CN109396209B

CN109396209B - Synchronous extrusion forming die for steel H-shaped connecting pieces with different wall thicknesses

Info

Publication number: CN109396209B
Application number: CN201811538537.8A
Authority: CN
Inventors: 张治民; 闫林; 徐健; 薛勇; 李国俊; 于建民
Original assignee: North University of China
Current assignee: North University of China
Priority date: 2018-12-03
Filing date: 2018-12-03
Publication date: 2020-05-26
Anticipated expiration: 2038-12-03
Also published as: CN109396209A

Abstract

The invention discloses a synchronous extrusion forming die for steel H-shaped connecting pieces with different wall thicknesses, which comprises an upper die component, a lower die component and a guiding and ejecting device component, wherein the upper die component is fixed on a base; the upper die assembly comprises an upper die plate, an insert, an upper die base, a male die, an upper die sleeve plate, a helicoid and a withdrawing ring; the lower die assembly comprises a lower die plate, a lower die base plate, a lower die supporting plate, a bottom core, a pressing sleeve, a shrinking sleeve and a female die, an inner flange is formed inside the female die, the female die is sleeved above the bottom core, and the bottom core and the male die form a transition fillet and an inclination; the guiding and ejecting device component comprises a guide pillar, a guide sleeve, an ejector rod, a bottom plate, a pull rod, a sleeve and a connection. The invention adopts a warm extrusion synchronous forming method to realize the precise plastic forming of the H-shaped connecting piece with different wall thicknesses, aims to effectively overcome the problems brought by the traditional processing and manufacturing method, improves the formability of the alloy, improves the comprehensive mechanical property of a formed piece, greatly improves the material utilization rate and the production efficiency, saves energy and reduces emission.

Description

Synchronous extrusion forming die for steel H-shaped connecting pieces with different wall thicknesses

Technical Field

The invention belongs to the technical field of plastic processing and forming of metal materials, and particularly relates to a synchronous extrusion forming die for steel H-shaped connecting pieces with different wall thicknesses.

Background

With the rapid development of aerospace technology, high and new technology weaponry and ocean development in China, H-shaped connecting pieces with different wall thicknesses (the upper and lower inner parts of a workpiece are hollow, a partition wall is arranged in the middle, and the wall thicknesses of the upper wall and the lower wall are different) are more and more widely applied to various fields of military and civilian. For example, the joint of the missile warhead, the aircraft, the automobile and other parts of the weapon equipment and the joints of various pipes with different diameters can be seen everywhere in daily life. The "H" shaped parts may have varying degrees of steps and re-entrant corners within the part and may be thin walled, as is conventionally done by welding, casting or most commonly machining the part between two "U" shaped pieces. Welding seams of the welding parts are cracked, shrunk and fall off to different degrees, and the welding performance of a plurality of materials is poor; the casting also has the defects of incompact casting structure, shrinkage cavity, air bubble, uneven grain size and the like; the simple machining has low production efficiency, serious raw material waste, time consumption and labor consumption. These methods have disadvantages and difficulties in meeting the service requirements of the part.

The forming difficulty of the parts is that the upper wall and the lower wall are formed at different thicknesses, the instability of the cup wall in the axial direction is prevented, and the uniformity of the finally formed wall thickness and the fact that the lower wall is thin are easy to take out and keep intact without fracture are ensured.

Disclosure of Invention

Aiming at the current situation of the prior processing technology, the invention provides a synchronous extrusion forming die for steel H-shaped connecting pieces with different wall thicknesses, which adopts a warm extrusion synchronous forming method to realize the precise plastic forming of the H-shaped connecting pieces with different wall thicknesses, and aims to effectively overcome the problems brought by the traditional processing and manufacturing method, improve the formability of alloy, improve the comprehensive mechanical property of a formed piece, greatly improve the material utilization rate and the production efficiency, save energy and reduce emission.

