Oblique tee extrusion die, extrusion molding system and extrusion molding method

Abstract

The present invention belongs to the technical field of metal pipe processing, and specifically relates to an oblique tee extrusion die, an extrusion molding system and an extrusion molding method. The present invention includes a mold body with a cavity, and the cavity is divided into a main cavity for forming an axial main pipe and an oblique branch cavity for forming an oblique branch pipe. The end of the main cavity that can be entered by the extrusion head is the top of the main cavity. The oblique branch cavity starts from the branch mouth and gradually extends obliquely toward the bottom end of the main cavity. The tail end of the main cavity is coaxially arranged with a plug, which includes a vertical section and a conical tip located at the top of the vertical section, and the tip of the conical tip points in the direction of the top of the main cavity. The present invention effectively increases the pressure at the branch mouth by designing the direction of the branch pipe and the plug, ensures the filling efficiency at this part, and effectively improves the product yield.

Description

Technical Field

[0001] The invention belongs to the technical field of metal pipe processing, and in particular relates to an oblique tee extrusion die, an extrusion molding system and an extrusion molding method. Background Art

[0002] The oblique tee is a type of pipe connector and belongs to the category of special-shaped tees. It is mainly used at the branch of pipelines to divert and change the direction of fluid movement. The current manufacturing method of the oblique tee is mostly to quickly form it through forging or extrusion molding. The forging operation is recorded in the invention patent text with the Chinese patent publication number "CN105750840A" and the title "Forging method of tee forging". On the one hand, its production cost is relatively high, and after forging, the inner and outer walls of the forging blank need to be cut to meet the final size requirements of the oblique tee, which increases production costs and has the disadvantages of low raw material utilization, long process time, and high energy consumption. In comparison, extrusion molding is relatively widely used, which is recorded in the patent text with the Chinese patent publication number "CN114669649A" and the title "A brass tee blank forming process".

[0003] Currently, extrusion dies suitable for oblique tees have gradually begun to use the structure described in the invention patent text with the Chinese patent announcement number "CN107876677A" and the name "A large oblique tee die forging production process and die", that is, using "mutually symmetrical left and right dies, a die cavity is formed between the left and right dies, the die cavity includes a main cavity and an oblique branch cavity, the inner surface of the die cavity is adapted to the outer structure of the oblique tee, and the bottom of the main cavity is provided with a die bottom plate". The characteristics of this type of structure are flexible and convenient use, and demolding is very convenient; however, the problems caused should not be underestimated: first, the cold extrusion process can only be applied to thin and medium-walled oblique tees, and thick-walled oblique tees (D / S ≥ 0.1) are difficult to adopt the cold extrusion process; and although the hot forging process is suitable for the forming of thick-walled oblique tees, the production cost is relatively high, and after hot forging, the inner and outer walls of the forging blank need to be cut to meet the final size requirements of the oblique tee, which increases the production cost. Secondly, the deformation of the oblique tee is large, and conventional cold forming cannot be done in one go. It requires multiple cold extrusion forming + intermediate annealing processes, and the press tonnage requirement is high. Thirdly, the traditional left and right molds are symmetrically arranged. During production, the two molds must be adaptively replaced at the same time according to the current model of the oblique tee, which puts certain requirements on the manufacture, storage, handling and use of the molds. Fourthly, for molds with separate left and right molds, there is the problem of how to reliably position them after bearing the load; the traditional method of positioning is to use hydraulic cylinders to apply lateral pressure, that is, to use several symmetrical cylinders to apply radial pressure to the mold to ensure the pressing effect and constant position of the left and right molds. The above-mentioned operation mode not only causes the complexity of the molding equipment and process, but also results in that when the oblique tee in the mold is axially extruded and fills the cavity, the traditional simple lateral pressure method can only balance the radial stress of the oblique tee from the inside to the outside on the left and right molds, but the entire mold may also produce axial stress upward or downward along the axis of the extrusion head due to the compression deformation of the oblique tee, which can easily cause the mold to produce axial movement during extrusion. Finally, when using steel pipes as ingredients for extrusion molding, the traditional oblique branch cavity extends obliquely upward and the bottom of the main cavity is completely flush, which can easily lead to wrinkles on the inner wall of the oblique tee. This situation is particularly prone to occur at the junction of the branch pipe and the main pipe, that is, the branch port, thereby reducing the product yield; at the same time, the material diffusion at the branch pipe of the oblique tee is poor, which will also increase the pressure at the branch port, making it difficult to fill the branch port, and ultimately further affecting the product quality. Summary of the Invention

