阅读说明：本技术 一种差厚管制管方法 (Method for manufacturing differential thickness pipe ) 是由 陈钢 刘培星 初冠南 金光宇 殷继丽 展英姿 侯晓英 汤化胜 孙卫华 于 2021-08-13 设计创作，主要内容包括：本发明公开了一种差厚管制管方法,包括以下步骤：1)根据差厚管方案选择等壁厚基础管；2)将原补丁管端部外圆倒斜角形成补丁管；3)将补丁管与基础管套在一起,组成套管；4)设计压紧模具；5)将套管放入下模中,并对补丁管的位置进行定位,上模向下运动,将套管处的圆形截面压成椭圆截面；6)上模后退至不影响管件取出,取出管件,差厚管制坯结束；7)将套管作为预制管进行下一步成形；本发明制管工艺简单、灵活,成本低；模具结构简单,压机所需吨位小；采用镀层管时,加热后400-950℃套管结合面可发生冶金结合；此工艺不需要施加内压即可对管坯进行截面改变,同时可以实现管坯的压扁、缩管和弯管工艺,具有非常高的应用前景。(The invention discloses a method for manufacturing a differential thickness pipe, which comprises the following steps: 1) selecting a base pipe with equal wall thickness according to the scheme of the differential thickness pipe; 2) chamfering the outer circle of the end part of the original patch tube to form a patch tube; 3) sleeving the patch pipe and the base pipe together to form a sleeve; 4) designing a compaction mould; 5) placing the sleeve into the lower die, positioning the patch tube, and moving the upper die downwards to press the circular section of the sleeve into an elliptical section; 6) the upper die is retreated until the pipe fitting is not influenced to be taken out, the pipe fitting is taken out, and the differential thickness pipe blank making is finished; 7) taking the sleeve as a prefabricated pipe to carry out next-step forming; the pipe manufacturing process is simple and flexible, and the cost is low; the die has simple structure and small tonnage required by the press; when the coating pipe is adopted, metallurgical bonding can occur on the joint surface of the sleeve pipe at the temperature of 400-950 ℃ after heating; the process can change the section of the tube blank without applying internal pressure, can realize the processes of flattening, shrinking and bending the tube blank, and has very high application prospect.)

1. A method for manufacturing a differential thickness pipe is characterized by comprising the following steps:

1) selecting a base pipe with equal wall thickness according to the scheme of the differential thickness pipe, wherein the wall thickness of the base pipe is the minimum wall thickness of the differential thickness pipe;

2) designing a section of original patch pipe according to the scheme of the differential thickness pipe, wherein the wall thickness of the original patch pipe is the difference between the wall thickness of the designed patch pipe and the wall thickness of the basic pipe, and chamfering the outer circle of the end part of the original patch pipe to form the patch pipe;

3) sleeving the patch tube and the base tube together to form a sleeve, wherein the section circle outer diameter of the sleeve is D;

4) designing a compaction die, wherein the outline shape is oval after die assembly, the horizontal major axis of the oval is (1-1.2) D, and the perimeter of the oval is (0.9-0.9999) pi D;

5) placing the sleeve into the lower die, positioning the patch tube, and moving the upper die downwards to press the circular section of the sleeve into an elliptical section;

6) the upper die is retreated until the pipe fitting is not influenced to be taken out, the pipe fitting is taken out, and the differential thickness pipe blank making is finished;

7) and (3) taking the sleeve as a prefabricated pipe to carry out next-step forming, wherein the forming procedures comprise low-pressure forming and pressure-charging upsetting of the pipe, and comprise normal-temperature forming and hot forming.

2. The method for manufacturing a differential thickness tubular product according to claim 1, wherein the patch tube in the step 2) is arranged on the outer layer of the base tube or on the inner layer of the base tube, and the inner diameter of the patch tube is +/-0-2 mm of the outer diameter of the base tube.

3. The method for manufacturing the differential thickness pipe according to claim 2, wherein if the sleeve in the step 3) adopts the patch pipe on the outer layer of the base pipe, the patch pipe is heated or sleeved with the base pipe at normal temperature to form the sleeve; if the sleeve adopts the patch tube on the inner layer of the base tube, the base tube is heated or sleeved on the outer layer of the patch tube at normal temperature to form the sleeve.

