CN102248102A - Method for integrally forming aluminum alloy equal-diameter three-way member - Google Patents

Abstract

The invention discloses a method for integrally forming an aluminum alloy equal-diameter tee piece, which adopts a tee mold to integrally form the aluminum alloy equal-diameter tee piece. The invention adopts multi-directional active loading forming technology, and the loading forming process is that the horizontal punch moves first, the side punch moves later, and the three punches move together to the final forming position. By moving the side punch in advance to suppress the violent flow of metal to the cavity of the branch pipe, the defects in the prior art are eliminated, the overall one-time forming of the aluminum alloy equal-diameter tee is realized, and the process flow is simplified. The invention actively controls the metal flow in the forming process by coordinating the loading sequence of molds in different directions, and avoids the defects of cavities and folding. The invention reduces welding and machining processes, avoids defects such as weld seam corrosion and cutting flow lines, improves the reliability of components, and improves the utilization rate of materials at the same time, and has the characteristics of simple operation, convenience, and easy implementation.

Description

A method for integrally forming an aluminum alloy equal-diameter tee

technical field

The invention belongs to the field of thermal processing and relates to thermal forming of aluminum alloys, in particular to a method for integrally forming aluminum alloy equal-diameter tees through three-way active loading.

Background technique

Tee fittings are a kind of important industrial parts, which are widely used in pipeline industry, petrochemical industry and other fields. In recent years, the development of these fields has put forward higher and more requirements for the performance of the tee, not only requiring the tee to meet greater pressure requirements, but also requiring its overall performance to be good. At present, there are three main production methods for such components: one is casting forming, and the existence of casting defects makes it difficult for cast valve bodies to meet high-performance requirements; the other is welding forming, although there are advantages such as saving materials for the manufacture of such components, Welding defects and stress corrosion of welds and other issues; the third is the mechanical processing of forgings (the process flow is: ingot casting-bar rolling-cutting-multiple plastic forming-machining), at present, the method It is the main processing method of this kind of components, but the material utilization rate is low, and it is difficult to process complex inner cavities. Subsequent machining cuts off the metal streamlines, exposing the streamlines of the components, reducing the mechanical properties and corrosion resistance of the components, and cannot meet the requirements. Application requirements.

Chinese patent application CN 1056830A discloses a method for manufacturing a three-way pipe by filling the tube blank with liquid and utilizing hydraulic bulging. , liquid filling, relative movement of both ends of the mold, liquid discharge, return of both ends of the mold, return of the main cylinder, and ejection of the ejector cylinder to complete the entire process. First of all, this method forms the tee pipe at room temperature, by filling the tube blank with liquid, and using the liquid pressure to cause the material to undergo plastic deformation. The deformation resistance of the material is relatively large, and because the pressure generated by the liquid is limited, the wall thickness of the formed tee pipe Limited, this method cannot realize the forming of some tube blanks with relatively large wall thickness (tube blank wall thickness/tube blank outer diameter); secondly, the branch pipe of the tee pipe formed by this method is due to the thinning of the main pipe wall thickness and the material generation Plastic deformation flows to the cavity of the branch pipe of the mold, and the plastic deformation ability of the material at room temperature and the thickness reduction of the main pipe are limited, which makes it difficult to control the uniformity of the wall thickness of the branch pipe of the formed tee pipe and the height is limited (tube blank The wall thickness is prone to excessive thinning and cracking). Chinese patent application CN 101596559A discloses a step-by-step die forging process for a three-way pipe. Specifically, the heated bar is placed in the forging die for forming the three-way pipe, and the main pipe of the three-way pipe is forged first, and then the main pipe of the three-way pipe is forged. Branch pipe, finally forming a tee pipe. When using this method to forge the main pipe of the tee pipe in the first step, the metal will gradually break away from the mold surface of the main pipe due to the violent flow of metal to the branch pipe cavity in the later stage of forming, forming a cavity; while in the second step of forging and forming the branch pipe , the billet is subjected to the action of the lateral die to appear a reverse extrusion deformation mode, and part of the material flows along the direction of the main pipe under the action of compressive stress, so that folding defects are prone to appear in the cavity; at the same time, when the main pipe is formed by forging in the first step, part of the material flows The material flows violently to the branch pipe cavity, which causes the mold for forming the main pipe to produce an eccentric load force perpendicular to the axis of the main pipe, reducing the life of the mold, and even breaks the mold when the eccentric load is severe, and reduces the main pipe of the formed tee pipe. coaxiality. Tsinghua University adopts the same process plan as the patent CN 101596559A to carry out finite element simulation analysis on the forming process (Hu Zhong, Wang Yiben et al. Two-dimensional elastoplastic finite element simulation of three-way extrusion process. Plastic Engineering Journal, 3( 2) (1996) 33-40), the study found that the process scheme is prone to quality problems such as cavities, folding, and horizontal punch bending.