[0004] One of the purposes of the present invention is to overcome the shortcomings of the above-mentioned prior art and provide an inclined tee extrusion die, which effectively increases the pressure at the branch mouth through the design of the branch pipe direction and the head, ensures the filling efficiency at this part, and effectively improves the product yield.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] An oblique tee extrusion die comprises a die body with a cavity, wherein the cavity is divided into a main cavity for forming an axial main pipe and an oblique branch cavity for forming an oblique branch pipe. The die is characterized in that: the end of the main cavity into which the extrusion head can enter is the top end of the main cavity, and the oblique branch cavity starts from the branch opening and gradually extends obliquely toward the bottom end of the main cavity; a plug is coaxially arranged at the tail end of the main cavity, and the plug includes a vertical section and a conical tip located at the top of the vertical section, and the tip of the conical tip points in the direction of the top end of the main cavity; the size of the plug satisfies the following formula:

[0007]

[0008] in:

[0009] H is the height of the vertical section of the mandrel;

[0010] B is the distance from the intersection of the axial main pipe axis and the oblique branch pipe axis of the oblique tee to be formed to the bottom end of the axial main pipe;

[0011] D1 is the designed outer diameter of the axial main pipe;

[0012] t1 is the design wall thickness of the axial main pipe;

[0013] D2 is the designed outer diameter of the oblique branch pipe;

[0014] T2 is the designed wall thickness of the oblique branch pipe;

[0015] D3 is the diameter of the plug;

[0016] b is the design gap between the outer wall of the vertical section and the wall of the main cavity;

[0017] β is the apex angle of the cone tip;

[0018] α is the angle between the axis of the axial main pipe and the axis of the oblique branch pipe.

[0019] Preferably, the mold body includes a left mold and a right mold that are surface-fitted to each other, an arc-shaped through groove is arranged on the outer wall of the left mold, and an arc-shaped matching groove is provided on the right mold, so that after the left mold and the right mold surfaces are fitted together, the arc-shaped through groove and the arc-shaped matching groove enclose the main cavity; the oblique branch cavity is recessed at the bottom of the arc-shaped matching groove.

[0020] Preferably, an extrusion molding system using the oblique tee extrusion die is characterized in that: the extrusion molding system includes a positioning fixture, the positioning fixture includes a fastening sleeve that can be axially sleeved on the outside of the oblique tee extrusion die along the oblique tee extrusion die, the fastening sleeve includes two U-shaped sleeve rods arranged crosswise to each other, the notches of the two U-shaped sleeve rods are opposite to each other, thereby enclosing a space for the oblique tee extrusion die to be placed, and the two groups of straight rod sections located on the same side of the oblique tee extrusion die are hinged by the same horizontal hinge axis; the positioning fixture also includes The tooling hook comprises a rod body hinged on the horizontal hinge shaft, and the rod body of the tooling hook extends upward along the axial direction of the inclined tee extrusion mold, and the extension section is arranged with an inner flange so as to be hooked from top to bottom on the top surfaces of the left mold and the right mold that constitute the inclined tee extrusion mold; the positioning fixture also includes a positioning plate padded on the bottom surface of the inclined tee extrusion mold; the positioning plate is provided with a locking portion for locking the U-shaped sleeve rod when the inner flange is hooked on the top surface of the inclined tee extrusion mold and the bottom of the groove of the U-shaped sleeve rod is against the outer wall of the inclined tee extrusion mold.

[0021] Preferably, the locking portion includes a gantry-shaped gantry buckle fixed on the positioning plate, a horizontally extending extension plate is arranged at the slot end of the U-shaped sleeve rod, the extension plate extends into the gantry buckle, and a pad is provided between the upper surface of the extension plate and the lower surface of the beam at the gantry buckle to fill the gap between the two.

[0022] Preferably, the bottom of the gantry buckle is hinged to the positioning plate through a first hinge shaft, and the axis of the first hinge shaft is parallel to the axis of the horizontal hinge shaft; the slot end of the U-shaped sleeve rod is hinged with a conduction connecting rod through a second hinge shaft, and the rod body of the conduction connecting rod extends axially downward along the oblique tee extrusion mold, and then extends horizontally out of the extension plate.

