Extrusion process of special-shaped aluminum alloy pipe fitting

Abstract

The invention discloses an extrusion process of a special-shaped aluminum alloy pipe fitting, which is used for extrusion forming of an aluminum alloy thin-wall pipe fitting, a middle boss is arranged in the middle of the outer wall of the pipe fitting, a bottom boss is formed by bottom flaring, and a blind hole is formed in the pipe fitting, and comprises the following steps: calculating the length of a blank according to the volume of an extruded part, cutting an aluminum alloy solid cylindrical blank for blanking, the diameter of the cylindrical solid blank is smaller than the outer diameter of the extrusion part main body; heating the aluminum alloy cylindrical material to a temperature required by an extrusion process; carrying out primary backward extrusion on a station of the opening and closing extrusion die to form a station extrusion piece; and carrying out secondary backward extrusion and forming on the extrusion of the first station on the second station of the opening and closing extrusion die. The method is suitable for producing and processing the aluminum alloy product with the pipe fitting with the boss in the middle, the pipe fitting can be conveniently processed, extruded and formed, materials are saved, and the problems that in the casting and machining process, due to the common casting strength performance, appearance processing is difficult, and the cost is high are solved.

Description

Technical Field

[0001] The invention relates to the technical field of aluminum alloy pipe fitting processing, in particular to an extrusion process for special-shaped aluminum alloy pipe fittings. Background Art

[0002] In pipe fitting processing, there is an aluminum alloy thin-walled pipe fitting with a circular boss 20 in the middle and a flared bottom. The commonly used molding processes are mainly casting and machining, but the strength performance of the casting is average, and the shape processing is difficult and costly. Figures 1 to 3 Taking the shape of the pipe fitting as an example, the pipe fitting body is cylindrical, with a large bottom diameter, a circular boss in the middle of the outer circle, and a square boss 30 at the bottom of the outer circle. The forging product has an internal blind hole 10 and a groove 40 at the bottom. It is not punched. After extrusion forming, the outer circle is not processed, but the inner hole, the middle of the outer side, the bottom boss, and the upper and lower end faces are processed. Summary of the invention

[0003] The purpose of the present invention is to overcome the shortcomings and defects of the prior art and to provide an extrusion process for special-shaped aluminum alloy pipe fittings, which is used to solve the production and processing of aluminum alloy products with boss pipe fittings in the middle.

[0004] An extrusion process for a special-shaped aluminum alloy pipe fitting is used for extrusion molding of an aluminum alloy thin-walled pipe fitting, wherein a middle boss is provided in the middle of the outer wall of the pipe fitting, the bottom is expanded to form a bottom boss, and the inside of the pipe fitting is a blind hole, comprising the following steps: The length of the billet is calculated according to the volume of the extruded part, and the solid cylindrical billet of the aluminum alloy is cut for blanking, and the diameter of the solid cylindrical billet is smaller than the outer diameter of the main body of the extruded part; Heat the aluminum alloy cylindrical material to the temperature required for the extrusion process; Perform a reverse extrusion at one station of the opening and closing extrusion die to form a station extrusion part; The extrusion at one station is subjected to secondary reverse extrusion at the second station of the opening and closing extrusion die to form the product.

[0005] In a reverse extrusion process, a blind hole is formed inside the aluminum alloy cylindrical material by extrusion, a groove is formed at the bottom, a middle boss is formed in the middle of the outer wall, and a prototype of the bottom boss is initially formed.

[0006] In one reverse extrusion process, the initially formed bottom boss prototype fills 60-80% of the space of the bottom boss cavity of the mold.

[0007] Among them, in the primary reverse extrusion process, the primary extrusion punch is extruded to below the primary extrusion position of the formed middle boss.

[0008] Among them, in the secondary reverse extrusion process, the position of the middle boss formed in the primary reverse extrusion process in the height direction is corrected by extrusion, and finally located at the final position of the middle circular boss, and the bottom boss formed in the primary reverse extrusion process is further extended to fill the bottom boss cavity of the mold.