Contents of the invention

In order to overcome the shortcomings of the above existing technologies that cannot meet the overall high performance requirements, low material utilization rate, and avoid defects such as cavities and folds, the present invention proposes a method for integrally forming aluminum alloy equal-diameter tees.

The present invention comprises the following steps:

Step 1, preheating the blank and the mold: heating the prepared blank to 430-470°C, and preheating the mold to 350-400°C.

Step 2, placing the blank: place the heated blank into the main cavity of the lower die, and make the centerline of the length direction of the blank coincide with the axis of the branch cavity of the lower die.

Step 3, placing the punch: place two horizontal punches in the main cavity of the lower die respectively, and on both sides of the blank, the end face of the working section of the horizontal punch is 1 mm from the end face of the billet; the side punch is placed on the bottom The distance between the end face of the working section of the side punch and the axis of the blank is the same as the height L of the branch pipe of the tee to be formed.

Step 4, die clamping: the upper die is clamped with the lower die driven by the main slider of the multi-directional forging hydraulic press.

Step 5, loading and forming: loading and forming by multi-directional die forging hydraulic press; in loading and forming, firstly, the horizontal punches are moved in opposite directions at the same speed at the same time, and the moving distance is (H-h+1) mm, where H is the forming tee The depth of the main pipe, h is the depth of the branch pipe of the forming tee and 0.5H≤h≤H; when the movement distance is (H-h+1) mm, the side punch starts to move. The three punches move at the same time, the moving distance is h, and the three-way active loading process is completed. The movement speed of the side punch is the same as that of the horizontal punch. The movement speed of the punch is (5-15) mm/s.

Step 6, demoulding: After the forming is completed, unload and withdraw the mold; the side punches are withdrawn first, and then the two horizontal punches are withdrawn at the same time; a tee piece is obtained.

Step 7, cooling and heat treatment: air-cool the formed tee to 15-25° C., and perform solid solution and aging heat treatment.

The invention adopts multi-directional active loading forming technology, and the loading forming process is that the horizontal punch moves first, the side punch moves later, and the three punches move together to the final forming position. By moving the side punch in advance to suppress the violent flow of metal to the branch pipe cavity, the defects in the prior art are eliminated, and the overall one-time forming of the aluminum alloy equal-diameter tee is realized, which simplifies the process flow; due to the reduction of welding and machine During the processing, defects such as weld seam corrosion and flow line cutting are avoided, the reliability of components is improved, and the utilization rate of materials is improved at the same time; by coordinating the loading sequence of molds in different directions, the metal flow during the forming process is actively controlled to avoid empty space. Cavities, folds and other defects.

Description of drawings

Fig. 1 is the structural representation of upper die;

Fig. 2 is the structural representation of lower die;

Fig. 3 is the schematic diagram that lower die cooperates with punch;

Fig. 4 is the structural representation of equal-diameter tee;

Fig. 5 is the integral forming flowchart of equal diameter tee;

Figure 6 is a schematic diagram of the tee forming process.

1. Upper die 2. Lower die 3. Main cavity 4. Branch cavity 5. Horizontal punch

6. Blank 7. Side punch 8. Branch pipe 9. Supervisor

Detailed ways

The embodiment proposed by the present invention is a method for integrally forming an aluminum alloy equal-diameter tee piece. Each embodiment adopts a three-way mold to implement integrally formed aluminum alloy equal-diameter three-way parts.

