A tee fitting forming apparatus and method

Abstract

The application discloses a tee pipe fitting forming device and method, and relates to the field of metal pipe fitting processing; the device comprises a die holder, which is used for fixing and placing a forming die; the forming die is capable of placing a pipe blank to be processed; a pushing component is arranged outside the die holder and is capable of applying a pushing force with a set size to the pipe blank to be processed along the axis of the pipe blank to be processed; the tee pipe fitting forming method is characterized in that: after filling filler in the pipe blank to be processed, the pipe blank to be processed is arranged in the forming die; 20% of the total pushing stroke is pre-applied; 40% of the total pushing stroke is applied to push the forming; the pipe blank to be processed is taken out for cleaning and solid solution treatment; after the pipe blank to be processed is filled with filler again, the pipe blank to be processed is arranged in the forming die, and 40% of the total pushing stroke is finally applied; the formed pipe fitting is taken out for cleaning and post-treatment. The problems of low strength, poor precision and high thinning rate of the tee pipe fitting can be avoided.

Description

Technical Field

[0001] This invention relates to the field of metal pipe processing technology, and in particular to a tee pipe forming apparatus and method. Background Technology

[0002] In current industrial production, there are various forming methods for tee fittings, such as welding, integral forging, and traditional hydraulic bulging. However, all existing tee fitting forming methods have certain drawbacks. Welding requires professional welders and has high requirements for welding technology; otherwise, defects (such as porosity, slag inclusions, and incomplete fusion) are prone to occur. The high temperature of welding can lead to localized thermal stress, which may remain after cooling, reducing the fatigue life of the fitting. Uneven heating can easily cause deformation of the fitting, especially in thin-walled or large-diameter fittings. Welded joints are prone to fatigue cracking under long-term vibration. Integral forging has high material consumption and complex processes. Metal flow during forging may lead to uneven wall thickness. If the forging process is not proper, defects such as shrinkage cavities and inclusions may remain. Traditional hydraulic bulging is prone to cracking during the forming process, and under branch ratio conditions, the thinning rate at the top of the branch pipe is prone to exceeding the tolerance (>30%), resulting in an excessively high thinning rate.

[0003] Therefore, there is an urgent need to design a technical solution that can avoid the problems of low strength, poor precision, and high thinning rate of tee fittings. Summary of the Invention

[0004] The purpose of this invention is to provide a tee fitting forming device and method to solve the problems existing in the prior art, and to avoid the problems of low strength, poor precision and high thinning rate of tee fittings.

[0005] To achieve the above objectives, the present invention provides the following solution: This invention provides a tee fitting forming apparatus, comprising: A mold base, which is used to fix and place a forming mold, and the forming mold can hold the tube blank to be processed; The pushing component, located on the outside of the mold base, is capable of applying a set amount of thrust along the axis of the tube blank to be processed from both ends of the tube blank.

[0006] Preferably, the mold base includes an upper mold base and a lower mold base arranged symmetrically on the upper and lower sides, and a cavity is provided between the upper mold base and the lower mold base. The cavity is used to fix the forming mold. A push channel is opened on the side wall of the mold base. The output end of the push component can move back and forth along the push channel on the same side to apply a set amount of thrust to the corresponding end of the tube blank to be processed.

[0007] Preferably, it also includes a platform base plate, and the mold base and the pushing component are both fixed on the platform base plate.

[0008] Preferably, the pushing component includes a hydraulic cylinder and a cylinder support. The bottom of the hydraulic cylinder is fixed to the platform base plate by the cylinder support. The hydraulic cylinder is arranged horizontally, and the output shaft of the hydraulic cylinder faces the mold base.

[0009] Preferably, the forming mold includes an upper mold and a lower mold that are symmetrically arranged and fixedly connected. Each of the upper mold and the lower mold has a main pipe groove and a branch pipe groove on opposite sides. The branch pipe groove is arranged at an angle to the main pipe groove, and one end of the branch pipe groove is connected to the side wall of the main pipe groove. After the upper mold and the lower mold are fixedly connected, the two main pipe grooves can form a main pipe processing channel, and the two branch pipe grooves can form a branch pipe processing channel. The main pipe processing channel is used to fix the pipe blank to be processed.

[0010] Preferably, the main processing channel is provided with main end seals symmetrically at both ends. One end of the main end seal abuts against the pushing component, and the other end extends into the tube blank to be processed and makes sealing contact with the inner wall of the tube blank.

[0011] Preferably, the branch pipe processing channel is provided with a branch end seal, one end of which abuts against the pushing component, and the other end is located at the connection position between the branch pipe processing channel and the main pipe processing channel. The end of the branch end seal away from the pushing component is a frustum-shaped cone with a gradually decreasing diameter.

