阅读说明：本技术 一种易脱模的芯棒和金属复合管的成形方法 (Forming method of easy-to-demould core rod and metal composite pipe ) 是由 李子轩 黄庆学 王涛 任忠凯 王志华 于 2020-10-30 设计创作，主要内容包括：本发明涉及金属复合管成形技术领域,具体涉及一种易脱模的芯棒和金属复合管的成形方法。本发明公开了一种易脱模的芯棒,它包括转轴,转轴上沿转轴的轴向依次分布有横纹芯棒、纵纹芯棒及轧平芯棒,横纹芯棒上设有沿转轴周向延伸的横轧纹,纵纹芯棒上设有沿转轴径向延伸的纵轧纹,横轧纹和纵轧纹均分布在以转轴轴线为中心线的柱面上。本发明还公开了一种应用易脱模的芯棒的金属复合管的成形方法,能够在基管与覆管之间轧出横纵交叉的内波纹结合面,提高金属复合管的抗扭和抗剥离强度,提高金属复合管的结合强度,同时降低金属复合管的脱模难度和脱模时间,提高具有内波纹的金属复合管的成形效率和成形质量。(The invention relates to the technical field of metal composite pipe forming, in particular to a core rod easy to demould and a forming method of a metal composite pipe. The invention discloses a core rod easy to demould, which comprises a rotating shaft, wherein a transverse grain core rod, a longitudinal grain core rod and a flattening core rod are sequentially distributed on the rotating shaft along the axial direction of the rotating shaft, transverse rolled grains extending along the circumferential direction of the rotating shaft are arranged on the transverse grain core rod, longitudinal rolled grains extending along the radial direction of the rotating shaft are arranged on the longitudinal grain core rod, and the transverse rolled grains and the longitudinal rolled grains are both distributed on a cylindrical surface taking the axis of the rotating shaft as a central line. The invention also discloses a forming method of the metal composite pipe by using the easily demoulded core rod, which can roll a horizontal and vertical crossed inner ripple joint surface between the base pipe and the cladding pipe, improve the torsion resistance and the peeling resistance of the metal composite pipe, improve the joint strength of the metal composite pipe, reduce the demoulding difficulty and the demoulding time of the metal composite pipe, and improve the forming efficiency and the forming quality of the metal composite pipe with inner ripples.)

1. The easy-demoulding mandrel is characterized by comprising a rotating shaft, wherein a transverse grain mandrel, a longitudinal grain mandrel and a flattening mandrel are sequentially distributed on the rotating shaft along the axial direction of the rotating shaft, transverse grains extending along the circumferential direction of the rotating shaft are arranged on the transverse grain mandrel, longitudinal grains extending along the radial direction of the rotating shaft are arranged on the longitudinal grain mandrel, and the transverse grains and the longitudinal grains are both distributed on a cylindrical surface with the axis of the rotating shaft as the central line.

2. The easy-to-demould mandrel as claimed in claim 1, wherein the transverse grain mandrel, the longitudinal grain mandrel and the flattening mandrel all use the axis of the rotating shaft as a rotation axis.

3. The easy-to-demould mandrel as claimed in claim 1, wherein the cross rolling lines are distributed on two positions on the cross rolling mandrel to form two cross rolling line sections, the longitudinal rolling lines are distributed on two positions on the longitudinal rolling mandrel to form two longitudinal rolling line sections, and the two cross rolling line sections or the two longitudinal rolling line sections are symmetrically distributed by taking the axis of the rotating shaft as a central axis.

4. An easily removable mandrel bar as claimed in claim 3 wherein said cross-or wale-embossed segment has a central angle of from 30 ° to 80 °.

5. An easy-to-strip mandrel as claimed in claim 3 or claim 4 in which the two transverse-rolling sections or the two longitudinal-rolling sections are connected by a transition plane.