In order to achieve the purpose, the technical scheme of the invention is as follows:

a steel H-shaped connecting piece synchronous extrusion forming die with different wall thicknesses comprises an upper die assembly connected with the upper part of a press machine, a lower die assembly connected with the lower part of the press machine and a guiding and ejecting device assembly;

the upper die assembly comprises an upper die plate connected with an upper workbench of the press machine, an insert and an upper die base connected with the upper die plate, a male die and an upper die sleeve plate connected with the insert, and a screw ring and a withdrawing ring connected with the upper die base; the insert is arranged in the upper die base, the coil ring is sleeved below the upper die base, the male die penetrates through the upper die base and the coil ring, the upper die sleeve plate is arranged between the upper die base and the male die, and the withdrawing ring is arranged between the coil ring and the male die;

the lower die assembly comprises a lower die plate, a lower die base plate, a lower die supporting plate, a bottom core, a pressing sleeve, a shrinking sleeve and a female die, wherein the lower die plate, the lower die base plate, the lower die supporting plate, the bottom core, the pressing sleeve, the shrinking sleeve and the female die are connected with a lower workbench of the press; the lower die plate, the lower die base plate and the lower die supporting plate are fixed together from bottom to top, and a core groove is formed in the middle of the lower die supporting plate for placing a bottom core; an inner flange is formed inside the female die, the female die is sleeved above the bottom core, the bottom core forms a transition fillet and an inclination, the male die forms an inclination, the tightening sleeve is clamped outside the female die, and the pressing sleeve is clamped outside the tightening sleeve and fixed on the lower die supporting plate;

the guiding and ejecting device component comprises a guide pillar, a guide sleeve, an ejector rod, a bottom plate, a pull rod, a sleeve and a connecting rod; the guide post is arranged on the upper template, the guide sleeve is arranged on the lower template, the guide post is matched and connected with the guide sleeve, the lower template and the lower die base plate are provided with sliding grooves communicated with the core groove for the insertion of the ejector rod, the ejector rod is connected with the bottom core, the bottom plate is positioned below the ejector rod and connected with the pull rod, the sleeve is positioned between the pull rod and the connecting rod, the required distance can be adjusted at will, and the upper end of the connecting rod is connected with the upper template.

Preferably, the upper die plate is assembled on an upper working table of the press machine by fastening bolts; the upper die base and the upper die plate are circumferentially positioned through the upper die cylindrical pin and then assembled together through the upper die inner hexagonal cylindrical head screw.

Preferably, the lower template is assembled on a lower worktable of the press by fastening bolts; the lower template and the female die are fixed together through an inner hexagonal cylindrical head screw; after the lower die plate, the lower die base plate and the lower die supporting plate are circumferentially positioned through the lower die cylindrical pin, the lower die plate and the lower die base plate are assembled together through the lower die inner hexagonal socket head cap screw, and the lower die base plate and the lower die supporting plate are assembled together through the lower die inner hexagonal socket head cap screw.

Preferably, the inclination of the bottom core is 10 °.

Preferably, the inclination of the punches is 12 °.

After the scheme is adopted, the invention has the beneficial effects that:

1. the male die, the female die and the bottom core jointly form a forming inner cavity of the H-shaped connecting piece, the stress condition of the H-shaped piece in the extrusion deformation process is changed by controlling process parameters (the gradient of each part of the forming inner cavity and a transition zone fillet), the smooth realization of the upper wall and the lower wall growth and the final forming stage in the forming stage is ensured, the metal stress state, the equivalent strain, the plastic deformation, the tissue uniformity and the like are better controlled, the forming is ensured to be carried out smoothly, and the final size and performance requirements of the H-shaped connecting piece are met;

2. the stripper ring cooperates with the guide and ejector assembly. The part withdrawing ring has a positioning and guiding function, can play a role of positioning a male die and ensure good forming of a lower wall difficult-to-form area in a final forming stage in the downward movement process of the press, and can be matched with a reverse pull rod structure to realize smooth demoulding of workpieces from top to bottom in the part withdrawing stage; the reverse pull rod type linkage ejection structure can be matched with any press machine for use, has no requirement on an ejection cylinder of the press machine, greatly increases the applicability of an extrusion die, and reduces the production cost;

3. the warm extrusion forming technology is adopted, so that the extrusion force is greatly reduced compared with cold extrusion, and the comprehensive mechanical property of the material is ensured to be optimal while the near-net forming is ensured;

4. the die has the advantages that the detachable female die, the shrink sleeve, the pressing sleeve and the bottom core structure are designed, parts of other sizes can be extruded only by replacing the male die, the female die, the bottom core and other structures, and the utilization rate of the die is improved.

