial left end and axial right end of the pipe to be extruded, and penetrate into the circular hole after the mold is closed from the left and right ends.

[0007] Furthermore, the upper template, the lower template, the left punch, the right punch and the through hole together form a three-way blank tube forming cavity.

[0008] Furthermore, the fixed mold includes an upper module and a lower module, and the flat-end three-way pipe is clearance-matched with the upper module and the lower module to facilitate fixing the position of the flat-end three-way pipe, and the first crimping mold, the second crimping mold and the third crimping mold are respectively placed at the flat first interface, the flat second interface and the flat third interface of the flat-end three-way pipe.

[0009] Furthermore, the first pressing mold, the second pressing mold and the third pressing mold all include a first core rod, a second core rod and a core rod chassis, the first core rod and the second core rod are fixed on the core rod chassis, and the core rod chassis drives the first core rod and the second core rod to rotate as a whole.

[0010] Furthermore, the first core rod comprises a first core rod upper portion and a first core rod lower portion, the first core rod upper portion and the first core rod lower portion are connected by a chamfer R1 in the middle, and arc-shaped second core rod protrusions are provided at both ends of the top of the second core rod.

[0011] A method for manufacturing a copper-nickel alloy single-press type seamless tee, comprising the following steps:

[0012] S1: Cutting, determining the size of the tee pipe, cutting the pipe to the specified size and removing the burrs at the end to obtain the pipe to be extruded;

[0013] S2: forming a tee, placing the pipe to be extruded into a forming tee mold in a tee forming machine to form a tee blank pipe;

[0014] S3: Flat port, process the length of the tee blank main pipe and the height of the tee blank branch pipe to the specified size, and then process the port wall thickness and port depth of each interface to the required size. The port processing depth is determined according to the port outer diameter;

[0015] S4: intermediate annealing, annealing the flat-end tee pipe after the flat end;

[0016] S5: Forming and pressing the end portion, placing the annealed flat-end tee pipe into a special tee forming machine, and using a forming and pressing end die to complete the forming and pressing end portion of the flat-end tee pipe, and finally obtaining a formed tee pipe;

[0017] S6: Secondary annealing: The formed tee pipe is subjected to secondary annealing.

[0018] Furthermore, the step S5 includes:

[0019] S51: Lubricant is evenly applied to the inner and outer surfaces of the flat-end tee pipe, and then the flat-end tee pipe is placed on the forming and pressing end mold of the tee forming machine.

[0020] S52: The ends of the three interfaces are formed by placing a first pressing die, a second pressing die and a third pressing die at the three interfaces of the flat-end tee pipe, the core rods used for pushing in the first pressing die, the second pressing die and the third pressing die are divided into a first core rod and a second core rod, the first core rod is used for expanding the diameter, and the inner diameter of the end of each interface of the flat-end tee pipe is expanded to two sizes, the inner diameter of the first section is a size suitable for inserting the pipe, and the size of the second section is a size suitable for forming a pressing bulge;

[0021] S53: After the diameter expansion is completed, the core rod bottom mold drives the first core rod and the second core rod to rotate 180 degrees as a whole, and the second core rod is aligned with the three interfaces of the flat-end tee pipe. The second core rod is used to form an end suitable for clamping.

[0022] Furthermore, in step S1, a copper-nickel alloy seamless hollow tube is used as a raw material.

[0023] Furthermore, the specific process of the intermediate annealing described in step S4 is as follows: the tee after the flat end is placed in a nitrogen protection heat treatment furnace for annealing, the heating temperature is 720-750°C, the insulation time is 30-45min, and the product is taken out after cooling to room temperature in the furnace; the specific process of the secondary annealing described in step S6 is as follows: the product is placed in a nitrogen protection heat treatment furnace for annealing, the heating temperature is 760-780°C, the insulation time is 45-60min, and the product is taken out after cooling to room temperature in the furnace.