6. A method for forming a metal composite pipe, wherein the easy-release core rod of any one of claims 1 to 5 is used, the method comprising the steps of:

s1, penetrating the transverse grain core rod into the metal composite pipe, rolling the metal composite pipe through two rollers of a first pass, and forming transverse ripples in a certain range on the inner surface of the metal composite pipe at positions corresponding to the transverse grains;

s2, rotating the core rod by an angle alpha, demoulding, and feeding the core rod for a certain distance to enable the longitudinal grain core rod to penetrate into the metal composite pipe, feeding the metal composite pipe with the longitudinal grain core rod between two rollers of a second pass for rolling, and forming longitudinal corrugations in a certain range at the positions, corresponding to the longitudinal grains, of the inner surface of the metal composite pipe;

s3, directly drawing out the longitudinal corrugated core rod to enable the flattening core rod to penetrate into the metal composite pipe, flattening the transverse corrugations and the longitudinal corrugations through subsequent series of pass forming, rolling the metal composite pipe to be round, enabling the metal composite pipe to obtain longitudinal corrugated joint surfaces on the cross section, and obtaining the transverse corrugated joint surfaces on the longitudinal section.

7. The method as claimed in claim 6, further comprising step S0 before step S1: selecting a base pipe and a cladding pipe, and combining and manufacturing blanks according to the sequence that the base pipe is arranged inside and the cladding pipe is arranged outside to obtain the metal composite pipe.

8. The method as claimed in claim 6, further comprising a step S4 after the step S3: and (4) extracting the rolled core rod from the metal composite pipe, and performing head circumference cutting, heat treatment, straightening and segmentation on the rolled metal composite pipe.

Technical Field

The invention relates to the technical field of metal composite pipe forming, in particular to a core rod easy to demould and a forming method of a metal composite pipe.

Background

The metal composite pipe is a metal composite pipe formed by combining an inner layer metal pipe (a base pipe and a cladding pipe) and an outer layer metal pipe (a cladding pipe) which are different, can fully utilize the best performance of the base pipe and the cladding pipe, and has quite wide application field due to the superior performance.

The combination ability of the base pipe and the cladding pipe is the key technology of the metal composite pipe, for example, Chinese patent application publication No. CN106734203A, application publication No. 2017.05.31, entitled "continuous casting-wedge cross rolling forming method of a stub bar-free double-metal layer composite hollow shaft" discloses a continuous casting-wedge cross rolling forming method of a stub bar-free double-metal layer composite hollow shaft, which is characterized in that coating molten steel is added into a coating tundish, the coating molten steel is solidified into a coating metal pipe between the coating pouring pipe and a base layer pouring pipe, the base layer molten steel is injected into the coating metal pipe along an annular gap between the base layer pouring pipe and a spacer bar, the coating metal pipe is solidified into a double-layer composite hollow bar under the cooling of a cooling crystallizer, the double-layer composite hollow bar is secondarily cooled, an annular groove is extruded on the outer surface of the double-layer composite hollow bar, and a cutting machine is used for radially cutting the double-layer composite hollow bar along the bottommost of the annular, and finally, immediately placing the double-layer composite hollow bar on a cross wedge rolling mill for rolling to obtain the stub bar-free double-metal-layer composite hollow shaft.

In the prior art, the rolling process of most metal composite pipes needs to adopt a hot rolling technology, the inner corrugation is rolled in the first pass, the inner corrugation is rolled and flattened in the second pass, and a key problem involved in the two-pass forming process is that the demoulding time (separation of the metal composite pipe and a core rod) is long after the first pass is rolled, and the rolling of the second pass can be carried out only after the workpiece is re-heated due to too large temperature drop.

Disclosure of Invention

Aiming at the defects that the combination capability of a base pipe and a cladding pipe of a metal composite pipe is limited, and the demoulding time is long so as to influence the forming efficiency and the forming quality of the metal composite pipe in the prior art, the invention aims to provide the core rod easy to demould and the forming method of the metal composite pipe.

In order to achieve the purpose, the invention provides the following technical scheme: the easy-demoulding mandrel comprises a rotating shaft, wherein a transverse grain mandrel, a longitudinal grain mandrel and a flattening mandrel are sequentially distributed on the rotating shaft along the axial direction of the rotating shaft, transverse grains extending along the circumferential direction of the rotating shaft are arranged on the transverse grain mandrel, longitudinal grains extending along the radial direction of the rotating shaft are arranged on the longitudinal grain mandrel, and the transverse grains and the longitudinal grains are both distributed on a cylindrical surface which takes the axis of the rotating shaft as a central line.