[0009] Among them, in the secondary reverse extrusion process, the stroke of the secondary extrusion punch is calculated according to the height difference between the primary extrusion position and the final position of the middle circular boss multiplied by the cross-sectional area of ​​the aluminum alloy solid cylindrical billet.

[0010] The outer diameter of the first-station extrusion piece formed at the first station and the second-station extrusion piece formed at the second station are the same.

[0011] Among them, when there are multiple middle bosses with different height positions, they are extruded multiple times. The bosses at the top and in the same horizontal section are extruded first, and the height difference of the bosses before and after each extrusion deformation is calculated. At the same time, a gap is left on the extrusion die of the next process for the formed boss to avoid secondary damage.

[0012] Among them, the opening and closing extrusion mold includes a first-station punch, a second-station punch, an opening and closing die, and a first-station bottom push rod and a second-station bottom push rod. The upper ends of the first-station bottom push rod and the second-station bottom push rod are small-diameter closing structures and are higher than the bottom of the concave model cavity, so as to form a groove at the top of the pipe fitting; the opening and closing die is a left and right opening and closing structure, and a first-station cavity for forming a primary extruded part and a second-station cavity for forming a secondary extruded part are formed inside.

[0013] Wherein, the inner wall of the cavity of the die has a boss extrusion molding structure for molding the middle boss.

[0014] The extrusion process of the special-shaped aluminum alloy pipe fittings of the present invention is mainly suitable for the production and processing of aluminum alloy products with boss pipe fittings in the middle, which facilitates the processing and extrusion molding of such pipe fittings and saves materials, and solves the problem in the casting and machining processes that the strength performance of the castings is general, the shape processing is difficult and the cost is high. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 , Figure 2 as well as Figure 3 They are respectively the cross-sectional view, the front view and the side view schematic diagram of the special-shaped aluminum alloy pipe formed by the embodiment of the present invention.

[0016] Figure 4 It is a flow chart of the extrusion process of the special-shaped aluminum alloy pipe fitting according to the embodiment of the present invention.

[0017] Figure 5 It is a schematic diagram of the extrusion molding of the special-shaped aluminum alloy pipe fitting according to an embodiment of the present invention.

[0018] Figure 6 It is a schematic diagram of the extrusion forming stroke control of the special-shaped aluminum alloy pipe fitting according to an embodiment of the present invention.

[0019] Figure 7 Schematic diagram of opening the extrusion die according to an embodiment of the present invention.

[0020] Figure 8 Schematic diagram of the closed state of the extrusion die according to the embodiment of the present invention. DETAILED DESCRIPTION

[0021] The present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0022] The extrusion process of a special-shaped aluminum alloy pipe fitting according to the embodiment of the present invention mainly includes blanking, heating, primary extrusion and secondary extrusion, which is suitable for the production and processing of aluminum alloy products with a central boss pipe fitting, is convenient for the processing and extrusion molding of such pipe fittings, and saves materials. After the secondary extrusion, the inner hole, the outer central boss, the bottom boss and the upper and lower end faces of the secondary extruded part are processed to form a molded part, and the outer circle is not processed after extrusion molding.

[0023] See also Figure 4 As shown, an extrusion process of a special-shaped aluminum alloy pipe fitting according to an embodiment of the present invention is used for extrusion molding of an aluminum alloy thin-walled pipe fitting, wherein a middle boss is provided in the middle of the outer wall of the pipe fitting, the bottom is expanded to form a bottom boss, and the inside of the pipe fitting is a blind hole, comprising the following steps: S1. Calculate the length of the billet by the volume of the extrusion, cut the solid cylindrical billet of aluminum alloy 100 for cutting, the diameter of the solid cylindrical billet is smaller than the outer diameter of the extrusion body; S2. heating the aluminum alloy cylindrical material to the temperature required for the extrusion process; S3. Perform a reverse extrusion at one station of the opening and closing extrusion die to form an extruded member 110 at one station; S4. Perform secondary reverse extrusion on the first-station extrusion at the second station of the opening and closing extrusion die to form a second-station extrusion piece 120.

