Thin-wall copper pipe bending surface quality optimization method based on microcosmic parameters

Abstract

The invention provides a thin-wall copper pipe bending surface quality optimization method based on microcosmic parameters. The method comprises the following steps that a finished copper pipe material is prepared through the procedures of horizontal continuous casting, three-roller planetary rolling, combined drawing, disc drawing, annealing and the like; sampling the obtained finished copper pipe material, and carrying out electron back scattering diffraction test to test microstructure parameters; and processing and analyzing according to a sample test result to obtain average grain size and Goss texture component data. The method has the advantages that on one hand, it is indicated that the average grain size and the soft orientation Goss texture mainly influence the bending performance of the copper pipe, and on the other hand, two methods for optimizing the bent surface are provided, and on the one hand, deformation inharmony between grains during bending deformation can be reduced, strain can be dispersed, and normal displacement of the bent surface can be reduced by refining the grains; and secondly, by introducing a soft oriented Goss texture component, plastic deformation can be facilitated, and roughening of a bent surface can also be avoided. The method provided by the invention is simple, easy to operate, rapid and practical, and the problems of wrinkles, orange peel, cracking and the like of the bent surface of the subsequent copper pipe product can be avoided by reasonably adjusting the tissue.

Description

Technical Field

[0001] The invention relates to the technical field of copper alloy material preparation, and in particular to a method for optimizing the bending surface quality of a thin-wall copper tube based on microscopic parameters. Background Art

[0002] Thin-walled precision copper tube materials have good thermal and electrical conductivity and processing properties. They are widely used in air conditioning, refrigeration, electronic heat pipes, cable conductors and other fields. They usually need to undergo bending deformation during use. As various devices develop towards miniaturization and thinness, the outer diameter and wall thickness of copper tubes are constantly decreasing, and the relative bending radius is also gradually decreasing. This makes it easy for wrinkles and even cracks to appear on the surface of copper tubes after bending, which seriously affects their application. It is very important to reasonably optimize the organization and obtain good surface quality after bending while ensuring the strength and conductivity of copper tubes. Summary of the invention

[0003] The purpose of the present invention is to reasonably design the grain size and texture components of copper tube materials to reduce and eliminate the roughening defects of the bending forming surface, and a method for optimizing the bending surface quality of thin-walled copper tubes based on microscopic parameters is provided.

[0004] In order to achieve the above object, the present invention mainly provides the following technical solutions:

[0005] The present invention provides a method for optimizing the bending surface quality of a thin-walled copper tube based on microscopic parameters, comprising the following steps:

[0006] The finished copper tube material is prepared by horizontal continuous casting, three-roller planetary rolling, joint drawing, coil drawing, annealing and other processes;

[0007] The finished copper tube material is sampled and subjected to electron backscatter diffraction test to test the microstructure parameters;

[0008] The sample test results were processed and analyzed to obtain the average grain size and Goss texture component data.

[0009] The copper tube grade in step 1 is TU or TP2; the drawing deformation in the preparation process is 0-99.99%, and the annealing temperature ranges from 200°C to 900°C.

[0010] In the step 2, the microstructure observation surface is the longitudinal section of the copper tube wall, the test magnification is 50-300 times, and the test step length is 0.1-10 μm.

[0011] The average grain size obtained in step 3 is the result of processing without annealing twins.

[0012] The calculation method of the Goss texture component content obtained in step 3 is the statistical result within 10° from the standard orientation.

[0013] When the average grain size and Goss texture components in step 3 meet the following two conditions, a better surface quality can be obtained after the copper tube is bent:

[0014] Average grain size ≤20μm, Goss texture component ≤50%

[0015] The average grain size is ≥120μm and the Goss texture component is ≥50%.

[0016] Advantages of the present invention:

[0017] Based on the previous research on the relationship between the microscopic parameters of copper tubes and the degree of roughening of the bending surface, the present invention clarifies that the key parameter indicators, namely the average grain size and the Goss texture components, are the key factors affecting the quality of the bending surface, and proposes an optimized control range. Specifically, on the one hand, the present invention points out that the average grain size and the soft-oriented Goss texture mainly affect the bending performance of the copper tube, and on the other hand, proposes two methods to optimize the bending surface: first, by refining the grains, reducing the incoordination of deformation between grains during bending deformation, dispersing strain, and reducing the normal displacement of the bending surface; second, by introducing the soft-oriented Goss texture components, although the grain size becomes larger at this time, the Goss texture has a larger Schmidt factor, which is conducive to plastic deformation, and thus the roughening of the bending surface can also be avoided. The method proposed by the present invention is simple and easy to operate, fast and practical, and can avoid problems such as wrinkles, orange peel, and cracking on the bending surface of subsequent copper tube products by reasonably adjusting the organization.

[0018] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention and implement it according to the contents of the specification, the preferred embodiments of the present invention are described in detail below. DETAILED DESCRIPTION

[0019] The present invention will be further explained below in conjunction with specific implementation plans, but the present invention is not limited thereto. Without affecting the effects and purposes that can be achieved by the present invention, all should still fall within the scope of the technical contents disclosed by the present invention.

[0020] Example 1

[0021] TU oxygen-free copper tubes with an outer diameter of 6 mm and a wall thickness of 0.3 mm were prepared by horizontal continuous casting, three-roll planetary rolling, joint drawing, disc drawing and annealing processes in sequence, wherein the total drawing variable was 99.9% and no annealing treatment was performed.

[0022] Samples were cut from the finished tubes for electron backscatter diffraction test. The observation surface was the longitudinal section of the tube wall. The test magnification was 300 times and the test step length was 0.1 μm.

