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钨极氩弧焊时,一般不采取接触短路引弧法引燃焊接电弧,因为接触短路引弧一方面由于较大的短路电流使钨极烧损严重;另一方面钨会进入焊缝中引起夹钨,这是一种类似于夹渣的缺陷。高频高压引弧法是将钨极接近焊件,但不直接接触,留有2～5 mm的间隙,扳动焊枪上的引弧开关后,立即在钨极与焊件之间加上2 000～3 000 V的空载电压,利用这种高电压直接将空气击穿电离,引发电弧。但由于高压电对操作者的人身安全会带来危险,因此,需同时将电流的频率提高到150～200 kHz,即利用高频电强烈的集肤效应,可以避免高压电对人体造成的危害。
Tungsten arc welding, the general does not take contact with the short circuit ignition arc ignition welding arc, because the contact short-circuit ignition on the one hand because of the larger short-circuit current tungsten burning serious; the other hand, tungsten will enter the weld caused Clamping tungsten, a defect similar to slag. High-frequency high-voltage arc ignition method is the tungsten electrode close to the weldment, but not in direct contact, leaving 2 ~ 5mm gap, turn the arc torch on the switch, immediately between the tungsten and weldment plus 2 000 ~ 3 000 V no-load voltage, the use of such high voltage direct ionization of air, causing the arc. However, since high-voltage electricity poses a danger to the safety of the operator, it is necessary to increase the current frequency to 150 to 200 kHz at the same time, that is to say, the strong skin effect of high-frequency electricity can prevent the high voltage from causing human body The harm.