CN113290198B - Method for preparing hollow integral structure by using pipe - Google Patents
Method for preparing hollow integral structure by using pipe Download PDFInfo
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- CN113290198B CN113290198B CN202110457209.0A CN202110457209A CN113290198B CN 113290198 B CN113290198 B CN 113290198B CN 202110457209 A CN202110457209 A CN 202110457209A CN 113290198 B CN113290198 B CN 113290198B
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21K—MAKING FORGED OR PRESSED METAL PRODUCTS, e.g. HORSE-SHOES, RIVETS, BOLTS OR WHEELS
- B21K1/00—Making machine elements
- B21K1/14—Making machine elements fittings
Abstract
The invention discloses a method for preparing a hollow integral structure by using a pipe, and relates to the field of metal structural member processing methods. The preparation method of the pipe superplastic forming diffusion connection hollow structure is simple in steps, high in machining efficiency, low in machining cost and high in structural strength of the machined hollow structure, and therefore the requirements of weight reduction, high strength, vibration reduction, energy absorption and the like are met. The preparation method comprises the following steps: s1, preparing a blank; s2, surface treatment; s3, opening an air channel; s4, sealing and welding; s5, checking air tightness; s6, closing the die, charging into the furnace, heating and performing gas expansion; and S7, cutting. The pipe arrangement structure of the scheme is relatively simple, easy to realize, capable of reducing the difficulty of the processing technology and good in overall structure strength and impact resistance.
Description
Technical Field
The invention relates to the field of metal structural part processing methods, in particular to a processing method for gas pressurization diffusion connection of a metal pipe and a panel made of the same material at high temperature.
Background
At present, in order to achieve the purposes of weight reduction, structural strength improvement, vibration reduction and energy absorption, a complex hollow multilayer structure is widely used in the fields of aviation, aerospace, automobiles and the like. In the field of aerospace, a complex hollow multilayer titanium plate structure generally adopts a process method of welding after stamping, and the process is complex and the forming quality is unstable. The superplastic forming/diffusion bonding technology combines forming and diffusion bonding processes together, can form large complex integral components at one time, has stable and reliable quality, can greatly reduce weight and improve the performance of the components.
The superplastic forming/diffusion bonding technology is applied to the bulging process of the multilayer hollow structure, and although the superplastic forming/diffusion bonding technology has various advantages, the technology has defects. For example, for superplastic forming/diffusion bonding of a four-layer hollow structure, an obvious incomplete diffusion welding air channel often appears at the joint of support plates, and obvious uneven wall thickness appears due to too large plastic deformation.
The prior art is specifically as follows:
the national patent office announces a Chinese patent invention named 'method for manufacturing hollow structure' on 2016, 5, 11, with application number '201310567183.0', wherein a method for manufacturing a multilayer hollow structure is proposed, firstly, multilayer plates are stacked together, a joint part and a non-joint part are arranged between the plates, the joint part between every two adjacent layers of plates is fixedly combined together, meanwhile, the multilayer plate structure is heated to a softening temperature, fluid is used for pressurizing between every two adjacent layers of plates, so that the multilayer plate structure is deformed, and the joint part of every two adjacent layers of plates is combined together, and the non-joint part forms a hollow structure with a cavity. The invention provides a general idea for forming a multilayer hollow structure, but a forming method and details are not specifically described, and specific forming methods such as how to determine a forming temperature, which fluid is used for pressurization, how to pressurize, and the advantages and disadvantages of pressurization of various fluids are not compared.
The State patent office announces a Ti product in 2018, 6 and 15 2 A preparation method of an AlNb/TA15 bimetal titanium alloy composite hollow structure, and a Chinese patent application with the application number of 201711296229.4, wherein a Ti is provided 2 The invention discloses a preparation method of an AlNb/TA15 bimetal titanium alloy composite hollow structure, which firstly carries out Ti-to-Ti ratio treatment by utilizing superplastic forming/diffusion bonding technology 2 The panel made of AlNb is subjected to gas bulging forming, the core plate is subjected to diffusion connection, and then the core plate is subjected to gas bulging forming, so that the whole process is simple. Although the four-layer plate structure formed by using the dissimilar materials has functional characteristics, Ti 2 The superplasticity of the AlNb is low, the rheological stress is high, when the material is subjected to a superplastic forming diffusion bonding process, the process window is narrow, the forming process is difficult to control, and the design freedom of the multilayer hollow structure core layer is also low due to the low elongation of the material.
The national patent office announced a name of 'A preparation of Ti' in 2016, 5, 11 2 The invention discloses a method for preparing an AlNb alloy lightweight three-layer hollow structure and a Chinese patent with application number of 201410531711.1, wherein the method comprises the following specific operation steps: firstly to Ti 2 Surface treatment is carried out on the AlNb core plate, the second step is to carry out hot bending treatment on the core plate, and the third step is to carry out secondary surface treatment on the core plate and surface treatment of upper and lower panelsAnd surface treatment, wherein the fourth step is to carry out heating diffusion connection on the face plate and the core plate. The invention solves the problem of Ti 2 The method solves the problem that materials such as AlNb which are high in strength and low in superplasticity are difficult to form by using a superplastic forming/diffusion bonding technology, provides a new idea for preparing a new multi-layer light hollow structure, but the forming process has high requirements on hot bending forming, and meanwhile, a cushion block must be added in the forming process to support a core plate after the hot bending forming, so that insufficient support under the pressure is prevented, and if the structure of an internal core plate is slightly complex, the processing of the cushion block can cause the process to become very complicated.
