CN115945587A - Die for reducing circumference of section of tube blank and method for machining tube blank - Google Patents

Die for reducing circumference of section of tube blank and method for machining tube blank Download PDF

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Publication number
CN115945587A
CN115945587A CN202310011089.0A CN202310011089A CN115945587A CN 115945587 A CN115945587 A CN 115945587A CN 202310011089 A CN202310011089 A CN 202310011089A CN 115945587 A CN115945587 A CN 115945587A
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China
Prior art keywords
die
tube blank
section
curve
mould
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CN202310011089.0A
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Chinese (zh)
Inventor
孙磊
初冠南
陈钢
张存生
刘培星
孟宪明
谢文才
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Individual
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Individual
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    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E30/00—Energy generation of nuclear origin
    • Y02E30/30—Nuclear fission reactors

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Abstract

The invention relates to a die for reducing the perimeter of the section of a pipe blank and a method for processing the pipe blank, wherein the die comprises an upper die and a lower die, the section of the upper die comprises an upper die body and an upper die cavity, the section of the upper die cavity is an arc-shaped curve, the span of the curve is equal to the width of the upper die body, the section of the lower die comprises a lower die body and a lower die cavity, the section of the lower die cavity is in a U-shaped structure, the U-shaped structure comprises an upper opening of the lower die and a bottom of the lower die, two sides of the upper opening of the lower die are parallel line segments, the bottom of the lower die is an arc-shaped curve A, and the span of the arc-shaped curve A is equal to the distance between the upper openings of the lower die and equal to the span of the curve. The invention provides a novel die and a corresponding processing method, which can process a tube blank material without high-temperature heat treatment to obtain the same metallographic structure.

