CN102228932A

CN102228932A - Forming method for improving stepped hollow reducing pipe wall thickness uniformity

Info

Publication number: CN102228932A
Application number: CN2011101025873A
Authority: CN
Inventors: 林俊峰; 李峰; 冯苏乐
Original assignee: Harbin Institute of Technology
Current assignee: Harbin Institute of Technology
Priority date: 2011-04-22
Filing date: 2011-04-22
Publication date: 2011-11-02
Anticipated expiration: 2031-04-22
Also published as: CN102228932B

Abstract

The invention discloses a forming method for improving stepped hollow reducing pipe wall thickness uniformity, and relates to a forming method of a stepped hollow reducing pipe. The method aims to solve the problem of cracking due to wall thickness reduction caused by high local deformation in the conventional stepped hollow reducing pipe forming method. The method comprises the following steps of: selecting a hollow pipe as an original blank; performing electromagnetic reducing formation on the hollow pipe, winding a coil at the middle part of the hollow pipe, performing connection to form a series circuit, and switching on a switch to electrify the coil, so that the coil generates a magnetic field force and the middle part of the hollow pipe generates reducing deformation; putting the reduced hollow pipe into a forming die, and simultaneously sealing two ports of the hollow pipe by adopting a left sealing punch head and a right sealing punch head; gradually applying internal pressure and performing internal high-pressure hydraulic formation; and relieving the internal pressure, removing the left sealing punch head and the right sealing punch head, and taking out the formed pipe. The method is used for forming the stepped hollow reducing pipe.

Description

Improve the manufacturing process of the hollow reducer pipe evenness of wall thickness of ladder

Technical field

The present invention relates to the manufacturing process of the hollow reducer pipe in a species stage.

Background technology

In fields such as Aeronautics and Astronautics and auto industrys, alleviating architecture quality is people's long-term aim to save operating energy, also is one of trend of modern advanced manufacturing technique development.Light in structure quantizes to have two main paties: the one, and the material approach adopts light materials such as aluminium alloy, magnesium alloy, titanium alloy and composite; The 2nd, structural approaches is main structure for bearing bending load, adopts hollow non-uniform member, can alleviate the strength and stiffness that quality can make full use of material again.A kind of loss of weight that internal high pressure forming develops under such background just, material-saving, energy-conservation have the novel advanced manufacturing technology of the hollow light body structure spare of wide application prospect.When lightweight metal materials such as aluminium alloy, magnesium alloy and high-strength steel were widely used, hollow non-uniform member became first-selected ideal structure form.

The hollow reducer pipe of ladder that a kind of special construction is arranged at industrial circle, its principal character is that the diameter of whole part interlude is the shortest, takes second place in two ends, the left and right sides, the position diameter maximum between centre and two ends, total is that left-right symmetry distributes, as shown in Figure 1.

The part forming method of former this structure generally is to choose the pipe fitting of locating (minimum diameter) same size with the centre position, is put in the shaping dies, and two ends pipe sealing then, middle high-pressure forming, as shown in Figure 2.But this method is for two positions of maximum swelling amount, can be because the local deformation amount be big, and cause wall thickness reduction and then ftracture.

Summary of the invention

The objective of the invention is provides a kind of manufacturing process that improves the hollow reducer pipe evenness of wall thickness of ladder in order to solve the existing hollow reducer pipe manufacturing process of ladder owing to the problem that the local deformation amount causes wall thickness reduction to ftracture greatly.

The present invention is achieved by following proposal: said method comprising the steps of: step 1, select hollow pipe fitting as original blank, the diameter of the hollow pipe fitting pipe fitting end diameter that equals to be shaped; Step 2, at first hollow pipe fitting is carried out the electromagnetism reducing formation, be wrapped with coil at the middle part of hollow pipe fitting, and be linked to be series circuit, close a switch then, with coil electricity, coil produces magnetic field force, make the middle part of hollow pipe fitting produce necking deformation, be 0.015 second-0.020 second conduction time; Step 3, the hollow pipe fitting centering behind the undergauge is put in the die cavity of shaping dies, the undergauge place that makes hollow pipe fitting between two protruding profiles, adopts left sealing punch and right sealing punch that two ports of hollow pipe fitting are implemented encapsulation process simultaneously in die cavity; Compress into capable inner high voltage fluid power in applying gradually then and be shaped, the interior pressure that applies is 20-100Mpa, and the time of pressing in applying is 30 seconds-120 seconds; After step 4, shaping finish, shed interior pressure, remove left sealing punch and right sealing punch, lift the patrix of mould, take out the shaping pipe fitting.

The present invention compared with prior art has following beneficial effect: the method that the present invention uses is to take pipe fitting with the end positions place diameter same size of the pipe fitting that is shaped as original blank, carry out electro-magnetic forming earlier, pipe to the place, centre carries out reducing formation, the pipe diameter at place is equal to or less than the minimum diameter of part middle part in the middle of making, and then is put into and carries out internal high pressure forming in the mould.The benefit of doing like this is that the swell increment at the maximum position of diameter of part is greatly lowered.

