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Laser surface modification method of copper-chromium alloy contact

A technology of laser surface modification and copper-chromium alloy, which is applied in the field of material processing, can solve the problems of increased surface roughness of copper-chromium alloy contacts, unstable molten pool, large thermal conductivity of copper, etc., and achieve surface contact resistance and surface resistance. Favorable welding ability, improved electrical performance and breaking current capacity, and improved yield strength

Active Publication Date: 2016-08-10
INST OF MECHANICS - CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] (1) Due to the high thermal conductivity of copper and the high reflectivity of laser in the infrared wavelength range (reflectivity greater than 98%), it is easy to cause chromium segregation during the remelting process
[0007] (2) When the surface of the copper-chromium alloy contact is treated at a low scanning speed, it is very easy to cause instability of the molten pool, serious sputtering and plasma, etc., which makes the surface of the modified copper-chromium alloy contact rough The temperature rises sharply, the thickness of the remelted layer is uneven, and cracks are prone to occur.
[0008] (3) After remelting, the particle size of chromium particles is still on the order of microns, and the saturated metal vapor pressure of copper-chromium alloys is still kept at a low level, which cannot effectively reduce the interception value

Method used

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  • Laser surface modification method of copper-chromium alloy contact
  • Laser surface modification method of copper-chromium alloy contact
  • Laser surface modification method of copper-chromium alloy contact

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0051] Step 1, prepare a copper-chromium alloy contact workpiece with a clean surface prepared by melting and casting, the workpiece size is 51 mm in diameter, and 3 mm in thickness; the mass percentage of chromium in it is about 25%, and the particle size is 20-70 μm;

[0052] Step 2, place the above-mentioned workpiece in an Ar gas environment with controllable oxygen content (oxygen content ≤ 1ppm), and fix it with a temperature-controlled fixture with water cooling; set the processing parameters for laser modification, including: power density 6.4×10 6 W / cm 2 , defocus amount -4mm, scanning speed 800mm / min, scanning distance 0.2mm;

[0053] Step 3, start the laser system, and automatically modify the surface of the copper-chromium alloy contact according to the planned movement trajectory; at the same time, turn on the infrared thermometer for temperature measurement, and the test temperature is 875K;

[0054] Step 4, after laser surface treatment, such as figure 2 , 3...

Embodiment 2

[0056] Step 1, prepare a copper-chromium alloy contact workpiece with a clean surface prepared by the infiltration method, the workpiece size is 51 mm in diameter, and 3 mm in thickness; the mass percentage of chromium in this workpiece is about 30%, and the particle size is 80-130 μm;

[0057] Step 2, place the above-mentioned workpiece in an Ar gas environment with controllable oxygen content (oxygen content ≤ 100ppm), and fix it with a temperature-controlled fixture with water cooling; set the processing parameters for laser modification, including: power density 3.5×10 6 W / cm 2 , defocus amount 2mm, scanning speed 8000mm / min;

[0058] Step 3, start the laser system, and automatically modify the surface of the copper-chromium alloy contact according to the planned movement trajectory; at the same time, turn on the infrared thermometer to measure the temperature, and the test temperature is 1853K;

[0059] Step 4, after laser surface treatment, such as Figure 4 , 5 As sh...

Embodiment 3

[0061] Step 1, prepare a copper-chromium alloy contact workpiece with a clean surface prepared by the mixed powder sintering method, the workpiece size is 51 mm in diameter, and 3 mm in thickness; the mass percentage of chromium in it is about 50%, and the particle size is 130-180 μm;

[0062] Step 2, place the above-mentioned workpiece in an Ar gas environment with controllable oxygen content (oxygen content ≤ 400ppm), and fix it with a temperature-controlled fixture with water cooling; set the processing parameters for laser modification, including: power density 8.5×10 5 W / cm 2 , Defocus amount +5mm, scanning speed 15000mm / min;

[0063] Step 3, start the laser system, and automatically modify the surface of the copper-chromium alloy contact according to the planned movement trajectory; at the same time, turn on the infrared thermometer for temperature measurement, and the test temperature is 1128K;

[0064] Step 4, after laser surface treatment, the cross-sectional microst...

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Abstract

The invention provides a laser surface modification method of a copper-chromium alloy contact, wherein the laser surface modification method comprises the following steps: step 100, a to-be-processed copper-chromium alloy contact is placed in an operating room with controllable oxygen content, and then the copper-chromium alloy contact is fixed by a temperature control fixture; step 200, according to the copper-chromium alloy contact modification requirements, the type of used laser is selected and processing parameters of the laser are adjusted; and step 300, the laser is controlled to gradually and comprehensively process the surface of the copper-chromium alloy contact along a set route, the copper-chromium alloy contact having the surface formed with a 10-300 [mu]m fine grain layer is obtained, and in the fine grain layer, the particle size of chromium particles is less than 1 [mu]m. The method has small thermal effect generated on a matrix; in addition to improving the yield strength, the tensile strength, the hardness and other mechanical properties, the more dense fine grain layer can be formed on the surface of the copper-chromium alloy contact, the roughness of the contact surface is greatly reduced, and the electrical properties of the copper-chromium alloy contact and the current breaking capacity are improved.

Description

technical field [0001] The invention relates to the field of material processing, in particular to a laser modification method for the surface of a copper-chromium alloy contact used in a vacuum interrupter. Background technique [0002] With the continuous expansion of the grid capacity and the continuous improvement of the voltage level, more stringent requirements are put forward for the protection of the control and switchgear used in the power system. The vacuum switch needs to have a long service life, a long maintenance interval, easy maintenance, suitable for Frequent operation, small size, light weight, etc., dominate the field of medium voltage and gradually penetrate into the field of low pressure and high pressure. The development of the vacuum interrupter is closely related to the development of the vacuum switch. The improvement of the contacts of the vacuum interrupter is one of the important factors that determine the characteristics of the interrupter. It al...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22F1/08C22F1/02
CPCC22F1/02C22F1/08
Inventor 虞钢张犁天李少霞郑彩云何秀丽宁伟健
Owner INST OF MECHANICS - CHINESE ACAD OF SCI
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