Described three-way die is made up of upper die 1, lower die 2, side punch 7 and horizontal punch 5. According to the symmetry of the structure of the tee, the die in the tee mold adopts the form of horizontal parting, which are the upper die 1 and the lower die 2 respectively. The cavities of the upper die 1 and the lower die 2 are all in the shape of a tee. In the cavity of the lower die 2 , the cavity for forming the main pipe 9 of the tee is the main cavity 3 , and the cavity for forming the branch pipe 8 of the tee is the branch cavity 4 . The diameter of the concave mold cavity is equal to the outer diameter of the formed tee. The punch consists of a side punch 7 and two horizontal punches 5 . Both the side punch 7 and the horizontal punch 5 are punches with flanges, that is, the punch is composed of a working section and a flange. During work, the horizontal punch 5 moves in the main pipe cavity of the die along the axis of the main pipe cavity to form the main pipe 9. The length of the working section of the horizontal punch 5 is equal to the depth of the main pipe 9, and the diameter of the working section is equal to the depth of the main pipe 9 The inner diameters are equal; the side punch 7 moves in the branch pipe cavity of the die along the axis direction of the branch pipe cavity to form the branch pipe 8, the length of the working section of the side punch 7 is equal to the depth of the branch pipe 8, and the diameter of the working section is the same equal inner diameter.

Embodiment one

In this embodiment, a tee mold is used to integrally form an aluminum alloy equal-diameter tee piece, and the formed tee piece includes a branch pipe 8 and a main pipe 9 . As shown in Figure 1, L is the height of the branch pipe, H is the depth of the main pipe, h is the depth of the branch pipe, and 0.5H<h<H, D1 is the inner diameter of the main pipe, and D2 is the outer diameter of the main pipe. The inner and outer diameters are correspondingly equal. In this embodiment, h=48mm, H=66mm, L=70mm, D1=32mm, D2=66mm.

In this embodiment, the above-mentioned tee piece is formed on a 40MN multi-directional die forging hydraulic press, and its specific steps are:

Step 1: Prepare the blank. The material used in this example is 7075 aluminum alloy extruded bar. First, the bar is turned to a diameter smaller than the outer diameter of the main pipe of the tee by 1mm, that is, φ65mm. Then, the blank is determined according to the principle of "constant volume" in the plastic forming process. The length of the bar is 140mm, and the bar is processed into a cylindrical billet of φ65mm×140mm, and the defects are partially ground; the billet is heated to 430°C-470°C at a speed of 2°C/s in a box-type resistance furnace and kept for 30min. Heat to 350-400°C and keep it warm for 1h.

Step 2: Place the blank. The heated blank 6 is placed in the main pipe cavity 3 of the lower die 2, and the centerline of the length direction of the blank 6 coincides with the axis of the branch cavity 4 of the lower die 2.

Step 3: Place the punch. Two horizontal punches 5 are respectively placed in the main cavity of the lower die 2 through a multi-directional die forging hydraulic press, and are located on both sides of the blank 6. The end face of the working section of the horizontal punch 5 is 1mm away from the end face of the blank 6; The mold 7 is placed in the branch pipe cavity of the lower die 2, and the distance between the end face of the working section of the side punch 7 and the axis of the blank 6 is the same as the height L of the branch pipe of the tee to be formed. In this embodiment , The distance between the end face of the working section of the punch 7 and the axis of the blank 6 is 70 mm.

Step 4: Clamp the die. The upper die 1 is mold-closed with the lower die 2 driven by the main slider of the multi-directional die forging hydraulic press. There is no offset in the positions of the horizontal punch 5 and the side punch 7 during the mold closing process.

Step 5: Loading and shaping. Loading and forming by a multi-directional die forging hydraulic press; in loading and forming, at first two horizontal punches 5 are moved in opposite directions at the same speed at the same time, and the movement distance is (H-h+1) mm. In this embodiment, two horizontal punches 5 The movement distance is 19mm; when the movement distance is 19mm, the side punch 7 starts to move; the three punches move simultaneously, and the movement distance is h, which is 48mm in this embodiment; the three-way active loading process is completed; the side punch 7 The speed of movement is the same as that of the horizontal punch 5, which is 5mm/s; the maximum forming force is about 1500KN.

Step 6: Demoulding. After forming, unload and withdraw from the mold; the side punch 7 is withdrawn first, and then the two horizontal punches 5 are simultaneously withdrawn; a tee piece is obtained.

Step 7: Cooling and heat treatment. Air-cool the formed tees to 15-25°C before heat treatment, the heat treatment system is solution treatment + aging, the solution treatment system is: 470°C×50min, water quenching; the aging system is: 120°C×24h+203°C ×10min+120℃×24h, air cooling.