[0024] Compared with the prior art, the invention has the following beneficial effects: the invention utilizes the water expansion forming technology and adopts the tee forming mold to form the single clamping tee copper tube in one piece, and can also form the three ends of the tee at the same time. The invention adopts the one-piece forming tee without weld seams, and the manufacturing process does not require welding or grinding steps, which can not only enable mass production, reduce manufacturing costs, avoid the heat effect caused by welding, but also greatly reduce the product defect rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a schematic diagram of the structure of a three-way forming mold of the present invention;

[0026] Figure 2 This is a schematic diagram of a three-way blank pipe of the present invention;

[0027] Figure 3 This is a schematic diagram of a flat-end three-way pipe of the present invention;

[0028] Figure 4It is a structural schematic diagram of the molding and pressing end mold of the present invention;

[0029] Figure 4a For the present invention Figure 4 A partial enlarged view of the middle A area;

[0030] Figure 5 Schematic diagram of the finished product of the single-clip press-type seamless tee pipe of the present invention

[0031] Reference numerals:

[0032] The forming three-way mold 1, the upper mold plate 11, the lower mold plate 12, the through hole 121, the left punch 131, the right punch 132, the left pressure plate 141, the right pressure plate 142, the round hole 15; the forming clamping end mold 2, the fixed mold 21, the upper module 211, the lower module 212; the first clamping mold 22, the second clamping mold 23, the third clamping mold 24, the first core rod 221, the upper part of the first core rod 2211, the lower part of the first core rod 2212; the second core rod Rod 222, second core rod protrusion 2221; core rod bottom mold 223; pipe to be extruded 3, three-way blank pipe 4, three-way blank main pipe 41, three-way blank branch pipe 42; flat-end three-way pipe 5, flat-end three-way main pipe 51, flat-end first interface 511, flat-end second interface 512; flat-end three-way branch pipe 52, flat-end third interface 523, first positioning groove 53; formed three-way pipe 6, formed three-way main pipe 61, formed three-way branch pipe 62, second positioning groove 63. DETAILED DESCRIPTION

[0033] The inventive concepts of the present disclosure will be described below using terms commonly used by those skilled in the art to convey the essence of their work to other persons skilled in the art. However, these inventive concepts can be embodied in many different forms and should not be considered limited to the embodiments described herein.

[0034] The present invention will be described in detail below with reference to the accompanying drawings and in conjunction with embodiments.

[0035] The present embodiment is directed to a copper-nickel alloy single-clip seamless tee forming device and method. In the press-type tee manufacturing method and production process mentioned in the existing patents, it can be seen that the existing press-type tee production process is mostly through methods and steps including: feeding, laser cutting, chamfering, water expansion forming, punching, high-frequency heating, drawing, flattening, pipe cleaning, bright solution annealing, polishing, installation of sealing rings, pipe testing, etc., which are costly, complicated in process and low in installation efficiency.

[0036] In order to solve the problems in the prior art of complex preparation methods of seamless tees, low manufacturing efficiency, and limited mass production of seamless tees, this embodiment proposes a copper-nickel alloy single-clip seamless tee forming device and method.

[0037] The forming device includes a forming three-way mold 1 and a forming clamping end mold 2. The forming three-way mold 1 includes an upper mold plate 11, a lower mold plate 12, a punch and a pressure plate, wherein a through hole 121 is provided at the bottom center of the lower mold plate 12, and the through hole 121 passes through the lower mold plate 12, and the height of the through hole 121 is equal to the height of the lower mold plate 12; after the extruded tube 3 is placed in the mold cavity of the lower mold plate 12, the upper mold plate 11 and the lower mold plate 12 are molded together, and the mold cavity of the lower mold plate 12 and the mold cavity of the upper mold plate 11 are both semi-cylindrical mold cavities After the mold is closed, a circular hole 15 is formed in the middle part, which is perpendicular to the through hole 121 and fits with the gap of the tube 3 to be extruded; the punch is divided into a left punch 131 and a right punch 132, which are respectively located at the axial left end and the axial right end of the tube 3 to be extruded, and penetrate into the circular hole after the mold is closed from the left and right ends. The height of the left punch 131 and the right punch 132 is equal to the diameter height of the tube 3 to be extruded, and is also equal to the distance between the upper template 11 and the lower template 12 after the mold is closed. The axial center of the left punch 131 and the right punch 132 is hollow, and the pressure plate is divided into a left pressure plate 141 and a right pressure plate 142. The left pressure plate 141 is fixedly connected to the left punch 131, and the right pressure plate 142 is fixedly connected to the right punch 132. Specifically, there is a groove in the center of the right side of the left pressure plate 141, and it is fixed with the left protrusion of the left punch 131 by threaded connection. When replacing the mold, only the punch and the mold need to be replaced; wherein the transverse center axis of the pipe 3 to be extruded, the punch, and the pressure plate are located in the same straight line. The upper mold plate 11, the lower mold plate 12, the left punch 131, the right punch 132 and the through hole 121 together form the forming cavity of the three-way blank pipe 4, specifically, the upper mold plate 11, the lower mold plate 12, the left punch 131 and the right punch 132 together form the forming cavity of the three-way blank main pipe 41, and the through hole 121 forms the forming cavity of the three-way blank branch pipe 42.