[0023] Preferably, two U-shaped sleeve rods arranged crosswise with each other form a group of locking units, and each locking unit is evenly distributed in sequence along the axial direction of the oblique tee extrusion die; the notch ends of the U-shaped sleeve rods with the same notch direction are hinged to the same conductive connecting rod through a second hinge shaft located on the notch end.

[0024] Preferably, the contact position between the inner flange and the top surface of the oblique tee extrusion die covers the matching gap formed by the left die and the right die.

[0025] Preferably, an extrusion molding method using an extrusion molding system is characterized in that:

[0026] S1. After the left and right molds are combined to form an oblique tee extrusion die, a fastening sleeve is put on the oblique tee extrusion die. At this time, the inner flange of the tooling hook will be hooked on the top surface of the oblique tee extrusion die; then, the fastening sleeve droops and stretches until the bottom of the groove of each U-shaped sleeve rod is in close contact with the outer surface of the oblique tee extrusion die;

[0027] S2. Flip the gantry buckle on the positioning plate so that the gantry buckle is in an upright position. At this time, the extension plate at the transmission link is directly below the crossbeam of the gantry buckle. Fill a spacer between the crossbeam of the gantry buckle and the extension plate until the fastening sleeve is axially tightened and positioned.

[0028] S3. Place a plug at the bottom of the tube cavity of the billet and fill it with solid powder. Then, heat the billet with solid powder and plug and place it into the main cavity of the oblique tee extrusion die.

[0029] S4, the extrusion head moves to the top of the main cavity and coaxially presses the blank downward. The extrusion head gradually extends into the main cavity until it reaches the designed depth E, at which point E = LAB;

[0030] S5. Remove the positioning fixture, disassemble the left mold and the right mold, take out the oblique tee that has been extruded, and complete the extrusion molding process.

[0031] Preferably, the tubular blank is heated by medium frequency induction heating, and the heating zone satisfies the following formula:

[0032]

[0033] in:

[0034] h1 is the distance between the heating zone and the bottom end of the blank;

[0035] h2 is the axial length of the heating zone;

[0036] C is the distance from the intersection of the axial main pipe axis and the oblique branch pipe axis of the oblique tee to the bottom end of the oblique branch pipe;

[0037] L is the length of the blank;

[0038] A is the distance from the intersection of the axis of the axial main pipe and the axis of the oblique branch pipe to the top of the axial main pipe.

[0039] Preferably, the blank tube cavity is filled with solid powder; and the vertical section of the plug is recessed with an annular material groove.

[0040] The beneficial effects of the present invention are:

[0041] 1) Through the above solution, on the one hand, by positioning the oblique branch cavity downward, the blank's filling direction is smoother, making it easier to press-form. On the other hand, by providing a plug, during the extrusion process, the blank can quickly spread downward along the tapered tip and quickly fill the oblique branch cavity, which not only increases pressure on the branch opening but also facilitates filling of the branch opening. Thus, the present invention enables one-time extrusion molding, higher production efficiency, more guaranteed dimensions, and effectively improves the product yield.

[0042] 2) The mold of the present invention utilizes an AB mold design, i.e., a left mold and a right mold. The oblique branch cavity of mold A is designed based on the oblique branch pipe. The arcuate through-slots and arcuate matching grooves in molds B and A together form the main cavity. The dimensions of this main cavity are designed based on the axial main pipe diameter. During operation, the AB molds are combined to form the entire oblique tee extrusion die. When separated, mold A serves as a universal mold, while mold B adapts to the dimensions of the oblique branch cavity, thereby reducing mold manufacturing costs.

[0043] 3) Furthermore, the present invention also uses a locking fixture, or positioning fixture, to lock and secure the AB mold. On the one hand, the present invention utilizes a fastening sleeve formed by the intersection of U-shaped sleeve rods to ensure a radial clamping effect on the mold, thereby providing radial protection when the oblique tee extrusion mold bulges during extrusion molding. On the other hand, the compressive deformation of the oblique tee generates axial stresses upward or downward along the axial direction of the extrusion head. This is achieved by the downward pull of the inner flange from above and the support of the positioning plate from below, thereby achieving a bidirectional pressure protection purpose.