The patent office of China announces a Chinese invention patent application with the name of 'a preparation method of a titanium alloy thin-wall multilayer hollow structure' and the application number of '201510940511.6' on 23.6.2017, wherein the invention provides a manufacturing method of the titanium alloy thin-wall multilayer hollow structure, and the invention comprises the steps of firstly carrying out independent hot forming on a panel and a core plate, then assembling, and finally carrying out integral diffusion connection to obtain the hollow thin-wall part. The invention avoids the problem of accurate forming of the inner cavity of the multilayer hollow structure and the problem that the inner layer and the outer layer can not adopt different materials, but the method leads the quantity and the complexity of the hot-pressing mould to be increased along with the increase of the types and the complexity of the core plates.
In combination with the above circumstances, with the continuous development of the manufacturing industry and the demands of the fields of aerospace, automobiles and the like for light weight, high strength, vibration reduction, energy absorption and the like, a simpler and more efficient method is urgently needed to complete the manufacture of a complex multilayer hollow structure.
Disclosure of Invention
Aiming at the problems, the invention provides the method for preparing the hollow integral structure by using the pipe, which has the advantages of simple steps, high processing efficiency, low processing cost and higher structural strength of the processed hollow structure, thereby meeting the requirements of weight reduction, high strength, vibration reduction, energy absorption and the like.
The technical scheme of the invention is as follows: the hollow structure comprises at least one layer of tube array, the tube array comprises a plurality of tubes 2 which are parallel to each other and are sequentially and tightly arranged, panels are arranged on two sides of the tube array, the panels are plane panels 4 or hollow cylindrical thin-wall panels 9, and the plane panels 4 or the cylindrical thin-wall panels 9 are fixedly connected with the tubes 2 in the tube array; the hollow structure is prepared by the following method:
s1, preparing a blank;
s1.1, processing by a drawing or extrusion process to obtain a plurality of pipes 2;
obtaining a plane panel 4 by linear cutting or laser cutting, or obtaining a cylindrical thin-wall panel 9 by drawing, combining and extruding;
s1.2, obtaining a plurality of gas-closed end plugging blocks 3 by wire cutting or laser cutting, and then drilling the centers of half of the gas-closed end plugging blocks 3 to obtain a ventilation end plugging block 1 with a ventilation hole;
s2, surface treatment: preparing titanium alloy pickling solution to pickle all the pipes 2, the panels, the ventilation end plugging blocks 1 and the gas-closed end plugging blocks 3, and removing surface oxide films and impurities, wherein the pickling time is 15 minutes; after the pickling, rinsing the blank by absolute ethyl alcohol for 3 to 5 minutes, and then drying the blank;
s3, opening an air channel:
s3.1, installing a ventilation end plugging block 1 at the pipe orifice at one side of the pipe 2, temporarily fixing the pipe 2 and the ventilation end plugging block 1 through spot welding, and then forming a horizontal groove penetrating through an air small hole at one side of the ventilation end plugging block 1 by using linear cutting to obtain a temporary structural member I5;
s3.2, installing a gas-closed end plugging block 3 at the pipe orifice of one side of the pipe 2, which is far away from the gas-permeable end plugging block 1, and temporarily fixing the pipe 2 and the gas-closed end plugging block 3 through spot welding to obtain a temporary structural member II 6;
s4, sealing and welding:
s4.1, sequentially and tightly arranging the second temporary structural members 6, and sequentially butting horizontal grooves in the second temporary structural members 6; then, seal welding is carried out between the ventilating end plugging block 1 and the inner wall of the pipe 2, between the gas-closing end plugging block 3 and the inner wall of the pipe 2 and between the outer walls of the ports of the adjacent pipes 2 in the temporary structural member II 6;
s4.2, sealing and welding the notches of the plurality of sequentially butted horizontal grooves, so that air passages are formed on one sides of the plurality of temporary structural members II 6, and the air passages are communicated with the interiors of the plurality of pipes 2 through the plurality of small ventilation holes respectively;
s4.3, blocking one side of the air passage, and welding a vent pipe communicated with the air passage on the other side to form a temporary structural part III 7;
or the two sides of the air passage are blocked, an air inlet communicated with the air passage is reserved on the surface of the groove, and an air pipe communicated with the air passage is welded on the air inlet to form a fifth temporary structural member 10;
s5, checking airtightness: the third temporary structural part 7 or the fifth temporary structural part 10 is wholly immersed in water, air is filled into the air passage and the plurality of pipes through the vent pipe, and the air tightness of the third temporary structural part 7 or the fifth temporary structural part 10 is checked; after the air tightness detection is finished, carrying out acid washing and absolute ethyl alcohol cleaning on the temporary structural part III 7 or the temporary structural part V10, and then drying;
s6, die assembly, charging, temperature rise and gas expansion:
s6.1, according to the design requirement of the number of the tube array layers in the hollow structure, placing a panel and a temporary structural member III 7 or a temporary structural member V10 in a mold, then placing a panel, and carrying out mold closing; the vent pipe on the third temporary structural part 7 penetrates out of the middle die of the die, and the vent pipe on the fifth temporary structural part (10) penetrates out of the position, close to the edge, of the contact position of the upper die and the lower die;
s6.2, putting the die assembly into superplastic forming equipment, pressurizing the upper surface of the whole die through a press machine, and keeping the step S6 to be finished;
s6.3, heating the interior of the equipment through superplastic forming equipment and preserving heat for 60 min;
s6.4, inflating and pressurizing the interior of the third temporary structural part 7 or the fifth temporary structural part 10 through the vent pipe, and maintaining the pressure for 120 min;
s7, cutting: after the pressure maintaining is finished, cooling the workpiece and the die along with the equipment, taking the die out of the equipment after the die is cooled, opening the die, and taking the workpiece out; then, the ventilation end plugging blocks 1 and the gas-closed end plugging blocks 3 on the two sides of the workpiece are all cut off to obtain a hollow structure.