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail below with reference to the accompanying drawings.

Drawings

FIG. 1 is a sectional view showing the overall structure of a die without a blank material being inserted in the embodiment of the present invention;

FIG. 2 is a cross-sectional view of a guide and ejector assembly in an embodiment provided by the present invention;

FIG. 3 is a cross-sectional view of the working state of the die when a billet is placed before extrusion in the embodiment provided by the invention;

FIG. 4 is a sectional view of the working state of the die when the blank is to be extruded according to the embodiment of the invention;

FIG. 5 is a cross-sectional view of the blank in the "H" blank forming deformation stage in the working state of the die in the embodiment provided by the invention;

FIG. 6 is a sectional view of the working state of the die at the stage of the growth of the upper and lower walls of the blank in the embodiment of the invention;

FIG. 7 is a sectional view of the die operating state of the blank in the extrusion final forming stage according to the embodiment of the present invention;

FIG. 8 is a schematic view of the male mold structure in an embodiment provided by the present invention;

FIG. 9 is a cross-sectional view of a female mold structure in an embodiment provided by the present invention;

FIG. 10 is a schematic view of a bottom core structure in an embodiment provided by the present invention;

FIG. 11 is a cross-sectional view of an exemplary stripper ring structure provided in accordance with the present invention;

FIG. 12 is a schematic illustration of a billet prior to extrusion in an embodiment provided by the present invention;

FIG. 13 is a schematic view of an extruded "H" shaped connector according to an embodiment of the present invention.

Description of reference numerals:

1, a lower template; 2-hexagonal socket cap screw in the lower die; 3, a lower die cylindrical pin; 4, a lower die base plate; 5, a top rod; 6, a guide pillar; 7-hexagonal socket head cap screw in the lower die; 8-bottom core; 9-lower die supporting plate; 10, pressing a sleeve; 11-a shrink sleeve; 12-a female die; 13-male die; 14-backing ring; 15-a helicoid; 16, a guide sleeve; 17-upper die base; 18, upper template; 19-an upper die cylindrical pin; 20-an insert; 21-upper die sleeve plate; 22-an upper die hexagon socket head cap screw; 23-a spring washer; 24-hexagonal nut; 25-a base plate; 26-a pull rod; 27-a sleeve; 28-a nut; 29-connecting rod; 30-hexagonal nut; 31-inner flange; 32-transition fillets.

Detailed Description

The invention discloses a synchronous extrusion forming die for steel H-shaped connecting pieces with different wall thicknesses, and the synchronous extrusion forming die comprises an upper die assembly connected with the upper part of a press, a lower die assembly connected with the lower part of the press and a guiding and ejecting device assembly, and is shown in figures 1-13.

As shown in fig. 1, the upper mold assembly includes: an upper die plate 18 connected to an upper table of the press, an insert 20 and an upper die base 17 connected to the upper die plate 18, a punch 13 and an upper die sleeve plate 21 connected to the insert 20, and a coil 15 and a stripper ring 14 connected to the upper die base 17. The insert 20 is arranged in the upper die base 17, the screw ring 15 is sleeved below the upper die base 17, the male die 13 penetrates through the upper die base 17 and the screw ring 15, the upper die sleeve plate 21 is arranged between the upper die base 17 and the male die 13, and the withdrawing ring 14 is arranged between the screw ring 15 and the male die 13. More specifically, the punch 13, the upper die sleeve plate 21 and the insert 20 are assembled together by clearance fit, and the stripper ring 14 is inserted into the threaded ring 15 and passes through the punch 13 to be connected with the upper die base 17 by fastening threads. The upper die base 17 and the upper die plate 18 are circumferentially positioned by an upper die cylindrical pin 19 and then assembled together by an upper die hexagon socket head cap screw 22 with a spring washer 23. The upper die plate 18 is mounted on the upper table of the press by means of fastening bolts (not shown in the figures).