[0044] Thus, the present invention can achieve a three-dimensional locking function for the oblique tee extrusion die while ensuring a stable locking effect for the oblique tee extrusion die, thereby effectively ensuring the molding quality of the product.

[0045] 4) As for the locking part, it can be implemented in a variety of ways, such as using bolts to directly fix the fastening sleeve, etc. It only needs to ensure that when the inner flange is hooked on the top surface of the inclined tee extrusion die and the bottom of the groove of the U-shaped sleeve rod is against the outer wall of the inclined tee extrusion die, the fastening sleeve can be stably fixed on the positioning plate. Preferably, the present invention adopts a gantry and a gasket cooperation structure, that is, relying on the gantry-shaped gantry buckle as a limiter, through cooperation with the extension plate, and inserting a gasket in the gap between the two, it can achieve a fastening effect without fasteners, and the operation is very flexible and convenient. The use of a gasket can ensure the positioning of the fastening sleeve, because the downward movement of the fastening sleeve will be limited by the positioning plate, while the upward movement is limited by the inner flange; the inner flange must produce an upward movement, and it is bound to drive the fastening sleeve to move axially upward, but the fastening sleeve itself is firmly limited in the axial upward direction by the gasket due to the existence of the extension plate, thereby ensuring the working reliability of the present invention.

[0046] 5) As for the inner flange, depending on the different placement directions of the oblique tee extrusion die, the matching points of the inner flange at the two sets of tooling hooks and the top surface of the oblique tee extrusion die are actually different. In specific use, it can be considered that the contact position of the inner flange and the top surface of the oblique tee extrusion die covers the matching gap formed by the left and right dies. On the one hand, this method limits the placement angle of the oblique tee extrusion die, so that the bottom of the groove of the U-shaped sleeve can always be clearly matched with the back of the left or right die, ensuring the reliability of the match; on the other hand, the inner flanges on both sides can be matched with the left and right dies at the same time, and the axial constraints of the left and right dies are doubly limited, which maximizes the actual constraint effect.

[0047] 6) Based on the above scheme, the present invention preferably uses medium-frequency induction heating technology to locally heat specific parts of the blank, which has a fast heating speed, higher thermal efficiency, and is more suitable for mass production. At the same time, this hot forming method also effectively reduces the tensile strength and yield strength of the metal material, facilitates forming, and can reduce the press tonnage requirements compared to cold forming. In addition, the above-mentioned hot extrusion forming process can also be applied to the production of thin, medium, and thick-walled oblique tees. When used with tube-shaped blanks, there is no need to cut the inner and outer walls of the blank after forming, which is very effective.

[0048] 7) Furthermore, the mold filling material of the present invention is a solid powder, such as furan resin sand. This allows the solid powder to pre-fill the inner cavity of the steel tube blank during the extrusion process, thereby preventing wrinkles on the inner wall of the oblique tee. After the oblique tee is formed, the solid powder can be easily removed to obtain the desired oblique tee shape. Furthermore, the solid powder is reusable, further reducing production costs.

[0049] 8) The design of the annular trough allows solid powder to be filled into the annular trough during the filling stage. After extrusion is completed, the solid powder hardens, and the trough can be used to firmly hold the plug, so that the plug can be hung inside the blank, ensuring its working reliability. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] Figure 1 It is a structural diagram of the oblique tee;

[0051] Figure 2 Schematic diagram of the structure of the blank;

[0052] Figure 3 、 Figure 4 、 Figure 5 、 Figure 6 ,as well as Figure 7 It is a processing flow chart of the present invention;

[0053] Figure 8It is the front view of the positioning fixture;

[0054] Figure 9 for Figure 8 Left view of;

[0055] Figure 10 for Figure 8 Top view of .

[0056] The actual correspondence between the reference numerals and component names of the present invention is as follows:

[0057] a--Blank; b-extrusion head;

[0058] 11-left mold; 11a-main cavity; 12-right mold; 12a-oblique branch cavity; 13-head;

[0059] 21-fastening sleeve; 21a-U-shaped sleeve rod; 21b-tooling buckle; 21c-inner flange;

[0060] 21d-horizontal hinge axis; 22-positioning plate; 23-locking part; 23a-gantry buckle;

[0061] 23b - second hinge shaft; 23c - transmission link; 23d - extension plate; 23e - first hinge shaft; 23f - pad. DETAILED DESCRIPTION

[0062] For ease of understanding, here we combine Figure 1-10 The specific structure and working mode of the present invention are further described as follows:

[0063] For the sake of convenience in description, the "axial" mentioned below refers to the axial direction of the main cavity 11a, or the axial direction after the sleeve-shaped blank as the raw material is placed into the main cavity 11a; the "radial" refers to the direction perpendicular to the above-mentioned "axial", and focuses on the direction in which the left mold 11 and the right mold 12 move away from each other. This direction of moving away from each other is also the direction in which the oblique tee extrusion mold is most likely to be accidentally demolded.