S6.2, loading 4-5MPa pressure on the upper surface of the whole die through a press machine; s6.3, heating the interior of the equipment to 900 ℃, and then preserving heat for 60 min; the maximum inlet pressure in step S6.4 is 3 MPa.
The hollow structure comprises a plurality of layers of tube arrays which are stacked up and down in sequence, and tubes in the tube arrays of the two adjacent layers are vertical to each other.
When the panel is a planar panel, the mold comprises an upper mold 101, a middle mold 102, a lower mold 103 and a guide post 104, wherein the upper mold 101, the middle mold 102 and the lower mold 103 are arranged in sequence from top to bottom, and the three are all sleeved with the guide post 104;
the middle mold 102 is provided with at least two cavities in the center for accommodating the hollow structure, the number of the middle molds is twice of the number of layers of the pipe array in the hollow structure, and grooves for accommodating vent pipes are respectively arranged on the end surfaces of the adjacent middle molds.
When the panel is a cylindrical thin-wall panel or a complex curved surface panel, the die comprises an upper die 105, a support column 106 and a lower die 107, wherein the upper die 105, the support column 106 and the lower die 107 are sequentially arranged from top to bottom, and the support column 106 is supported by circular notches at two sides of an upper wood and a lower wood;
a groove for accommodating the vent pipe is formed at the contact position of the upper die 105 and the lower die 107 close to the edge.
The invention has the beneficial effects that:
firstly, the pipes used by the method have different shapes and can be profiles such as round pipes, tubes, trapezoidal pipes and the like, so that when a hollow integral structure is formed by the method, the hollow integral structure can be selected according to specific conditions.
The pipe arrangement structure is regular and simple and is easy to realize, the straight-line structure is a structure with one layer of pipes arranged in parallel array and a staggered structure with two layers, each layer is arranged in parallel array of pipes, and a cross structure is arranged between the layers.
The panel of the invention has various forms, can be a flat panel, can also be a cylindrical thin-wall panel and other relatively complex curved-surface panels, and leads the hollow forming structure of the multilayer board to be more diversified.
The core plate is of a tubular structure before the structure is formed, so that the core plate superplastic forming process can be reduced, and only direct heating, pressurizing and diffusion are needed, so that the processing process difficulty can be reduced, and the problems of gas port defects between core plates, diffusion welding defects between core plates, incapability of fully expanding the core plates to form a rectangular section shape and the like caused by the existing multilayer plate forming process are solved.
The structure obtained by the invention has good structural strength and shock resistance effect, the I-shaped reinforcing ribs are arranged on the cross section of the in-line structure, the structural strength of the in-line structure is not greatly different from that of a four-layer plate, meanwhile, the wall thickness of the pipe can be adjusted, the shock resistance effect of the whole structure is better by increasing the wall thickness, the cross section of each layer of the staggered structure is the I-shaped reinforcing ribs, the cross sections among the layers are in a cross shape, and the strength and the shock resistance of the whole structure are better than those of the in-line structure.
The air passage is simple in design, the two ports of the pipe are plugged by the plugging blocks cut by the thick plate, the grooves and the holes are uniformly formed in the square block on one side of the pipe to serve as the air passage, the surfaces of the grooves are sealed by welding, and the air ports are reserved from one side of the grooves or the surfaces of the grooves.
The panel and the middle pipe structure are connected into a whole in a diffusion connection mode by heating and pressurizing the inside, the panel and the middle pipe structure are formed uniformly and have good forming quality, the panel and the pipe can achieve good die attaching effect by diffusing and expanding through air pressure, the shape and size change of the pipe caused by expansion and contraction of a die cavity in integral thermal forming is effectively solved, and the size precision of a final forming structure is ensured.
Drawings
FIG. 1 is a work flow diagram of the present invention;
FIG. 2 is a reference diagram of the structural state during processing according to an embodiment of the present invention;
FIG. 3 is a schematic diagram of a panel with a flat hollow structure when a core of the embodiment is only a layer of tube array;
FIG. 4 is a schematic diagram of a panel with a flat hollow structure when a core is two-layered tube array according to an embodiment of the present invention;
figure 5 is a top view of a post-clamp mold according to an embodiment of the present invention,
figure 6 is a cross-sectional view taken along line a-a of figure 5 according to one embodiment of the present invention,
FIG. 7 is a cross-sectional view taken along line B-B of FIG. 5 in accordance with an embodiment of the present invention;
FIG. 8 is a sectional view of the mold after the mold is closed with the panel being a flat hollow structure when the core is processed into a two-layer tube array according to one embodiment of the present invention;
FIG. 9 is a reference view of the structural state during the process of the second embodiment of the present invention;
FIG. 10 is a schematic view of the hollow structure of the panel with cylindrical thin-walled tube when the second core part is only one tube array according to the embodiment of the present invention;
FIG. 11 is a top view of the mold after closing of the second mold in accordance with an embodiment of the present invention;
FIG. 12 is a sectional view taken along line C-C of FIG. 11 in accordance with a second embodiment of the present invention.