As shown in figure 1, the lower die assembly comprises a lower die plate 1, a lower die cushion plate 4, a lower die supporting plate 9, a bottom core 8, a pressing sleeve 10, a tightening sleeve 11 and a female die 12, wherein the lower die plate 1, the lower die cushion plate 4 and the lower die supporting plate 9 are arranged from bottom to top and are connected with a lower working table of a press, after the lower die plate 1, the lower die cushion plate 4 and the lower die supporting plate 9 are circumferentially positioned through a lower die cylindrical pin 3, the lower die plate 1 and the lower die cushion plate 4 are assembled together through a lower die hexagon socket head cap screw 2, the lower die cushion plate 4 and the lower die supporting plate 9 are assembled together through a lower die socket head cap screw 7, the female die 12 is sleeved above the bottom core 8, as shown in figures 8, 9 and 10, an inner flange 31 is formed inside the female die 12, the bottom core 8 forms a transition fillet 32 and an inclination β, the male die 13 forms an inclination α, the lower die cushion plate 1 and the lower die cushion plate 4 are provided with a chute communicated with a core groove for inserting a mandril 5, as shown in figure 10, the mandril 5 is tightly inserted, the mandril 5 is in a clearance fit with the bottom core 8, the lower end of the mandril 5 is fastened by a bottom core 25, the bottom core 9, the bottom core is fastened by a corresponding bottom core support plate 9, the bottom core plate is fastened by a corresponding die supporting plate, the lower die supporting plate is sleeved with a corresponding die supporting plate 9, the lower die supporting plate, the punch block, the punch plate is fastened by a corresponding die supporting plate, the punch block is fastened by a corresponding T-pressing plate, the punch-pressing plate is fastened by a corresponding die supporting plate, the punch-pressing plate is fastened by.

As shown in fig. 1 and 2, the guiding and ejecting device assembly includes a guide post 6, a guide sleeve 16, a top rod 5, a bottom plate 25, a pull rod 26, a sleeve 27 and a connecting rod 29. The guide post 6 is arranged on the upper template 18, the guide sleeve 16 is arranged on the lower template 1, the guide post 6 is matched and connected with the guide sleeve 16, and the guide post 6 and the guide sleeve 16 play a role in guiding between the upper template 18 and the lower template 1. The ejector rod 5 is installed when the lower die assembly is installed, the lower end of the ejector rod is supported by a bottom plate 25, the bottom plate 25 is fixed at the lower end of a pull rod 26 through a hexagon nut 24, the pull rod 26 penetrates through a through hole in the lower die plate 1 and is connected with a connecting rod 29 through a sleeve 27, the distance between the upper part and the lower part of the pull rod 26 can be adjusted through an adjusting nut 28, and the connecting rod 29 is fixed on the upper die plate 18 through a hexagon nut 30. When the upper die plate 18 moves downwards, the pull rod 26 takes the ejector rods 5 to descend together to finish extrusion, when the extrusion is finished, the upper die plate 18 ascends, and the pull rod 26 supports the ejector rods 5 to jack the extrusion piece, so that the extrusion piece can be conveniently taken out.

Referring to fig. 1-13, a method for synchronously extruding H-shaped connectors made of steel with different wall thicknesses is briefly described below with reference to 45 steel as an example, and includes the following steps:

(1) preparation before forming: putting 45 steel bar materials into a tubular electric frequency induction heating furnace, heating to 200 ℃ at low temperature, uniformly spraying a water-based graphite lubricant, and heating to 950 ℃; mounting the mold in the assembled relationship illustrated in FIG. 1 on a press; and uniformly placing heated preheating mould bars inside and outside the cavity of the female mould and around the male mould to preheat the mould.

Referring to fig. 3, water-based graphite lubricant is uniformly coated on the surfaces of the male die 13, the bottom of the withdrawing ring 14, the cavity on the inner wall of the female die 12 and the bottom core 8 which are to be in contact with the steel piece, and after the preheating of the die is finished, the blank is placed on the bottom core 8. After completion, the upper platen 18 is moved downwards and the tie rods 26 are lowered, the lift pins 5 and the bottom core 8 are automatically lowered, and the bottom core 8 is returned to the bottom blank of the die 12 to the pre-extrusion position, as shown in fig. 4, ready for extrusion.