[0064] The specific structure of the present invention is as follows Figure 1-10 As shown, its purpose is to Figure 2 The tube-shaped billet a shown in FIG is further heated and extruded to form a Figure 2 Inclined tee shown.

[0065] The present invention includes an oblique tee extrusion die as the structural body. Because the oblique tee extrusion die is formed by combining a left die 11 and a right die 12, an additional positioning fixture is required to securely lock it. Subsequently, pressure is applied by the extrusion head b of existing extrusion equipment to achieve the extrusion molding effect.

[0066] Specifically, the structure of the left mold 11 and the right mold 12 can refer to Figure 3-7 As shown, the mold body includes a left mold 11 and a right mold 12 that are surface-fitted to each other, an arc-shaped through groove is arranged on the outer wall of the left mold 11, and an arc-shaped matching groove is provided on the right mold 12, so that after the left mold 11 and the right mold 12 are surface-fitted, the arc-shaped through groove and the arc-shaped matching groove enclose the main cavity 11a; the oblique branch cavity 12a is recessed at the bottom of the arc-shaped matching groove.

[0067] From the above process, it can be seen that one of the key points of the present invention is how to smoothly and efficiently achieve the flow effect of blank a into the oblique branch cavity 12a. To this end, the present invention provides a plug 13, and the size of plug 13 is matched with the model of the oblique tee to be formed. At the same time, the selection of the appropriate blank a and heating method are also crucial.

[0068] in:

[0069] The plug 13 includes a vertical section and a conical tip located at the top of the vertical section, with the tip of the conical tip pointing in the direction of the top of the main cavity 11a. At this time, the size of the plug 13 satisfies the following formula:

[0070]

[0071] in:

[0072] H is the height of the vertical section of the mandrel 13;

[0073] B is the distance from the intersection of the axial main pipe axis and the oblique branch pipe axis of the oblique tee to be formed to the bottom end of the axial main pipe;

[0074] D1 is the designed outer diameter of the axial main pipe;

[0075] t1 is the design wall thickness of the axial main pipe;

[0076] D2 is the designed outer diameter of the oblique branch pipe;

[0077] T2 is the designed wall thickness of the oblique branch pipe;

[0078] D3 is the diameter of the plug 13;

[0079] b is the design gap between the outer wall of the vertical section and the wall of the main cavity;

[0080] β is the apex angle of the cone tip;

[0081] α is the angle between the axis of the axial main pipe and the axis of the oblique branch pipe.

[0082] At the same time, the tubular blank a is heated by medium frequency induction heating, and the heating zone satisfies the following formula:

[0083]

[0084] in:

[0085] h1 is the distance between the heating zone and the bottom end of the blank a;

[0086] h2 is the axial length of the heating zone;

[0087] C is the distance from the intersection of the axial main pipe axis and the oblique branch pipe axis of the oblique tee to the bottom end of the oblique branch pipe;

[0088] L is the length of the blank a;

[0089] A is the distance from the intersection of the axis of the axial main pipe and the axis of the oblique branch pipe to the top of the axial main pipe.

[0090] For the positioning fixture, its main structure refers to Figure 8-10 As shown, it includes a fastening sleeve 21, a positioning plate 22 is padded at the bottom of the fastening sleeve 21, and the two are connected to each other through a locking portion 23 to form a whole.

[0091] In actual design, the structure of the fastening sleeve 21 is referred to Figure 8-10 As shown, it includes several sets of locking units. Each set of locking units includes two U-shaped sleeve rods 21a that cross each other and are hinged by a horizontal hinge shaft 21d. When assembled, the notches of the U-shaped sleeve rods 21a are opposite, with the bottom of the groove located at the top and the end of the notch located at the bottom, so as to form a Figure 10 The space shown is for the inclined tee extrusion die to be placed in. A tool hook 21b is also provided at the horizontal hinge shaft 21d. The top end of the tool hook 21b is turned inward to form an inward flange 21c, so that it can be placed on the top surface of the inclined tee extrusion die from top to bottom, while the bottom surface of the entire inclined tee extrusion die rests on the positioning plate 22.