4. The method for manufacturing the differential thickness pipe according to claim 1, wherein the lower die in the step 5) is in a U-shaped deep cavity structure or an L-shaped structure, and the axis is a curve or a straight line meeting the requirements of a forming part; the two ends of the pressing die are designed with transition areas for the ellipse to the circle.

5. The method for manufacturing the differential thickness pipe according to claim 1, wherein the patch pipe on the differential thickness pipe is provided with a plurality of sections, and the patch pipe is adopted to sleeve the outer layer of the foundation pipe or the patch pipe is adopted to sleeve the inner layer of the foundation pipe at different positions on the differential thickness pipe.

6. The method of claim 5, wherein the base pipe and the patch pipe are made of the same material or different materials of aluminum alloy, low-carbon steel, high-strength steel, magnesium alloy, or high-temperature alloy.

7. The method for manufacturing the differential thickness pipe according to claim 5, wherein the base pipe and the patch pipe are formed into a sleeve and then welded or spot welded or bonded at a joint or fixedly connected without welding, and the welding is performed by scraping the joint.

Technical Field

The invention relates to the technical field of industrial manufacturing, in particular to a method for manufacturing a pipe by using a differential thickness pipe.

Background

Because of its advantages of high bending strength, good integrity and crashworthiness, high material utilization rate, etc., the closed cross-section pipe fitting is widely used in the fields of automobiles, aviation, etc. But the bending modulus of each pipe fitting is different due to different stress conditions of each part. In order to fully utilize the strength and rigidity of materials and reduce weight, the differential thickness pipe is also applied to some automobile parts. At present, a differential thickness pipe is mainly manufactured by a differential thickness plate (TRB), and the process comprises the steps of variable thickness rolling of the differential thickness plate, annealing heat treatment, continuous roll bending, pipe welding and welding line treatment.

The adopted more pipe is a welded pipe with different thickness, which is formed by laser welding two or more pipe blanks with different thicknesses and has a plurality of wall thickness values along the axial direction. However, laser welding is high in cost, the wall thickness of the welding seam is changed violently, and the welding seam is easy to break in the forming process, so that the practical application of the tailor-welded pipe is few.

There is also a method of manufacturing a differential thickness steel pipe using a seamless pipe [ patent name: method for manufacturing differential thickness steel pipe and differential thickness steel pipe, application No.: 201780016090.5], a seamless tube is used as a blank, and the tube blank is mechanically expanded by a tapered plug under the restriction of an outer die. In the process, the adopted tube blank is a seamless tube, the cost is high, and the problem of local fracture of the tube blank is easy to occur under the action of friction force.

Therefore, a method for manufacturing a differential thickness pipe needs to be designed, so as to solve the problems of difficulty in manufacturing the differential thickness pipe, high cost, poor applicability and the like.

Disclosure of Invention

Aiming at the problems in the prior art, the invention aims to provide a differential thickness pipe manufacturing method.

The technical scheme adopted by the invention for solving the technical problems is as follows: a differential thickness pipe manufacturing method comprises the following steps:

1) selecting a base pipe with equal wall thickness according to the scheme of the differential thickness pipe, wherein the wall thickness of the base pipe is the minimum wall thickness of the differential thickness pipe;

2) designing a section of original patch pipe according to the scheme of the differential thickness pipe, wherein the wall thickness of the original patch pipe is the difference between the wall thickness of the designed patch pipe and the wall thickness of the basic pipe, and chamfering the outer circle of the end part of the original patch pipe to form the patch pipe;

3) sleeving the patch tube and the base tube together to form a sleeve, wherein the section circle outer diameter of the sleeve is D;

4) designing a compaction die, wherein the outline shape is oval after die assembly, the horizontal major axis of the oval is (1-1.2) D, and the perimeter of the oval is (0.9-0.9999) pi D;

5) placing the sleeve into the lower die, positioning the patch tube, and moving the upper die downwards to press the circular section of the sleeve into an elliptical section;

6) the upper die is retreated until the pipe fitting is not influenced to be taken out, the pipe fitting is taken out, and the differential thickness pipe blank making is finished;

7) and (3) taking the sleeve as a prefabricated pipe to carry out next-step forming, wherein the forming procedures comprise low-pressure forming and pressure-charging upsetting of the pipe, and comprise normal-temperature forming and hot forming.