[0038] The molding crimping end mold 2 is divided into a fixed mold 21, a first crimping mold 22, a second crimping mold 23 and a third crimping mold 24. The flat-end three-way pipe 5 is placed in the mold cavity of the fixed mold 21. The first crimping mold 22, the second crimping mold 23 and the third crimping mold 24 have the same shape and structure and are respectively placed at the flat first interface 511, the flat second interface 512 and the flat third interface 523 of the flat-end three-way pipe 5.

[0039] The fixed mold 21 includes an upper module 211 and a lower module 212. The mold cavity of the upper module 211 and the mold cavity of the lower module 212 jointly form a mold cavity of the flat-end three-way main pipe 51 in the middle thereof. The lower module 212 is also provided with a vertical manifold through hole 2121 from the center to the bottom. The manifold through hole 2121 forms a mold cavity for the flat-end three-way branch pipe 52. The upper module 211 and the lower module 212 jointly form a mold cavity for the flat-end three-way pipe 5, which is gap-matched with the flat-end three-way pipe 5 placed therein.

[0040] The first pressing mold 22, the second pressing mold 23 and the third pressing mold 24 all include a first core rod 221, a second core rod 222 and a core rod bottom mold 223. The core rod bottom mold 223 is fixedly connected to the three-way forming machine. The first core rod 221 and the second core rod 222 are of equal height and are fixedly connected to the core rod bottom mold 223. The core rod bottom mold 223 can drive the first core rod 221 and the second core rod 222 to rotate within a range of 0-180°. The first core rod 221 is divided into a first core rod upper part 2211 and a first core rod lower part 2212. The first core rod upper part 2211 has a height of H1 and a diameter of D1, and the first core rod lower part 2212 has a height of H2 and a diameter of D2. 1 is used for pushing and expanding the diameter, expanding the inner diameter of each interface of the flat-end tee pipe 5 to two sections of inner diameter, the first core rod upper part 2211 is pushed and expanded to obtain the first section of inner diameter, which is a size suitable for the insertion of the pipe, the first section of the inner diameter height H1, the diameter D1; the first core rod lower part 2212 is pushed and expanded to obtain the second section of inner diameter, which is a size suitable for forming a compression bulge, the second section of the inner diameter height H2, the diameter D2; wherein the connection between the first core rod upper part 2211 and the first core rod lower part 2212 has a chamfer R1, D2>D1; the second core rod 222 has a second core rod protrusion 2221 on the upper end, which is used to form an end suitable for compression, and the connection between the second core rod protrusion 2221 and the second core rod 222 has a chamfer R2.

[0041] A method for forming a copper-nickel alloy single-clip press seamless tee, comprising the following steps:

[0042] S1: Cutting: Determine the size of the tee pipe, use a copper-nickel alloy seamless pipe as the raw material, use a fully automatic laser to cut the pipe, and remove the burrs on the end to obtain the pipe 3 to be extruded, wherein the cutting length of the pipe 3 to be extruded is L1;

[0043] S2: Forming a tee: placing the pipe 3 to be extruded into the mold 1 in the tee forming machine, expanding the tee blank branch pipe 42 by internal high pressure forming, and finally forming the tee blank pipe 4; specifically: placing the pipe 3 to be extruded into the mold cavity of the lower template 12, and closing the upper template 11 and the lower template 12, after closing the mold, a circular hole is formed in the middle of the upper template 11 and the lower template 12, and the left punch 131 and the right punch 132 penetrate the circular hole from the left and right ends respectively, and push horizontally toward the center, forming a rigid seal with the upper template 11, the lower template 12 and the pipe 3 to be extruded, and the air in the pipe is discharged by pre-filling the pipe 3 to be extruded with liquid. While the tube 3 to be extruded is pressurized and expanded, the left punch 131 pushes the material horizontally to the right, and the right punch 132 pushes the material horizontally to the left. Under the combined action of the internal pressure and the axial material, the tube 3 to be extruded is tightly attached to the circular hole of the mold 1 after the mold is closed, forming a three-way blank main pipe 41; the internal pressure is increased, so that the pre-filled liquid inside the tube 3 to be extruded produces fluidity under high extrusion pressure and high water pressure. At the same time, the axial center of the left punch 131 and the right punch 132 is hollow, and liquid is filled through the center to increase the internal pressure of the tube; the tube 3 to be extruded is forced to move to the through hole 121 of the lower template 12, thereby forming a three-way blank branch pipe 42 in the through hole 121, and the three-way blank tube 4 is formed. The three-way blank tube 4 is demolded and taken out.