[0024] by Figure 6 For example, the outer diameter of the billet is smaller than the outer diameter of the extruded part, such as 0.5mm-1mm smaller. Further, the billet length is calculated according to the volume of the extruded part, and preferably 5-10% of the extrusion margin is increased. The heating temperature of the billet is determined according to the aluminum alloy model and properties, and the heating temperature is generally between 400-480℃.

[0025] A preferred embodiment is that, in the second reverse extrusion of the second station, a gap is left on the opening and closing mold at the position of the formed boss to avoid secondary extrusion deformation of the middle boss.

[0026] In a reverse extrusion process, a blind hole 111 is formed inside the aluminum alloy cylindrical material by extrusion, a groove 114 is formed at the bottom, a middle boss 112 is formed at the middle of the outer wall, and a bottom boss 113 is initially formed. In the reverse extrusion of a station, the punch of the station first reversely extrude the barrel wall downwards. When the bottom surface of the punch approaches the mold position corresponding to the middle boss 112 of the station, the material will automatically fill the mold forming position corresponding to the middle boss 112 of the station. The larger the volume of the protruding part, the earlier the filling starts, and the more obvious the sinking of the tube wall mouth at the corresponding position is. The smaller the volume of the protruding part, the later the filling starts, and the less obvious the sinking of the tube wall mouth at the corresponding position is. After that, the punch stops at a position several millimeters below the position of the middle boss 112 of the station after forming. If it continues to go down, the middle boss 112 of the station after forming will be cut off and separated from the barrel wall because it cannot participate in the deformation.

[0027] Preferably, in the one-time reverse extrusion process, the initially formed bottom boss prototype fills 60-80%, preferably 70%, of the space of the bottom boss cavity of the mold, but does not completely fill the mold. More preferably, in the one-time reverse extrusion process, the primary extrusion punch extrude to below the primary extrusion position of the formed middle boss.

[0028] In the one-time reverse extrusion process, the main part of the tube wall and the middle boss are reverse extruded. The punch is extruded to about 10mm below the one-time extrusion position of the middle boss, such as plus or minus 5mm, that is, 9.5mm-10.5mm. If the extrusion depth is too deep, the middle boss will be cut off as the tube wall rises and damage the mold.

[0029] Among them, in the secondary reverse extrusion process, the position of the middle boss formed in the first reverse extrusion process in the height direction is corrected by extrusion, and finally located at the final position of the middle circular boss, thereby obtaining the second-station boss 122, and the bottom boss formed in the first reverse extrusion process is further extended to fill the bottom boss cavity of the mold to form the second-station bottom boss 123. At the same time, a second-station blind hole 121 is formed on the basis of the first-station blind hole, and its length is larger than that of the first-station blind hole, and a second-station groove 124 is formed on the basis of the first-station groove, and the distance from the second-station blind hole 121 is reduced, and only a thinner part is separated in the middle.

[0030] In the embodiments of the present application, the main forming is in one extrusion, and the secondary extrusion amount is relatively small. It has three functions: one is to correct the position of the middle boss in the height direction, the second is to completely fill the bottom boss into the mold, and the third is to save raw materials.

[0031] See also Figure 6As shown, in the secondary reverse extrusion process, the stroke of the secondary extrusion punch, i.e., the second-station extrusion stroke H2, is calculated based on the height difference L-L1 between the first extrusion position and the final position of the central circular boss, multiplied by the cross-sectional area s (the annular shaded part in the figure) of the ØD of the aluminum alloy solid cylindrical billet 100, and the first-station extrusion stroke H1 is from the top of the billet to 10 below the central boss of the first station. + 5mm position, 10mm downward from the center of the middle boss + 5mm.