Specifically, the patch tube in the step 2) is arranged on the outer layer of the base tube or on the inner layer of the base tube, and the inner diameter of the patch tube is equal to the outer diameter +/-0-2 mm of the base tube.

Specifically, if the sleeve in the step 3) adopts the patch tube on the outer layer of the base tube, the patch tube is heated or sleeved with the base tube at normal temperature to form the sleeve; if the sleeve adopts the patch tube on the inner layer of the base tube, the base tube is heated or sleeved on the outer layer of the patch tube at normal temperature to form the sleeve.

Specifically, the lower die in the step 5) is in a U-shaped deep cavity structure or an L-shaped structure, and the axis of the lower die is a curve or a straight line meeting the requirements of a forming piece; the two ends of the pressing die are designed with transition areas for the ellipse to the circle.

Specifically, the patch pipe on the differential thickness pipe is provided with a plurality of sections, and the patch pipe is arranged on the differential thickness pipe at different positions and sleeved on the outer layer of the foundation pipe or the inner layer of the foundation pipe.

Specifically, the base pipe and the patch pipe are made of the same material or different materials of aluminum alloy, low-carbon steel, high-strength steel, magnesium alloy or high-temperature alloy.

Specifically, after the base pipe and the patch pipe form the sleeve, laser welding or spot welding or bonding or no fixed connection is adopted at the joint, and the welding seam needs to be strickled off during welding.

The invention has the following beneficial effects:

compared with the TRB differential thickness pipe, the differential thickness pipe manufacturing method designed by the invention has the advantages of simple and flexible pipe manufacturing process and low cost; the die has simple structure and small tonnage required by the press; when the coating pipe is adopted, metallurgical bonding can occur on the joint surface of the sleeve after heating (400-; the process can change the section of the tube blank without applying internal pressure, can realize the processes of flattening, shrinking and bending the tube blank, and has very high application prospect.

Drawings

FIG. 1 is a schematic view of a pipe making process using an outer layer thickened differential thickness pipe.

Fig. 2 is a sectional view taken along the line a-a in fig. 1.

Fig. 3 is a sectional view taken along line B-B in fig. 1.

FIG. 4 is a schematic view of a pipe making process using an inner layer thickened differential pipe.

Fig. 5 is a sectional view taken along line C-C in fig. 4.

Fig. 6 is a sectional view taken along the direction D-D in fig. 4.

Fig. 7 is a schematic structural view of the L-shaped pressing die before pressing.

Fig. 8 is a schematic structural diagram of the L-shaped compaction die after compaction.

In the figure: 1-a base pipe; 2-original patch pipe; 2-1-patch tube; 3-1-cannula; 3-2-differential thickness tube; 4, pressing the mold; 4-1-upper mold; 4-2-lower die.

Detailed Description

The technical solutions in the embodiments of the present invention will be described in further detail in the following clearly and completely with reference to the accompanying drawings in the embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example 1: as shown in fig. 1-3, a method for manufacturing a differential thickness pipe with a thickened outer layer comprises the following steps:

the method comprises the following steps: and selecting the base pipe 1 with the equal wall thickness according to the design requirement of the differential thickness pipe, wherein the wall thickness of the base pipe 1 is the minimum wall thickness of the differential thickness pipe.

Step two: selecting a section of original patch tube 2 according to the design requirement of the differential thickness tube, wherein the wall thickness of the original patch tube 2 is the difference between the design wall thickness and the wall thickness of the base tube 1, the inner diameter of the original patch tube 2 is equal to the outer diameter of the base tube 1 plus or minus (0-2) mm, and chamfering the outer circles of the two ends of the original patch tube 2 to form the patch tube 2-1.