By adopting the technical scheme, when the cross grain plug, indulge the grain plug and roll the flat plug and penetrate the metal composite tube respectively, the cross grain plug can form out the cross ripple at the internal surface of metal composite tube, the cross ripple can improve the peel strength of metal composite tube, indulge the grain plug and can form out the vertical ripple at the internal surface of metal composite tube, the anti-torque strength between parent tube and the cover pipe can be improved to indulging the ripple, cross ripple and the vertical ripple that has crisscross distribution on the metal composite tube, the area of contact of parent tube and cover pipe has been increased, the peel strength and the anti-torque strength of metal composite tube have been improved simultaneously, thereby the joint strength of metal composite tube has been improved greatly.

The invention is further configured to: the transverse grain core rod, the longitudinal grain core rod and the rolling flat core rod all use the axis of the rotating shaft as a rotation axis. Through the arrangement, the rotating shaft can be rotated to adjust the positions of the transverse corrugations and the longitudinal corrugations in the metal composite pipe, so that the transverse corrugations and the longitudinal corrugations can be rolled at appropriate positions on the inner surface of the metal composite pipe.

The invention is further configured to: the transverse rolling lines are distributed on two positions on the transverse rolling line core rod to form two transverse rolling line sections, the longitudinal rolling lines are distributed on two positions on the longitudinal rolling line core rod to form two longitudinal rolling line sections, and the two transverse rolling line sections or the two longitudinal rolling line sections are symmetrically distributed by taking the axis of the rotating shaft as a central axis. Through the arrangement, two transverse corrugations or longitudinal corrugations can be formed on the inner surface of the metal composite pipe at one time, and the forming efficiency of the corrugations in the metal composite pipe is improved.

The invention is further configured to: the central angle of the transverse embossing section or the longitudinal embossing section is 30-80 degrees. The transverse corrugated section or the longitudinal corrugated section has a certain range, the forming area is low if the transverse corrugated section or the longitudinal corrugated section is too small, the bonding capacity between the base pipe and the cladding pipe is poor, the transverse corrugations and the longitudinal corrugations are interfered mutually if the transverse corrugated section or the longitudinal corrugated section is too large, and the metal composite pipe can have a proper bonding area and cannot be interfered with each other within a reasonable range.

The invention is further configured to: the two transverse embossed sections or the two longitudinal embossed sections are connected through a transition plane. Through this setting, all have the clearance between horizontal line plug or the vertical line plug and the metal composite tube, this clearance is located between transition plane and the internal surface of metal composite tube, and the instrument of being convenient for like this stretches into centre gripping horizontal line plug or vertical line plug, realizes the quick drawing of patterns.

The invention also provides a forming method of the metal composite pipe, which applies the easy-demoulding core rod and comprises the following steps:

s1, penetrating the transverse grain core rod into the metal composite pipe, rolling the metal composite pipe through two rollers of a first pass, and forming transverse ripples in a certain range on the inner surface of the metal composite pipe at positions corresponding to the transverse grains;

s2, rotating the core rod by an angle alpha, demoulding, and feeding the core rod for a certain distance to enable the longitudinal grain core rod to penetrate into the metal composite pipe, feeding the metal composite pipe with the longitudinal grain core rod between two rollers of a second pass for rolling, and forming longitudinal corrugations in a certain range at the positions, corresponding to the longitudinal grains, of the inner surface of the metal composite pipe;

s3, directly drawing out the longitudinal corrugated core rod to enable the flattening core rod to penetrate into the metal composite pipe, flattening the transverse corrugations and the longitudinal corrugations through subsequent series of pass forming, rolling the metal composite pipe to be round, enabling the metal composite pipe to obtain longitudinal corrugated joint surfaces on the cross section, and obtaining the transverse corrugated joint surfaces on the longitudinal section.