[0032] The outer diameter of the first-station extrusion piece formed at the first station and the second-station extrusion piece formed at the second station are the same.

[0033] Furthermore, when there are multiple middle bosses with different height positions, they are extruded multiple times. The bosses at the top and in the same horizontal section are extruded first, and the height difference of the bosses before and after each extrusion deformation is calculated. At the same time, a gap is left on the extrusion die of the next process for the formed boss to avoid secondary damage.

[0034] The process of the present invention is applicable to similarly shaped pipes with a central boss, wherein the second-station and first-station extruded parts formed can be designed with an anti-rotation process table, such as located at the bottom of the pipe, to ensure that the first-station extruded parts are accurately positioned at the second station.

[0035] The process of the present invention is applicable to similar pipe-like parts with a central boss, wherein the shape and position of the central boss are not limited, and the shape of the central boss can be a whole ring or a square partial protrusion, and can be one central boss or multiple central bosses.

[0036] If there are multiple intermediate bosses with large height differences, multiple extrusions are required. First, extrude the bosses at the top and in the same horizontal section, and calculate the height difference of the bosses before and after each deformation. Leave a gap for the formed bosses on the extrusion die of the next process to avoid secondary damage.

[0037] Correspondingly, the opening and closing mold can be divided into multiple parts and opened and closed in multiple directions to ensure demoulding. The number of opening and closing mold combinations and the opening and closing method are designed according to the specific shape of the product.

[0038] Among them, it should be noted that if the directions of multiple middle bosses are inconsistent, the middle boss will have dimensional deviation after secondary extrusion or multiple extrusions. The boss allowance should be increased according to the actual situation to ensure the processing volume.

[0039] In addition, when the relative position of the middle boss is calculated inaccurately during multiple extrusions, the port length and skin thickness can be appropriately increased or decreased to make up for the difference by increasing or decreasing the billet.

[0040] Since the product in this application is a special-shaped product with a large bottom diameter, in order to ensure that the boss does not affect the demoulding of the forging, the concave dies of the two stations are open and close dies. The die schematic diagram is shown in Figure 7 , 8 shown.

[0041] See also Figure 7 , Figure 8 The opening and closing extrusion die comprises a first-station punch 210, a second-station punch 230, an opening and closing die 200, a first-station bottom push rod 220, and a second-station bottom push rod 240. The upper ends of the first-station bottom push rod and the second-station bottom push rod are small-diameter closing structures and are higher than the bottom of the concave mold cavity to form a groove at the top of the pipe fitting; the opening and closing die is a left and right opening and closing structure, comprising a left half mold 201 and a right half mold 202, each of which has a corresponding mold cavity 203 formed therein, so that a first-station cavity for forming a primary extruded part and a second-station cavity for forming a secondary extruded part are formed inside the opening and closing die.

[0042] Wherein, the inner wall of the cavity of the die has a boss extrusion molding structure for molding the middle boss.

[0043] The processing workflow of the pipe fittings in this application is as follows: Heat the blank to the forging temperature, close the first and second station dies, spray lubricant evenly, put the blank into the first station die, and move the first station punch downward for one extrusion; after the extrusion is completed, the first station punch returns, the first and second station dies are opened, the extruded part is taken out and placed on the second station ejector, the first and second station dies are closed, the second station punch moves downward for a second extrusion. After the extrusion is completed, open the first and second station dies, take out the extruded part, and the extrusion is completed.

[0044] The extrusion process of the special-shaped aluminum alloy pipe fittings of the present invention is mainly suitable for the production and processing of aluminum alloy products with boss pipe fittings in the middle, which facilitates the processing and extrusion molding of such pipe fittings and saves materials, and solves the problem in the casting and machining processes that the strength performance of the castings is general, the shape processing is difficult and the cost is high.