[0092] In order to ensure the reliable cooperation between the fastening sleeve 21 and the positioning plate 22, the present invention Figure 8-10 The locking portion 23 in the embodiment adopts a gantry structure. The gantry buckle 23a is shaped like a gantry frame, and its bottom is hinged to the positioning plate 22 via a second hinge shaft 23b. The U-shaped sleeve rods 21a constituting each locking unit are provided with a first hinge shaft 23e at the notch end located on the same side of the oblique tee extrusion die, and are hinged to the transmission link 23c via the first hinge shaft 23e. Figure 8 As shown, since the locking units arranged from top to bottom are connected on the same side by the same transmission link 23c, the synchronization of the locking units is ensured. Furthermore, once the transmission link 23c is locked, the entire fastening sleeve 21 is locked. To ensure the locked state, an extension plate 23d extends from the bottom end of the transmission link 23c. The gap between the extension plate 23d and the upright gantry buckle 23a is filled with several spacers 23f to achieve the axial downward positioning effect of the fastening sleeve 21.

[0093] Since the fastening sleeve 21 itself can reach the axial downward limit by relying on the inner flange 21c at the tooling hook 21b, at this time, the groove bottom of the U-shaped sleeve rod 21a of the fastening sleeve 21 is tightly attached to the outer wall of the oblique tee extrusion mold, ensuring the circumferential covering or radial protection effect of the oblique tee extrusion mold; and the cooperation between the extension plate 23d and the gantry buckle 23a further ensures the axial downward pulling function of the fastening sleeve 21, and cooperates with the positioning plate 22, thereby greatly ensuring the axial positioning effect of the oblique tee extrusion mold.

[0094] From the above, the steps of the extrusion molding method of the extrusion molding system of the present invention can be further obtained as follows:

[0095] S1. After the left die 11 and the right die 12 are combined to form an oblique tee extrusion die, the fastening sleeve 21 is put on the oblique tee extrusion die. At this time, the inner flange 21c of the tooling hook 21b is hooked on the top surface of the oblique tee extrusion die; then, the fastening sleeve 21 droops and stretches until the bottom of the groove of each U-shaped sleeve rod 21a is in close contact with the outer surface of the oblique tee extrusion die;

[0096] S2. Flip the gantry buckle 23a on the positioning plate 22 so that the gantry buckle 23a is in an upright position. At this time, the extension plate 23d at the conductive link 23c is directly below the crossbeam of the gantry buckle 23a. Fill the spacer 23f between the crossbeam of the gantry buckle 23a and the extension plate 23d until the fastening sleeve 21 is axially tightened and positioned.

[0097] S3, placing a plug 13 at the bottom end of the tube cavity of the blank a and filling it with solid powder, then heating the blank a with the solid powder and the plug 13 and placing it into the main cavity of the oblique tee extrusion die;

[0098] S4, the extrusion head b moves to the top of the main cavity 11a and coaxially presses the blank a downward. The extrusion head gradually extends into the main cavity 11a until it reaches the designed depth E, at which point E = LAB;

[0099] S5, remove the positioning fixture, disassemble the left mold 11 and the right mold 12, take out the oblique tee formed by extrusion, and complete the extrusion molding process.

[0100] So far, the technical advantages of the present invention are as follows:

[0101] 1) The wall thickness of the processing object is not limited, and it can be applied to the production of thin, medium and thick wall oblique tees.

[0102] 2) Suitable for mass production.

[0103] 3) Steel pipe is used as blank a, and the material utilization rate is high.

[0104] 4) It can be almost completely mechanized and has low labor intensity.

[0105] 5) One-time extrusion molding, use the mold to control the size of the oblique tee, good appearance, smooth surface, no need for plastic surgery.

[0106] 6) The overall wall thickness at the elbow or branch is relatively uniform and hardly thins.

[0107] 7) Adopt AB mold design, B mold is designed according to the oblique branch pipe, and A mold is designed according to the axial main pipe diameter; A mold is a universal mold, which reduces the mold manufacturing cost.