Description

Die for reducing circumference of section of tube blank and method for machining tube blank
Technical Field
The invention relates to a die for reducing the circumference of the section of a tube blank and a method for processing the tube blank, belonging to the technical field of tube blank processing.
Background
The pipe blank can fully utilize the rigidity of materials, has better bending resistance and safety performance, and is widely applied to mechanical structures. The required section circumference of a typical tube blank is different at different positions. At present, various technologies can realize the change of the section perimeter of a part, for example, patent application No. 202110664990.9, proposes a method for locally shortening a tube blank, and has the defects that rigid support needs to be applied to the interior of the tube blank, the implementation of the method is poor for parts with the length exceeding 1m, and the rigid support cannot be applied to parts with bending axes; another application, no. 202210195399.8, proposes a perimeter reduction during heating, which is associated with significant disadvantages of high temperature over mold life and operator comfort. Therefore, the person skilled in the art is always seeking a method suitable for rapidly reducing the circumference of the tube blank at normal temperature.
Disclosure of Invention
The application provides a die for reducing the section perimeter of a tube blank and a method for processing the tube blank; the purpose is to shorten the circumference of a pipe blank at normal temperature without filling and supporting the inside of the pipe blank.
The invention solves the technical problems through the following technical scheme: a mould for reducing the perimeter of the section of a tube blank comprises an upper mould and a lower mould and is characterized in that the section of the upper mould comprises an upper mould body and an upper mould cavity, the section of the upper mould cavity is an arc-shaped curve, and the span of the curve is equal to the width of the upper mould body; the cross-section of lower mould includes lower mould body and lower mould chamber, the cross-section of lower mould chamber becomes U font structure, U font structure includes lower mould suitable for reading and lower mould bottom, and the both sides of lower mould suitable for reading are parallel line segment, and the lower mould bottom is arc curve A, and arc curve A's span equals the interval of lower mould suitable for reading, and equals curved span.
On the basis of the technical scheme, the application makes the following improvements and improvements on the technical scheme:
furthermore, tangents at end points of two ends of the curve and the arc-shaped curve A are parallel to a line segment of the upper opening of the lower die.
Further, the span of the curve is not less than the diameter of the tube blank to be processed.
Further, the mold may be provided with a plurality of upper mold cavities and/or lower mold cavities having different circumferences in the axial direction.
The method for processing the tube blank by reducing the perimeter of the section of the tube blank by the die comprises the following steps:
step 1, selecting an initial tube blank, determining the perimeter of each section of a finished product, finding out the maximum perimeter, selecting the tube blank according to the maximum perimeter, calculating the radius R of the tube blank, and determining the thickness t of the tube blank;
2, selecting a mold, namely determining the section perimeter L of the mold cavity when an upper mold cavity and a lower mold cavity of the mold are butted according to the perimeter L of each section of the finished part 0 ，L 0 Is greater than L; the span of the upper die cavity is equal to 2R, the span of the lower die cavity is 2R, the distance between the upper openings of the lower die cavity is 2R, and the span of the lower die bottom which is an arc curve A is 2R;
step 3, mounting the upper die and the lower die on a press, and placing the tube blank into a lower die cavity;
and 4, closing the die and carrying out extrusion forming.
The application has the advantages that through the design of the inner cavity structure of the die, the stress of the tube blank is controlled when the upper die and the lower die are extruded, after the stress of the tube blank is guaranteed, the tube blank is attached to the inner cavity of the die, and the perimeter of each part can reach the designed length. The mould of this application shortens the pipe girth under the condition of not having inside support and heating, the engineering of being convenient for to implement.
Drawings
FIG. 1 is a schematic perspective view of a mold for reducing the circumference of a cross section of a tube blank;
FIG. 2 is a schematic cross-sectional view of a cavity of the mold shown in FIG. 1;
FIG. 3 is a schematic view of the circular tube blank being placed in a die cavity under stress;
FIG. 4 is a schematic view of sectional stress during the tube blank press forming process;
FIG. 5 is a schematic cross-sectional view of a mold cavity having a plurality of different perimeters;
FIG. 6 is a metallographic structure of a tube blank material processed using the die of example 1;
fig. 7 shows the metallographic structure of the blank material of fig. 6 before machining.
The labels are as follows:
an upper die-1, an upper die body-1.1, an upper die cavity-1.2 and a curve-1.21;
lower die-2, lower die body-2.1, lower die bottom-2.22, line segment-2.23;
curve segment S-101, straight line segment A-102, straight line segment B-103, and curve segment G-104.
Detailed Description
The following examples are given for the purpose of illustration only and are not intended to limit the scope of the claims in combination with the drawings.
Example 1
With reference to fig. 1-2, a die for reducing the perimeter of the section of a tube blank comprises an upper die 1 and a lower die 2, wherein the section of the upper die 1 comprises an upper die body 1.1 and an upper die cavity 1.2, the section of the upper die cavity 1.2 forms an arc-shaped curve 1.21, and the span of the curve 1.21 is equal to the width of the upper die body 1.1; the cross section of the lower die 2 comprises a lower die body 2.1 and a lower die cavity 2.2, the cross section of the lower die cavity 2.2 is of a U-shaped structure, the U-shaped structure comprises a lower die upper opening 2.21 and a lower die bottom 2.22, and two sides of the lower die upper opening 2.21 are parallel line segments 2.23; the bottom 2.22 of the lower die is an arc curve A; the span of the arc curve A is equal to the distance of 2.21 of the upper opening of the lower die and equal to the span of 1.21 of the curve; tangents at end points of two ends of the curve 1.21 and the arc-shaped curve A are parallel to a line segment of the upper opening 2.21 of the lower die; the span of curve 1.21 is the diameter of the tube blank to be machined.
The mould can be provided with a plurality of upper mould cavities and/or lower mould cavities with different circumferences along the axial direction so as to adapt to the change of the circumferences of the finished product in the axial direction.
The die realizes the shortening of the circumference of the tube blank by the following steps:
step 1, selecting an initial tube blank, determining the perimeter of each section of a finished product, finding out the maximum perimeter, selecting the tube blank according to the maximum perimeter, calculating the radius R of the tube blank, and determining the thickness t of the tube blank;