Step three: when the inner diameter of the patch tube 2-1 is less than or equal to the outer diameter of the base tube 1, the patch tube 2-1 is heated to be sleeved on the outer wall of the base tube 1 to form a sleeve 3-1. When the inner diameter of the patch tube 2-1 is larger than the outer diameter of the base tube 1, the patch tube is sleeved on the outer wall of the base tube 1 without heating to form a sleeve 3-1, and the section circle outer diameter at the position of the sleeve 3-1 is D.

Step four: and designing a compaction die 4, wherein the outline shape of the A-A section is oval after die assembly, the horizontal major axis 2a of the oval is (1-1.2) D, and the perimeter of the oval is (0.9-0.9999) pi D. Wherein, the lower die 4-2 is in a U-shaped deep cavity structure.

Step five: the sleeve 3-1 is placed into the lower die 4-2, the position of the patch tube 2-1 is located at the same time, and the upper die 4-1 moves downwards to press the section of the patch tube of the sleeve 3-1 into an elliptical section to form the differential thickness tube 3-2.

Step six: and the upper die 4-1 retreats until the pipe fitting is not influenced to be taken out, the pipe fitting is taken out, and the blank making of the differential thickness pipe 3-2 is finished.

Step seven: after the differential thickness pipe is manufactured, the differential thickness pipe is used as a pre-formed pipe to be formed in the next step, and the forming procedures comprise pipe low-pressure forming, pressure-charging upsetting and the like and comprise cold forming and hot forming.

Example 2: as shown in fig. 4-6, a method for manufacturing a differential thickness pipe with a thickened inner layer comprises the following steps:

step two: a section of original patch tube 2 is selected according to the design requirement of a differential thickness tube, the thickness of the original patch tube 2 is the difference between the design wall thickness and the wall thickness of a base tube 1, the outer diameter of the original patch tube 2 is equal to the inner diameter of the base tube 1 plus or minus (0-2) mm, and the inner circles at two ends of the original patch tube 2 are chamfered to form a patch tube 2-1.

Step three: when the outer diameter of the patch tube 2-1 is larger than or equal to the inner diameter of the base tube 1, the base tube 1 is heated to be sleeved on the outer wall of the patch tube 2-1 to form a sleeve 3-1, when the outer diameter of the patch tube 2-1 is smaller than the inner diameter of the base tube 1, the patch tube 2-1 is sleeved on the inner wall of the base tube 1 to form the sleeve 3-1, and the section circle outer diameter of the sleeve is D.

The other steps are the same as in example 1.

Example 3:

the pressing mold 4 is designed, and the lower mold 4-2 is an L-shaped structure, as shown in fig. 7-8. The other steps are the same as in example 1 or example 2.

Example 4:

the materials of the base pipe and the patch pipe are aluminum alloy, low-carbon steel (including a coating pipe, such as GI/GA zinc coating, zinc-aluminum-magnesium, aluminum-silicon coating and the like), high-strength steel (including a coating pipe, the same as above), magnesium alloy or high-temperature alloy, and the same material or different materials. After the circular section of the sleeve in the step five is pressed into an elliptical section, the gap of the sleeve can be eliminated; when the tube blank is a coated tube, the coated metal can be liquefied and diffused into a bare plate after heating (400-.

Example 5:

the original patch tube 2 may not be chamfered when the wall thickness is thin.

Example 6:

the patch tube 2-1 and the base tube 1 can be welded or spot welded or bonded or not connected after sleeving, and the welding seam needs to be strickled off during welding.

The patch pipe 2-1 on the differential thickness pipe 3-2 is provided with a plurality of sections, and the patch pipe 2-1 is adopted to sleeve the outer layer of the foundation pipe 1 or the patch pipe 2-1 is adopted to sleeve the inner layer of the foundation pipe 1 at different positions on the differential thickness pipe 3-2.

The present invention is not limited to the above embodiments, and any structural changes made under the teaching of the present invention shall fall within the scope of the present invention, which is similar or similar to the technical solutions of the present invention.

The techniques, shapes, and configurations not described in detail in the present invention are all known techniques.