[0012] The present invention also provides a forming method based on the above-mentioned tee fitting forming device, comprising the following steps: After filling the tube blank with filler, it is placed inside the forming mold; Pre-push involves pushing the packing body axially from both ends of the tube blank by a pushing component, with the pushing stroke being 20% ​​of the total pushing stroke; The push-form process involves pushing the packing material axially from both ends of the tube blank to be processed, based on the pre-push stroke. The push stroke is 40% of the total push stroke, causing the sidewall of the tube blank to be processed to deform towards the branch pipe processing channel. The tube blank to be processed is removed, cleaned, and then subjected to solution treatment; After the filler is refilled inside the tube blank to be processed, it is placed inside the forming mold; The final push, based on the pushing stroke of the pusher, involves pushing the packing body axially from both ends of the tube blank to be processed by the pushing component, with the pushing stroke being 40% of the total pushing stroke; The formed tubular parts are removed, cleaned, and then post-processed.

[0013] Preferably, during the pre-push, push-shape, and final push, the required recommended stroke is achieved through multiple pushes. During each push, the pushing component on the outside of the branch pipe processing channel retracts by 40%-50% of the push amount.

[0014] Preferably, the filler is made of a tin-bismuth alloy.

[0015] The present invention achieves the following technical effects compared to the prior art: The forming apparatus and method for tee fittings of this invention proposes a phased pushing process involving pre-pushing, shaping, and final pushing. By controlling the pushing speed and stroke at different stages, material stress concentration is reduced, preventing cracks or uneven wall thickness. The thinning rate can be controlled at around 8%, solving the problem of excessively high thinning rates in traditional technologies. Different pushing forces and directions are designed for the main and branch pipes of the tee fitting to achieve integral forming, resulting in stronger fatigue and corrosion resistance, replacing traditional processing methods. By controlling the pushing ratio at each stage, precise material cutting is achieved, reducing subsequent processing allowances and improving fitting accuracy. Solution treatment of the blank during forming increases the strength of the fitting. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the forming method of the tee fitting of the present invention; Figure 2 This is a schematic diagram of the tee fitting forming device in one or more embodiments of the present invention; Figure 3 This is a schematic diagram illustrating the forming principle of a tee fitting in one or more embodiments of the present invention; Figure 4 This is a schematic diagram of the mold structure in one or more embodiments of the present invention; Figure 5 This is a schematic diagram of the main end seal structure in one or more embodiments of the present invention; Figure 6 This is a schematic diagram of the support seal structure in one or more embodiments of the present invention.

[0018] In the diagram: 1-Platform base plate, 2-Cylinder support, 3-Hydraulic cylinder, 4-Lower mold base, 5-Upper mold base, 6-Support end seal, 7-Main end seal, 8-Tube blank to be processed, 9-Filling, 10-Forming mold. Detailed Implementation

[0019] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] The purpose of this invention is to provide a tee fitting forming device and method to solve the problems existing in the prior art, and to avoid the problems of low strength, poor precision and high thinning rate of tee fittings.

[0021] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0022] Existing tee fitting forming methods suffer from low strength, poor precision, and high thinning rate. To address these issues, this invention provides a tee fitting forming apparatus, such as... Figures 2-6 As shown, the device includes a mold base and a pushing component. The mold base is used to fix and place the forming mold 10, and the forming mold 10 can hold the tube blank 8 to be processed. The pushing component is located outside the mold base and can apply a set amount of pushing force from both ends of the tube blank 8 along the axis of the tube blank 8. This invention is based on a tee pipe fitting forming device and proposes a staged pushing process of pre-pushing, pushing and shaping, and final pushing. By controlling the pushing speed and stroke of different stages, material stress concentration is reduced, cracks or uneven wall thickness are avoided, and the thinning rate can be controlled at about 8%, solving the problem of excessively high thinning rate in traditional technology. Different pushing forces and directions are designed for the main pipe and branch pipe of the tee pipe fitting to achieve one-piece forming, which has stronger fatigue resistance and corrosion resistance, replacing the traditional processing method. By controlling the pushing and forming ratio of each pushing stage, precise blanking is achieved, reducing subsequent processing allowances and improving the accuracy of the pipe fitting. The tube blank 8 to be processed is solution treated during the forming process, which increases the strength of the pipe fitting.

