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Laser-pulsed magnetism-based welded-pipe welding residual stress relieving method

A technology of residual stress and pulsed magnetism, applied in the direction of improving process efficiency, etc., can solve problems such as inability to eliminate thermal stress, and achieve the effect of eliminating residual stress

Active Publication Date: 2014-11-05
NANJING UNIV OF AERONAUTICS & ASTRONAUTICS
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, since pulsed magnetism does not produce temperature changes, it is impossible to effectively eliminate thermal stress

Method used

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  • Laser-pulsed magnetism-based welded-pipe welding residual stress relieving method
  • Laser-pulsed magnetism-based welded-pipe welding residual stress relieving method
  • Laser-pulsed magnetism-based welded-pipe welding residual stress relieving method

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0039] The test object of the embodiment of the present invention is 45 steel plates of 300 × 150 × 15 mm. The two steel plates are welded by double-sided automatic submerged arc welding, and then laser treatment and pulse magnetic treatment are carried out successively. The residual stress is measured by the blind hole method. Measure the first principal stress values ​​at 50mm, 100mm, 150mm, 200mm and 250mm.

[0040]The laser processing parameters are determined as follows: the output power is 10kW, the moving speed is 20mm / s, the diameter of the central beam spot is 8mm, the spot diameter of beams 1 and 2 is 5mm, the spot diameter of beams 3 and 4 is 2, and the overlapping amount is 0.5mm , the number of scans is 3 times; the pulse magnetic treatment parameters are determined as follows: the pulse magnetic field strength is 10 5 A / m, the frequency is 0.5Hz, the pulse width is 20%, the processing time is 120s, and the number of scans is 3 times. The residual stress measurem...

Embodiment 2

[0042] The pulse magnetic treatment parameters are the same as those in Example 1. Among the laser treatment parameters, the moving speed is 35 mm / s, the number of scans is 5 times, and other parameters remain unchanged. The residual stress measurement results are as image 3 shown.

Embodiment 3

[0044] The laser treatment parameters are the same as those in Example 1. Among the pulse magnetic treatment parameters, the treatment time is 90 s, the number of scans is 5 times, and other parameters remain unchanged. The residual stress measurement results are as Figure 4 shown.

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Abstract

The invention provides a laser-pulsed magnetism-based welded-pipe welding residual stress relieving method. The laser-pulsed magnetism-based welded-pipe welding residual stress relieving method comprises laser splitting treatment and pulsed magnetism treatment and concretely comprises the following steps of 1, laser treatment: by a spectroscope, carrying out splitting on an original laser beam emitted by a laser, treating the laser beams by a first grating to obtain a central beam, a beam a, b and a beam c, d, and controlling spot sizes and positions of the three beams by a reflector and a second grating, and 2, pulsed magnetism treatment: carrying out pulsed discharging by different types of magnetizers of a pulsed discharging device to obtain a strong pulsed magnet field, and carrying out pulsed magnetism treatment on a welded-pipe welding line by outputting pulsed magnetism having pulsed magnetism treatment parameters by a magnetic read to carry out scanning treatment on the welding line. The method provided by the invention utilizes combination of laser treatment and pulsed magnetism treatment. The laser treatment aims at thermal stress and the pulsed magnetism treatment aims at structural stress and thus surface treatment can be realized by the laser treatment and the inner treatment can be realized by the pulsed magnetism treatment.

Description

technical field [0001] The patent of this invention is a method for eliminating residual stress of welded pipe welding based on laser and pulsed magnetism. The residual thermal stress in the surface area of ​​the weld seam and the internal tissue stress of the weld seam are eliminated by the laser in turn, so that the residual stress is released. Improve the mechanical properties and corrosion resistance of welds. Background technique [0002] As important energy sources, oil and natural gas occupy an unshakable position in my country's energy structure. However, with the gradual depletion of land oil and gas resources, people are turning their attention to the wider ocean. It is estimated that in the next five to ten years, my country's development and utilization of offshore oil and gas resources will usher in a new round of peaks. Using long-distance subsea oil and gas pipelines to transport oil and natural gas from offshore exploration platforms to their destinations is...

Claims

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Application Information

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IPC IPC(8): C21D10/00
CPCY02P10/20
Inventor 姚正军徐尚君
Owner NANJING UNIV OF AERONAUTICS & ASTRONAUTICS
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