[0045] The basic principles and main features of the present invention and the advantages of the present invention are shown and described above. It is obvious to those skilled in the art that the present invention is not limited to the details of the above exemplary embodiments, and the present invention can be implemented in other specific forms without departing from the spirit or basic features of the present 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 rather than the foregoing description, and it is therefore intended that all changes falling within the meaning and range of equivalent elements of the claims are included in the present invention.

[0046] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description 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 may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. The extrusion process of special-shaped aluminum alloy pipe fittings is characterized by: Used for extrusion molding of aluminum alloy thin-walled pipe fittings, the pipe fittings have a middle boss in the middle of the outer wall, the bottom is expanded to form a bottom boss and the inside of the pipe fittings is a blind hole, including the following steps: The length of the billet is calculated according to the volume of the extruded part, and the solid cylindrical billet of the aluminum alloy is cut for blanking, and the diameter of the solid cylindrical billet is smaller than the outer diameter of the main body of the extruded part; Heat the aluminum alloy cylindrical material to the temperature required for the extrusion process; Perform a reverse extrusion at one station of the opening and closing extrusion die to form a station extrusion part; The extrusion at one station is subjected to secondary reverse extrusion at the second station of the opening and closing extrusion die to form the product.

2. The extrusion process of special-shaped aluminum alloy pipe according to claim 1 is characterized in that: In a reverse extrusion process, a blind hole is formed inside the aluminum alloy cylindrical material by extrusion, a groove is formed at the bottom, a middle boss is formed in the middle of the outer wall, and a prototype of the bottom boss is initially formed.

3. The extrusion process of special-shaped aluminum alloy pipe according to claim 2 is characterized in that: In a reverse extrusion process, the initially formed bottom boss prototype fills 60-80% of the space of the bottom boss cavity of the mold.

4. The extrusion process of special-shaped aluminum alloy pipe according to claim 2 is characterized in that: In the primary reverse extrusion process, the primary extrusion punch is extruded to below the primary extrusion position of the formed middle boss.

5. The extrusion process of special-shaped aluminum alloy pipe according to claim 3 is characterized in that: In the secondary reverse extrusion process, the position of the middle boss formed in the primary reverse extrusion process in the height direction is corrected by extrusion, and finally located at the final position of the middle circular boss, and the bottom boss formed in the primary reverse extrusion process is further extended to fill the bottom boss cavity of the mold.

6. The extrusion process of special-shaped aluminum alloy pipe according to claim 1, characterized in that: In the secondary reverse extrusion process, the stroke of the secondary extrusion punch is calculated based on the height difference between the primary extrusion position and the final position of the central circular boss multiplied by the cross-sectional area of ​​the aluminum alloy solid cylindrical billet.

7. The extrusion process of special-shaped aluminum alloy pipe according to claim 1, characterized in that: The outer diameter of the first-station extrusion part formed at the first station is the same as the outer diameter of the second-station extrusion part formed at the second station.

8. The extrusion process of special-shaped aluminum alloy pipe according to claim 1, characterized in that: When there are multiple middle bosses with different height positions, they are extruded multiple times. The bosses at the top and in the same horizontal section are extruded first, and the height difference of the bosses before and after each extrusion deformation is calculated. At the same time, a gap is left on the extrusion die of the next process for the formed boss to avoid secondary damage.

9. The extrusion process of special-shaped aluminum alloy pipe according to claim 1, characterized in that: The opening and closing extrusion die comprises a first-station punch, a second-station punch, an opening and closing die, and a first-station bottom push rod and a second-station bottom push rod. The upper ends of the first-station bottom push rod and the second-station bottom push rod are small-diameter closing structures and are higher than the bottom of the concave model cavity, so as to form a groove at the top of the pipe fitting. The opening and closing die is a left and right opening and closing structure, and a first-station cavity for forming a primary extruded part and a second-station cavity for forming a secondary extruded part are formed inside.

10. The extrusion process of special-shaped aluminum alloy pipe according to claim 9, characterized in that: The inner wall of the cavity of the concave die is provided with a boss extrusion molding structure for molding the middle boss.

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