By adopting the technical scheme, when the first rolling is carried out, the transverse corrugation is formed on the inner surface of the metal composite pipe through the transverse corrugation mandrel, after the rolling is finished, after the core rod is rotated for a certain angle, the transverse grains are separated from the transverse corrugations, the transverse grain core rod can be axially drawn out at the moment, the quick demoulding can be realized, and when the second pass of rolling is carried out, the longitudinal grain core rod is passed through, longitudinal corrugations are formed on the inner surface of the metal composite pipe, after rolling is finished, the longitudinal corrugated core rod can be directly drawn out from the metal composite pipe due to the fact that the extending direction of the longitudinal corrugations is consistent with the drawing direction of the longitudinal corrugated core rod, rapid demoulding is achieved, in subsequent passes, because the rolled flat core rod is a smooth round core rod, the demoulding can be conveniently and quickly realized, so far, the transverse grain core rod, the longitudinal grain core rod and the rolled flat core rod in the technical scheme can realize quick demoulding, and the forming efficiency of the metal composite pipe with the inner corrugation and the forming quality of a microstructure are improved. Meanwhile, the metal composite pipe is provided with a longitudinal corrugated joint surface on the cross section, and a transverse corrugated joint surface on the longitudinal section, wherein the single transverse corrugated joint surface can greatly improve the anti-peeling strength of the metal composite pipe, but can not improve the anti-torsion strength between the base pipe and the cladding pipe, and the single longitudinal corrugated joint surface can improve the anti-torsion strength of the metal composite pipe, but can not improve the anti-peeling strength.

The invention is further configured to: step S0 is further included before step S1: selecting a base pipe and a cladding pipe, and combining and manufacturing blanks according to the sequence that the base pipe is arranged inside and the cladding pipe is arranged outside to obtain the metal composite pipe. Through this setting, can select suitable parent tube and cover the pipe, it is comparatively ideal, cover the deformation resistance of pipe and want to be less than the deformation resistance of parent tube for the deformation can deepen the cover the pipe when horizontal ripple or longitudinal corrugation take shape.

The invention is further configured to: step S4 is also included after step S3: and (4) extracting the rolled core rod from the metal composite pipe, and performing head circumference cutting, heat treatment, straightening and segmentation on the rolled metal composite pipe. Through the arrangement, the metal composite pipe can be subjected to post-rolling treatment to obtain a final metal composite pipe finished product.

The invention has the advantages that: 1) the cross corrugated joint surfaces and the longitudinal corrugated joint surfaces which are distributed in a staggered manner are formed on the metal composite pipe, so that the contact area between the base pipe and the cladding pipe is increased, and the anti-peeling strength and the anti-torsion strength of the metal composite pipe are improved, so that the joint strength of the metal composite pipe is greatly improved; 2) after the first pass of rolling is finished, after the core rod is rotated for a certain angle, the transverse grains are separated from the transverse corrugations, the transverse grains can be axially drawn out, rapid demoulding is realized, after the second pass of rolling is finished, the longitudinal grains can be directly drawn out from the metal composite pipe due to the fact that the extending direction of the longitudinal corrugations is consistent with the drawing direction of the longitudinal grains, rapid demoulding is realized, in the subsequent pass, the smooth round core rod is adopted as the rolling flat core rod, demoulding can also be conveniently and rapidly realized, and therefore, rapid demoulding can be realized for the transverse grains, the longitudinal grains and the rolling flat core rod, and therefore the forming efficiency of the metal composite pipe with the inner corrugations and the forming quality of microstructures are improved.

Drawings

FIG. 1 is a schematic view of the structure of a mandrel according to the present invention;

FIG. 2 is a schematic view of the structure of a lower core rod according to another aspect of the present invention;

FIG. 3 is a schematic view of the forming of a first pass metal composite tube according to the present invention;

FIG. 4 is a schematic diagram illustrating the formation of a second pass metal clad pipe according to the present invention;

FIG. 5 is a schematic cross-sectional view of the metal composite tube of the present invention after rolling is completed;

fig. 6 is a schematic longitudinal sectional view of the metal composite pipe of the present invention after rolling is completed.

Reference numerals: the device comprises a rotating shaft 1, a transverse grain core rod 2, a transverse grain 21, a longitudinal grain core rod 3, a longitudinal grain 31, a flattening core rod 4, a transition plane 5, a base pipe 61, a covering pipe 62, a transverse ripple 63, a longitudinal ripple 64, a longitudinal ripple joint surface 65, a transverse ripple joint surface 66, an upper roller 71, a lower roller 72, a left roller 81 and a right roller 82.