In the figure, 1 is a ventilation end plugging block, 2 is a pipe, 3 is a gas-closing end plugging block, 4 is a panel, 5 is a temporary structural member I, 6 is a temporary structural member II, 7 is a temporary structural member III, and 8 is a temporary structural member IV; 9 is inner and outer cylindrical thin-wall panel; 10 is a temporary structural member five;
when the panel is a plane panel, 101 in the die is an upper die, 102 is a middle die, 103 is a lower die, and 104 is a guide post;
when the panel is a cylindrical thin-walled panel, the mold 105 is an upper mold, 106 is a support column, and 107 is a lower mold.
Detailed Description
In order to clearly explain the technical features of the present patent, the following detailed description is given in conjunction with the accompanying drawings.
The invention is shown in fig. 1-12, wherein the pipe, panel, block (including vent end block, gas end block) and so on are TA2 material, and the following detailed description is made with reference to the accompanying drawings, and the specific operation steps are as follows:
example one
In the first embodiment, as shown in fig. 1 to 8, the hollow structure comprises at least one layer of tube array, the tube array comprises a plurality of tubes 2 which are parallel to each other and are closely arranged in sequence, panels 4 with flat panels are arranged on the upper side and the lower side of the tube array, and the panels 4 are fixedly connected with the tubes 2 in the tube array; the pipe 2 structure is adopted before the structure is formed, so that the core plate superplastic forming process can be reduced, and only direct heating and pressurizing diffusion is required, so that the processing process difficulty can be reduced, and the problems of gas port defects among core plates, diffusion welding defects among core plates, incapability of fully expanding the core plates to form a rectangular section shape and the like caused by the existing multi-layer plate forming process are avoided.
When the panel is a flat plate, the hollow structure is prepared by the following method:
s1, preparing a blank;
s1.1, processing a plurality of TA2 pipes 2 through a drawing or extrusion process according to the design required size, wherein the pipes 2 can also be directly obtained through purchase, and a plurality of TA2 planar panels 4 can be obtained through linear cutting or laser cutting;
s1.2, cutting a 10mm thick plate by wire cutting or laser cutting to obtain a plurality of gas-closed end plugging blocks 3, and then drilling the centers of half of the gas-closed end plugging blocks 3 to obtain a ventilation end plugging block 1 with a ventilation small hole.
And surface treatment: preparing titanium alloy pickling solution to pickle all the pipes 2, the plane panel 4, the ventilation end plugging block 1 and the gas-closed end plugging block 3 to remove surface oxide films and impurities, wherein the titanium alloy pickling solution is prepared from 10 percent of HF and 65 percent of HNO 3 10% by volume of HF: 65% HNO 3 ：H 2 O =1:9:10, and the pickling time is 15 minutes; and after the acid washing is finished, rinsing the blank by using absolute ethyl alcohol for 3 to 5 minutes, and then drying the blank.
Opening an air passage:
s3.1, installing a ventilation end plugging block 1 at the pipe orifice at one side of the pipe 2, and temporarily fixing the pipe 2 and the ventilation end plugging block 1 through spot welding to keep the ventilation end plugging block 1 and the pipe 2 from relatively moving; then, a horizontal groove which penetrates through the air small hole is formed in one side of the ventilation end plugging block 1 through linear cutting, and a temporary structural member I5 is obtained;
s3.2, installing a gas-closed end plugging block 3 at the pipe orifice of one side of the pipe 2, which is far away from the gas-permeable end plugging block 1, and realizing temporary fixation between the pipe 2 and the gas-closed end plugging block 3 through spot welding so as to keep the gas-closed end plugging block 3 and the pipe 2 from moving relatively; and obtaining a second temporary structural part 6.
And sealing and welding:
s4.1, sequentially and tightly arranging the temporary structural members II 6, and sequentially butting the horizontal grooves in the temporary structural members II 6; then, seal welding is carried out between the ventilation end plugging block 1 and the inner wall of the pipe 2, between the gas closing end plugging block 3 and the inner wall of the pipe 2 and between the outer walls of the ports of the adjacent pipes 2 in the temporary structural member II 6;
s4.2, sealing and welding the notches of the plurality of sequentially butted horizontal grooves, so that air passages are formed on one sides of the plurality of temporary structural members II 6, and the air passages are communicated with the interiors of the plurality of pipes 2 through the plurality of small air holes respectively;
and S4.3, blocking one side of the air passage, and welding a vent pipe communicated with the air passage on the other side to form a temporary structural member III 7.
The air flue of present case designs simply, the square of cutting down with the thick plate plugs pipe both ends mouth, unified on the square on pipe one side out groove and hole as the air flue, seal the groove surface through the welding at last, reserve the blow vent from one side, whole air flue design is fairly simple, and be convenient for realize, and the solder that the thick square was left is more sufficient, compensate the not enough condition of wall thickness material, be favorable to realizing that whole structure is airtight after the sealing, make the core structure of this kind of a font and crisscross form can be better utilize gas to take shape.
Checking the air tightness: the temporary structural part III 7 is wholly immersed into water, and air is filled into the air passage and the plurality of pipes through the vent pipe, so that the air tightness of the temporary structural part III 7 is checked; ensuring no air leakage and air blowby; if no bubble exists in the water, the air tightness is good, the next step is carried out, if the bubble exists in the water, the position where the bubble flows out is welded again, and the air tightness is checked again; and after the air tightness is checked, performing acid washing and absolute ethyl alcohol cleaning on the temporary structural part III 7, and then drying.