2, selecting a mould, and determining the perimeter L of the section of the mould cavity when the upper mould cavity 1.2 and the lower mould cavity 2.2 of the mould are butted according to the perimeter L of the section of each part of the finished product part 0 ，L 0 Is greater than L; the span of the upper die cavity 1.2 is equal to 2R, the span of the lower die cavity 2.2 is 2R, the distance between the upper openings of the lower die cavity 2.2 is 2R, and the span of the lower die bottom 2.22 which is an arc curve A is 2R;
step 3, mounting the upper die 1 and the lower die 2 on a press, and placing the tube blank into a lower die cavity 2.2;
and step 4, die assembly and extrusion forming.
Example 2
The implementation process is described by taking the tube blank as an example with reference to fig. 1-5.
Selecting an initial tube blank: the circumference of the tube blank is determined according to the maximum section circumference of the finished product; the section of the tube blank is circular, the radius is R, and the perimeter of the section is L 0 (ii) a The finished product refers to a product to be processed into which the tube blank is finally processed, and for example, the finished product can refer to a B column of an automobile.
With reference to fig. 1, die selection: the mould for reducing the perimeter of the section of the tube blank consists of an upper mould 1 and a lower mould 2; the section of the inner molded surface of the upper die 1 is an arc-shaped curve, the span of the curve is 2R, and the width W of the upper die 1 is 2R; the cross section of the inner molded surface of the lower die 2 comprises an arc curve A at the bottom and line segments 2.23 at two sides, and the connecting end of the arc curve A is connected with the line segments 2.23 at two sides to form a U-shaped inner molded surface; the upper die 1 is contacted with the lower die 2, an arc curve 1.21, an arc curve A and line sections 2.23 at two sides form the whole die cavity, the centers of the curvatures of the curve 1.21 and the arc curve A need to be positioned in the die cavity, namely the curve bends towards the outer side of the die cavity, and a tangent line at the end point of the curve 1.21 and the arc curve A needs to be parallel to the line section 2.23.
The line segments 2.23 on the two sides are parallel, the distance between the two line segments is 2R, and the line segments 2.23 are parallel to the die closing direction, so that the movement in the die closing direction in the lower die cavity is ensured. When the end of the arc-shaped curve is connected with the upper end point of the line segment 2.23, the shapeThe perimeter of the cross section of the formed die cavity is larger than L 0 The key is to ensure that the tube blank is always wrapped in the die cavity in the circumference reducing process, and the circumference of the cross section of the formed die cavity is less than L when the end part of the arc-shaped curve is connected with the lower end points of the line segments 2.23 at two sides 0 。
With reference to fig. 2 to 4, the mechanical principle of the compression of the circumferential length of the cross section will be described with respect to 1/2 of the tube blank: the upper die 1 moves downwards along the die closing direction to contact the tube blank, a downward pressing force F1 is formed on the tube blank, meanwhile, the lower die 2 forms an upward force F2 on the tube blank, the tube blank is widened by the aid of the F1 and F2, and then a force F3 pointing to the cavity of the die is formed on the side wall (namely the line segment 2.23) of the lower die 2 on the tube blank. Under the action of the forces F1 and F3, the circular arc of the upper part of the tube blank gradually fits the curve 1.21 and the side wall line segment 2.23, under the action of the forces F2 and F3, the lower part of the tube blank gradually fits the curve of the bottom 2.22 of the lower die, and the side surface of the tube blank fits the line segment 2.23.
Referring to fig. 3 and 4, the shape is changed into a tube blank, and the section of the tube blank can be divided into four characteristic parts, namely a curved section S101, a curved section G104, a linear section a 102 and a linear section B103. Controlling the length of the straight line segment A102 and the straight line segment B103 to be less than 10t during compression 0 ，t 0 The wall thickness of the tube blank is equal to or less than 10t of the straight line sections A102 and B103 0 When the compression head is pressed in a direction parallel to the length direction of the compression head, the rigidity of the compression head can ensure that the compression head is not buckled and wrinkled to be upset and shortened when being compressed. Because the tangents at the end points of the straight line segment a 102 and the straight line segment B103 are parallel to the straight line segment a 102, the tangents of the curve segment S101 and the curve segment G104 after the die is completely attached are parallel to the straight line 102, the pressure F4 on the straight line segment a 102 is parallel to the straight line segment 102, and the upset can be smoothly shortened when the upset is compressed. In addition, because the curved sections S101 and G104 bow outward of the mold cavity, the reaction force F5 of the linear section a 102 on the curved sections S101 and G104 has the effect of pressing the curved sections against the mold cavity, preventing them from leaving the mold cavity. Under these two conditions, when the upper die 2 continues to close the die in the die closing direction, the tube blank always abuts against the die cavity, the circumference is smoothly shortened, and the tube blank is formed.
Along the axial direction of the die cavity (namely the axial direction of the tube blank), a plurality of die cavities with different circumferences can be arranged, so that the circumferences of different sections can be shortened through one-time die assembly, and the axial direction of the die cavity can also be bent. The process has the advantages that other supports do not need to be applied to the inner part of the tube blank, the operation difficulty is greatly simplified, and the implementation performance of the process is improved.
Fig. 6 shows a metallographic structure of a material pipe machined by the die and machining method of the present invention, and fig. 7 shows a metallographic structure of a material pipe before machining. It can be seen that the structure is a large amount of equiaxed ferrite and a small amount of pearlite before and after the die and the processing method are adopted, and the structure is not changed. This is very important for parts requiring subsequent heat treatment, because in practical application, some regions of the parts need to be shrunk in circumference length, while other regions do not need to be shrunk in circumference length, if the structures of the two regions are not consistent, corresponding heat treatment parameters need to be formulated respectively in the subsequent heat treatment process (such as quenching, etc.), which brings much trouble to practical production. Therefore, the invention provides a novel die and a corresponding processing method, and the same metallographic structure can be obtained by processing the tube blank material by adopting the die and the corresponding processing method without high-temperature heat treatment.
The above description is only for the purpose of illustrating the preferred embodiments of the present invention and should not be taken as limiting the scope of the present invention, which is intended to cover any modifications, equivalents, improvements, etc. within the spirit and scope of the present invention.