[0023] According to the test results, the average grain size is 20 μm, excluding annealing twins, the Goss texture component is 10%, and the threshold is set within 10° when the texture is counted.

[0024] The above copper tube samples were subjected to a bending test with a bending radius of R=6 mm and a bending angle of 90°. The results showed that cracks appeared on the surface after bending.

[0025] Example 2

[0026] TU oxygen-free copper tube with an outer diameter of 6 mm and a wall thickness of 0.3 mm was prepared by horizontal continuous casting, three-roll planetary rolling, joint drawing, disc drawing and annealing processes in sequence, wherein the total drawing variation was 99.9% and the final annealing temperature was 200°C.

[0027] Samples were cut from the finished tubes for electron backscatter diffraction test. The observation surface was the longitudinal section of the tube wall. The test magnification was 250 times and the test step length was 0.2 μm.

[0028] According to the test results, the average grain size is 20 μm, excluding annealing twins, the Goss texture component is 30%, and the threshold is set within 10° when the texture is counted.

[0029] The above copper tube samples were subjected to a bending test with a bending radius of R=6mm and a bending angle of 90°. The results showed that the surface quality after bending was good and no obvious defects appeared.

[0030] Example 3

[0031] TU oxygen-free copper tube with an outer diameter of 6 mm and a wall thickness of 0.3 mm was prepared by horizontal continuous casting, three-roll planetary rolling, joint drawing, disc drawing and annealing processes in sequence, wherein the total drawing variation was 99.9% and the final annealing temperature was 500°C.

[0032] Samples were cut from the finished tubes for electron backscatter diffraction test. The observation surface was the longitudinal section of the tube wall. The test magnification was 150 times and the test step length was 0.4 μm.

[0033] According to the test results, the average grain size is 70 μm, excluding annealing twins, the Goss texture component is 55%, and the threshold is set within 10° when the texture is counted.

[0034] The above copper tube samples were subjected to a bending test with a bending radius of R=6 mm and a bending angle of 90°. The results showed that wrinkles appeared on the surface after bending.

[0035] Example 4

[0036] TU oxygen-free copper tube with an outer diameter of 6 mm and a wall thickness of 0.3 mm was prepared by horizontal continuous casting, three-roll planetary rolling, joint drawing, disc drawing and annealing processes in sequence, wherein the total drawing variation was 99.9% and the final annealing temperature was 800°C.

[0037] Samples were cut from the finished tubes for electron backscatter diffraction test. The observation surface was the longitudinal section of the tube wall. The test magnification was 100 times and the test step length was 0.6 μm.

[0038] According to the test results, the average grain size is 120 μm, annealing twins are not included, the Goss texture component is 70%, and the threshold is set within 10° for texture statistics.

[0039] The above copper tube samples were subjected to a bending test with a bending radius of R=6mm and a bending angle of 90°. The results showed that the surface quality after bending was good and no obvious defects appeared.

[0040] Example 5

[0041] TU oxygen-free copper tube with an outer diameter of 6 mm and a wall thickness of 0.3 mm was prepared by horizontal continuous casting, three-roll planetary rolling, joint drawing, disc drawing and annealing processes in sequence, wherein the total drawing variation was 99.9% and the final annealing temperature was 500°C.

[0042] Samples were cut from the finished tubes for electron backscatter diffraction test. The observation surface was the longitudinal section of the tube wall. The test magnification was 150 times and the test step length was 0.4 μm.

[0043] According to the test results, the average grain size is 60 μm, excluding annealing twins, the Goss texture component is 55%, and the threshold is set within 10° when the texture is counted.

[0044] The above copper tube samples were subjected to a bending test with a bending radius of R=6 mm and a bending angle of 90°. The results showed that wrinkles appeared on the surface after bending.

Claims

1. A method for optimizing the bending surface quality of a thin-walled copper tube based on microscopic parameters, comprising the following steps: Step (1): preparing the finished copper tube material by horizontal continuous casting, three-roll planetary rolling, joint drawing, coil drawing, and annealing processes; Step (2): taking samples of the finished copper tube material and conducting an electron backscatter diffraction test to test microstructural parameters; Step (3): Process and analyze the sample test results to obtain average grain size and Goss texture component data.

2. The method for optimizing the bending surface quality of a thin-walled copper tube based on microscopic parameters according to claim 1 is characterized in that: The grade of the copper tube in step (1) is TU, the drawing deformation in the preparation process is 0-99.99%, and the annealing temperature ranges from 200°C to 900°C.

3. The method for optimizing the bending surface quality of a thin-walled copper tube based on microscopic parameters according to claim 1 is characterized in that: In the step (2), the microstructure observation surface is the longitudinal section of the copper tube wall, the test magnification is 50-300 times, and the test step length is 0.1-10 μm.

4. The method for optimizing the bending surface quality of a thin-walled copper tube based on microscopic parameters according to claim 1 is characterized in that: The average grain size obtained in step (3) is the result of processing without annealing twins.

5. A method for optimizing the bending surface quality of a thin-walled copper tube based on microscopic parameters according to claim 1, characterized in that: The Goss texture component content obtained in step (3) is calculated as a statistical result within 10° from the standard orientation.

6. A method for optimizing the bending surface quality of a thin-walled copper tube based on microscopic parameters according to claim 1, characterized in that: The average grain size and Goss texture components in step (3) meet one of the following conditions: Average grain size ≤20μm, Goss texture component ≤50%; The average grain size is ≥120μm and the Goss texture component is ≥50%.