Embodiment two

In this embodiment, a tee mold is used to integrally form an aluminum alloy equal-diameter tee piece, and the formed tee piece includes a branch pipe 8 and a main pipe 9 . As shown in Figure 1, L is the height of the branch pipe, H is the depth of the main pipe, h is the depth of the branch pipe, and 0.5H<h<H, D1 is the inner diameter of the main pipe, and D2 is the outer diameter of the main pipe. The inner and outer diameters are correspondingly equal. In this embodiment, h=70mm, H=96mm, L=103mm, D1=30mm, D2=60mm.

In this embodiment, the above-mentioned tee piece is formed on a 40MN multi-directional die forging hydraulic press, and its specific steps are:

Step 1: Prepare the blank. The material used in this example is 7075 aluminum alloy extruded bar. First, the bar is turned to a diameter smaller than the outer diameter of the main pipe of the tee (0.5-1) mm, that is, φ59mm. Then, according to the "volume constant" in the plastic forming process According to the principle, the length of the billet is determined to be 200mm, and the bar is processed into a cylindrical billet of φ59mm×200mm, and the defects are partially ground; Keep warm for 30min, preheat the mold to 350-400℃ and keep warm for 1h.

Step 2: Place the blank. The heated bar 5 is placed in the main cavity 3 of the lower die 2, and the center line of the length direction of the blank 6 coincides with the axis of the branch cavity 4 of the lower die 2.

Step 3: Place the punch. Two horizontal punches 5 are respectively placed in the main cavity of the lower die 2 through a multi-directional die forging hydraulic press, and are located on both sides of the blank 6. The end face of the working section of the horizontal punch 5 is 1mm away from the end face of the blank 6; The die 7 is placed in the branch pipe cavity of the lower die 2, and the distance between the end face of the working section of the side punch 7 and the axis of the blank 6 is the same as the height L of the branch pipe of the tee to be formed. In this embodiment, The distance between the end face of the working section of the side punch 7 and the axis of the blank 6 is 103mm.

Step 4: Clamp the die. The upper die 1 is mold-closed with the lower die 2 under the drive of the main slider of the multi-directional forging hydraulic press; the positions of the horizontal punch 5 and the side punch 7 are not shifted during the die-closing process.

Step 5: Loading and forming. Loading and forming by a multi-directional die forging hydraulic press; in loading and forming, at first two horizontal punches 5 are moved in opposite directions at the same speed at the same time, and the movement distance is (H-h+1) mm. In this embodiment, two horizontal punches 5 The movement distance is 27mm; when the movement distance is 27mm, the side punch 7 starts to move; the three punches move simultaneously, and the movement distance is h, which is 70mm in this embodiment; the three-way active loading process is completed; the side punch 7 The speed of movement is the same as that of the horizontal punch 5, which is 15mm/s; the maximum forming force is about 2500KN.

Step 6: Demoulding. After forming, unload and withdraw from the mold; the side punch 7 is withdrawn first, and then the two horizontal punches 5 are simultaneously withdrawn; a tee piece is obtained.

Step 7: Cooling and heat treatment. Air-cool the formed tees to 15-25°C before heat treatment, the heat treatment system is solution treatment + aging, the solution treatment system is: 470°C×50min, water quenching; the aging system is: 120°C×24h+203°C ×10min+120℃×24h, air cooling.

Embodiment three

In this embodiment, a tee mold is used to integrally form an aluminum alloy equal-diameter tee piece, and the formed tee piece includes a branch pipe 8 and a main pipe 9 . As shown in Figure 1, L is the height of the branch pipe, H is the depth of the main pipe, h is the depth of the branch pipe, and 0.5H<h<H, D1 is the inner diameter of the main pipe, and D2 is the outer diameter of the main pipe. The inner and outer diameters are correspondingly equal. In this embodiment, h=55mm, H=75mm, L=80mm, D1=35mm, D2=65mm.

In this embodiment, the above-mentioned tee piece is formed on a 40MN multi-directional die forging hydraulic press, and its specific steps are:

Step 1: Prepare the blank. The material used in this example is 7075 aluminum alloy extruded bar. First, the bar is turned to a diameter smaller than the outer diameter of the main pipe of the tee (0.5-1) mm, that is, φ64mm. Then, according to the "volume constant" in the plastic forming process According to the principle, the length of the billet is determined to be 160mm, and the bar is processed into a cylindrical billet of φ64mm×160mm, and the defects are partially ground; Keep warm for 30min, preheat the mold to 350-400℃ and keep warm for 1h.