Detailed Description

In the description of the present embodiment, it should be noted that, as the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", "front", "rear", etc. appear, their indicated orientations or positional relationships are based on those shown in the drawings, and are only for convenience of describing the present invention and simplifying the description, but do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" as appearing herein are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

The invention is further described with reference to the drawings and the specific embodiments in the following description.

Example (b): as shown in figures 1 to 6 of the drawings,

the easy-demoulding mandrel comprises a rotating shaft 1, wherein a transverse grain mandrel 2, a longitudinal grain mandrel 3 and a flattening mandrel 4 are sequentially distributed on the rotating shaft along the axial direction of the rotating shaft, a transverse grain 21 extending along the circumferential direction of the rotating shaft is arranged on the transverse grain mandrel, a longitudinal grain 31 extending along the radial direction of the rotating shaft is arranged on the longitudinal grain mandrel, and the transverse grain and the longitudinal grain are both distributed on a cylindrical surface taking the axis of the rotating shaft as a central line.

When this embodiment is implemented, the striation plug, indulge the striation plug and roll the flat plug and penetrate the metal composite tube respectively when, the striation plug can form out the striation at the internal surface of metal composite tube, the striation can improve the anti peel strength of metal composite tube, indulge the striation plug and can form out the vertical ripple at the internal surface of metal composite tube, the vertical ripple can improve the torsional strength between parent tube and the cover pipe, the last crisscross cross ripple and the vertical ripple that distributes that have of metal composite tube, the area of contact of parent tube with the cover pipe has been increased, the anti peel strength and the torsional strength of metal composite tube have been improved simultaneously, thereby the joint strength of metal composite tube has been improved greatly.

In the specific design of the core rod, the transverse grain core rod, the longitudinal grain core rod and the flattening core rod all use the axis of the rotating shaft as a rotation axis, and the rotating shaft can be rotated to adjust the positions of the transverse grains and the longitudinal grains in the metal composite pipe so as to roll transverse corrugations and longitudinal corrugations at proper positions on the inner surface of the metal composite pipe. The transverse rolling lines are distributed on two positions of the transverse rolling line core rod to form two transverse rolling line sections, the longitudinal rolling lines are distributed on two positions of the longitudinal rolling line core rod to form two longitudinal rolling line sections, the two transverse rolling line sections or the two longitudinal rolling line sections are symmetrically distributed by taking the axis of the rotating shaft as a central axis, two transverse corrugations or longitudinal corrugations can be formed on the inner surface of the metal composite pipe at one time, and the forming efficiency of the corrugations in the metal composite pipe is improved. The central angle beta of the transverse corrugated section or the longitudinal corrugated section is 30-80 degrees, the transverse corrugated section or the longitudinal corrugated section has a certain range, the forming area is low if the transverse corrugated section or the longitudinal corrugated section is too small, the combination capacity between the base pipe and the cladding pipe is poor, the transverse corrugations and the longitudinal corrugations are interfered with each other if the transverse corrugated section or the longitudinal corrugated section is too large, the metal composite pipe can have a proper combination area within a reasonable range, and the transverse corrugations and the longitudinal corrugations cannot be interfered with each other. The two transverse-rolling line sections or the two longitudinal-rolling line sections are connected through the transition plane 5, gaps are formed between the transverse-rolling core rods or the vertical-rolling core rods and the metal composite pipe, the gaps are located between the transition plane and the inner surface of the metal composite pipe, so that tools can conveniently stretch into the clamping transverse-rolling core rods or the vertical-rolling core rods, and rapid demoulding is realized.

The embodiment also provides a forming method of the metal composite pipe, which applies the easy-demoulding core rod and comprises the following steps:

firstly, selecting a base pipe 61 and a cladding pipe 62, and combining and blanking the base pipe in the sequence of the inner cladding pipe and the outer cladding pipe to obtain the metal composite pipe. The appropriate base pipe and the appropriate cover pipe can be selected, and the deformation resistance of the cover pipe is ideally smaller than that of the base pipe, so that the deformation can penetrate into the cover pipe when the transverse corrugations or the longitudinal corrugations are formed.