(2) Referring to fig. 5, 6 and 7, the press drives the upper die plate 18, the insert 20, the upper die sleeve plate 21, the upper die base 17, the male die 13 and the stripper ring 14 of the upper die assembly to move downward, the male die 13 contacts the blank and continues to extrude downward, and the stripper ring 14 also enters the female die 12 along with the downward extrusion of the male die 13, so that a certain positioning effect is exerted on the male die 13, because the male die 13 is provided with an inclination α, the female die 12 is provided with an inner flange 31, and the bottom core 8 is provided with a transition fillet 32 and an inclination β, as shown in fig. 8, 9 and 10, the blank undergoes three-stage deformation under the action of the male die 13:

firstly, in the stage of forming an H-shaped blank, referring to fig. 5 and 9, when the blank is just extruded, the blank is limited by an inner flange 31 of a female die, the radial resistance of the blank is greater than the axial direction, the blank flows into a bottom core 8 and a cavity of the female die 12 firstly, and the radial resistance of the blank is smaller than the axial direction as the bottom core 8 has a gradient of 10 degrees and the resistance is smaller as the space is smaller as the bottom core is lower, so that the blank upsetting action is intensified, the blank is filled in the inner flange 31 of the female die and moves upwards along the inclined wall of the male die 13, and an H-shaped preform is formed;

secondly, in the stage of increasing the upper wall and the lower wall of the H shape, as shown in fig. 6 and 8, as the press drives the male die 13 to continue to extrude downwards, the male die 13 has an upward inclination of 12 degrees, and the space between the male die 13 and the female die 12 is larger than the space between the bottom core 8 and the female die 12, so that the resistance of the upper part is smaller than that of the lower part, and the material of the lower part also moves from top to bottom, so that the height of the upper wall is higher than that of the lower wall, and at the moment, the space is filled in the female die 12 in the radial direction, and the height of the upper wall and the lower wall is not increased in the radial direction in the stage, but the height of the upper wall and the lower wall is increased, and the upper wall and the lower wall contact the bottom of the stripper;

and thirdly, in the H-full forming stage, as shown in fig. 7, the press continues to press the blank downwards with the male die 13, at this time, the H shape is substantially completed, the upper wall has not reached the final height and the bottom corner hard-forming region of the lower wall has not completed final forming, at this time, the stripper ring 14 has contacted the upper wall, the stripper ring 14 and the coil 15 have a certain height fit, when the male die 13 continues to descend, the upper wall pushes the stripper ring 14 to move upwards, when the stripper ring 14 contacts the upper die sleeve plate 21, the stripper ring 14 stops rising, at this time, the male die 13, the stripper ring 14 and the female die 12 form a closed cavity, the only flow direction of the blank is the bottom corner hard-forming region of the lower wall, and the bottom corner filling is completed with the downward impact force, and the extrusion final forming is completed.

(3) After the extrusion forming is finished: stopping the downward movement of the press machine workbench, and driving the male die 13 to ascend and separate from the upper wall of the workpiece by the upward movement of the press machine workbench in the reverse direction, wherein even if the upper part of the male die 13 is not automatically separated, the upper part of the withdrawing ring 14 is automatically dropped for a certain distance by gravity along with the ascending of the male die 13, and the workpiece is separated from the male die 13 by a downward impact force; the pull rod 26 is driven to ascend in the ascending process of the upper die plate 18, the pull rod 26 simultaneously drives the bottom plate 25 to ascend, the bottom plate 25 contacts the ejector rod 5 after ascending for a certain distance and drives the bottom core 8 to ascend together with a workpiece to separate from the female die 12, the time of the whole extrusion process is short, the workpiece can automatically pop up the female die 12 after separating from the die, the workpiece can be smoothly and easily taken down, and the extrusion part is formed.