[0108] 8) One-shot extrusion and medium-frequency induction heating ensure precise product dimensional control, eliminate the need for additional shaping, and minimize energy consumption. The metal undergoes dynamic recovery and recrystallization during the hot extrusion process, resulting in high plasticity. Product dimensions are controlled by the die, ensuring a high yield rate.

[0109] 9) Considering factors such as materials, molds, energy consumption, labor intensity, and product qualification rate, the cost per piece is extremely low.

[0110] 10) During extrusion molding, no additional cylinder is required. Only a general-purpose four-column hydraulic press is needed to put into production, which has good mobility.

[0111] 11) During thermal deformation, the metal itself is only subjected to extrusion and compression, the metal micro-grains are refined, and the metal mechanical properties are enhanced, with significant results.

[0112] Of course, it will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, but also encompasses the same or similar structures that can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims, not the foregoing description, and it is intended that all variations that fall within the meaning and range of equivalents of the claims be encompassed within the present invention. Any reference signs in the claims should not be construed as limiting the claim to which they relate.

[0113] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

[0114] The technology, shape, and structure not described in detail in the present invention are all well-known technologies.

Claims

1. An oblique tee extrusion die, comprising a die body with a cavity, wherein the cavity is divided into a main cavity (11a) for forming an axial main pipe and an oblique branch cavity (12a) for forming an oblique branch pipe, characterized in that: The end of the main cavity (11a) into which the extrusion head can enter is the top of the main cavity (11a), and the oblique branch cavity (12a) is formed by starting from the branch opening and gradually extending obliquely toward the bottom of the main cavity (11a); a mandrel (13) is coaxially arranged at the bottom of the main cavity (11a), and the mandrel (13) includes a vertical section and a conical tip located at the top of the vertical section, and the tip of the conical tip points in the direction of the top of the main cavity (11a); the size of the mandrel (13) satisfies the following formula: in: H is the height of the vertical section of the mandrel (13); B is the distance from the intersection of the axial main pipe axis and the oblique branch pipe axis of the oblique tee to be formed to the bottom end of the axial main pipe; D1 is the designed outer diameter of the axial main pipe; t1 is the design wall thickness of the axial main pipe; D2 is the designed outer diameter of the oblique branch pipe; t2 is the designed wall thickness of the oblique branch pipe; D3 is the diameter of the plug (13); b is the design gap between the outer wall of the vertical section and the wall of the main cavity; β is the apex angle of the cone tip; α is the angle between the axis of the axial main pipe and the axis of the oblique branch pipe.

2. The oblique tee extrusion die according to claim 1, characterized in that: The mold body comprises a left mold (11) and a right mold (12) which are in contact with each other. An arcuate through groove is arranged on the outer wall of the left mold (11), and an arcuate matching groove is provided on the right mold (12), so that after the left mold (11) and the right mold (12) are in contact with each other, the arcuate through groove and the arcuate matching groove enclose the main cavity (11a); the oblique branch cavity (12a) is recessed at the bottom of the arcuate matching groove.

3. An extrusion molding system using the oblique tee extrusion die according to claim 2, characterized in that: The extrusion molding system includes a positioning fixture, which includes a fastening sleeve (21) that can be sleeved outside the oblique tee extrusion mold along the axial direction of the oblique tee extrusion mold, and the fastening sleeve (21) includes two U-shaped sleeve rods (21a) arranged crosswise with each other, and the notches of the two U-shaped sleeve rods (21a) are opposite to each other to enclose a space for the oblique tee extrusion mold to be placed, and the two groups of straight rod sections located on the same side of the oblique tee extrusion mold are hinged through the same horizontal hinge axis (21d); the positioning fixture also includes a tool hanging buckle (21b), the rod body of the tool hanging buckle (21b) is hinged on the horizontal hinge axis (21d), the rod of the tool hook (21b) extends upward along the axial direction of the inclined tee extrusion mold, and the extended section is provided with an inner flange (21c) so as to be hooked from top to bottom on the top surfaces of the left mold (11) and the right mold (12) constituting the inclined tee extrusion mold; the positioning fixture also includes a positioning plate (22) cushioned on the bottom surface of the inclined tee extrusion mold; the positioning plate (22) is provided with a locking portion (23) for locking the U-shaped sleeve rod (21a) when the inner flange (21c) is hooked on the top surface of the inclined tee extrusion mold and the bottom of the groove of the U-shaped sleeve rod (21a) is against the outer wall of the inclined tee extrusion mold.