[0044] The three-way blank pipe 4 includes a three-way blank main pipe 41 and a three-way blank branch pipe 42. The interior of the three-way blank pipe 4 is a hollow pipe, wherein the three-way blank main pipe 41 is open on both sides of the axial direction, and the three-way blank branch pipe 42 is closed at one end away from the three-way blank main pipe 41 and is perpendicular to the three-way blank main pipe 41.

[0045] S3: Flat port: The length of the tee blank main pipe 41 and the height of the tee blank branch pipe 42 are processed to the specified size to obtain a flat port tee main pipe 51 and a flat port tee branch pipe 52; the port wall thickness and port depth of each interface are processed to the required size, and the port processing depth of each interface is determined according to the port outer diameter to obtain a flat port first interface 511, a flat port second interface 512, and a flat port third interface 523;

[0046] Due to the high extrusion pressure of the left punch 131 and the right punch 132, the wall thickness of the three-way blank main pipe 41 will increase compared with the wall thickness of the pipe 3 to be extruded, and the wall thickness of the three-way blank branch pipe 42 is uneven. Therefore, the three-way blank pipe 4 is flattened to make its size uniform and shape matching to form a tee; the obtained flat-end three-way pipe 5 includes a flat-end three-way main pipe 51 and a flat-end three-way branch pipe 52, the flat-end three-way main pipe 51 is open on both sides of the axial direction, the flat-end three-way branch pipe 52 is perpendicular to the flat-end three-way main pipe 51, and is open on one side away from the flat-end three-way main pipe 51, and a first positioning groove 53 is provided at each interface, wherein the positioning groove is trapezoidal; the length of the flat-end three-way main pipe 51 is L3, the height of the flat-end three-way branch pipe 52 is H3, the length of the flat-end first interface 511, the flat-end second interface 512, and the flat-end third interface 523 are L4 and H4, wherein the dimensions of L4 and H4 are determined according to the size of the port;

[0047] S4: Intermediate annealing: the flat-end tee pipe 5 obtained after flattening is subjected to annealing treatment; the hardness of the flat-end tee pipe 5 is increased compared with the straight pipe 3 to be extruded, and the plasticity is reduced, so it cannot be directly used for forming and pressing the end, and needs to be subjected to intermediate annealing treatment. The specific operation is to put the flat-end tee pipe 5 into a nitrogen protection heat treatment furnace for annealing, the heating temperature is 720-750°C, the insulation time is 30-45min, and the flat-end tee pipe 5 is taken out after cooling to room temperature with the furnace. The hardness of the flat-end tee pipe 5 obtained after the intermediate annealing treatment should be lower than 120HV5;

[0048] S5: Forming and pressing the end: Lubricant is evenly applied to the inner and outer surfaces of the end interfaces of the annealed flat-end tee pipe 5 , and then it is placed into the mold cavity of the fixed mold 21 in the molding and pressing end mold 2 . The ends of the three interfaces are formed by the first crimping mold 22, the second crimping mold 23 and the third crimping mold 24 which are respectively placed at the three interfaces of the flat-end three-way pipe 5. Specifically, the core rods used for pushing on the first crimping mold 22, the second crimping mold 23 and the third crimping mold 24 are divided into a first core rod 221 and a second core rod 222. The first core rod 221 is used for diameter expansion to expand the inner diameter of each end of the flat-end three-way pipe 5 to two two-section sizes. The upper part 2211 of the first core rod is expanded to obtain a first section inner diameter, which is a size suitable for pipe insertion; the upper part 2211 of the first core rod is expanded to obtain a second section inner diameter, which is a size suitable for forming a crimping bulge; after the diameter expansion is completed, the core rod bottom mold 223 is rotated 180° as a whole, and the second core rod 222 is aligned with each port of the flat-end three-way pipe 5, wherein the second core rod 222 is used to form an end suitable for crimping; the third mold 23 and the fourth mold 24 have the same shape and structure as the second mold 22, and only the position is different.