Step 2: Place the blank. The heated bar 5 is placed in the main cavity 3 of the lower die 2, and the center line of the length direction of the blank 6 coincides with the axis of the branch cavity 4 of the lower die 2.

Step 3: Place the punch. Two horizontal punches 5 are respectively placed in the main cavity of the lower die 2 through a multi-directional die forging hydraulic press, and are located on both sides of the blank 6. The end face of the working section of the horizontal punch 5 is 1mm away from the end face of the blank 6; The die 7 is placed in the branch pipe cavity of the lower die 2, and the distance between the end face of the working section of the side punch 7 and the axis of the blank 6 is the same as the height L of the branch pipe of the tee to be formed. In this embodiment, The distance between the end face of the working section of the side punch 7 and the axis of the blank 6 is 80mm.

Step 4: Clamp the die. The upper die 1 is mold-closed with the lower die 2 under the drive of the main slider of the multi-directional forging hydraulic press; the positions of the horizontal punch 5 and the side punch 7 are not shifted during the die-closing process.

Step 5: Loading and shaping. Load forming by multi-directional die forging hydraulic press; in loading forming, at first make two horizontal punches 5 move towards the same speed at the same time, the movement distance is (H-h+1)mm, in the present embodiment, two horizontal punches 5 The moving distance is 21mm; when the moving distance is 21mm, the side punch 7 starts to move; the three punches move simultaneously, and the moving distance is h, which is 55mm in this embodiment; the three-way active loading process is completed; the side punch 7 The speed of movement is the same as that of the horizontal punch 5, which is 10mm/s; the maximum forming force is about 2000KN.

Step 6: Demoulding. After forming, unload and withdraw from the mold; the side punch 7 is withdrawn first, and then the two horizontal punches 5 are simultaneously withdrawn; a tee piece is obtained.

Step 7: Cooling and heat treatment. Air-cool the formed tees to 15-25°C before heat treatment, the heat treatment system is solution treatment + aging, the solution treatment system is: 470°C×50min, water quenching; the aging system is: 120°C×24h+203°C ×10min+120℃×24h, air cooling.

Claims (1)

1. the method for a monolithic molding aluminium alloy equal tee spare is characterized in that, may further comprise the steps:

Step 1, preheated charge and mould: with blank heating to 430～470 that prepare ℃, with mould and die preheating to 350 ℃～400 ℃;

Step 2 is placed blank: the blank that heats is placed in person in charge's die cavity of lower cavity die, and makes the dead in line of propping up tubular cavity of the center line and the lower cavity die of charge length direction;

Step 3 is placed punch: 2 horizontal punch are placed respectively in person in charge's die cavity of lower cavity die, and be positioned at the both sides of blank, the tip to face distance blank end face 1mm of horizontal punch active section; The side punch places in the tubular cavity of lower cavity die, and makes the distance between the axis of tip to face distance blank of side punch active section identical with the arm height L that intends the shaping three-way piece;

Step 4, the die matched moulds: upper cavity die under the drive of multi-ram forging hydraulic press master slider with the lower cavity die matched moulds;

Step 5, loading and shaping: by multi-ram forging hydraulic press loading and shaping; In the loading and shaping, at first make horizontal punch simultaneously in opposite directions with the speed motion, move distance is (H-h+1) mm, and wherein, H is the degree of depth that the shaping three-way piece is responsible for, and h is the degree of depth and the 0.5H≤h≤H of shaping three-way piece arm; When move distance is (H-h+1) mm, side punch setting in motion; Three punch move simultaneously, and move distance is h, finish initiatively loading procedure of three-dimensional; The movement velocity of side punch is identical with horizontal punch; The punch movement velocity is (5～15) mm/s;

Step 6, the demoulding: be shaped after the end, unload and move back mould; The side punch withdraws from earlier, 2 horizontal punch is withdrawed from simultaneously again; Obtain three-way piece;

Step 7, cooling and heat treatment:, and carry out solution treatment and timeliness heat treatment with three-way piece air cooling to 15～25 of formed thereby ℃.

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