Secondly, the transverse grain core rod penetrates into the metal composite pipe, the metal composite pipe is rolled through two rollers of a first pass, and transverse corrugations 63 in a certain range are formed on the inner surface of the metal composite pipe at positions corresponding to the transverse grains;

thirdly, rotating the core rod to alpha for demoulding, feeding the core rod for a certain distance to enable the longitudinal grain core rod to penetrate into the metal composite pipe, feeding the metal composite pipe with the longitudinal grain core rod between two rollers of a second pass for rolling, and forming longitudinal corrugations 64 in a certain range at positions, corresponding to the longitudinal grains, on the inner surface of the metal composite pipe;

and fourthly, directly drawing out the longitudinal corrugated core rod to enable the flattening core rod to penetrate into the metal composite pipe, flattening the transverse corrugations and the longitudinal corrugations through subsequent series of passes of forming, rolling the metal composite pipe to be round, enabling the metal composite pipe to obtain longitudinal corrugated joint surfaces 65 on the cross section, and obtaining transverse corrugated joint surfaces 66 on the longitudinal section.

And fifthly, extracting the rolled core rod from the metal composite pipe, cutting the rolled metal composite pipe to form a head circumference, performing heat treatment, straightening and segmenting, and performing post-rolling treatment on the metal composite pipe to obtain a final metal composite pipe finished product.

In the implementation of this embodiment, the various rolls mentioned in the above-mentioned passes have circular pass to meet the forming requirement of the pipe (reducing diameter and reducing wall rolling circle, etc.), there is no deflection angle between the transverse grain core rod and the longitudinal grain core rod, the two rolls in the first pass are arranged up and down, under the combined action of the upper roll 71, the lower roll 72 and the transverse grain core rod, transverse corrugations are formed on the upper and lower sides of the inner surface of the metal composite pipe, in order to enable the metal to flow, the upper roll and the lower roll are not completely butted and closed circular holes, a gap is formed between the upper roll and the lower roll, the metal on the metal composite pipe will flow to the left and right sides, so that the inner diameter of the metal composite pipe on the left and right sides is larger than the inner diameter of the upper and lower sides (similar to an ellipse as shown in fig. 3), after the first pass is finished, the core rod is rotated 90 °, the transverse grains are separated from the transverse corrugations, at the moment, the cross grain core rod can be conveniently pulled out along the axial direction, and the rapid demoulding is realized; two rollers of a second pass are arranged left and right, longitudinal corrugations are formed on the left side and the right side of the inner surface of the metal composite pipe under the combined action of the left roller 81, the right roller 82 and the longitudinal corrugated core rod, the rollers of the first pass and the rollers of the second pass are arranged orthogonally to roll the metal composite pipe in all directions after the two passes are performed, and after the second pass is finished, the longitudinal corrugated core rod can be directly drawn out of the metal composite pipe due to the fact that the extending direction of the longitudinal corrugations is consistent with the drawing direction of the longitudinal corrugated core rod, so that rapid demoulding is achieved, the transverse corrugated core rod and the longitudinal corrugated core rod are not complete cylindrical, interference with the metal composite pipe can be reduced, and tools can be conveniently drawn into and clamped; in subsequent passes, because the flattening core rod is a smooth round core rod, the demoulding can be conveniently and quickly realized, so far, the transverse grain core rod, the longitudinal grain core rod and the flattening core rod in the embodiment can realize quick demoulding, and the continuous rolling of the metal composite pipe can be realized by the rotation matching of the core rod and the feeding of the metal composite pipe, so that the forming efficiency of the metal composite pipe with the inner corrugation and the forming quality of a microstructure are improved. Meanwhile, the metal composite pipe is provided with a longitudinal corrugated joint surface on the cross section, and a transverse corrugated joint surface on the longitudinal section, wherein the single transverse corrugated joint surface can improve the anti-peeling strength of the metal composite pipe, but can not improve the anti-torsion strength between the base pipe and the cladding pipe, and the single longitudinal corrugated joint surface can improve the anti-torsion strength of the metal composite pipe, but can not improve the anti-peeling strength.

The above embodiments are described in detail for the purpose of further illustrating the present invention and should not be construed as limiting the scope of the present invention, and the skilled engineer can make insubstantial modifications and variations of the present invention based on the above disclosure.