[0023] In one embodiment, the mold base includes an upper mold base 5 and a lower mold base 4 arranged symmetrically. A cavity is provided between the upper mold base 5 and the lower mold base 4 for fixing the forming mold 10. A pushing channel is provided on the side wall of the mold base. The output end of the pushing component can reciprocate along the pushing channel on the same side to apply a set amount of thrust to the corresponding end of the tube blank 8 to be processed. The mold base and the pushing component are both fixed on the platform base plate 1. The pushing component includes a hydraulic cylinder 3 and a cylinder support 2. The bottom of the hydraulic cylinder 3 is fixed to the platform base plate 1 through the cylinder support 2. The hydraulic cylinder 3 is arranged horizontally, and the output shaft of the hydraulic cylinder 3 faces the mold base. In this embodiment, there are three pushing components, two of which are located at both ends of the main pipe processing channel, and the third is located outside the branch pipe processing channel. The forming mold 10 includes an upper mold and a lower mold that are symmetrically arranged and can be fixedly connected. The upper mold and the lower mold each have a main pipe groove and a branch pipe groove on opposite sides. The branch pipe groove is arranged at an angle to the main pipe groove, and one end of the branch pipe groove is connected to the side wall of the main pipe groove. After the upper mold and the lower mold are fixedly connected, the two main pipe grooves can form a main pipe processing channel, and the two branch pipe grooves can form a branch pipe processing channel. The main pipe processing channel is used to fix the tube blank 8 to be processed.

[0024] In one embodiment, the diameter of the main pipe processing channel and the branch pipe processing channel are 0.1 mm larger than the pipe diameter. The main pipe processing channel has symmetrically arranged cylindrical main end seals 7 at both ends. One end of the main end seal 7 abuts against the pushing component, and the other end extends into the pipe blank 8 to be processed, making sealing contact with the inner wall of the pipe blank 8. The branch pipe processing channel has a branch end seal 6 inside. One end of the branch end seal 6 abuts against the pushing component, and the other end is located at the connection between the branch pipe processing channel and the main pipe processing channel. The main body of the branch end seal 6 is a cylindrical segment, and its end away from the pushing component is a frustum-shaped section with a gradually decreasing diameter.

[0025] This invention also provides a forming method based on the above-mentioned tee fitting forming device. This method is applicable to tee fittings with a main pipe diameter of 8mm~53mm; a branch diameter ratio (branch pipe diameter to main pipe diameter ratio) ≤0.5; a branch height ratio (height from main pipe center to branch top / nominal main pipe diameter) ≥0.8; and a branch pipe axis angle between the branch pipe axis and the main pipe axis between 40° and 90°. The method achieves integral forming through a push-forming process assisted by filler 9. Figure 1 As shown, the method includes the following steps: The blank 8 to be processed is formed by cutting the blank. Tin-bismuth alloy filler 9 is filled into the blank 8. After filling the blank 9, the blank 8 is placed in the forming mold 10. Pre-push: The filler 9 is pushed axially from both ends of the blank 8 by the pushing component. The pushing stroke is 20% of the total pushing stroke. The pre-push process can effectively prevent the formation of wrinkles by compressing the filler 9. In the first stage, the push-forming process involves pushing the filler 9 axially from both ends of the tube blank 8, based on the pre-push stroke. This push stroke is 40% of the total push stroke, causing the sidewall of the tube blank 8 to deform towards the branch pipe processing channel. The tube blank 8 is then removed, cleaned, and subjected to solution treatment. The wall thickness of the tube blank 8 is then increased, removing the thickened portion of the main pipe diameter. The filler 9 is refilled into the tube blank 8 and placed within the forming mold 10. In the final push stage, based on the push-forming stroke, the filler 9 is pushed axially from both ends of the tube blank 8, based on the push stroke. This push stroke is 40% of the total push stroke. After each push to the set stroke, internal pressure needs to be maintained. This internal pressure is indirectly controlled by adjusting the pushing speed and displacement of the pusher. When the internal pressure exceeds 3300 MPa, the pipe branch will rupture and overflow material, which will be discharged through the gap between the frustum-shaped tip of the branch seal 6 and the mold. When the internal pressure is below 3300 MPa, a sealed state is maintained. The formed tubular parts are removed, cleaned, and then subjected to solution treatment and machining.

[0026] The main end's advancing speed is 0.5-1 mm / s in the pre-pushing stage, 1-2 mm / s in the shaping stage, and 2-3 mm / s in the final pushing stage. The branch end's retraction speed is 1-2 mm / s in the pre-pushing stage, 2-4 mm / s in the shaping stage, and 4-6 mm / s in the final pushing stage. The amount of overflow is controlled by the gap between the frustum-shaped tip of the branch end seal 6 and the mold. During pre-pushing, shaping, and final pushing, the required recommended stroke is achieved through multiple pushes, with each push involving 0.2-0.5 mm. During each push, the pushing component outside the branch pipe processing channel retracts 40%-50% of the pushed amount.