[0049] Finally, a formed tee pipe 6 is obtained, and a clamping end is provided at each interface of the formed tee pipe 6, wherein the length of the formed tee pipe main pipe 61 is L5, and the height of the formed tee pipe branch pipe 72 is H5, wherein the length L5 and the height H5 of the formed tee pipe 6 are both smaller than the size of the flat-end tee pipe, and a first positioning groove 53 is provided inside the three interfaces, and a second positioning groove 63 is provided at the ends of the three interfaces, wherein the first positioning groove 53 is obtained by flat-end processing, and the second positioning groove 63 is obtained by pushing and expanding the first core rod 221 and the second core rod 222.

[0050] S6: Secondary annealing: The formed tee pipe 6 is annealed again; the hardness of each end of the formed tee pipe 6 will increase, and it cannot be directly used for compression connection, and needs to be annealed; specifically, the formed tee pipe 6 is placed in a nitrogen protection heat treatment furnace for annealing, the heating temperature is 760-780°C, the insulation time is 45-60 minutes, and it is taken out after cooling to room temperature in the furnace. The hardness of the end of the formed tee pipe 6 after the secondary annealing should be less than 100HV5.

[0051] Example 1

[0052] The present invention has been applied to the manufacture of DN65 copper-nickel alloy single-clip seamless equal-diameter tee, as follows:

[0053] 1. Cutting: Use Φ76.1×2.5mm copper-nickel alloy seamless pipes and use fully automatic laser cutting to cut the pipes. The laser cutting has high precision and small deformation of the pipes. The cutting length L1 is 320±1mm, and the burrs on the ends are removed after cutting;

[0054] 2. Tee forming: put the pipe 3 to be extruded into the mold 1 in the tee forming machine, expand the tee blank branch pipe 42 by internal high pressure forming, and form the tee blank pipe 4. The forming pressure is 20-22MPa, and the height H2 of the tee blank branch pipe 42 is not less than 130mm;

[0055] 3. Flat port: The length of the tee blank main pipe 41 and the height of the tee blank branch pipe 42 are processed to the specified size, and then the port wall thickness and port depth of each interface are processed to the required size to obtain a flat port tee pipe 5. The length of the flat port main pipe 51 is L3 = 248 ± 1 mm, the height of the flat port branch pipe 52 is H3 = 121 ± 1 mm, the length of the flat port first interface 511, the flat port second interface 512 and the flat port third interface 523 are L4 = 2 ± 0.2 mm, and the height is H4 = 63 ± 0.5 mm;

[0056] 4. Intermediate annealing: The hardness of the tee blank after forming will increase, and the plasticity will decrease. It cannot be directly used for forming and pressing the end, and needs intermediate annealing. Put the flat tee into a nitrogen protection heat treatment furnace for annealing. The heating temperature is 730±10℃, the insulation time is 40min, and it is taken out after cooling to room temperature. The hardness of the tee blank after annealing is 100~120HV5;

[0057] 5. Forming and pressing the end: Lubricant is evenly applied to the inner and outer surfaces of the end interfaces of the annealed flat-end tee pipe 5, and the second mold 22, the third mold 23 and the fourth mold 24 are respectively placed at the three interfaces of the flat-end tee pipe 5 to form the ends of the three interfaces. The inner diameter of the first section is the size suitable for the insertion of the pipe, which is 77.3 +1 0mm, the second section size is suitable for forming a compression bulge, which is 90.7±0.5mm; after the diameter expansion is completed, the core rod bottom mold 223 is rotated 180° as a whole, and the second core rod 222 is aligned with each port of the flat-end three-way pipe 5 to form an end suitable for compression;

[0058] 6. Annealing: The hardness of each end of the formed tee pipe 6 will increase, and it cannot be directly used for compression connection, and needs to be annealed. Put the formed tee pipe 6 into a nitrogen protection heat treatment furnace for annealing, the heating temperature is 760-780℃, the insulation time is 50min, and it is taken out after cooling to room temperature. The hardness of the tee end after annealing is 85-100HV5.

