Argon Arc Welding Rare Earth Tungsten Electrode

Argon arc welding is an arc welding method using argon as a protective gas. Argon gas is used around the arc to form a continuous closed air flow to protect the arc and pool.

Argon is an inert gas. It exists in the form of a single atom. It does not decompose at high temperature and does not react with metals. Therefore, it can not only be used for welding all kinds of alloy steels, but also can be used for welding rare metals such as alumina, magnesium and zirconium, tantalum and molybdenum.

The properties of the tungsten electrode, which contain a variety of rare earth elements, are made by adding a variety of rare earth elements such as cerium, lanthanum, yttrium, erbium and so on in the pure tungsten electrode. The preparation steps of the multiple composite argon arc welding rare earth tungsten electrode are as follows:

(1) The powder of tungsten matrix is poured into the doping pot according to the proportioning weight, and the suspended water is stirred by adding deionized water to get the suspension. The mixture of lanthanum nitrate, cerium nitrate, yttrium nitrate and erbium nitrate were mixed into the solution according to the weight of proportion.

(2) The mixed alloy powder was reduced by two times: First reduction: the mixed powder was reduced in a single tube hydrogen reduction furnace, the dew point was lower than -30°C pure hydrogen protection, the temperature was 500~600°C, the reduction time was 30-60 minutes; the second reduction: the reduced powder was reduced in the thirteen tube furnace and the dew point was lower than the pure hydrogen at -30°C. The protection temperature is 800~900°C and the reduction time is 30-40 minutes. After two reduction, the re tungsten composite powder is screened and then reserved.

(3) After the reduction of rare earth tungsten composite powder, the molding agent is added 0.2 to 1%, and the bar is pressed on the die of the oil press, and the applied pressure is 100 ~ 150Mpa.

(4) The pressed billet is sintered in two stages. The first stage is 300~800°C, 3-5 hours; the second stage: the temperature is 800~1200°C, 1-3 hours.

(5) The sintered tungsten strip was sintered at the vertical sintering equipment with hydrogen protection. The sintering temperature was 2600~2800°C and the sintering time was 30-50 minutes.

(6) The sintered strip is heated to 1400~1450°C and heat preservation for 10-20 minutes. The billet and rotary forging are made on the rotary forging machine, and the alloy wire is processed by spinning and drawing to the wire diameter of the product. Finally, the electrode products are made after cutting, polishing and cleaning.

The addition of rare earth elements in the tungsten electrode can reduce the electron escape work of the tungsten element and replace the use of the radioactive element thorium. At the same time, the use of the four rare earth elements makes the use performance of the prepared tungsten electrode better than the use of the single rare earth element. 

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