Compared with the prior art, the invention has the following technical effects:

1. the male die 13, the female die 12 and the bottom core 8 jointly form a forming inner cavity of the H-shaped connecting piece, the stress condition of the H-shaped piece in the extrusion deformation process is changed by controlling process parameters (the gradient and the transition fillet of each part of the forming inner cavity), the smooth realization of the upper wall and the lower wall growth and the final forming stage in the forming stage is ensured, the metal stress state, the equivalent strain, the plastic deformation, the tissue uniformity and the like are better controlled, the forming is ensured to be carried out smoothly, and the final size and performance requirements of the H-shaped connecting piece are met;

2. the stripper ring cooperates with the guide and ejector assembly. The part withdrawing ring 14 with the positioning and guiding functions can play a role of positioning the male die 13 and ensure good forming of a lower wall difficult-to-form area in the final forming stage in the downward movement process of the press, and the part withdrawing ring 14 is matched with a reverse pull rod structure to realize smooth demoulding of workpieces from top to bottom in the part withdrawing stage; the reverse pull rod type linkage ejection structure can be matched with any press machine for use, has no requirement on an ejection cylinder of the press machine, greatly increases the applicability of an extrusion die, and reduces the production cost;

4. the detachable female die 12, the shrink sleeve 11, the pressing sleeve 10 and the bottom core 8 are designed, H-shaped pieces with different sizes and different wall thicknesses can be extruded on the premise that only a small number of parts such as the male die 13, the female die 12 and the bottom core 8 are replaced, and the utilization rate of the die is improved.

It should be noted that, for the first forming difficulty, the present invention adopts the female die 12 with the inner flange 31, the male die 13 and the bottom core 8 with specific inclinations α, β and transition fillets 32 to overcome the forming surfaces of the female die 12, the male die 13 and the bottom core 8, an optimal forming curve is optimized according to corresponding part diagrams to match with the inner flange 31 of the female die 12, which can prevent the cup wall from axial instability and well form the upper and lower walls, for the second forming difficulty, the present invention adopts the male die 13 with the withdrawing ring 14, and combines the guiding and ejecting device components to realize the reverse pull rod type linkage ejection to overcome the second forming difficulty, the withdrawing ring 14 with the male die 13 enters the female die 12 together to play a good positioning role, and the withdrawing ring 14 and the male and female die 12,13 structures form three-way pressure stress on the cup wall in the final forming stage, which can ensure the uniformity of the wall thickness and also play a certain complementary role in the perfect forming of the lower wall, the withdrawing ring matching guiding and ejecting device components can play a role in facilitating material taking, the design structure is ingenious and has good reliability and high forming precision.

The above are merely specific examples of the present invention, and do not limit the scope of the present invention. All equivalent changes made according to the design idea of the present application fall within the protection scope of the present application.

Claims

1. A steel H-shaped connecting piece synchronous extrusion forming die with different wall thicknesses comprises an upper die assembly connected with the upper part of a press machine, a lower die assembly connected with the lower part of the press machine and a guiding and ejecting device assembly;

2. The synchronous extrusion forming die for the H-shaped connecting piece made of steel and provided with different wall thicknesses as in claim 1, wherein: the upper template is assembled on an upper working table of the press machine by fastening bolts; the upper die base and the upper die plate are circumferentially positioned through the upper die cylindrical pin and then assembled together through the upper die inner hexagonal cylindrical head screw.

3. The synchronous extrusion forming die for the H-shaped connecting piece made of steel and provided with different wall thicknesses as in claim 1, wherein: the lower template is assembled on a lower worktable of the press machine by fastening bolts; the lower template and the female die are fixed together through an inner hexagonal cylindrical head screw; after the lower die plate, the lower die base plate and the lower die supporting plate are circumferentially positioned through the lower die cylindrical pin, the lower die plate and the lower die base plate are assembled together through the lower die inner hexagonal socket head cap screw, and the lower die base plate and the lower die supporting plate are assembled together through the lower die inner hexagonal socket head cap screw.

4. The synchronous extrusion forming die for the H-shaped connecting piece made of steel and provided with different wall thicknesses as in claim 1, wherein: the inclination of the bottom core is 10 degrees.

5. The synchronous extrusion forming die for the H-shaped connecting piece made of steel and provided with different wall thicknesses as in claim 1, wherein: the inclination of the male die is 12 degrees.