[0059] Example 2

[0060] The present invention has been applied to the manufacture of DN80 / DN50 copper-nickel alloy single-clip seamless equal-diameter tees, as follows:

[0061] 1. Cutting: Select Φ88.9×2mm copper-nickel alloy seamless pipes and use fully automatic laser cutting to cut the pipes. The laser cutting has high precision and small deformation of the pipes. The cutting length L1 is 350±1mm, and the burrs on the ends are removed after cutting;

[0062] 2. Tee forming: put the pipe 3 to be extruded into the mold 1 in the tee forming machine, expand the tee blank branch pipe 42 by internal high pressure forming, and form the tee blank pipe 4. The forming pressure is 22-24MPa, and the height H2 of the tee blank branch pipe 42 is not less than 140mm;

[0063] 3. Flat port: The length of the tee blank main pipe 41 and the height of the tee blank branch pipe 42 are processed to the specified size, and then the port wall thickness and port depth of each interface are processed to the required size to obtain a flat port tee pipe 5. The length of the flat port main pipe 51 is L3 = 276 ± 1 mm, the height of the flat port branch pipe 52 is H3 = 127.4 ± 1 mm, the length of the flat port first interface 511, the flat port second interface 512 and the flat port third interface 523 are L4 = 1.5 ± 0.15 mm, and the height is H4 = 44.4 ± 0.5 mm;

[0064] 4. Intermediate annealing: The hardness of the tee blank after forming will increase, and the plasticity will decrease. It cannot be directly used for forming and pressing the end, and needs intermediate annealing. Put the flat tee into a nitrogen protection heat treatment furnace for annealing. The heating temperature is 740±10℃, the insulation time is 45min, and it is taken out after cooling to room temperature. The hardness of the tee blank after annealing is 100~120HV5;

[0065] 5. Forming and pressing the end: Lubricant is evenly applied to the inner and outer surfaces of the end interfaces of the annealed flat-end tee pipe 5, and the end interfaces are formed by placing the second mold 22, the third mold 23 and the fourth mold 24 at the three interfaces of the flat-end tee pipe 5 respectively. The inner diameter of the first section is suitable for the insertion of the pipe, and the size of the second section is suitable for the size of the forming and pressing bulging; the two inner diameters of the forming tee main pipe 61 are respectively and 105.5±0.5mm, the two inner diameters of the formed three-way branch pipe 62 are and 62.4±0.4mm; after the diameter expansion is completed, the core rod bottom mold 223 is rotated 180° as a whole, and the second core rod 222 is aligned with each port of the flat-end tee pipe 5 to form an end suitable for clamping;

[0066] 6. Annealing: The hardness of each end of the formed tee pipe 6 will increase, and it cannot be directly used for compression connection, and needs to be annealed. Put the formed tee pipe 6 into a nitrogen protection heat treatment furnace for annealing, the heating temperature is 760-780℃, the insulation time is 55min, and it is taken out after cooling to room temperature. The hardness of the tee end after annealing is 85-100HV5.

[0067] Although the present invention is disclosed as above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the scope defined by the claims.

Claims

1. A copper-nickel alloy single-clip seamless tee forming device, characterized in that: The molding device comprises a molding three-way mold (1) and a molding clamping end mold (2), wherein the molding three-way mold (1) comprises an upper mold plate (11), a lower mold plate (12), a punch and a pressure plate, wherein a through hole (121) is provided at the center of the bottom of the lower mold plate (12), and the height of the through hole (121) is the same as that of the lower mold plate (12); after the upper mold plate (11) and the lower mold plate (12) are molded together, a circular hole (15) is formed in the middle that passes through the left and right sides, and the circular hole (15) and the through hole (121) are perpendicular to each other. The molding crimping end mold (2) comprises a fixed mold (21), a first crimping mold (22), a second crimping mold (23) and a third crimping mold (24); the flat-end three-way pipe (5) is placed in the mold cavity of the fixed mold (21); the first crimping mold (22), the second crimping mold (23) and the third crimping mold (24) are respectively placed at the flat-end first interface (511), the flat-end second interface (512) and the flat-end third interface (523) of the flat-end three-way pipe (5).

2. The molding device according to claim 1, characterized in that: The punch is divided into a left punch (131) and a right punch (132), and the pressure plate is divided into a left pressure plate (141) and a right pressure plate (142). The left punch (131) is fixedly connected to the left pressure plate (141), and the right punch (132) is fixedly connected to the right pressure plate (142). The left punch (131) and the right punch (132) are respectively located at the axial left end and the axial right end of the pipe (3) to be extruded, and penetrate into the circular hole (15) after the mold is closed from the left and right ends.

