Analysis of common problems in the use of tungsten electrode
1, fast loss, burning resistance, "tungsten", or even tungsten melting situation.
The reason:
(1) The current is high, which has exceeded the allowable current of the tungsten electrode of this diameter, and it is easy to cause fast burning loss and even melting of the tungsten electrode.
(2) The problem of selection of tungsten electrode. For example, in the case of AC, if you choose cerium tungsten, it must be possible to melt the electrode head. Or if the diameter of tungsten electrode is too small, it should be 2.4, but you choose 2.0.
(3) Improper sharpening of the tungsten electrode will also lead to tungsten electrode melting. When the welding current is large, the use of fine diameter tip vertebral Angle will make the current density too concentrated on the tungsten electrode tip, which will lead to tungsten extremely easy to burn and even melt.
(4) welding operation problem, tungsten tip and base metal contact ignition easily lead to tip burning and passivation, frequent sharpening leads to fast loss of tungsten electrode.
(5) In the mixing process of rare earth oxides and tungsten, a trace of low melting point metal is mixed, and the requirements for the environment of the powder mixing process are very large. If the low melting point metal is mixed in without good control accidentally, it will lead to the precipice reduction of the melting point of tungsten, and there will be the ignition melting situation.
2, tungsten arc, or arc after the arc column drifting weak, melting depth can not meet the requirements
The reason:
(1), the choice of tungsten electrode is not correct, pure tungsten and zirconium tungsten are only suitable for welding in the case of alternating current, commonly used current is no arc.
(2), rare earth oxides added quantity is little, the effect of rare earth oxides is to reduce the electronic work function, if adding quantity is not enough, will cause arc starting is difficult, the previous two years because thorium ore control lead to price jumped 20 times, leading to a manufacturer will reduce the thorium content, in fact leads to a tungsten electrode arc starting is difficult, after striking power.
(3) Uneven mixing of rare earth oxides and tungsten.
3, the welding process appeared "crackling" sound, and even the end of the explosion
Reason: the tip of tungsten electrode is split or bubble, which is caused by the mismatch of temperature and speed in the process of rotary forging drawing.
4. Flat fracture occurs when the tungsten electrode is sharpened after use.
Reason: during the welding process, the front end of tungsten electrode is always in the state of high temperature recrystallization, and the material after recrystallization is easy to fracture because of the coarse grain size. So don't apply too much vertical force when sharpening.
5, arc, arc, arc column drifting weak
The reason:
(1) The tungsten electrode sharpening method is wrong. The tungsten electrode sharpening is rough, which will lead to scattered arc. The abrasion mark of tungsten electrode is perpendicular to the axis line of the electrode, which will also lead to scattered arc, especially under the condition of low current. Tungsten electrode sharpening out of center will lead to arc deviation, so the correct sharpening method is longitudinal sharpening.
(2) uneven metal mixing.