Closing the die, charging into the furnace, raising the temperature and performing gas expansion:
s6.1, placing a panel and temporary structural members III with the same number of layers in a mould according to the design requirement of the number of layers of the tube array in the hollow structure, and finally placing a panel and then closing the mould; tubes in the adjacent third temporary structural members are vertical, and orifices of the upper vent pipes of all the third temporary structural members on one side far away from the air passage penetrate out of a middle die of the die;
as shown in fig. 2 and 3, when the core of the hollow structure is only a layer of tube array, the core is composed of a temporary structural member three to form a linear intermediate structure, and when the hollow structure is placed in a mold, the first panel, the temporary structural member three and the second panel are required to be sequentially placed from bottom to top;
as shown in fig. 2 and 4, when the core of the hollow structure is two layers of tube arrays, the core, i.e. the temporary structural member four 8, is composed of two vertically stacked and mutually perpendicular temporary structural members three, and a panel is arranged between the two temporary structural members three to form a staggered intermediate structure; when the panel is placed into a die, the first panel, the first temporary structural member III, the second temporary structural member III and the second panel are required to be sequentially placed from bottom to top;
when the core of hollow structure is n layers of pipe arrays, when putting into the mould, need to place in proper order from the bottom up with the order of first panel, first temporary structural component three, second temporary structural component three, third temporary structural component three … … nth temporary structural component three, second panel.
S6.2, putting the die assembly into superplastic forming equipment, pressurizing the upper surface of the whole die through a press machine, and keeping the step S6 to be finished;
s6.3, heating the interior of the equipment through superplastic forming equipment and preserving heat for 60 min;
and S6.4, inflating and pressurizing the interiors of all the third temporary structural parts 7 through the vent pipes, and maintaining the pressure for 120 min.
Like this, through to inside heating and pressurizing for connect through diffusion bonding's mode between panel and the middle tubular structure integrative, it is more even to form between panel and the pipe, and it is of high quality to take shape, and carry out diffusion and bulging through atmospheric pressure and can make panel and pipe reach fine die-attaching effect, solved effectively in the whole thermoforming because of the pipe fitting shape and the dimensional change that the mould die cavity expend with heat and contract with cold arouses, guarantee the dimensional accuracy of final shaping structure.
And cutting: after the pressure maintaining is finished, cooling the workpiece and the die along with the equipment, taking the die out of the equipment after the die is cooled, opening the die, and taking the workpiece out; then, the ventilation end plugging blocks 1 and the gas-closed end plugging blocks 3 on the two sides of the workpiece are all cut off to obtain a hollow structure, namely a hollow integral structure.
S6.2, loading 4-5MPa pressure on the upper surface of the whole die through a press machine;
s6.3, heating the interior of the equipment to 900 ℃, and then preserving heat for 60 min;
the air inlet process in step S6.4 is slow, too fast air inlet rate may cause deformation and rupture, and the maximum air inlet pressure is 3 Mpa.
The multilayer hollow structure comprises a plurality of layers of tube arrays stacked up and down in sequence, wherein tubes in the tube arrays in the two adjacent layers are perpendicular to each other, and the adjacent tube arrays are separated through a panel. As shown in fig. 4, when the multi-layer hollow structure includes two layers of tube arrays, i.e. the core is two layers of tube arrays, the support structure of the core after processing is i-shaped, and the upper and lower layers of i-shaped structures are perpendicular to each other.
Structurally, the method comprises the following steps:
the pipe arrangement structure of the scheme is relatively regular and simple and is easy to realize, the straight-line structure is a layer of parallel pipe array arrangement, the staggered structure is a two-layer structure, each layer of parallel pipe array arrangement is realized, and a cross structure is formed between layers.
The structure that the present case obtained has fine structural strength and impact resistance, and a line structure cross-section is the I-shaped strengthening rib, and is little with four-layer board structural strength, and the pipe wall thickness is adjustable simultaneously, increases the wall thickness and can make overall structure impact resistance better, and every layer of cross-section of crisscross shape structure is the I-shaped strengthening rib, and the cross-section is the cross form between the layer, and overall structure intensity is better with the line of shock resistance ratio.
The die comprises an upper die 101, a middle die 102, a lower die 103 and a guide post 104, wherein the upper die 101, the middle die 102 and the lower die 103 are arranged in sequence from top to bottom, and the upper die, the middle die 102 and the lower die 103 are all sleeved with the guide post 104;
the middle mold 102 is provided with at least two cavities in the center for accommodating the multilayer hollow structure, the number of the middle molds is twice of the number of the pipe arrays in the multilayer hollow structure, and grooves for accommodating the vent pipes are respectively arranged on the end surfaces of the adjacent middle molds. Therefore, a middle die can be placed along the guide post, a temporary structural part III is placed in the middle die, and the vent pipe is placed in the groove and then placed in the next middle die.
When the device is used, the workpiece can keep a better structural form in the heating and gas expansion processes through pressurization on the top surface of the upper die and structural stability of the middle die, so that efficient diffusion connection is carried out.