3. The molding device according to claim 1, characterized in that: The upper template (11), the lower template (12), the left punch (131), the right punch (132) and the through hole (121) together form a forming cavity for the three-way blank tube (4).

4. The molding device according to claim 1, characterized in that: The fixed mold (21) comprises an upper module (211) and a lower module (212); the flat-end three-way pipe (5) is clearance-matched with the upper module (211) and the lower module (212); the first pressing mold (22), the second pressing mold (23) and the third pressing mold (24) are respectively placed at the flat-end first interface (511), the flat-end second interface (512) and the flat-end third interface (523) of the flat-end three-way pipe (5).

5. The molding device according to claim 4, characterized in that: The first pressing mold (22), the second pressing mold (23) and the third pressing mold (24) all comprise a first core rod (221), a second core rod (222) and a core rod chassis (223); the first core rod (221) and the second core rod (222) are fixed on the core rod chassis (223); and the core rod chassis (223) drives the first core rod (221) and the second core rod (222) to rotate as a whole.

6. The forming device according to claim 5, characterized in that: The first core rod (221) comprises a first core rod upper portion (2211) and a first core rod lower portion (2212), the first core rod upper portion (2211) and the first core rod lower portion (2212) are connected by a chamfer in the middle, and arc-shaped second core rod protrusions (2221) are provided at both ends of the top of the second core rod (222).

7. A method for forming a copper-nickel alloy single-clip seamless tee, characterized in that: Utilizing the copper-nickel alloy single-clip press seamless tee forming device according to any one of claims 1 to 6, the forming method comprises the following steps: S1: Cutting the material, determining the size of the tee pipe, cutting the pipe to the specified size and removing the burrs on the end to obtain the pipe to be extruded (3); S2: forming a tee, placing the pipe to be extruded (3) into a tee forming mold (1) in a tee forming machine to form a tee blank pipe (4); S3: Flat end, the length of the tee blank main pipe (41) and the height of the tee blank branch pipe (42) are processed to the specified size, and then the port wall thickness and port depth of each interface are processed to the required size to obtain a flat end tee pipe (5), wherein the port processing depth is determined according to the port outer diameter; S4: intermediate annealing, annealing the flat-end tee pipe (5); S5: forming and pressing the end portion, placing the annealed flat-end tee pipe (5) into a special tee forming machine, and using a forming and pressing end portion mold (2) to complete the forming and pressing end portion of the flat-end tee pipe (5), and finally obtaining a formed tee pipe (6); S6: Secondary annealing: The formed three-way pipe (6) is subjected to secondary annealing treatment.

8. The molding method according to claim 7, characterized in that: Step S5 includes: S51: Lubricant is evenly applied to the inner and outer surfaces of the flat-end tee pipe (5), and then the flat-end tee pipe (5) is placed on the forming and pressing end mold (2) of the tee forming machine; S52: The three interfaces of the flat-end three-way pipe (5) are formed by placing a first pressing mold (22), a second pressing mold (23) and a third pressing mold (24) at the three interfaces, wherein the core rods used for pushing in the first pressing mold (22), the second pressing mold (23) and the third pressing mold (24) are divided into a first core rod (221) and a second core rod (222), and the first core rod (221) is used for expanding the diameter, so as to expand the inner diameter of the end of each interface of the flat-end three-way pipe (5) to two sizes, wherein the inner diameter of the first section is a size suitable for inserting the pipe, and the size of the second section is a size suitable for forming a pressing bulge; S53: After the diameter expansion is completed, the core rod bottom mold (223) drives the first core rod (221) and the second core rod (222) to rotate 180 degrees as a whole, and the second core rod (222) is aligned with the three interfaces of the flat-end three-way pipe (5). The second core rod (222) is used to form an end suitable for clamping.

9. The molding method according to claim 7, characterized in that: In step S1, a copper-nickel alloy seamless hollow tube is used as a raw material.

10. The molding method according to claim 7, characterized in that: The specific process of the intermediate annealing described in step S4 is as follows: the tee after the flat end is placed in a nitrogen protection heat treatment furnace for annealing, the heating temperature is 720-750°C, the insulation time is 30-45min, and the product is taken out after cooling to room temperature in the furnace; the specific process of the secondary annealing described in step S6 is as follows: the product is placed in a nitrogen protection heat treatment furnace for annealing, the heating temperature is 760-780°C, the insulation time is 45-60min, and the product is taken out after cooling to room temperature in the furnace.

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