[0027] Example 1 This embodiment uses a 1Cr18Ni9Ti stainless steel tee pipe (main pipe φ24×1mm, branch pipe φ10mm, branch ratio 0.42) as an example. The push ratio and material flow path are calculated to determine the blanking length. A tin-bismuth alloy is filled into the pipe blank. During the pre-push stage, the main end is pushed forward 0.5mm at a speed of 0.5mm / s, and the branch end retracts 0.25mm. During the push-forming stage, the main end is pushed forward 0.5mm at a speed of 1mm / s, and the branch end retracts 0.25mm. After cleaning and solution treatment, the main end wall thickness is machined to remove the thickened portion of the main diameter, and the pipe is filled with the tin-bismuth alloy. During the final push stage, the main end is pushed forward 0.5mm at a speed of 2mm / s, and the branch end retracts 0.25mm. After cleaning and solution treatment, the main diameter and branch diameter are machined to form a tee pipe fitting. The branch pipe has a height of 10mm, a top wall thickness of 0.92mm (thinning rate of 8%), no visible cracks, and an inner surface roughness of Ra3.2μm.

[0028] Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this invention. Furthermore, those skilled in the art will recognize that, based on the ideas of this invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this invention.

Claims

1. A method for forming a tee fitting, characterized in that: The tee fitting forming device used includes: A mold base, which is used to fix and place a forming mold, and the forming mold can hold the tube blank to be processed; A pushing component, located outside the mold base, can apply a set amount of thrust along the axis of the tube blank to be processed from both ends of the tube blank. The forming mold includes an upper mold and a lower mold arranged symmetrically and fixedly connected. Each of the upper and lower molds has a main pipe groove and a branch pipe groove on opposite sides. After the upper and lower molds are fixedly connected, the two branch pipe grooves can form a branch pipe processing channel. A branch pipe processing channel is provided inside a branch end seal, and the end of the branch end seal away from the pushing component is a frustum-shaped section with a gradually decreasing diameter. The method includes the following steps: After filling the tube blank with filler, it is placed inside the forming mold; Pre-push involves pushing the packing body axially from both ends of the tube blank by a pushing component, with the pushing stroke being 20% ​​of the total pushing stroke; The push-form process involves pushing the packing material axially from both ends of the tube blank to be processed, based on the pre-push stroke. The push stroke is 40% of the total push stroke, causing the sidewall of the tube blank to be processed to deform towards the branch pipe processing channel. The tube blank to be processed is removed, cleaned, and then subjected to solution treatment; After the filler is refilled inside the tube blank to be processed, it is placed inside the forming mold; The final push, based on the pushing stroke of the pusher, involves pushing the packing body axially from both ends of the tube blank to be processed by the pushing component, with the pushing stroke being 40% of the total pushing stroke; The formed tubular parts are removed, cleaned, and then post-processed.

2. The method for forming a tee fitting according to claim 1, characterized in that: The mold base includes an upper mold base and a lower mold base arranged symmetrically. A cavity is provided between the upper mold base and the lower mold base. The cavity is used to fix the forming mold. A push channel is opened on the side wall of the mold base. The output end of the push component can move back and forth along the push channel on the same side to apply a set amount of thrust to the corresponding end of the tube blank to be processed.

3. The method for forming a tee fitting according to claim 1, characterized in that: It also includes a platform base plate, on which the mold base and the pushing component are fixed.

4. The method for forming a tee fitting according to claim 3, characterized in that: The pushing component includes a hydraulic cylinder and a cylinder support. The bottom of the hydraulic cylinder is fixed to the platform base plate by the cylinder support. The hydraulic cylinder is arranged horizontally, and the output shaft of the hydraulic cylinder faces the mold base.

5. The method for forming a tee fitting according to claim 1, characterized in that: The branch pipe groove is arranged at an angle to the main pipe groove, and one end of the branch pipe groove is connected to the side wall of the main pipe groove; after the upper mold and the lower mold are fixedly connected, the two main pipe grooves can form a main pipe processing channel, and the main pipe processing channel is used to fix the pipe blank to be processed.

6. The method for forming a tee fitting according to claim 5, characterized in that: The main processing channel is symmetrically provided with main end seals at both ends. One end of the main end seal abuts against the pushing component, and the other end extends into the tube blank to be processed and makes sealing contact with the inner wall of the tube blank.

7. The method for forming a tee fitting according to claim 5, characterized in that: One end of the support seal abuts against the pushing component, and the other end is located at the connection between the branch pipe processing channel and the main pipe processing channel.

8. The method for forming a tee fitting according to claim 1, characterized in that: During the pre-push, push-shape, and final push stages, the required push stroke is achieved through multiple pushes. During each push, the push component on the outside of the branch pipe processing channel retracts 40%-50% of the push amount.

9. The method for forming a tee fitting according to claim 1, characterized in that: The filler is made of tin-bismuth alloy.

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