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Starting method of plasma keyhole welding

A technology of plasma welding and plasma arc, applied in the direction of plasma welding equipment, welding equipment, arc welding equipment, etc., can solve the problem of inability to distinguish voltage changes

Active Publication Date: 2014-12-03
DAIHEN CORP
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

In addition, when the formation of the small hole 7 is completed, even if the voltage fluctuation detection device 8 tries to detect the fluctuation of the plasma arc voltage, it cannot distinguish between the fluctuation of the plasma arc voltage of 2 V or more and the time when the small hole 7 of 1 to 2 V penetrates. voltage change
Therefore, it cannot be judged that the small hole of the plasma small hole welding has penetrated.

Method used

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  • Starting method of plasma keyhole welding
  • Starting method of plasma keyhole welding
  • Starting method of plasma keyhole welding

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Embodiment approach 1

[0071] Embodiments of the invention will be described based on examples with reference to the drawings. figure 1It is a figure which shows the structure of the arc ignition method of the plasma keyhole welding in Embodiment 1 of this invention. In this figure, the power supply main circuit PM in the plasma welding power supply is input with AC commercial power (3-phase 200V, etc.), and the power control of the inverter control is performed according to the error amplifier signal Ei described later, and the output is suitable for plasma keyhole welding. The plasma arc current Ip and the plasma arc voltage Vp. The current detector ID detects the plasma arc current Ip to output a current detection signal Id. The current absolute value circuit IA calculates the absolute value of the current detection signal Id to output a current absolute value signal Ia. The current setter IS sets the plasma arc current to output a current setting signal Is. The error amplification circuit EI...

Embodiment approach 2

[0082] In the arc ignition method of plasma keyhole welding according to Embodiment 1 of the present invention described above, if the movement of the plasma torch is started when the penetration of the small hole does not have a sufficient width, for example, as Figure 4 As shown in the cross-sectional view of the object to be welded in (A), the molten metal around the small hole on the surface of the object to be welded is blown away by the plasma arc, and may fly to the top. Furthermore, at this time, there are times when the root bead is not sufficiently formed as shown in the figure (B) viewed from the rear surface of the object to be welded. In addition, as shown in the sectional view of the object to be welded in (A) and the surface of the object to be welded in (C), even when the small hole is completely penetrated, the movement of the plasma torch is delayed. At this time, the molten metal burns through, and the molten metal flowing on the opposite side to the advanc...

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Abstract

The invention provides a starting method of the plasma keyhole welding obtaining a weld bead having an adequately formed penetration bead. The plasma arc voltage when the conduction of the plasma welding current is started, the plasma arc voltage is consistent, and it is discriminated that forming of the plasma keyhole is started is set as a keyhole starting reference voltage. Thereafter, when the difference between the plasma arc voltage and the keyhole starting reference voltage is equal to or more than the predetermined reference value, it is discriminated that the plasma keyhole is penetrated, and the movement of a plasma torch is started. As a result, even when the output from a power source for the plasma welding is any one the AC voltage, the AC pulse voltage or the DC pulse voltage, penetration of the keyhole of the plasma keyhole welding can be discriminated.

Description

technical field [0001] The present invention relates to an improved arc ignition method for plasma keyhole welding. Background technique [0002] Plasma keyhole welding, when the welded object is welded to the butt joint of the I-shaped groove, the plasma arc when the tungsten electrode is generally used as the cathode to discharge is limited by the water-cooled plasma nozzle and the gas flow of the plasma gas. Furthermore, in order to generate a high-temperature plasma flow with good concentration, the high-temperature plasma flow is welded while moving while forming a circular hole penetrating the workpiece from the tip of the molten pool on the welding line. This welding is provided directly until the arc heat reaches the back surface, and the melting of the back surface can also proceed appropriately. [0003] When the arc is ignited in plasma keyhole welding, the high-temperature plasma flow penetrates the object to be welded, but when the keyhole penetrates, the plasm...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B23K9/067B23K10/00
Inventor 刘忠杰波多晓盐崎秀男惠良哲生上山智之
Owner DAIHEN CORP