Example II
In the second embodiment, as shown in fig. 1 and 9-12, the tube array comprises a plurality of tubes 2 which are parallel to each other and are closely arranged in sequence, cylindrical thin-wall panels 9 with cylindrical thin-wall tubes are arranged on the inner side and the outer side of the tube array, and the cylindrical thin-wall panels 9 are fixedly connected with the tubes 2 in the tube array; the structure is a pipe structure before forming, so that the core plate superplastic forming process can be reduced, and the core plate superplastic forming process can be directly heated, pressurized and diffused, so that the processing process difficulty can be reduced, and the problems of gas port defects between core plates, diffusion welding defects between core plates, incapability of fully expanding the core plates to form a rectangular section shape and the like caused by the existing multilayer plate forming process are solved.
When the panel is a cylindrical thin-walled tube, the hollow structure is prepared by the following method:
s1, preparing a blank;
s1.1, processing a plurality of TA2 tubes 2 through drawing or extrusion process according to the design requirements, wherein the tubes 2 can be directly obtained through purchase, and a plurality of TA2 cylindrical thin-wall panels 9 can be obtained through extrusion or drawing;
s1.2, cutting a 10mm thick plate by wire cutting or laser cutting to obtain a plurality of gas-closed end plugging blocks 3, and then drilling the centers of half of the gas-closed end plugging blocks 3 to obtain a ventilation end plugging block 1 with a ventilation small hole.
And surface treatment: preparing titanium alloy pickling solution to pickle all the pipes 2, the cylindrical thin-wall panel 9, the ventilation end plugging block 1 and the gas-closing end plugging block 3 to remove surface oxide films and impurities, wherein the titanium alloy pickling solution is prepared from 10 percent of HF and 65 percent of HNO 3 10% by volume of HF: 65% HNO 3 ：H 2 O =1:9:10, and the pickling time is 15 minutes; and after the acid washing is finished, rinsing the blank by using absolute ethyl alcohol for 3 to 5 minutes, and then drying the blank.
Opening a gas passage:
s3.1, installing a ventilation end plugging block 1 at the pipe orifice at one side of the pipe 2, and temporarily fixing the pipe 2 and the ventilation end plugging block 1 through spot welding to keep the ventilation end plugging block 1 and the pipe 2 from moving relatively; then, a horizontal groove which penetrates through the air small hole is formed in one side of the ventilation end plugging block 1 through linear cutting, and a temporary structural member I5 is obtained;
s3.2, installing a gas-closed end plugging block 3 at the pipe orifice of one side of the pipe 2, which is far away from the gas-permeable end plugging block 1, and realizing temporary fixation between the pipe 2 and the gas-closed end plugging block 3 through spot welding so as to keep the gas-closed end plugging block 3 and the pipe 2 from moving relatively; and obtaining a second temporary structural part 6.
And sealing and welding:
s4.1, sealing and welding the ventilating end plugging block 1 and the inner wall of the pipe 2, the gas-closing end plugging block 3 and the inner wall of the pipe 2 and the outer wall of the port of the adjacent pipe 2 in the temporary structural member II 6;
s4.2, the temporary structural members II 6 are sequentially and tightly arranged, horizontal grooves in the temporary structural members II 6 are sequentially butted, the butted shape is circular, and the circular temporary structural members can be placed in gaps formed by the cylindrical thin-wall panels 9; sealing and welding the notches of the horizontal grooves which are sequentially butted, so that air passages are formed on one sides of the temporary structural members 6, and the air passages are communicated with the interiors of the pipes 2 through the small air holes respectively;
and S4.3, sealing and welding the surface of the air channel, reserving an air port on the surface of the sealing and welding to be communicated with the air channel, and discharging a welding air pipe from the air port to form a fifth temporary structural member 10.
The air flue design of present case is simple, stop up pipe both ends mouth with the square that the thick plate was cut off, unified on the shutoff piece on one side of pipe open groove and hole as the air flue, seal the groove surface through the welding at last, reserve the blow vent from the surface, whole air flue design is fairly simple, and convenient to realize, and the solder that thick shutoff piece left is more sufficient, remedy the not enough condition of wall thickness material, be favorable to realizing that whole structure is airtight after the sealing, make the gaseous shaping of utilization that this type of core structure can be better.
Checking the air tightness: immersing the whole temporary structural part five 10 into water, and inflating air into an air passage and a plurality of pipes through an air pipe to check the air tightness of the temporary structural part five 10; ensuring no air leakage and air blowby; if no bubble exists in the water, the air tightness is good, the next step is carried out, if the bubble exists in the water, the position where the bubble flows out is welded again, and the air tightness is checked again; and after the air tightness is checked, pickling and cleaning the temporary structural part five 10 by absolute ethyl alcohol, and then drying.
Closing the die, charging into the furnace, raising the temperature and performing gas expansion:
s6.1, according to the design requirement of a hollow structure, alternately placing the panels and the temporary structural members in the mold, and finally placing one panel and then closing the mold; wherein, the vent pipe on the temporary structural member five (10) is led out from the place close to the edge where the upper die and the lower die are contacted;
s6.2, putting the die assembly into superplastic forming equipment, pressurizing the upper surface of the whole die through a press machine, and keeping the step S6 to be finished;
s6.3, heating the interior of the equipment through superplastic forming equipment and preserving heat for 60 min;
and S6.4, inflating and pressurizing the interior of the temporary structural part five through the vent pipe, and maintaining the pressure for 120 min.