Description of drawings

The design of part schematic diagram that Fig. 1 the inventive method is shaped, wherein D2＞D1＞D3; Die profile when Fig. 2 is to use traditional inside high-pressure forming method formation of parts; Fig. 3 is the die profile when utilizing the inventive method to be shaped this type of part; Fig. 4 is the schematic diagram that original pipe is carried out the electromagnetism reducing formation.

The specific embodiment

The specific embodiment one: below in conjunction with Fig. 3 and the bright present embodiment of Fig. 4, the method for present embodiment may further comprise the steps: step 1, select hollow pipe fitting 3 as original blank, the diameter of the hollow pipe fitting 3 pipe fitting end diameter D2 that equals to be shaped; Step 2, at first hollow pipe fitting 3 is carried out the electromagnetism reducing formation, be wrapped with coil 5 at the middle part of hollow pipe fitting 3, and be linked to be series circuit, close a switch then, with coil 5 energisings, coil 5 produces magnetic field force, makes the middle part of hollow pipe fitting 3 produce necking deformation, and be 0.015 second-0.020 second conduction time;

Step

3,3 centerings of the hollow pipe fitting behind the undergauge are put in the die cavity of shaping dies 2, the undergauge place that makes hollow pipe fitting 3 between two protruding profiles, adopts two ports of left sealing

punch

1 and 4 pairs of hollow pipe fittings 3 of right sealing punch to implement encapsulation process simultaneously in die cavity; Compress into capable inner high voltage fluid power in applying gradually then and be shaped, the interior pressure that applies is 20-100Mpa, and the time of pressing in applying is 30 seconds-120 seconds; After step 4, shaping finish, shed interior pressure, remove left sealing punch 1 and right sealing punch 3, lift the patrix of mould 2, take out the shaping pipe fitting.

With accessory size shown in Figure 1 is example, and with the shaping dies profile of conventional hydroforming method as shown in Figure 3, the changes of section of its maximum distortion section is for to be formed into Φ 32mm by Φ 16mm, and swell increment is 100%.And the shaping dies profile of using manufacturing process of the present invention as shown in Figure 4, the changes of section of its maximum distortion section is for to be formed into Φ 32mm by Φ 20mm, swell increment is 60%, as seen its swell increment reduces to 60% by 100%, improved the inhomogeneities of distortion, lowered the reduction of wall thickness, made the Thickness Distribution of the part after the shaping more even, especially for the part of this structure of big section difference (the maximum and minimum diameter ratio of pipe fitting), the superiority of this method embodies more obviously.

The specific embodiment two: when the material of original blank was aluminium alloy, the interior pressure that applies was 20-30Mpa in the step 3 of present embodiment.Other step is identical with the specific embodiment one.

The specific embodiment three: when the material of original blank was high-strength steel, the interior pressure that applies was 80-100Mpa in the step 3 of present embodiment.Other step is identical with the specific embodiment one.

The specific embodiment four: the scope of necking deformation amount in the step 2 of present embodiment (ratio of shaping pipe fitting minimum diameter and original pipe diameter) is 0.5-1.Other step is identical with the specific embodiment one.

Claims

1. manufacturing process that improves the hollow reducer pipe evenness of wall thickness of ladder is characterized in that said method comprising the steps of: step 1, select hollow pipe fitting (3) as original blank, the diameter of hollow pipe fitting (3) the pipe fitting end diameter (D2) that equals to be shaped; Step 2, at first hollow pipe fitting (3) is carried out the electromagnetism reducing formation, be wrapped with coil (5) at the middle part of hollow pipe fitting (3), and be linked to be series circuit, close a switch then, coil (5) is switched on, coil (5) produces magnetic field force, makes the middle part of hollow pipe fitting (3) produce necking deformation, and be 0.015 second-0.020 second conduction time; Step 3, the hollow pipe fitting behind the undergauge (3) centering is put in the die cavity of shaping dies (2), the undergauge place that makes hollow pipe fitting (3) between two protruding profiles, adopts left sealing punch (1) and right sealing punch (4) that two ports of hollow pipe fitting (3) are implemented encapsulation process simultaneously in die cavity; Compress into capable inner high voltage fluid power in applying gradually then and be shaped, the interior pressure that applies is 20-100Mpa, and the time of pressing in applying is 30 seconds-120 seconds; After step 4, shaping finish, shed interior pressure, remove left sealing punch (1) and right sealing punch (3), lift the patrix of mould (2), take out the shaping pipe fitting.

2. according to the manufacturing process of the hollow reducer pipe evenness of wall thickness of the described raising ladder of claim 1, it is characterized in that the interior pressure that applies in the step 3 is 20-30Mpa.

3. according to the manufacturing process of claim 1 or the hollow reducer pipe evenness of wall thickness of 2 described raising ladders, it is characterized in that the interior pressure that applies in the step 3 is 80-100Mpa.

4. according to the manufacturing process of claim 1 or the hollow reducer pipe evenness of wall thickness of 2 described raising ladders, the scope that it is characterized in that necking deformation amount in the step 2 is 0.5-1.