4. The extrusion molding system of the oblique tee extrusion die according to claim 3, characterized in that: The locking portion (23) comprises a gantry-shaped gantry buckle (23a) fixed on the positioning plate (22); a horizontally extending extension plate (23d) is arranged at the notch end of the U-shaped sleeve rod (21a); the extension plate (23d) extends into the gantry buckle (23a); and a spacer (23f) is provided between the upper plate surface of the extension plate (23d) and the lower surface of the crossbeam of the gantry buckle (23a) to fill the gap between the two.

5. The extrusion molding system of the oblique tee extrusion die according to claim 4, characterized in that: The bottom of the gantry buckle (23a) is hinged on the positioning plate (22) through a second hinge shaft (23b), and the axis of the second hinge shaft (23b) is parallel to the axis of the horizontal hinge shaft (21d); the notch end of the U-shaped sleeve rod (21a) is hinged with a conductive connecting rod (23c) through a first hinge shaft (23e), and the rod body of the conductive connecting rod (23c) extends downward along the axial direction of the oblique three-way extrusion die and then extends horizontally out of the extension plate (23d).

6. The extrusion molding system of the oblique tee extrusion die according to claim 5, characterized in that: Two U-shaped sleeve rods (21a) arranged crosswise with each other form a group of locking units, and the locking units are evenly distributed in sequence along the axial direction of the oblique tee extrusion die; the notch ends of the U-shaped sleeve rods (21a) with the same notch direction are hinged to the same conductive connecting rod (23c) through a second hinge shaft (23b) located on the notch end.

7. The extrusion molding system of the oblique tee extrusion die according to claim 3, 4, 5 or 6, characterized in that: The contact position between the inner flange (21c) and the top surface of the oblique three-way extrusion die covers the matching gap formed by the left die (11) and the right die (12).

8. An extrusion molding method using the extrusion molding system according to claim 4, characterized in that: S1. After the left mold (11) and the right mold (12) are combined to form an oblique tee extrusion mold, the fastening sleeve (21) is put on the oblique tee extrusion mold. At this time, the inner flange (21c) of the tooling hook (21b) is hooked on the top surface of the oblique tee extrusion mold; then, the fastening sleeve (21) droops and stretches until the bottom of the groove of each U-shaped sleeve rod (21a) is in close contact with the outer surface of the oblique tee extrusion mold; S2. Flip the gantry buckle (23a) on the positioning plate (22) so that the gantry buckle (23a) is in an upright state. At this time, the extension plate (23d) at the conductive connecting rod (23c) is located directly below the crossbeam of the gantry buckle (23a); fill a spacer (23f) between the crossbeam of the gantry buckle (23a) and the extension plate (23d) until the fastening sleeve (21) is axially tightened and positioned; S3, placing a plug (13) at the bottom end of the tube cavity of the blank (a) and filling it with solid powder, then heating the blank (a) with the solid powder and the plug (13), and placing it into the main cavity (11a) of the oblique three-way extrusion die; S4, the extrusion head moves to the top of the main cavity (11a) and coaxially presses the blank (a) downward, and the extrusion head gradually extends into the main cavity (11a) until it reaches the designed depth E, where E = LAB; L is the length of the blank (a); A is the distance from the intersection of the axis of the axial main pipe and the axis of the oblique branch pipe to the top of the axial main pipe; S5, remove the positioning fixture, disassemble the left mold (11) and the right mold (12), take out the oblique tee that has been extruded, and complete the extrusion molding process.

9. The extrusion molding method of the extrusion molding system according to claim 8, characterized in that: The tubular blank (a) is heated by medium frequency induction heating, and the heating zone satisfies the following formula: in: h1 is the distance between the heating zone and the bottom end of the blank (a); h2 is the axial length of the heating zone; C is the distance from the intersection of the axial main pipe axis and the oblique branch pipe axis of the oblique tee to the bottom end of the oblique branch pipe; L is the length of the blank (a); A is the distance from the intersection of the axis of the axial main pipe and the axis of the oblique branch pipe to the top of the axial main pipe.

10. The extrusion molding method of the extrusion molding system according to claim 8, characterized in that: The cavity of the blank (a) is filled with solid powder; the vertical section of the mandrel (13) is concavely provided with an annular material groove.

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