Method for obtaining ultrahigh vacuum in vacuum electron beam welding of niobium materials

A vacuum electron beam and ultra-high vacuum technology, applied in electron beam welding equipment, welding equipment, manufacturing tools, etc., can solve problems such as niobium material pollution

Inactive Publication Date: 2013-06-12
NINGXIA ORIENT SUPERCONDUCTOR TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The vacuum obtained in this way is relatively pure, but the corresponding oxygen and nitrogen content under the vacuum condition still exists in the vacuum, and the niobium material will be polluted when the niobium material is welded.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0022] (1) Take niobium plate A with a purity of 99.99% as the sacrificial metal, and the size of the niobium plate is 60mm×150mm×40mm. The niobium plate is pickled with hydrofluoric acid (concentration 40%), nitric acid (concentration 65%), phosphoric acid (concentration 85%) (volume ratio 1:1:2), and the temperature of the acid is controlled below 20°C for 20 minute. Then rinse with pure water greater than 10MΩ·cm for 30 minutes, and then dry it in a class 100 ultra-clean room for 2 hours.

[0023] (2) Put the niobium plate A and the niobium workpiece into the vacuum chamber of the electron beam welding machine to evacuate. Vacuum up to 7.4×10 -4 At Pa, start the electron beam with a power of 0.5Kw, the surface focus, the oscillation pattern of the electron beam is circular, the oscillation frequency is 1000 Hz, and the diameter of the oscillation circle is 5.0mm.

[0024] (3) The moving speed of molten pool is 0.2mm / sec. The trajectory of the molten pool movement is a s...

Embodiment 2

[0028] (1) Take tantalum plate B with a purity of 99.95% as the sacrificial metal, and the size of the tantalum plate is 150mm×650mm×25mm. The tantalum plate is pickled with a mixed acid of hydrofluoric acid, nitric acid, and sulfuric acid (volume ratio of 2:2:5) for 4 minutes. Then rinse with pure water greater than 10MΩ·cm for 30 minutes, and then dry it in a class 100 ultra-clean room for 2 hours.

[0029] (2) Put the tantalum plate B and the niobium workpiece into the vacuum chamber of the electron beam welding machine to evacuate. Vacuum up to 3.6×10 -3 At Pa, start the electron beam with a power of 15Kw, the lower focus, the oscillation pattern of the electron beam is circular, the oscillation frequency is 1000 Hz, and the diameter of the oscillation circle is 4.5mm.

[0030] (3) The moving speed of molten pool is 50mm / sec. The trajectory of the molten pool movement is a straight line back and forth, and the lateral deviation is 10mm each time the direction is changed...

Embodiment 3

[0034] (1) A titanium plate C with a purity of 99.95% is used as the sacrificial metal, and the size of the titanium plate is 200mm×580mm×30mm. The titanium plate was pickled with a mixed acid of hydrofluoric acid and nitric acid (1:5 molar ratio) for 2 minutes. Then rinse with pure water greater than 10MΩ·cm for 30 minutes, and then dry it in a class 100 ultra-clean room for 2 hours.

[0035] (2) Put the titanium plate C and the niobium workpiece into the vacuum chamber of the electron beam welding machine to evacuate. Vacuum up to 5.3×10 -3 At Pa, start the electron beam with a power of 1.3Kw, the upper focus, the oscillation pattern of the electron beam is a circle, the oscillation frequency is 1000 Hz, and the diameter of the oscillation circle is 2.5mm.

[0036] (3) The moving speed of molten pool is 25mm / sec. The trajectory of the molten pool movement is a straight line back and forth, and the lateral deviation is 10mm each time the direction is changed. The electron...

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PUM

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Abstract

The invention provides a method for obtaining ultrahigh vacuum in the vacuum electron beam welding of niobium materials, which includes the following steps: niobium workpieces and sacrificial metal are put into a welding vacuum room; the welding vacuum room is vacuumized by a vacuum system of a vacuum electron beam welding machine until ultimate vacuum is reached; the electron beam of the vacuum electron beam welding machine is used for bombarding the sacrificial metal, so that a weld crater is formed in the electron beam spot area of the surface of the heated sacrificial metal; and within ten minutes, the electron beam is started to weld the niobium workpieces within the shortest time. The method can be adopted to provide a higher vacuum environment for the welding of niobium materials, so that the welding of niobium materials can sufficiently avoid the pollution of oxygen, nitrogen and other gaseous impurities, and thereby better niobium material-welding purity can be obtained.

Description

technical field [0001] The invention relates to a vacuum electron beam welding method, in particular to a method for obtaining ultra-high vacuum during vacuum electron beam welding of niobium materials. Background technique [0002] In the manufacturing process of radio frequency superconducting cavity, high purity niobium material should be welded by vacuum electron beam. One reason for vacuum electron beam welding is that it takes place in a vacuum. The chemical properties of niobium are very active, and its ability to combine with impurity gases such as oxygen and nitrogen is very strong at high temperatures. The manufacture of radio frequency superconducting cavities requires very high-purity niobium materials, and the absorption of oxygen, nitrogen and other impurity gases by niobium should be avoided as much as possible during the welding process. This requires welding to be carried out in as high a vacuum as possible. [0003] At present, the method of obtaining hi...

Claims

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Application Information

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IPC IPC(8): B23K15/06B23K103/08
CPCB23K15/0046B23K15/06B23K2103/08
Inventor 赵红运陈林黄俊峰陈明伦张宁峰范青张良玉
Owner NINGXIA ORIENT SUPERCONDUCTOR TECH
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