Like this, through to inside heating and pressurizing for connect through diffusion bonding's mode between the cylindrical thin wall panel of inside and outside and the middle tubular structure and be integrative, it is more even to form between panel and the pipe, and shaping quality is good, and carry out diffusion and bulging through atmospheric pressure and can make panel and pipe reach fine die-attaching effect, solved effectively in the whole thermoforming because of the pipe fitting shape and the dimensional change that mould cavity expend with heat and contract with cold arouses, guarantee the size precision of final shaping structure.
And cutting: after the pressure maintaining is finished, cooling the workpiece and the die along with the equipment, taking the die out of the equipment after the die is cooled, opening the die, and taking the workpiece out; then, the ventilation end plugging blocks 1 and the gas-closed end plugging blocks 3 on the two sides of the workpiece are all cut off to obtain a hollow structure, namely a hollow integral structure.
S6.2, loading pressure of 4-5MPa on the upper surface of the whole die through a press machine;
s6.3, heating the interior of the equipment to 900 ℃, and then preserving heat for 60 min;
in step S6.4, the air intake process is performed slowly, the deformation and rupture may be caused by the excessively fast air intake rate, and the maximum air intake pressure is 3 MPa.
The hollow structure comprises inner and outer cylindrical thin-walled panels, and the core is a layer of tubing, as shown in fig. 10. The whole structure is a curved surface-shaped four-layer plate structure, and the support structure of the core part is I-shaped after the whole structure is processed.
Structurally, the method comprises the following steps:
in the second embodiment, the arrangement structure of the pipes is relatively regular and simple, and is easy to realize, and the pipes in the first layer are annularly arranged in parallel in an array.
The structure that embodiment two obtained has fine structural strength and impact effect, and the I-shaped structure cross-section is the I-shaped strengthening rib, and is little with four-layer plate structural strength differences, and the pipe wall thickness is adjustable simultaneously, and it can make overall structure impact effect better to increase the wall thickness.
The die comprises an upper die 105, a support 106 and a lower die 107, wherein the upper die 105, the support 106 and the lower die 107 are sequentially arranged from top to bottom, the upper die and the lower die are connected through a guide pillar, and the support is supported through circular notches at two sides of an upper wood and a lower wood;
the strut 106 is supported by circular notches at two sides of the upper and lower wood and is mainly used for supporting an inner cylindrical thin-wall panel, and a groove for accommodating a vent pipe is formed at a position close to the edge of the contact part of the upper mold 105 and the lower mold 107.
When the device is used, the top surface of the upper die is pressurized, so that the workpiece can keep a better structural form in the heating and air inflation processes, and efficient diffusion connection is performed.
By combining the first embodiment and the second embodiment, the invention can solve the following problems: firstly, how to adopt a simpler arrangement form to realize a reinforcing rib structure similar to a four-layer plate and a six-layer plate so as to improve the strength of the whole structure; secondly, how to adopt a new, direct and simple gas path layout to carry out gas bulging forming, the gas path layout can ensure that the whole structure is airtight after sealing and welding, thereby better playing the advantages of gas bulging forming; and thirdly, how to realize the forming process of the structure by using a simplified process, and the problems of gas port defects between core plates, diffusion welding defects between core plates, incapability of fully expanding the core plates to form a rectangular section shape and the like generated by the existing multilayer plate forming process can be avoided as much as possible.
Aiming at the defects of superplastic forming/diffusion connection in the prior art, the invention selects hollow pipes which are firstly drawn or extruded to form, and then forms a corresponding hollow structure at one time by combining methods of array tiling, array interlacing and the like and a superplastic forming/diffusion connection technology, thereby better realizing the purposes of weight reduction, vibration reduction, energy absorption and structural strength improvement.
Because the invention uses the tube formed by drawing/extrusion to form the structure, the air passage layout design and sealing welding are particularly important, and once air leakage occurs, a larger structural defect problem can occur. Aiming at the problems, a thick plate is cut by electrospark wire cutting to seal a pipe orifice, a groove is formed in one side of the pipe, and finally argon arc welding is used for sealing the periphery of a gateway and the surface of the groove, so that the design of an air passage and sealing welding is completed. Through the technology, the ventilation in the pipe and the air leakage in the pipe can be realized, and the foundation is better made by utilizing the air pressure forming technology.
While the invention has been described in terms of its preferred embodiments, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention.
