A low heat input dual DC pulse compound arc welding method for thin-walled metal pipes

An arc welding method and DC pulse technology, which is applied in arc welding equipment, metal processing, welding equipment, etc., can solve the problems of long residence time of metal at high temperature, grain growth of welded joints, and reduction of mechanical properties of welded seams, etc. The existence time of molten pool, the effect of reducing corrosion resistance and improving mechanical properties

Active Publication Date: 2018-05-15
SHANDONG UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] However, the DC double TIG arc welding process has a large heat input during the welding process and the arrangement of the two arcs makes the weld seam and the metal in the heat-affected zone stay at high temperature for a long time, causing the grain growth of the welded joint to be more serious, which will cause the joint decline in mechanical properties
For example, for ferritic stainless steel pipes, the severe growth of the grains in the weld seam and the heat-affected zone will not only reduce the mechanical properties of the weld seam, but also cause a decline in its corrosion resistance.

Method used

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  • A low heat input dual DC pulse compound arc welding method for thin-walled metal pipes
  • A low heat input dual DC pulse compound arc welding method for thin-walled metal pipes

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0028] Taking the production of Φ48×1.5mm 409L ferritic stainless steel pipe as an example, the implementation of the DC pulse double TIG arc high-speed welding process is illustrated.

[0029] Two identical digital inverter DC pulse TIG power supplies are selected as the first DC pulse power supply 1 and the second DC pulse power supply 4, the pulse waveform is square wave, and the pulse duty cycle is 50%. The average welding current of the first DC pulse power supply 1 is set to 240A, and the pulse frequency is 20Hz. The average current of the second DC pulse power supply 4 is set to 160A, and the pulse frequency is also 20Hz. The angle of the main welding torch 2 is 80°. The angle of the auxiliary welding torch 3 is 65°, the distance between the two tungsten electrodes is 21mm, the distance between the tungsten electrode tip of the main welding torch 2 and the workpiece is 1.2mm, the distance between the tungsten electrode tip of the auxiliary welding torch 3 and the workpie...

Embodiment 2

[0032] Taking the production of Φ32×1.2mm 409L ferritic stainless steel pipe as an example, the implementation of DC pulsed double TIG arc high-speed welding process is illustrated.

[0033] Two identical digital inverter DC pulse TIG power supplies are selected as the first DC pulse power supply 1 and the second DC pulse power supply 4, the pulse waveform is a sawtooth wave, and the pulse duty cycle is 30%. The average welding current of the first DC pulse power supply 1 is set to 300A, and the pulse frequency is 30Hz. The average current of the second DC pulse power supply 4 is set to 150A, and the pulse frequency is also 30Hz. The angle of the main welding torch 2 is 80°. The angle of the auxiliary torch 3 is 65°, the distance between the two tungsten electrodes is 21mm, the distance between the tip of the tungsten electrode of the main welding torch 2 and the workpiece is 1.2mm, the distance between the tip of the tungsten electrode of the auxiliary welding torch 3 and the ...

Embodiment 3

[0036] Taking the welding of 2.0mm thick 409L ferritic stainless steel sheet as an example to illustrate the implementation of DC pulse double TIG arc high-speed welding process.

[0037] Two identical digital inverter DC pulse TIG power supplies are selected as the first DC pulse power supply 1 and the second DC pulse power supply 4. The pulse waveform is a ladder wave and the pulse duty cycle is 40%. The average welding current of the first DC pulse power supply 1 is set to 300A, and the pulse frequency is 10Hz. The average current of the second DC pulse power supply 4 is set to 200A, and the pulse frequency is also 10Hz. The angle of the main welding torch 2 is 80°. The angle of the auxiliary welding torch 3 is 65°, the distance between the two tungsten electrodes is 21mm, the distance between the tungsten electrode tip of the main welding torch 2 and the workpiece is 1.2mm, the distance between the tungsten electrode tip of the auxiliary welding torch 3 and the workpiece is...

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Abstract

The invention discloses a low-heat-input double-DC (Direct Current) pulse hybrid electric arc welding device and a welding method. The low-heat-input double-DC pulse hybrid electric arc welding device comprises a first DC pulse power, a second DC pulse power, a main welding gun and an auxiliary welding gun, wherein the two electrodes of the first DC pulse power are separately connected with the main welding gun and a workpiece; and the two electrodes of the second DC pulse power are separately connected with the auxiliary welding gun and the workpiece. During welding, the main welding gun and the auxiliary welding gun are separately arranged along the welding direction front and back; and a preset phase difference is maintained between the first DC pulse power and the second DC pulse power, so that when the electric arc of the main welding gun is at a peak value period, the electric arc of the auxiliary welding gun is at a basic value pilot arc period. When the main electric arc is at the peak value period, the auxiliary electric arc is at the basic value pilot arc period, and when the auxiliary electric arc is at the peak value period, the main electric arc is at the basic value pilot arc period, so that a sufficient fusion depth is generated by the main electric arc; the auxiliary electric arc can adjust and control the metal flowing of a weld pool, and can prolong the existence time of the weld pool; and unnecessary welding heat input is reduced.

Description

technical field [0001] The invention belongs to the field of welding, and in particular relates to a low heat input dual direct current pulse composite arc welding device and a welding method. Background technique [0002] DC TIG welding is one of the main welding methods used in the production process of thin-walled steel pipes. It is a key technology for steel pipe production, which determines the efficiency and quality of steel pipe production. However, limited by the shortcomings of TIG welding itself, such as low deposition rate and shallow penetration, it is difficult for ordinary TIG welding to achieve high-speed welding. At the same time, a large number of actual production and theoretical studies have shown that with the synchronous increase of welding current and welding speed, the welding process gradually becomes unstable, and forming defects such as undercuts and hump welds are prone to occur, seriously affecting welding quality. Therefore, the welding speed ha...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B23K9/167B23K9/09B23K9/095B23K9/28
CPCB23K9/092B23K9/095B23K9/1675B23K9/28B23K2101/06B23K2103/04
Inventor 秦国梁孟祥萌王严白晓阳李飞马肖飞
Owner SHANDONG UNIV
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