Claims (5)

1. A mould for reducing the circumference of the section of a tube blank comprises an upper mould (1) and a lower mould (2), and is characterized in that the section of the upper mould (1) comprises an upper mould body (1.1) and an upper mould cavity (1.2), the section of the upper mould cavity (1.2) is an arc-shaped curve (1.21), and the span of the curve (1.21) is equal to the width of the upper mould body (1.1); the cross-section of lower mould (2) includes lower mould body (2.1) and lower mould cavity (2.2), the cross-section of lower mould cavity (2.2) becomes U font structure, U font structure includes lower mould suitable for reading (2.21) and lower mould bottom (2.22), and the both sides of lower mould suitable for reading (2.21) are the line segment of parallel, and lower mould bottom (2.22) are arc curve A, and arc curve A's span equals the interval of lower mould suitable for reading (2.21), and equals the span of curve (1.21).
2. A die for reducing the section perimeter of a tube blank according to claim 1, characterized in that the tangent lines at the end points of the two ends of the curve (1.21) and the arc-shaped curve a are parallel to the line segment of the lower die upper opening (2.21).
3. A mould for reducing the circumference of a section of a tube blank according to claim 1, characterised in that the span of the curve (1.21) is not less than the diameter of the tube blank to be machined.
4. A die for reducing the circumference of a section of a tube blank according to claim 1, wherein the die is provided with a plurality of upper die cavities and/or lower die cavities having different circumferences in the axial direction.
5. A method for machining a tube blank using a die according to any one of claims 1-4, characterized in that it comprises the following steps:
step 1, selecting an initial tube blank, determining the circumferences of all sections of a finished product part, finding out the maximum circumference, selecting the tube blank according to the maximum circumference, calculating the radius R of the tube blank, and determining the thickness t of the tube blank;
step 2, selecting a mold, namely determining the section perimeter L of the mold cavity when an upper mold cavity (1.2) and a lower mold cavity (2.2) of the mold are butted according to the perimeter L of the sections of all parts of the finished product 0 ，L 0 Is greater than L; the span of the upper die cavity (1.2) is equal to 2R, the span of the lower die cavity (2.2) is 2R, the distance between the upper openings of the lower die cavities (2.2) is 2R, and the span of the lower die bottom (2.22) which is an arc curve A is 2R;
step 3, mounting the upper die (1) and the lower die (2) on an extruder, and placing the tube blank into a lower die cavity (2.2);
and step 4, die assembly and extrusion forming.
CN202310011089.0A 2023-01-05 2023-01-05 Die for reducing circumference of section of tube blank and method for machining tube blank Pending CN115945587A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202310011089.0A CN115945587A (en) 2023-01-05 2023-01-05 Die for reducing circumference of section of tube blank and method for machining tube blank

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202310011089.0A CN115945587A (en) 2023-01-05 2023-01-05 Die for reducing circumference of section of tube blank and method for machining tube blank

Publications (1)

Publication Number Publication Date
CN115945587A true CN115945587A (en) 2023-04-11

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ID=87282155

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202310011089.0A Pending CN115945587A (en) 2023-01-05 2023-01-05 Die for reducing circumference of section of tube blank and method for machining tube blank

Country Status (1)

Country Link
CN (1) CN115945587A (en)

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