Claims (5)
1. A method for preparing a hollow integral structure by using a pipe is characterized in that the hollow structure comprises at least one layer of pipe array, the pipe array comprises a plurality of pipes (2) which are parallel to each other and are sequentially and tightly arranged, panels are arranged on two sides of the pipe array, the panels are plane panels (4) or hollow cylindrical thin-wall panels (9), and the plane panels (4) or the cylindrical thin-wall panels (9) are fixedly connected with the pipes (2) in the pipe array; the hollow structure is prepared by the following method:
s1, preparing a blank;
s1.1, processing by drawing or extrusion technology to obtain a plurality of pipes (2);
obtaining a plane panel (4) by wire cutting or laser cutting, or obtaining a cylindrical thin-wall panel (9) by drawing, combining and extruding;
s1.2, obtaining a plurality of gas-closed end plugging blocks (3) by wire cutting or laser cutting, and then drilling the centers of half of the gas-closed end plugging blocks (3) to obtain a gas-permeable end plugging block (1) with a small gas-permeable hole;
s2, surface treatment: preparing titanium alloy pickling solution to pickle all the pipes (2), the panels, the ventilation end plugging blocks (1) and the gas-closed end plugging blocks (3) to remove surface oxide films and impurities, wherein the pickling time is 15 minutes; rinsing with absolute ethyl alcohol for 3-5 minutes after the pickling is finished, and then drying the blank;
s3, opening an air channel:
s3.1, installing a ventilation end plugging block (1) at the pipe orifice at one side of the pipe (2), temporarily fixing the pipe (2) and the ventilation end plugging block (1) through spot welding, and then forming a horizontal groove penetrating through an air small hole at one side of the ventilation end plugging block (1) through linear cutting to obtain a temporary structural member I (5);
s3.2, installing a gas-closed end plugging block (3) at the pipe orifice of one side of the pipe (2) far away from the gas-permeable end plugging block (1), and temporarily fixing the pipe (2) and the gas-closed end plugging block (3) through spot welding to obtain a second temporary structural member (6);
s4, sealing and welding:
s4.1, sequentially and tightly arranging the second temporary structural members (6), and sequentially butting horizontal grooves in the second temporary structural members (6); then, seal welding is carried out between the ventilation end plugging block (1) and the inner wall of the pipe (2), between the gas closing end plugging block (3) and the inner wall of the pipe (2) and between the outer walls of the ports of the adjacent pipes (2) in the temporary structural member II (6);
s4.2, sealing and welding the notches of the plurality of sequentially butted horizontal grooves, so that air passages are formed on one sides of the plurality of temporary structural members II (6), and the air passages are communicated with the interiors of the plurality of pipes (2) through the plurality of small air holes respectively;
s4.3, blocking one side of the air passage, and welding a vent pipe communicated with the air passage on the other side to form a third temporary structural member (7);
or the two sides of the air passage are blocked, an air inlet communicated with the air passage is reserved on the surface of the groove, and an air pipe communicated with the air passage is welded on the air inlet to form a fifth temporary structural member (10);
s5, checking airtightness: immersing the temporary structural part three (7) or the temporary structural part five (10) into water, inflating air into the air passage and the plurality of pipes through the vent pipe, and checking the air tightness of the temporary structural part three (7) or the temporary structural part five (10); after the air tightness detection is finished, carrying out acid washing and absolute ethyl alcohol cleaning on the temporary structural part III (7) or the temporary structural part V (10), and then drying;
s6, die assembly, charging and temperature rise, and air inflation:
s6.1, placing a panel and a temporary structural part III (7) or a temporary structural part V (10) in the die according to the design requirement of the number of layers of the tube array in the hollow structure, then placing the panel, and carrying out die assembly; wherein, the vent pipe on the third temporary structural member (7) penetrates out from the middle die of the die, and the vent pipe on the fifth temporary structural member (10) penetrates out from the position close to the edge at the contact position of the upper die and the lower die;
when the core of the hollow structure is only one layer of tube array, the core comprises a temporary structural part III;
when the core part of the hollow structure is two layers of tube arrays, the core part is a temporary structural part four (8), and the temporary structural part four (8) comprises two temporary structural parts three;
when the core of the hollow structure is n layers of tube arrays, the core comprises n temporary structural members III;
s6.2, putting the die assembly into superplastic forming equipment, pressurizing the upper surface of the whole die through a press machine, and keeping until the step S6 is finished;
s6.3, heating the interior of the equipment through superplastic forming equipment and preserving heat for 60 min;
s6.4, inflating and pressurizing the interior of the temporary structural part III (7) or the temporary structural part V (10) through a vent pipe, and maintaining the pressure for 120 min;
s7, cutting: after the pressure maintaining is finished, cooling the workpiece and the die along with the equipment, taking the die out of the equipment after the die is cooled, opening the die, and taking the workpiece out; then, cutting off all the ventilation end plugging blocks (1) and the gas-closed end plugging blocks (3) on the two sides of the workpiece to obtain a hollow structure, namely a hollow integral structure.
2. The method for preparing hollow integral structure by using the pipe material as claimed in claim 1, wherein the pressure of 4-5MPa is applied to the upper surface of the whole die by the press in step S6.2; s6.3, heating the interior of the equipment to 900 ℃, and then preserving heat for 60 min; the maximum inlet pressure in step S6.4 is 3 MPa.
3. The method for preparing a hollow integral structure from the tubular product as claimed in claim 1, wherein the hollow structure comprises a plurality of layers of tube arrays stacked one above the other, and the tubes in two adjacent layers of the tube arrays are perpendicular to each other.
4. The method for preparing a hollow integral structure by using the pipe material as claimed in claim 1, wherein when the panel is a planar panel, the mold comprises an upper mold (101), a middle mold (102), a lower mold (103) and a guide pillar (104), the upper mold (101), the middle mold (102) and the lower mold (103) are arranged in sequence from top to bottom, and the three are all sleeved with the guide pillar (104);
the central cavity of the middle mold (102) is used for containing the hollow structure, the middle mold (102) is provided with at least two middle molds, the number of the middle molds is twice of the number of layers of the pipe array in the hollow structure, and grooves used for containing the vent pipes are respectively arranged on the end faces of the adjacent middle molds.
5. The method for preparing the hollow integral structure by using the pipe according to the claim 1, wherein when the panel is a cylindrical thin-wall panel or a complex curved panel, the mould comprises an upper mould (105), a support pillar (106) and a lower mould (107), the upper mould (105), the support pillar (106) and the lower mould (107) are arranged in sequence from top to bottom, and the support pillar (106) is supported by circular notches at two sides of an upper wood and a lower wood;
a groove for accommodating the vent pipe is formed in the position, close to the edge, of the contact position of the upper die (105) and the lower die (107).
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